Cold-Formed Welded and Seamless Carbon Steel Structural Tubing as per ASTM A36 / A36M. LSAW Steel Pipe. Longitudinal Submerged-Arc Welded Steel Pipe. Usage: Used for low pressure liquid delivery, such as water, gas, and oil. Standard: API 5L, API 5CT, ASTM 53, EN10217, DIN 2458. IS 3589, GB/T3091, GB/T9711.