2016年6月30日星期四

The advantages of the alloy steel pipe

The advantages of the alloy steel pipe
Alloy steel pipe can be 100% recovery, accord with environmental protection, energy saving, saving resource of national strategy, the national policy to encourage the expansion of high-pressure alloy pipe applications. Alloy steel pipe in China at present the proportion of the total consumption of steel products is half that of developed countries, the alloy steel pipe used areas provide a broader space for the development of industry. According to the research of the China association of special steel alloy steel pipe branch expert group, the future of our country high alloy steel tube material demand grew by an average of up to 10-12%.
The material of alloy steel pipe is roughly: 16-50 mn, 27 simn, 40 cr, 12-42 crmo 16 mn 12 cr1mov T91 27 simn 30 crmo 15 crmo 20 g Cr9Mo 10 crmo910 15 mo3 15 35 crmov 45 crmov crmo, 15 crmog, 12 crmov, 45 crnimo 45 50 cr, cr, etc.
Alloy steel pipe and seamless steel tube relationship and there's a difference
Alloy steel pipe is a steel pipe according to the production of materials (i.e., material) to define, as the name suggests is made of alloy pipe; And seamless steel pipe is a steel pipe according to the production process (a seam seamless) defined, is different from that of seamless tube is tube, including straight seam welded pipe and spiral tube.

2016年6月28日星期二

High-frequency welded pipe production line - spiral loop

High frequency welded steel pipe (ERW) 244.5 711.2 mm in diameter line - spiral loop device, can store 500 tons of raw materials, also is one of the current domestic biggest spiral loop equipment, F - F - X process is the most important link. Spiral loop is one of the important equipment for tube welding, cold bending production line, is a new type of material storage mode, high speed can satisfy the welded pipe production lines, continuous operation mode. The equipment is horizontal structure, has the characteristics of simple structural steel pipe, convenient operation. The loop is a kind of new high-tech products, with principle of runoff will no wreck a steel band, no scratch stored within the loop, exported to Indonesia, is the national key promotion project. The loading weight 300-400 - m; Strip thickness 1.2 3.5 MM; Strip width of 60-200 - mm; Maximum speed of 150 m/MIN. The equipment to fill the domestic blank, its technical performance reached the international advanced level. Welded pipe production line is suitable for oil, building materials, special-shaped material production line can also be used in metallurgical industry. Saturation of the country for more than 1800 units. Horizontal spiral loop is to guarantee the high frequency welded pipe an latest automated production equipment, it act as a storage material, feed, ensure the main mill continuous work. Looping in the loading circle fixed number, when change the volume, decoiling, shearing and butt welding stop to feed in the loop, the loop by outside the cage material in each circle to rely on tight inside the cage, guarantee continuous discharge. When finished steel strip butt welding with welding pipe 2 - times as fast as the speed of the filling material within the loop, allowing the near the cage of steel belt under the action of runoff in a natural expansion trend by circle by outward cage, cage outward until all rely on, to achieve full. At this moment, and then let the speed of filling material and tube welding speed is equal, this is phase synchronization, in this cycle loop can guarantee to mill feed. Spiral loop to characteristic is: the largest storage 500 tons of raw materials equipment, working principle is clever, structure design, advanced technology to improve the quality of welded steel pipe, improve the mill and roll life. Safe and reliable, easy to operate.

More information,pls visit :Hunan great steel pipe co.,ltd

Production technology of ERW steel pipe

ERW steel pipe production process. High frequency straight seam welded steel pipe has a relatively simple process. The characteristics of continuous production quickly, in civil construction, petrochemicals, light industry and other departments have broad USES. Used for low pressure liquid or make it more all kinds of engineering components and light industrial products. 1, the high frequency straight seam welded steel pipe production process: straight seam welded steel pipe by high frequency welding machine to certain specifications of strip steel coil into circular tube and straight seam welded steel pipe. The shape of the steel tube can be round, also can be square or aliens, it depends on the sizing rolling after welding. Material of welded steel pipe are mainly: low carbon steel and sigma acuities were 300 n/s was, sigma acuities were 500 n/s was of low alloy steel and other steel products. Straight seam steel pipe production technology of high frequency welding process is as follows: 2, high frequency welding, high frequency welding is according to the principle of electromagnetic induction and ac electric charge in the conductor skin effect and proximity effect and eddy current heating effect, make the edge of the weld steel locally heated to a molten state. The squeezing roller, to realize the joint between the crystal butt weld, so as to achieve the purpose of the welding seam, high frequency welding is a kind of induction (or contact pressure welding) welding. It doesn't need weld filler, no welding spatter, narrow welding heat affected zone, weld moulding beauty, weld the advantages of good mechanical performance, so is widely used in steel production. Steel tube of high frequency welding is using alternating current (ac) of skin effect and proximity effect, steel (strip) after rolling forming, form a cross section of broken circular tube billet. Within the tube billet near the center of induction coil rotating one or a set of impedance (magnet). Impedance and pipe opening form a electromagnetic induction loop. Under the action of skin effect and proximity effect, the welded steel pipe opening edges produce powerful and concentrated heating effect. Make weld edge rapidly heated to required after roller extrusion temperature, welding metal molten state to realize the joint between the crystal, after cooling to form a firm butt weld.

2016年6月14日星期二

Compared of seamless steel pipe and ERW steel pipe

1, the outer diameter of tolerance
ERW steel pipe, is made of cold bending forming, by reducing 0.6% complete sizing, the basic technological process temperature constant at room temperature, and outside diameter control accuracy and small range, which is conducive to eliminate black buckle;
Seamless steel pipe: the hot rolling molding process, the sizing was completed in about 8000 c, steel tube raw material component, cooling condition and roll cooling condition has great influence on its outer diameter, and outside diameter control is difficult to accurately, and the fluctuation range is larger.
2, the wall thickness tolerance
ERW steel pipe: the hot rolled strip coil as raw materials, modern hot even thickness tolerance can control within 0.05 mm, and seamless steel tube production adopts the round steel perforated way, wall thickness deviation is bigger, then the hot rolling can partly eliminate wall thickness nonuniformity, but at present the most advanced unit can only control within + / - 5 ~ 10% t, corresponding to the 8.94 mm thickness of steel pipe.
Seamless steel pipe: the limit of the wall thickness control precision is 0.9 mm.
3, ovality
ERW steel pipe, is made of cold bending forming, and outside diameter control accurately, small range.
Seamless steel pipe: the hot rolling molding process, the steel tube raw material component, cooling condition and roll cooling condition has great influence on its outer diameter, and outside diameter control is difficult to accurately, and the fluctuation range is larger.
4, tensile test,
Seamless steel pipe and ERW pipe tensile performance indexes accord with standard of API, but the strength of the seamless steel tube is generally in the ceiling, the plastic is in lower limit, by comparison, ERW steel pipe strength index in the best state, plasticity index is higher than the standard 33.3%, the reason for the ERW welded steel pipe of raw materials - hot rolled coil is depend on the performance of micro alloying of smelting, refining outside the furnace and controlled rolling of cooling means to guarantee; Seamless steel pipe mainly, by the means of increasing carbon content is difficult to ensure the reasonable match of strength and plasticity.
5, hardness
ERW steel tube of raw materials - hot rolled coil in central controlled rolling high precision cold rolling process, to ensure uniform coil parts performance.
6, the grain body
ERW steel tube of raw materials - casting billet, hot rolled coil USES is generous with thicker fine crystal surface solidification layer, no columnar crystal zone and shrinkage cavity and osteoporosis, composition deviation is small, compact structure; Later in the rolling process, the application of controlled rolling technology of controlled cooling further ensures that the grain size of raw materials.
7, collapse resistance test
ERW steel pipe because of its raw materials, the characteristics of the pipe technology. The wall thickness uniformity, ovality is much better than the seamless steel tube, is the main reason for the collapse resistance higher than that of seamless steel tube.

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