Steel pipe is generally divided into seamless steel pipe and welded steel pipe according to production methods. This time we mainly introduce welded steel pipe,that is,welded steel pipe.Its production is to bend the tube blank (steel plate and steel strip into the required cross-section shape and size tube by various forming methods,and then weld the weld by different welding methods to get the steel pipe.
Compared with welded seamless steel pipe, it has product precision with the characteristics of high precision, especially high wall thickness.simple main equipment,small floor area,continuous operation in production and flexible production, welded pipe can be divided into spiralsubmerged arc welded pipe, straight seam double-sided submerged arc welded pipe and resistance welded pipe.
1.The production process of spiral steel pipe is as follows:
The raw materials of spiral steel pipe are strip coil,welding wire and flux.Before forming,the strip is leveled,trimmed, planed,cleaned and transported on the surface, and bent.The weld gap control device is used to ensure that the weld gap meets the welding requirements. The pipe diameter,misalignment and weld gap are strictly controlled.After cutting into a single steel pipe the first three of each batch of steel pipes are subject to strict first inspection system,n order to check the mechanical properties, chemical composition, fusion state and surface quality of the weld,as well as through non-destructive testing to ensure that the pipe manufacturing process is qualified. it can be formally put into production.
2.LSAW pipe:
Generally speaking,LSAW pipe is made of steel plate through different forming processes, such as double-sided submerged arc welding and expanding after welding.The forming methods of LSAW pipe include uo(UOE),Rb(RBE),JCO(JCOE), etc.
Forming process of UOE LSAW pipe:
The forming process of UOE longitudinal submerged arc welded pipe mainly includes three forming processes：steel plate pre bending, u forming and O forming. Each process uses a special forming press to complete the three processes of steel plate edge pre bending, u forming and O forming in order to deform the steel plate into a circular tube.The forming process of JCOE longitudinal submerged arc welded pipe: in jc0 After repeated stamping on the forming machine,the first half of the steel plate is pressed into a J shape, and then the other half of the steel plate is pressed into a J shape to form a C shape.
Comparison of JCO and uo molding methods:
JCO forming is progressive pressure forming.,which changes the forming process of steel pipe from two steps of UO forming to multi steps.In the forming process, the steel plate has uniform deformation, small residual stress and no scratch on the surface. The processed steel pipe has great flexibility in the size range of diameter and wall thickness. It can produce large quantities of products and small quantities of products. as well as large caliber and high-quality products It can also produce small diameter and large wall steel pipes. especially in the production of high-quality thick wall pipes especially in the production of medium and small diameter thick wall pipes. It has incomparable advantages over other processes, and can meet more requirements of users for steel pipe specifications.Uo molding adopts u and O two-step pressure forming, which is characterized by large capacity and high output.Generally, the annual output can reach 30-30% 1 million tons,suitable for single specification mass production.
3. Straight seam high frequency welded pipe
The straight seam high frequency welded pipe(ERW)is formed by heating the edge of the tube billet with the skin effect and proximity effect of high frequency current after the hot rolled coil is shaped by the forming machine, and then pressure welding is carried out under the action of the extrusion roller.
Post time: Jul-31-2023