2017年5月31日星期三

Applications of Structural Steel Pipe

Structural steel pipe are used in many ways and their application can be diverse. They are particularly useful because they offer the unique combination of good welding properties with guaranteed strengths. Structural Steel is an extremely adaptable product and is often favoured by the engineer trying to maximise strength or s structure while minimising its weight.
It will come as no surprise that the construction industry is the biggest consumer of Structural Steel, where it is used for all manner of purposes and employed at diverse scales. Whether a small box lintel is used to carry the load of a structural wall in a residential property or a vast I-beam is bolted in place to hold the road surface on a bridge, structural steel pipe can be specified, designed and fabricated for the job.
  • High Rise Buildings / Skyscrapers
  • Houses
  • Factories
  • Offices
  • Shopping Malls
  • Train Tracks
  • Road barriers
  • Bridges

Chemical Composition of Structural Steels Pipe - S235, S275 and S355

The Chemical composition of Structural Steel pipe is extremely important and highly regulated. It is a fundamental factor which defines the Mechanical properties of the steel material. In the following table you can see the Max % levels of certain regulated elements present in European Structural steel grades S235, S275 and S355.



The chemical composition of Structural Steel is incredibly important to the engineer and will change with specific Grades depending on their intended use. For Example; S355K2W is a Structural Steel that has been hardened (K2) and has been designed with a chemical composition to withstand increased weathering (W). Therefore, this grade of Structural Steel pipe will have a slightly different chemical composition to the standard S355 grade.

Introduction of Structural Steel in Europe Standard

Introduction

Structural steel pipe is a standard construction material, made from specific grades of steel and formed in a range of industry standard cross-sectional shapes (or ‘Sections’). Structural steel grades are designed with specific chemical compositions and mechanical properties formulated for particular applications.
In Europe, Structural Steel must comply with the European Standard EN 10025 a Governed by the ECISS (European Committee for Iron and Steel Standardization) a subset of CEN (European Committee for Standardization.
There are many examples of European grades of structural steel such as; S195, S235, S275, S355, S420, S460 etc. However, for the purposes of this article we will focus on the Chemical Composition, Mechanical Properties and Applications of S235, S275, S355. Three common structural steel grades used in all manner of Construction projects across the EU.
Inline with the European Standard classifications, Structural steel pipe must be referenced using standard symbols including but not limited to: "S"235"J2’‘K2’’C’’Z’’W’’JR’’JO’’
Where:
  • – denotes the fact that it is Structural Steel
  • 235 – related to the minimum yield strength of the steel (tested at a thickness of 16mm)
  • J2 / K2 / JR / JO – material toughness in relation to the Charpy impact or ‘V’notch test methodology
  • – Weathering Steel (Atmospheric Corrosion Resistant)
  • Z – Structural steel with improved strength perpendicular to the surface
  • C – Cold-formed
Depending on the manufacturing process, chemical composition and relevant application, further letters and classifications might be used to reference particular grades/products of structural steel pipe.
The EU Standard classifications are inherently not a global standard and therefore a number of corresponding grades with the same Chemical and Mechanical properties may be used in other parts of the world. For example, Structural Steels fabricated for the US market must be specified in accordance with the ASTM (American Society for Testing and Materials) International guidelines and will be referenced with an ‘A’ and then the relevant Grade such as A36, A53 etc.

2017年5月27日星期六

Difference of PSL1 and PSL2(API 5L)

The API 5L has two standards, PSL1 and PSL2, which are very different from each other. I'll talk more about the differences between PSL1 and PSL2.
API 5L is similar to GB/T9711, and PSL1 is equivalent to GB/T9711.1, PSL2 is equivalent to PSL2.
PSL2 just needs to do some more subzero impact work. Domestic individual manufacturer said can do, is actually made of better material, structural steel pipe out self can pass the requirements on the feeling, but the factory's own levels and knowledge level is not high, not the ability to do relevant test is a serious of experiment report and PSL2 do special material.
PSL2 sometimes customers want to do NACE, they want to do hardness and acid resistance, and that's a problem
PSL is short for product specification level. The product specification level of the pipeline tube is divided into PSL1 and PSL2, which can also be said to be PSL1 and PSL2. PSL1 above PSL2, these two levels is not only different inspection requirements, and chemical composition, mechanical performance requirements are different, so the order in API 5 l, the terms of the contract in addition to indicate the specifications and grade of steel usually indicators, must also indicate the level of product specification, namely PSL1 or PSL2.
PSL2 is strict on the chemical composition, tensile properties, impact work, nondestructive testing, etc.
PSL1 does not require shock performance
PSL2 all except x80 grade steel, full size 0 ℃ average Akv: longitudinal p j, 41 lateral acuity 27 j.
Average grade X80 steel, full size 0 ℃ Akv: longitudinal 101 j, or lateral acuity 68 j.
The carbon steel pipe should be tested for water pressure by branch, and the standard is not allowed to allow non-destructive generation of water pressure, which is also a big difference between API standard and the standard of our country.
PSL1 does not require non-destructive testing, and PSL2 should be tested for non-destructive inspection.

Difference of ERW and EFW


ERW namely resistance welding Electric hold welding the abbreviation of the first letter of the ERW carbon steel pipe with submerged arc welding pipe welding way have significant difference, is without the pressure of the filler metal welding method, welding seam, not fill other ingredients in skin effect by the high frequency current and near effect, make the edge instant heating to welding temperature, formed by squeezing roller extrusion forging welding seam of the organization. High quality steel pipe require the use of online or offline weld heat treatment, thus refine welding area organization, high grade ERW welded steel pipe weld can reach the same as the parent metal toughness, it is out of reach for submerged arc welding process. 


EFW namely Electric welding Electric fusion welding of the abbreviation of the first letters Submerged arc welding (SAW) - a kind of electric welded (EFW), is by one or a few consumable electrode and workpiece between the metallic heating combination between the metal in a process, the arc melted metal and the filler material fully, do not need to pressure, filler metal part work makes all come from the electrode. Melting gas shielded arc welding (GMAW), a kind of electric welded (EFW), the process is similar to submerged arc welding, but it is from the inert gas protection, the effect will be better. Spiral welding - this is one of the submerged arc welding, with a spiral weld structural steel pipe.

2017年5月23日星期二

The Basic Requirement of steel for Pipeline


heart of the impact of natural and human factors that may occur in the course of leaking or breaking all sorts of accidents. Not only due to leakage of pipeline accidents affect transport caused economic losses, but also pollute the environment. To ensure the safe operation of the pipeline and generate pipeline accident prevention should be the design, construction and operation of three aspects, including design and reasonable choice of pipe is very important. As for the carbon steel pipe, the strength, toughness and weldability are three basic quality standards. It should also consider the environmental and transport medium for pipe corrosion, corrosion-resistant steel choice. 

(1) Mechanical properties: The main indicator to measure the mechanical properties of the pipe have strength, yield limit, elongation, etc. 
① Tensile strength: tube in a tensile test, when a sample corresponding to the maximum stress of pulling off. 
② Yield strength: steel in tensile test, the specimen tensile deformation, when excluding the initial transient effect flexor, the minimum stress in the service phase. 
③ Elongation: a measure of shaping steel refers to steel in the tensile test, the sample is drawn off, and the elongation percentage of the original distance of the standard gauge. 
④ Bauschinger effect: metal or alloy to produce pre-loaded micro plastic deformation after unloading and then increased with the elastic limit of the load, reverse load is reduced elasticity of the elastic limit is not complete phenomenon. 

(2) Fracture toughness: Pipeline rupture can be divided into fracture and brittle fracture toughness structural steel pipe.
① Ductile fracture: the gradual expansion and eventually rupture caused by tiny cracks in the conditions of excessive tensile stress and cracks exist simultaneously.
② Brittle fracture: the temperature, stress and cracks caused by the combined effect of three conditions, the fracture is often much lower than earlier in the yield stress under conditions of a sudden. 
③ Fracture toughness: energy and the ability to attribute the deformation of metallic materials with crack before breaking absorption. 
④ Ductile-brittle transition temperature: at a certain temperature range, fracture toughness just with the use of lower temperatures.
Reduced. When a temperature near Avenue frontage temperature, there will be a sudden drop in toughness phenomenon, the steel from breaking into brittle fracture toughness, this temperature is called steel ductile-brittle transition temperature.

Weld Microstructure Analysis of Carbon Steel DSAW Steel Pipe


The microstructure of weld seam of high frequency DSAW steel pipe reflects the welding process performance and weld quality of the steel pipe.

High-frequency straight seam welding production is mainly the use of high-frequency current with the skin effect and the proximity effect of the two characteristics, the current is highly concentrated in the tube side welding surface, the tube side quickly heated to the welding temperature, Extrusion welding to complete. During the welding process, the metal undergoes a crystallization transition (solidification transition) from the liquid phase to the solid phase, and then undergoes a recrystallization transition (solid phase transition) after cooling to a lower temperature, Carbon steel pipe, mainly formed by fusion of melting material into crystalline structure of the fusion zone, and from the fusion line to the organization does not occur between the base metal heat affected zone. The transformation of the weld zone and the hot zone during the welding and continuous cooling processes is a continuous gradient of the organization formed. As the welding temperature is 1350 ~ 1500 ℃, the metal is heated in the peritectic range of welding, when the condensation occurs to 1493 ℃ peritectic reaction of the formation of austenite, in the continuous cooling to below the GS line will occur austenite Ferrite transformation, cooled to slightly lower than 723 ° c eutectoid reaction, the remaining austenite into pearlite, in the fusion zone eventually the formation of ferrite and pearlite structure. In the heat affected zone, a series of unbalanced microstructures are formed by the effect of welding heat, which is different from the original microstructure and properties of the base metal. When the peak value of welding thermal cycle is lower than Ac1, the metallographic structure is still primitive The ferrite and pearlite of the base metal structure, when heated to Ac1 or more, the organization will be significant changes. Steel in about 750 ℃ tissue changes occur, the first austenite pearlite formation of small austenite, austenite transformation in the ferrite has not yet occurred, because the welding heating speed, and soon cooled down by the pearlite transformation Into austenite in the subsequent cooling process to recrystallize into fine ferrite and pearlite. This area consists of fine ferrite and pearlite recrystallization and no phase transformation of coarse ferrite structure. In the region where the peak temperature is higher than this region, the pearlite and ferrite are fully austenitized at a temperature ranging from Ac3 to the grain coarsening initiation temperature of the steel at 900 to 1100C, but the grain size is not drastically long Large, in the continuous cooling to get small and uniform ferrite and pearlite structural steel pipe. When the heating temperature is above 1100 ℃, the austenite grains are coarse and coarse, and the grains are coarsest near the fusion zone. After cooling, the coarse ferrite and pearlite structure are formed,

Summary:
(1) The microstructures of high-frequency straight seam welds are composed of unbalanced continuous gradient microstructures, and the peak temperatures of different welding heat cycles form different microstructures.

(2) Welding speed too fast, too much extrusion pressure lead to unqualified weld fusion zone is too narrow, metal flow line rising angle steep, and affect the quality of the weld. Therefore, the welding speed should be properly controlled to reduce the pressure, so that the weld fusion completely, in order to improve the quality of the weld.

(3) The existence of more non-metallic inclusions in the weld, weakening the continuity of the metal, so that the weld strength, crushed unqualified. Welding temperature and extrusion pressure should not be too high, to minimize the inclusion content, improve the weld strength.

(4) Weld's associated coarse-grained structural steel pipe can make mechanical properties of welds decreased, especially the plasticity and toughness decreased significantly, the same cooling conditions in the welding, the heating temperature should not be too high, the cooling rate should not be too Fast, as far as possible to reduce the weld in the Wechsler organization.

Shinestar Uncover the "Routine" of Steel Market

As a LSAW steel pipe, open flat, steel springboard, hot plate, scaffolding and other products of  the production service providers, Shinestar holdings group published some views according to 2017 steel  market, steel industry and how to maintain market stability problems.
Viewpoint 1: On the demand forecast, excessive interpretation of the policy, and under the influence of  hype, steel inventories on the market, steel prices fall.
First, the current fundamentals of China's economy is good, some emerging areas of steel demand  corresponding increase in the market a substantial increase in inventory, resulting in steel prices fell.  Second, the implementation of national policy to the production capacity, many iron and steel enterprises  limited production, production, steel trade accordingly made the market in short supply to judge. Under  the influence of this expectation, steel trade enterprises continue to increase inventory. Third, house  prices rose sharply, stimulate the construction steel prices soared, thus promote the overall steel  prices. Steel trade merchants began to increase, according to the cargo, and look forward to the Spring  Festival after the steel price rise as expected. Fourth, due to the general reduction in inventory on the  market, the market stocks and prices showed a proportional relationship, this time, enterprises to  increase inventory is equivalent to increase efficiency. Coupled with some people on the relevant policy  of excessive interpretation, triggering a steel trade to increase the inventory of the "herd".
Viewpoint 2: Respect the law of value, according to the laws of the market, is to maintain the  fundamental guarantee of market stability.
First, in the process of removing excess and backward production capacity, we should give full play to  the role of the market only "invisible hand", supplemented by administrative means of guidance and legal  constraints. Second, through administrative means, legal means and the combination of market rules, and  resolutely ban high pollution, high energy consumption capacity. Third, we should widely publicize the  party's principles and policies, promote the socialist core values, improve the trade ethics and social  responsibility. Fourth, call for the majority of steel trade workers care, maintenance of steel market  order, to reduce human speculation and other undesirable phenomena, work together to maintain the healthy  and stable development of steel market.
Viewpoint 3: The overall steel market will be characterized by tight trading range this year.
Steel prices from the previous year's "cliff" fell to last year's value of return, and then to the recent  "diving", in essence, is the value of the return journey of a repair process. Steel prices will be with  the gradual realization of China's economic transformation, rhythmically running in the appropriate  range. From the big trend, this year's steel market price should be a value to continue the process of  repair. May Day after market prices sharply rise, terminal engineering to procurement, market clinch a  deal the splurge produced. However, in this process, the high turnover is not ideal, indicating that  short-term steel prices easy to touch the top down, the overall performance of steel prices within a  narrow range, or this year is also the overall microcosm of steel market operation.
Shinestar holdings group as a steel procurement overall service providers, will continue to focus on  steel market dynamics. At the same time, we will also develop high-quality DSAW steel pipe, open  flat, steel springboard, hot-rolled plate, scaffolding and other products, to provide the best service.

2017年5月22日星期一

How to Detect the Quality of Spiral Steel Pipe Factory

Spiral steel pipe in the factory should do before the mechanical performance test and flattening test and flaring test, and to meet the requirements of the standard requirements. 

Spiral structural steel pipe quality testing methods are as follows:
1, From the surface to judge, that is, in the appearance of inspection. The appearance of the welded joint inspection is a simple procedure and a wide range of inspection methods, is an important part of the finished product inspection, mainly to find the weld surface defects and size of the deviation. Generally through the naked eye observation, with the standard model, gauge and magnifying glass and other tools for testing. If there is a defect on the surface of the weld, there may be a defect in the weld.

2, The physical method of inspection: the physical test method is the use of some physical phenomena for testing or testing methods. Materials or parts of the internal defects of the inspection, are generally used non-destructive testing methods. Non-destructive testing of ultrasonic testing, ray detection, penetration testing, magnetic detection and so on.

3, The strength of the pressure vessel test: pressure vessel, in addition to sealing test, but also for strength test. Commonly there are two kinds of hydraulic pressure test and air pressure test. They are able to test the weld densities of containers and pipes working under pressure. Pneumatic test is more sensitive and faster than hydraulic pressure test, while the product after the test without drainage, especially for difficult drainage products. But the risk of testing than the hydraulic test. During the test, the corresponding safety and technical measures must be observed to prevent accidents during the test.

4, Compactness test: the storage of liquid or gas welding containers, the weld is not dense defects, such as penetrating cracks, pores, slag, not penetration and loose tissue, etc., can be used to find the compact test. Densification test methods are: kerosene test, water test, water test and so on.

5, Hydrostatic test Each steel pipe should be hydrostatic test without leakage phenomenon, the test pressure by the test P = 2ST / D where the S-hydrostatic test test stress Mpa, hydrostatic test test stress by the corresponding The strip standard specifies 60% of the minimum yield. Regulator time: D <508 test pressure holding time of not less than 5 seconds; D ≥ 508 test pressure retention time of not less than 10 seconds.

6, Non-destructive testing of steel pipe welding seam, steel head weld and ring joints should be X-ray or ultrasonic testing. For helical welds of steel for combustible ordinary fluid delivery, a 100% SX-ray or ultrasonic test shall be carried out. The spiral welds of steel pipes for general fluid delivery such as water, sewage, air, heating steam shall be subjected to X-ray or Ultrasonic examination checks (20%).

According to the results of spiral carbon steel pipe inspection, spiral steel pipe is usually divided into three categories: qualified goods, rework and waste. Qualified refers to the appearance of quality and quality of the quality of the relevant standards or delivery acceptance of technical conditions of the spiral steel pipe; Refurbished goods refers to the appearance of quality and internal quality is not fully meet the standards and acceptance of the bar, but to allow rework, rework after the standard and acceptance conditions Of the spiral steel pipe; scrap refers to the appearance of quality and quality of the internal failure, does not allow rework or rework after still fail to meet the standard and acceptance conditions of the spiral steel pipe.

Waste is divided into two kinds of waste and waste. Internal waste refers to the waste steel pipe found in the foundry or foundry workshop. The waste material found after the delivery of the spiral steel pipe is usually exposed to mechanical processing, heat treatment or use. The economic loss caused by it is far Much larger than the inside. In order to reduce the external waste, batch production of spiral steel pipe in the factory before the best sampling test heat treatment and rough processing, as far as possible in the spiral steel pipe plant found in the potential spiral steel pipe defects in order to take the necessary early remedial instructions.

ASTM Standard

For the astm standard, different material with different steel grade,besides, their mechanical properties and chemical composition, metallurgical properties are all different.

There are list for astm standard with different steel grade.
ASTM A53 / A53M Standard Specification for Pipe, Steel, Black and Hot-Dipped, Zinc-Coated, Welded and Seamless
ASTM A106 / A106M Standard Specification for Seamless Carbon Steel Pipe for High-Temperature Service
ASTM A134 - 96 Standard Specification for Pipe, Steel, Electric-Fusion (Arc)-Welded (Sizes NPS 16 and Over)
ASTM A135 / A135M Standard Specification for Electric-Resistance-Welded Steel Pipe
ASTM A139 / A139M Standard Specification for Electric-Fusion (Arc)-Welded Steel Pipe (NPS 4 and Over)
ASTM A178 / A178M Standard Specification for Electric-Resistance-Welded Carbon Steel and Carbon-Manganese Steel Boiler and Superheater Tubes
ASTM A179 / A179M Standard Specification for Seamless Cold-Drawn Low-Carbon Steel Heat-Exchanger and Condenser Tubes
ASTM A192 / A192M Standard Specification for Seamless Carbon Steel Boiler Tubes for High-Pressure Service
ASTM A210 / A210M Standard Specification for Seamless Medium-Carbon Steel Boiler and Superheater Tubes
ASTM A214 / A214M Standard Specification for Electric-Resistance-Welded Carbon Steel Heat-Exchanger and Condenser Tubes
ASTM A252 Standard Specification for Welded and Seamless Structural Steel Pipe Piles
ASTM A254 / A254M Standard Specification for Copper-Brazed Steel Tubing
ASTM A381 - 96(2012) Standard Specification for Metal-Arc-Welded Steel Pipe for Use With High-Pressure Transmission Systems
ASTM A423 / A423M Standard Specification for Seamless and Electric-Welded Low-Alloy Steel Tubes
ASTM A450 / A450M Standard Specification for General Requirements for Carbon and Low Alloy Steel Tubes
ASTM A498 / A498M Standard Specification for Seamless and Welded Carbon Steel Heat-Exchanger Tubes with Integral Fins
ASTM A500 / A500MStandard Specification for Cold-Formed Welded and Seamless Carbon Steel Structural Tubing in Rounds and Shapes
ASTM A501 / A501M Standard Specification for Hot-Formed Welded and Seamless Carbon Steel Structural Tubing
ASTM A512Standard Specification for Cold-Drawn Buttweld Carbon Steel Mechanical Tubing
ASTM A513 / A513M Standard Specification for Electric-Resistance-Welded Carbon and Alloy Steel Mechanical Tubing
ASTM A519 Standard Specification for Seamless Carbon and Alloy Steel Mechanical Tubing
ASTM A523 Standard Specification for Plain End Seamless and Electric-Resistance-Welded Steel Pipe for High-Pressure Pipe-Type Cable Circuits
ASTM A524 Standard Specification for Seamless Carbon Steel Pipe for Atmospheric and Lower Temperatures
ASTM A530 / A530M Standard Specification for General Requirements for Specialized Carbon and Alloy Steel Pipe
ASTM A556 / A556M Standard Specification for Seamless Cold-Drawn Carbon Steel Feedwater Heater Tubes
ASTM A587 - 96Standard Specification for Electric-Resistance-Welded Low-Carbon Steel Pipe for the Chemical Industry
ASTM A589 / A589M Standard Specification for Seamless and Welded Carbon Steel Water-Well Pipe
ASTM A595 / A595M Standard Specification for Steel Tubes, Low-Carbon or High-Strength Low-Alloy, Tapered for Structural Use
ASTM A618 / A618M Standard Specification for Hot-Formed Welded and Seamless High-Strength Low-Alloy Structural Tubing
ASTM A671 / A671M Standard Specification for Electric-Fusion-Welded Steel Pipe for Atmospheric and Lower Temperatures
ASTM A672 / A672M Standard Specification for Electric-Fusion-Welded Steel Pipe for High-Pressure Service at Moderate Temperatures
ASTM A691 / A691M Standard Specification for Carbon and Alloy Steel Pipe, Electric-Fusion-Welded for High-Pressure Service at High Temperatures
ASTM A733 Standard Specification for Welded and Seamless Carbon Steel and Austenitic Stainless Steel Pipe Nipples
ASTM A787 / A787M Standard Specification for Electric-Resistance-Welded Metallic-Coated Carbon Steel Mechanical Tubing
ASTM A795 / A795MStandard Specification for Black and Hot-Dipped Zinc-Coated (Galvanized) Welded and Seamless Steel Pipe for Fire Protection Use
ASTM A822 / A822M Standard Specification for Seamless Cold-Drawn Carbon Steel Tubing for Hydraulic System Service
ASTM A847 / A847M Standard Specification for Cold-Formed Welded and Seamless High-Strength, Low-Alloy Structural Tubing with Improved Atmospheric Corrosion Resistance
ASTM A865 / A865M Standard Specification for Threaded Couplings, Steel, Black or Zinc-Coated (Galvanized) Welded or Seamless, for Use in Carbon Steel Pipe Joints
ASTM A972 / A972M Standard Specification for Fusion Bonded Epoxy-Coated Pipe Piles
ASTM A1020 / A1020M Standard Specification for Steel Tubes, Carbon and Carbon Manganese, Fusion Welded, for Boiler, Superheater, Heat Exchanger and Condenser Applications
ASTM A1024 / A1024MStandard Specification for Steel Line Pipe, Black, Plain-End, Seamless
ASTM A1037 / A1037M Standard Specification for Steel Line Pipe, Black, Furnace-Butt-Welded
ASTM A1065 / A1065M Standard Specification for Cold-Formed Electric-Fusion (Arc) Welded High-Strength Low–Alloy Structural Tubing in Shapes, with 50 ksi [345 MPa] Minimum Yield Point
ASTM A1076 / A1076MStandard Specification for Cold Formed Carbon Structural Steel Tubing Made from Metallic Precoated Sheet Steel
ASTM A1085 / A1085M Standard Specification for Cold-Formed Welded Carbon Steel Hollow Structural Sections (HSS)
ASTM A1097 Standard Specification for Steel Casing Pipe, Electric-Fusion (Arc)-Welded (Outside Diameter of 10 in. and Larger)
ASTM A1103 / A1103M Standard Specification for Seamless Cold-Finished Carbon Structural Steel Pipe for Automotive Racing Applications

2017年5月18日星期四

The standard Index of Precision seamless tube

1) Precision Seamless main varieties: DIN Precision Series high precision seamless bright, dedicated precision seamless hydraulic system, automobile manufacturing special precision seamless tube.

2) Main standards: DIN2391, DIN2445, EN10305, DIN1629, DIN1630, ASTM A179

3) The main material precision seamless carbon steel pipe:ST35(E235) ST37.4 ST45(E255) ST52(E355)

4) The state of the main delivery:NBK(+N) GBK(+A) BK(+C) BKW(+LC) BKS(+SR)

5) Main features: precision seamless internal and external walls without the oxide layer, to withstand high pressure without leakage, high-precision, high finish, cold deformation, flaring, flattening without cracks

6) precision seamless steel pipe main purposes: used in the hydraulic system piping, piping automotive, military, engineering machinery, railway locomotive, aerospace, shipbuilding, injection molding machines, die-casting machines, machine tools, diesel, petrochemical, power plant, boiler equipment and other industries

API 5L PSL2 DSAW Steel Pipe

​DSAW steel pipe are manufactured of metal in-house produced and smelted in the electric furnace, treated with synthetic slags and cast by continuous casters. The applied steel making process ensures the achievement of chemically pure steel with reference to sulphur and phosphor contents providing high tensile, ductility and corrosion resistance properties of pipes to be operated at low temperatures in various corrosion media.

Rolling using a press piercing mill and continuous mill equipped with a fixed mandrel allows strict measurement tolerances to be obtained and ensures a lack of pipe body and surface defects.

In order to achieve high tensile and ductility steel as well as its required structure, providing a high corrosion resistance in various corrosion media, pipes are heat treated in a computerized walking beam furnace. 70% of oil line pipes are subject to heat treatment.

Pipes are inspected for internal and external flows by automatic non-distructive testing of ultrasonic and electromagnetic inspection. Carbon steel pipe ends inspection after beveling is done by magnetic-fluoroscopic flaw detection.

While manufacturing seamless line pipes ensures testing of corrosion-resistance properties through hydrogen included cracking method under NACE MR 02-84 and sulphide stress corrosion cracking method under NACE MR 01-77.

Participate in the "One Belt, One Road",Shinestar in action

Recently, the "One Belt, One Road" International Cooperation Forum in Beijing perfect ending, the forum aims to find solutions to face better solve the current global and regional economic issues, attracted attention around the world.As a service based on China, global procurement of steel integrated service providers, shinestar full attention to this dynamic forum.

It is reported that this forum is rich in content, including the forum opening ceremony, roundtable summit and the high level meeting of three most of the activities.President Xi jinping delivered a keynote speech titled "working together to promote the development of One Belt,One Road",the silk road spirit of peaceful cooperation, openness, inclusiveness, mutual learning, mutual benefit and win-win cooperation is the key to the development of the One Belt,One Road,we will establish the "One Belt,One Road" as a path of peace, prosperity, openness, innovation and civilization.

During the summit, the relevant departments of our country developed nearly 20 action plans with national counterparts along the line, involving infrastructure, energy resources, capacity cooperation, trade, investment and other fields.Today, with the development of economic globalization, the interests of various countries are closely linked, and international trade in steel is closely related.As everyone knows, the iron and steel industry is one of the key areas of international production cooperation, international cooperation is the production of iron and steel industry China seek to upgrade, an important way to promote the development of the world iron and steel industry healthy, iron and steel industry in the"One Belt,One Road"will undoubtedly promote the development of steel demand.

Then, the iron and steel industry in the end how to participate in the construction of the "One Belt,One Road"? Shinestar that will begin from the following three points:

First of all, we must keep going.Shinestar believes that China's iron and steel enterprises must combine their own actual situation, go out and explore a kind of industry chain cooperation model, establish the whole industrial chain alliance, and actively introducing foreign advanced technology and equipment.To completely copy the foreign model, we should gradually find out our own set of ways, not only to learn what others do well, but also to learn from other people's lessons.Shinestar as a force in the international steel market, steel's outstanding products have been exported to Europe, Africa, South America and other international markets, has been widely recognized by customers. We are looking forward to cooperate with more international customers to provide more quality products and services for them.

Secondly, we must adhere to the drive for independent innovation.The iron and steel industry to strengthen the development of institutional construction, accelerate the breakthrough technology bottleneck restricting the development of the industry, promote industry innovation and development, for the development of service innovation, to provide support for business model innovation and product innovation.In recent years shinestar has been increasing R & D investment and construction of professional personnel, in order to improve the intelligent level of R & D, production and service, through continuous technological innovation to develop their own.

Finally, we must grasp the quality and improve the quality of our products.Quality is the cornerstone of the brand, is the core of enterprise survival.Iron and steel enterprises will win the trust of consumers by laying down the quality foundation, thus winning the market.Good product quality is also an important factor in the healthy and sustainable development of international steel trade.In the future, shinestar will fully grasp the important opportunity of the "One Belt, One Road", and strive to develop their own, and constantly improve product quality, provide quality assurance for China's iron and steel industry to participate in international competition.

Iron and steel enterprises in China by only a few scattered opportunities are not enough, we want to go out and explore a kind of industry chain cooperation model, establish the whole industrial chain alliance. Shinestar think,it's a real walk out,that's what we're going to do.' We will also give good, do good amount, produce the high quality carbon steel pipe, welded steel pipe, line pipe, galvanized steel pipe, scaffolding, and other structural steel pipe , for China's steady and fast economic development in the relay.


How does the steel industry participate in "One Belt , One Road"?

As carbon steel pipe, welded steel pipe, line pipe, galvanized steel pipe, scaffolding, and other products production services vendors, Shinestar think, remarkable "One Belt,One Road" all the way there is no doubt that will boost steel demand. So how does China's steel industry get involved in the country's "One Belt, One Road" construction?

At present, "One Belt , One Road" international cooperation peak is being held in Beijing. The most fundamental purpose of the steel industry's participation in the "One Belt , One Road" initiative is to promote mutual benefit. Some areas may require a lot of steel, but lack of production capacity and technology, so China can develop the steel industry locally. As a result, the steel industry in the region has been developed, and Chinese steelmakers have benefited from investment, which is mutually beneficial.

As the domestic and foreign markets become more and more connected, China's steel industry has become inseparable from the world in many ways. The steel industry is involved in "One Belt, One Road", and one important thing is international production capacity cooperation. International cooperation capacity to open market economy development the objective law, is a common and in-depth development of the global economy the important engine and the power, promoting the construction of "One Belt,One Road" is the important fulcrum. Iron and steel industry is one of the key areas of cooperation in the field of international production, international cooperation capacity and transformation and upgrading of China's iron and steel industry seeking, important way to promote the healthy development of the world steel industry.

In addition, steel companies have to go out and combine their own reality. For the time being, China has not been able to fully learn how to move abroad. We must gradually develop our own method, not only to learn what others do well, but also to learn from others.

Iron and steel enterprises to go out, no matter what way, want to consider first whether can achieve the purpose of mutual benefit and win-win results, conform to the interests and the interests of the enterprise of the industry, in compliance with local interests. Iron and steel enterprises to go out, no matter adopt what kind of mode, acquisition or investment cooperation factory, want to answer a question first: what this model can bring benefits? As a steel company, we should have a strategy of development of our company. Don't go out blindly.

Iron and steel enterprises in China by only a few scattered opportunities are not enough, we want to go out and explore a kind of industry chain cooperation model, establish the whole industrial chain alliance. Shinestar think,it's a real walk out,that's what we're going to do.' We will also give good, do good amount, produce the high quality carbon steel pipe, structural steel pipe, line pipe, galvanized steel pipe, scaffolding, and other products, for China's steady and fast economic development in the relay.

2017年5月17日星期三

Spiral Pipe Weld Requirements Specification

Spiral carbon steel pipe into the steel unit, multi-channel roll rolling strip gradually rolled up, a gap is formed with an opening round tube, squeeze rollers reduction adjustment, the weld gap control at 1 ~ 3mm, and the weld ends flush.
1. If the gap is too large, resulting in reducing the proximity effect, eddy current lack of heat, weld crystal combined indirect adverse arising from lack of fusion or cracking.
2. The gap is too small, causing the proximity effect increases, excessive soldering heat, cause weld Burning; weld or extruded, rolled after the formation of the pit, affecting the quality of the weld surface.

After the two edges of the tube is heated to welding temperature in the extrusion of squeeze rollers form a common metal grain mutual penetration, crystallization, eventually forming a strong weld. If the structural steel pipe extrusion pressure is too small to form a common crystal number is small, the weld metal strength is reduced by the force will produce cracking; if the pressing force is too large, will make the molten metal is extruded weld, not only reduced weld strength, and will generate a lot of internal and external burrs, and even cause welding take sewing and other defects.

2017年5月16日星期二

Processing Techniques of Large-caliber LSAW Steel Pipe

Processing techniques of large-caliber LSAW steel pipe:
① Thread processing steel wire head Wuxi large diameter pipe, tooth shape, pitch and so it is necessary to link up with the sleeve-shaped teeth, pitch together, and by supporting the gauge view qualified.
② When processing steel thread should be used in water-soluble cutting fluid lubrication; when the temperature is below 0 ℃, should be incorporated into the 15% -20% of large diameter pipe Wuxi sodium nitrite, do not use oil lubrication fluid or without lubricating fluid threading.
③ Each operator should view the appearance of quality steel wire head and make the operator symbol.
④ Self-qualified by the head of steel wire, each standard response processing capacity of large diameter carbon steel pipe, Jiangsu random sampling of 10%, and not less than 10, if a failure that the batch processing of the full view, he failed wire head should be re-processed after passing through the inspection can use it again.
⑤ Silk has been the identification of eligible head wear should be preserved to maintain the cap, according to the standard classification of regular stand-by.

Cold Expanded of Large Diameter Straight Welded Pipe

Cold expanded of large diameter straight welded structural steel pipe is a use of hydraulic or mechanical means urging the steel pipe from the steel wall along the radially outward dilatation pressure molding process. Mechanical than hydraulic mode, the device is simple and more efficient use of steel in high-precision machining conditions more precise, in the reservoir emptying large diameter pipe joints straight no need to use, now the world's most advanced several large-caliber straight seam steel pipe expanding pipeline processes are adopted, the process is as follows:

Mechanical expanding is the use of the split-side diameter-enlarged portion of the expansion segments radially, so that the longitudinal direction of the tube in a stepwise manner, the full length of the tube segments to achieve plastic deformation process. It is divided into five stages
1, The initial stage of a full circle. Segments open until all the segments are exposed to the pipe wall, this time in the step length range within steel tube radius of each point are almost identical, steel preliminary full circle.
2, Nominal inside diameter of the stage. Anterior segments from the start position to reduce the speed of movement, until reaching the required position, this position is within the finished pipe quality requirements circumferential position.
3, Springback compensation stage. Segments 2 at the position of the start phase further low speed, until reaching the required position, this position is within the requirements of the design process of elastic recovery before the carbon steel pipe circumferential position.
4, Pressure stable stage. Segments before playing the complex inner pipe circumferential position remain intact for some time, this is the stable phase packing equipment and expanding process requirements.
5, Unloading regression phase. Circumferential segments starting position quickly retracted from the inner pipe bomb before the complex until the arrival of the initial position of the enlarged diameter, which is expanding process requirements shrink the diameter of the smallest segments.

Quality Requirements for Seamless Steel Pipe

Quality requirements for seamless carbon steel pipe
1, Chemical composition
In order to improve the uniformity of chemical composition in steel and the purity of steel, to reduce the non-metallic inclusions in the tube and to improve the distribution state, it is often used to improve the chemical composition of the steel, such as As Sn Sb Bi Pb and gas NHO. External refining equipment for refining of molten steel, and even the use of electroslag furnace on the tube re-melting refining.
 
2, Dimensional accuracy and shape
The geometry of the seamless steel pipe mainly includes the outer diameter, wall thickness, ellipticity, length, curvature, pipe end face inclination, groove angle and the blunt edge, cross-sectional size of the steel pipe.
 
3, Surface quality
The standard specifies the requirements for the "smooth surface" of seamless steel tubes. Common defects include: cracks, hair lines, inside the fold, outside the fold, rolling broken, the straight, outside the straight, separated layer, scar, pits, convex package, Ma Hang (Ma) , The spiral Road, outside the spiral Road, Green Line, correction concave, such as roller. Crack, slight internal and external straight, minor internal and external spiral, straightening, and so on. In addition to the internal and external cracks, cracks, broken, rolling, Concave, roll as a general defect of structural steel pipe.
 
4, Physical and chemical properties
Including mechanical properties at room temperature and mechanical properties at certain temperatures (heat and low temperature properties) and corrosion resistance (such as anti-oxidation, water erosion, acid and alkali resistance and other properties) under normal circumstances depends on the chemical composition of steel, Performance and steel purity and steel heat treatment methods. In some cases, the rolling temperature and the degree of deformation of the steel pipe will also affect the performance of the steel pipe.
 
5, Process performance
Including flaring, flattening, crimping, bending, pulling and welding performance.
 
6, Microstructure
Including the low-power mild steel pipe and high-power organization.

7, Special requirements
In the user's use of steel pipe other than the standard requirements.

2017年5月15日星期一

ASTM A53 Thick Wall Seamless Steel Pipe Crack

1. ASTM A53 thick-walled seamless steel pipe hot rolling position were from the steel head 38,118m, mainly in the middle of the strip. 
2. It is speculated that the gap starts at the middle of the width of the strip, because the rolling force and shear force in the rolling process cause the gap to be stretched to form a macroscopic macropore.
3. Seamless carbon steel pipe in the cold rolling production process interrupted with the fracture surface smooth, no obvious before and after fracture surface defects. 
The microstructure of the fracture was observed, and the typical ductile ductile fracture morphology was observed. At the same time, the fracture was layered, the central dimple was larger, the dimple was narrowed near the surface, and the crack appeared the center fracture And the depth of fracture at the center is deep, and it is presumed that the stratified topography is closely related to the central segregation.

ASTM A53 thick-walled seamless steel pipe analysis:
1. Under the scanning electron microscope, the surface morphology of the hot-rolled and cold-rolled steel pipe was observed, and the crack was observed in the middle of the fracture.
2. The results show that there are obvious oxidized particles in the vicinity of the crack, and there is a complete polygonal ferrite morphology near the crack in the crack and near the crack. 
3. The characteristics of the oxidized particles in the 30um near the crack are closely related to the original defects of the continuous casting billet. The continuous casting slab is heated in the heating furnace for a long time to cause the elements near the crack to be oxidized to form a thicker oxide layer. Inherited to the last volume.
4. The results show that there are obvious cracks and oxidation zones of structural steel pipe in the center of thickness and 1/4, and there are also oxidized particles near the crack.

American Steel Product Standards

US mild steel pipe products are with more standards, mainly in the following categories:
ANSI--American National Standard
AISI--American Society of Iron and Steel Standards
ASTM--American Society for Testing and Materials
ASME--American Society of Mechanical Engineers
AMS--Aerospace material specifications (one of the most commonly used materials specifications in the US aviation industry, developed by SAE)
API--American Petroleum Institute standards
AWS--American Welding Association Standard
SAE--American Society of Automotive Engineers Standards
MIL--US military standards
Qq--US federal government standards
API--American Petroleum Institute standards
ANSI--American National Standard
ASME--American Society of Mechanical Engineers
ASTM--American Society for Testing and Materials

These standards, all belong to the US steel standards, such as ASME in the material used by the standards are from ASTM, the valve in the standard reference API, and carbon steel pipe fittings from the ANSI standard. The difference lies in the different focus of the industry, so the adoption of different standards. API, ASTM, ASME are members of ANSI. American National Standards Institute standards, the vast majority from the professional standards. On the other hand, the professional associations, associations, groups can also be based on existing national standards to develop certain product standards. Of course, can not follow the national standard to develop their own association standards. ANSI standards are voluntary. The United States believes that mandatory standards may limit productivity gains. But by the law and the government departments to develop standards, generally a mandatory standard.

Steel Delivery Status and Heat Treatment Requirements

Other countries and ISO stainless structural steel pipe standards are provided for hot-rolled (forged) steel, in addition to heating pressure processing steel, the general heat treatment delivery (heat treatment requirements need to be specified in the contract). After heat treatment, according to the requirements, to conduct pickling, shot peening or turning peeling and other surface treatment or surface finishing. For cold-rolled or cold-drawn steel, or cold working conditions, or cold processing after heat treatment, pickling or shot blasting, or heat treatment after the formation, grinding, polishing, or further to varying degrees of hardening processing and other state delivery.

ISO and EN, DIN standards, the delivery status of steel should be according to the production and processing methods and surface conditions of several different types of combinations, more scientific and reasonable, conducive to the implementation of standards.

With regard to the heat treatment system, in addition to the ASTM standard of carbon steel pipe, national and ISO standards specify the heat treatment system for each grade delivery steel or the heat treatment system for measuring mechanical properties. Only the ASTM standard, in addition to precipitation hardening steel, in the steel standard is generally not for each grade of heat treatment system for specific provisions, only provisions of heat treatment types (such as annealing, co-solution or aging), all kinds of steel heat treatment requirements Varieties of the general technical requirements of the standard described in the standard.

2017年5月14日星期日

Structural Steel Pipe

Shape:
Hollow Sections: Square Tube and Rectangular Tube
Round Pipe
 
Usage:
1.Construction: Hall Structure, Sea Trestle, Airport Structural steel pipe, Shipbuilding, Security Door Frames, Garage Doors, Strengthening Liners of Steel Doors and Windows,Decorating, Residential, Ornamental structural steel pipe
2.Automotive Parts:Motorcar Case,Car and Bus Manufacture, Vehicles
3.Agriculture: Agricultural Equipment
4.Industry:Machinery,Solar Stent, Offshore Oil Field, Mine Equipment, Electromechanical Hardware , heavy engineering, Mining and Resources, Process Engineering
5.Traffic:Walking Rails, Roll-up Doors, Guardrail, Plaza Structure, Signage, Road Furniture, Fencing
6.Logistics Storage: Supermarket Shelves, Containers, Transport Industries, Commercial Construction
7.Other: Sports Apparatus, Leisure Equipment, Furniture, School Furniture
 
 
Quality Standard:
 
1.ASTM A500 Cold Formed Welded and Seamless structural Steel pipe ;
2.ASTM A 53 Standard Specification for Pipe, Steel, Black and Hot-Dipped, Zinc-Coated,
Welded and Seamless structural steel pipe;
3.EN 10210 Hot finished structural hollow sections of non-alloy and fine grain structural steel pipe;
4.EN 10219 Cold formed welded structural hollow sections of non-alloy and fine grain steels ;
5.JIS G 3466 Carbon steel Square for general structural purposes ;
6.BS 1387 Steel Tubes for use for Water, Gas, Air and Steam
7.DIN 1626: Welded Circular tubes of non alloy steels with special quality standard;
8.DIN 2394: Welded and sized precision steel tubes;
 
Size:
Square:10 mmx10mm - 500 mmx500mm
Rectangular:10mm x 20mm - 600mmx500mm
Round: 1/8" - 4"
Wall Thickness: 0.5 - 20.0mm
Length:0.3 mtr - 18 mtr as customer required

2017年5月12日星期五

Seamless Steel Hardness Inspection Tool

6.0mm or more in diameter seamless steel pipe, 13mm wall thickness seamless steel pipe material following annealing can be used W-B75-based Webster hardness tester, it tests very fast, easy, seamless steel tubes suitable for rapid non-destructive materials to do qualified test. Seamless steel pipe inner diameter greater than 30mm, wall thickness greater than 1.2mm seamless steel tubes, the use of Rockwell hardness test HRB, HRC hardness. Seamless steel pipe inner diameter greater than 30mm, the seamless steel pipe wall thickness less than 1.2mm, a surface Rockwell hardness tester, hardness testing HRT or HRN. Diameter less than 0mm, more than 4.8mm of seamless steel pipe, using pipe-specific Rockwell hardness test HR15T hardness. When the seamless steel pipe diameter greater than 26mm, you can also use the Rockwell or Rockwell hardness test the surface of carbon steel pipe wall hardness. 

Gerneral Welded Seamless Steel Pipe for Transporting Low-Pressure Fluid

General welding seamless steel pipe used to transport low-pressure fluid. With Q195A, Q215A, Q235A steel. Also can be easily welded to other soft steel. Seamless to the pressure, bending, flattening, or other experimental conditions, the manufacturer according to their own more advanced testing, welding seamless pipe usually has a certain surface quality requirements, delivery is usually the length of 4-10m, according to the the actual requirements of the manufacturer shall be required to cut to length or double length delivery. Specifications with the nominal pipe diameter that different from the actual nominal diameter, pipe wall thickness required to have thin-walled and thick-walled seamless tube seamless two, seamless form divided by the carbon steel pipe end with a threaded and non threaded two.

The Application of Spiral Steel Pipe in the Urban Central Heating

Urban central heating is generated by the concentrated heat of steam, hot water supply pipe network through a city or parts of the heating used in the production and living way, which consists of heat, heat networks, heat users of three parts.

Urban central heating system, the urban economic and social development, infrastructure, and its level of development is a sign of urban modernization. The development of urban central heating area of ??urban construction in China has become a basic policy.

Central heating cogeneration and distributed mainly to the superiority of heating comparison, the focus in the following areas: 
1, there is good value for money. carbon steel pipe for central heating with large capacity, high thermal efficiency can reach 90%, and scattered small boiler thermal efficiency of heating is only about 60% or less. Therefore, instead of scattered urban central heating heating together can save 20 to 30% of energy.

2, good environmental benefits. Urban pollution comes mainly from direct coal combustion produces carbon dioxide and soot. Central heating boiler capacity, and have better dust removal equipment, using high-efficiency filter, dust removal rate of 90 to 98% or even higher, can effectively reduce urban pollution.

3, good social benefits. Urban central heating for the convenience of people's living, saving precious urban construction sites, to ease the power shortage situation in urban areas of great significance of structural steel pipe.