What measures can be taken to control the welding quality of SSAW steel pipe?
The control measures for SSAW steel pipe welding quality are mainly pre-control and process control.
1. Prior control
The work content of prior control includes: construction plan formulation and review, welder qualification and ability verification, welding equipment verification, construction material inspection, etc.
First, the construction unit formulates a special welding construction plan and operating procedures, and the supervision unit conducts detailed review and approval.
Secondly, the supervision unit will check the welder qualifications to see whether it holds a welder qualification certificate that is still valid, whether the welding categories listed in the certificate correspond to the project requirements, and whether the welding is qualified. The equipment meets technical specification requirements. The owner hires industry experts to test the welding ability of the incoming welders. Actual welding work is allowed only after passing the test.
The supervision unit inspects spiral steel pipes and welding materials. The pipe inspection content includes whether the material certificate is complete, whether the heat number, batch number, specification and other pipe identifications correspond to the material certificate, whether the pipe warehouse inspection record is complete, whether the geometric size of the steel pipe does not meet the requirements of the disposal method, and there are obvious signs; the welding material data verification content Including complete specifications of welding materials, factory certificate and furnace batch number, complete personnel warehousing and delivery procedures, and sampling re-inspection records.
2. Instant control
During the welding process, a professional construction plan should be implemented to ensure a qualified welding environment, and construction should be carried out in strict accordance with the operating instructions. When the pipe is placed in the trench, it should not be tied directly with steel wire ropes to avoid scratching the surface of the pipe. It should be placed steadily on the pipe rack and non-metallic gaskets should be used for buffering.
Before welding and assembly, the oil stain, paint, oxide scale, rust, burrs and galvanized layer within a range of not less than 10mm on the groove and its inner and outer surfaces should be removed, and there should be no cracks, interlayers and other defects. Clean with a spiral steel pipe brush and add acetone when removing. After the groove is processed by thermal processing, the oxide scale and slag on the surface of the groove are removed, and the uneven areas are smoothed. Bevel processing uses electric bevel processing or lathe turning.
Within 100mm on both sides of the groove of the submerged arc welded steel pipe weldment, measures should be taken to prevent welding spatter from contaminating the surface of the weldment before welding. Welding rods and flux should be dried as required before use and kept dry during use. Remove oil, rust, etc. from the surface of the welding wire before use. Welds are cleaned and passivated instinctively.
The welding inspector of the construction unit should inspect the appearance quality of the weld, check the weld forming status, check the surface color for defects such as undercuts, misalignments, pits, spatter, etc., and keep inspection records. Each process includes weld position and welder number records, weld bevel and butt gap inspection records, weld geometric size inspection records, and appearance quality inspection records. The supervisor of the supervisory unit will conduct inspections and spot checks on key processes, including steel pipe matching parts. Check whether the groove is stained, nicked, arc burned, water stained, etc. The roundness of the nozzle, diameter deviation, matching gap, misalignment, etc.
