Spiral submerged-arc welding is a process of welding steel pipes, industry insiders always regard SSAW as the spiral submerged-arc welding steel pipe.The SSAW API steel pipe use a narrow billet and produces large diameter pipe, and you can also use the same width billets to produce different diameter pipes. The production cost is lower and it’s process is simple. It is generally used in metal structures, welded pipes for fluid transport, foundation, and some other structures. It is used in power industry, and urban construction. It is one of the China’s 20 key developed products.
The SSAW API steel pipe uses steel coil strip as row materials, after extrusion molding in normal atmospheric temperature, uses the automatic double wires and double side submerged arc welding process to weld steel pipes. The production processes are:
- The materials are steel strip, welding flux and welding wire.
- Before using, they must go through rigorous physical and chemical tests.
- The strip steel should use automatic submerged welding after the steel rolled into steel pipe.
- Before molding, the strip goes though flattening, cutting, trimming, planning, surface cleaning, transportation and edge curved processes.
- Use electrical contacts to control the cylinder pressure on both sides of the conveyor, that will ensure the strip deliver smoothly.
- Use the weld gap control can ensure the weld gaps to meet the welding’s requirements, the wrong side,the diameter, and weld gap should have been controlled strictly.
- Outside and the inner welding use the welding machine for single or double wire submerged arc welding.
- All the finished welds should go through the online continuous ultrasonic injury check, it will help to get the 100% welds non-destructive testing coverage. If there is any defective, it will alarm automatically and spray markers, production workers can adjust the process parameters at any time, and they can eliminate the defects timely.
- Using air plasma cutting machine to cut the steel pipe to single one.
- After the steel pipe into single pipes, each batch will go through the strict inspection system and the DNT inspection, to check the welds’ mechanical properties, chemical composition, fusion status, steel surface quality, only all the pipes’ process are qualified, can they be formally put into production.
- If there is a continuous acoustic detection marker on the weld, this pipe need manual ultrasonic and X-ray review, if the defective is true, after repairing, it need non-destructive testing again until the defect has been eliminated.
(This article comes from southlandpipe edit released)