Square Steel Pipe The product is double-faced submerged-arc welded pipes. Now the diameter of our product is from Ï?219mm to Ï?3500mm and wall thickness is from 6mm to 28mm. Our product comply with the standard of SY/T5037-2000, GB/T9711.1ï¼?GB/T9711.2 and API SPEC 5L PSL-1ï¼?API SPEC 5L PSL-2, the material can be Q235A/B,Q345B, L245ï¼?L360 and X42-X80 grade plate. The prod Xinrisheng is a China manufacturer of square steel pipe, square hollow sections, rectangular hollow sections and spiral steel pipe. For so many years, our company put the customer first, establishes pre-sale, on sale and after sale service standard, welcome to contact us.