Large diameter spiral submerged arc welded steel pipe from the wide range
Large diameter spiral submerged arc welded steel pipe from the wide range of products used in water works, petrochemical industry, chemical industry, electric power industry, agricultural irrigation, urban construction, and is one of the 20 major products in China. For liquid transfer by: water supply, water drainage. Gas: gas, steam, liquid petroleum gas. Structure: piling pipe, bridge, port, road and building construction, such as. Large diameter spiral submerged arc welded steel pipe production process Spiral steel pipe is to strip rolling for raw material, often warm extrusion molding, to automatically double wire of double submerged arc welded spiral seam pipe. (1) the raw material Strip, welding wire, flux. In front of the input must pass a strict physical and chemical examination. (2) the Strip head and tail docking, single-wire or two-wire submerged arc welding, in rolled steel by submerged arc welding-welding. (3) before molding Strip after leveling, edge cutting, Beveling, surface cleaning, transportation and curved edges.
(4) controlled by electric contact pressure gauge pressure of cylinders under pressure on both sides of the conveyor to ensure the smooth transportation of the Strip. (5) using the external or internal roll forming. (6) use weld leakage control device to ensure the weld gap to meet the requirements pipe diameter, unfitness and weld gap were strictly controlled. (7) within and outside welding using United States Lincoln Electric welding machine for single or twin-wire submerged arc welding, welding so as to secure a stable specification.
(8) finished welding the weld passes through the automatic on-line ultrasonic instrument hurt checks ensure the spiral of 100% coverage of nondestructive testing of welds. If there are defects, automatic alarm and sprayed the tag, and accordingly adjust the parameters of production workers, eliminate the defects in a timely manner. (9) air plasma cutting machine cut the pipe into the single. (10) after the cut pipe, each batch of steel tubes to conduct strict inspection system, check the mechanical properties of the weld seam, chemical composition, mix, steel surface quality as well as NDT inspection, ensure that the pipe-making process after passing to be put into production. (11) the weld seam continuous acoustic inspection marks appear on the site, after manual ultrasonic and x-ray examination, if there are defects, after repair, again through non-destructive testing until defects have been eliminated. (12) the Strip butt weld and d-type connector that intersects the spiral welded tubes, all x-ray TV or film to check. (13) each pipe passed a hydrostatic test pressure radial seals. Test pressure and time were tightly controlled by microcomputer detection device of steel pipe water pressure. Automatic printing of test parameters. (14) the pipe end machining, surface perpendicularity, blunt edge and Groove angle accurately controlled. Despite the recent arrival of began to increase, but the overall pressure on the stock is small, individual State needs more specification is still in stock, market prices are more confusing, basically there is no city, coupled with shrinking demand, and raw materials purchasing enthusiasm down, poor market transactions, the market decline has not fundamentally changed. In addition, the recent steel, billets, ore prices continue to trend lower, it results in a certain amount of pressure on the market, businesses see an empty future. Taken together, the author expects local prices in the short term or to continue to hold on the sidelines.
Source:http://www.jnsteelpipe.com/
