The process of the one·step method is: loading and preparation _ unwinding _ initial correction. Multi-roller straightening_shearing, butt welding_trimming (milling edge)-steel strip pre-bending_forming and internal welding_external welding_internal inspection (slag cleaning) Imaging-hydrostatic pressure test_Flat-head chamfering-Ultrasonic detection with ultrasonic probe_X-ray tube end film-X-ray tube body film_Finished product inspection-Weighing and length measurement-Spray standard-crossing warehouse (different production The manufacturer is slightly different). In production, the forming and submerged arc welding processes are carried out simultaneously and completed in one step.

The advantages of the one·step method production process of SSAW steel pipe

(1) Strip steel with the same width can produce steel pipes with different diameters.

(2) Steel pipes of the same diameter can be produced with strips of different widths.

(3) The diameter and wall thickness ratio of the steel pipe can reach 100.

(4) Low investment in production equipment, short construction period and rapid development.

(5) Both internal and external welding are performed with single wire or double wire welding.

The disadvantages of the one·step method production process

(1) While the welded pipe is being formed, internal welding is performed by submerged arc welding, which causes defects in the forming process.

(2) After the 6 o'clock position of the internal welding, the welding is downhill, which results in the formation of grooves on the surface of the internal welding seam, and the transition angle between the edge of the weld and the base material is too small, which affects the performance of the welding process.

(3) Welding during the forming process is likely to cause stress concentration in the internal welding seam and large changes in the metallographic structure, affecting the mechanical properties of the welding seam.

(4) Affected by the position or straightness of the steel belt, the quality of the steel pipe fluctuates greatly, and welding defects cannot be completely eliminated.

(5) The welding speed is limited by molding and production efficiency is low.