... widely used in transportation of oil, natural gas, gas, water and some solid materials, pipes, etc., lighter, is an economic cross-section ... steel, widely used in the manufacture structural parts and mechanical parts, such as oil drill ... pressure boiler tube10#20#GB3087-199910-530×2-40(mm)Oil cracking tube2012CrMo 15CrMoGB9948-8810.530×1.5-36(mm)Chemical ...