large diameter welded spiral pipe 1. Grade: Q345B, API X42 - X80, ... , L555, J55, N80 2. Standard: SY/T5037-2000, GB/T Large diameter welded spiral pipeSSAW (Spirally Submerged Arc Welding) pipes are ... are mainly used for oil, natural gas, gas, central heating, water supply, sewage treatment, low-pressure fluid delivery and so on.