Longitudinal submerged arc welding process and its applications
Submerged arc steel pipe forming method:
The most common submerged arc steel pipe forming methods are three UOE (the Uing-Oing method of forming), RBE (Rolling Bending Expanding), JCOE (Jing Cing Oing Expanding).
1. UOE forming method: The forming process of UOE equipment is divided into three steps: pre-bending, U-shaped press forming and O-shaped press forming, followed by cold expansion of the entire pipe to eliminate the stress generated during the pipe making process .
--Features: The forming unit has huge equipment and high cost. Each set of forming equipment needs to be equipped with multiple casing inner and outer welding machines, and the production efficiency is high.
--Disadvantages: Due to the large number of forming equipment, each specification of steel pipe requires a specific set of forming molds, and these molds need to be changed at the same time when changing product specifications. The internal stress of the formed welded pipe is relatively large, and generally an expanding machine is required. The UOE unit has mature technology, high automation level, and reliable products, but the unit equipment investment is huge, which is suitable for the production of large-volume products.
2. RBE forming method: The stages of RBE forming are rolling, bending and diameter expansion
--Features: Since ordinary enterprises cannot bear the huge investment of UOE pipe making units, RBE pipe making units developed on the basis of RB have the characteristics of small investment, moderate batch size, and convenient product specification change, so they have developed rapidly.
The RBE pipe-making unit uses three-roll rolling to realize the steel pipe forming. The pipe-making process is that the three-roll forming machine rolls the steel plate into a steel pipe with a caliber, and then bends its edge with a forming roller, or it can be bent after , and then bend its edges with forming rollers, or it can also be bent afterward. Since it is a three-roll continuous roll bending forming, the stress distribution generated during the steel pipe forming process is relatively uniform. However, when changing the bending product specifications, it is necessary to change the core roll and adjust the lower roll appropriately. A set of core rolls of this forming equipment can take care of several specifications of products.
--Disadvantage: The production scale is small, and due to the influence of the strength and rigidity of the core roll, the wall thickness and diameter of the steel pipe are greatly restricted.
3. JCOE forming method: JCOE forming has three stages, that is, the steel plate is first pressed into a J shape, and then pressed into a C shape and an O shape in turn, and E stands for diameter expansion.
--Features: small investment, good product molding, and thicker wall thickness.
JCOE forming pipe making unit is developed on the basis of UOE forming process. It learns from the working principle of U-shape and releases and implements UOE forming process, which greatly reduces the tonnage of the forming machine and saves equipment investment. The steel pipe produced is the same as the UOE welded pipe in terms of quality, but the output is lower than that of the UOE welded pipe unit. This process is easy to realize automatic control in the forming process, and the product is formed better. JCOE forming equipment can be roughly divided into two types, one is bending forming, and the other is compression forming. Bending forming is mainly used in the forming process of thick plate and medium plate, with small steps and low output. The forming process is to roll the two edges of the steel plate into an arc shape according to the curvature radius of the welded pipe on the edge bending machine, and then use the forming machine to press half of the steel plate into a C shape through multiple step stamping, and then start from the other side of the steel plate Stamping, after multiple steps of stamping, the other side of the steel plate is also pressed into a C shape, and the whole steel plate becomes an open O shape from the surface.
-- Disadvantage: Relatively low output.
Huayang LSAW steel pipe produced by RBE production line, W.T :9.5-25MM:
HUAYANG SAWL pipe produced by JCOE production line，W.T：15-50MM:
Hebei Huayang Steel Pipe Co., Ltd. has 3 submerged arc production lines to produce LSAW pipes, 1 RBE, 2 JCOE, used to produce 457-1422, wall thickness 8-50mm, fluid, piling, structure, oil and gas, etc., to meet the needs of different customers.
