» How Welded Pipes are Manufactured?

Welded pipe to be divided from the production process, and divided into: spiral submerged arc welding pipe SSAW (Spirally Submerged Arc Welding); LSAW pipe(LongitudinallySubmerged Arc Welding); resistance welded pipe ERW (Electric Resistance Welding) three.The next welded pipe supplier will explain the forming process of welded pipes.

A spiral steel pipe production process is roughly as follows
1.Spiral steel pipe raw materials, i.e. strip coil, welding wire and flux.

Before forming, the strip steel is leveled, sheared and planed, and the surface is cleaned and conveyed and bent to the edge.

2. Weld gap control device is used to ensure that the weld gap meets the welding requirements, and the pipe diameter, misalignment and weld gap are strictly controlled.

3.After cutting into single steel pipes, the first three pipes of each batch are subjected to a strict first inspection system to check the mechanical properties of the weld seam, chemical composition, dissolution condition, surface quality of the pipe and non-destructive flaw detection inspection to ensure that the pipe making process is qualified before it is officially put into production.

The forming type of LSAW pipe
The LSAW pipe is generally made of steel plate, and is formed by different forming processes, such as double-sided submerged arc welding and post-welding expansion.

The main equipments are edge milling machine, pre-bending machine, forming machine, pre-welding machine, resizing machine, etc. Meanwhile, the forming type of LSAW pipe is UO (UOE), RB (RBE), JCO (JCOE) and so on. The steel plate is first pressed into U shape in the forming die, then pressed into O shape, and then internal and external submerged arc welding, after welding is usually expanded at the end or full-length range (Expanding) is called UOE welded pipe, not expanded is called UO welded pipe.

LSAW Pipes

The steel plate is roll bent (Roll Bending) and then submerged arc welded inside and outside, after welding, the expanded diameter is RBE welded pipe or not expanded diameter is RB welded pipe. The steel plate is formed in the order of J type – C type – O type, and after welding, it is expanded to JCOE welded pipe or JCO welded pipe without expansion.

UOE longitudinal submerged arc welded pipe forming process
The three main forming processes of UOE LSAW steel pipe forming process include: 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 turn to deform the steel plate into a round tube.

Comparison of JCO and UO forming method
JCO forming is progressive pressure forming, which turns the process of forming steel pipe from two steps of UO forming into multiple steps. During the forming process, the steel plate deforms evenly, residual stresses are small, and the surface is not scratched. The processed steel pipe has greater flexibility in the size range of diameter and wall thickness, and can be produced in large quantities as well as small quantities; it can produce both large-diameter high-strength thick-walled steel pipe and small-diameter large-walled thick steel pipe; especially in the production of high steel grade thick-walled pipe, especially small and medium-diameter thick-walled pipe has advantages that cannot be matched by other processes. Can meet the user in the steel pipe specifications more requirements. Less investment, but lower production efficiency, the general annual output of 100 ~ 250,000 t.