Seamless steel pipe has thick wall seamless steel pipe and thin wall seamless steel pipe according to different purposes. Seamless steel pipe is widely used.
1. Seamless steel pipes for general purposes are rolled from ordinary carbon structural steel, low alloy structural steel or alloy structural steel according to the material. For example, seamless pipes made of low carbon steel such as No. 10 and No. 20 are mainly used as transmission pipelines for steam, gas, liquefied gas, natural gas, various petroleum products and various other gases or liquids; Seamless pipes made of medium carbon steel such as 45 and 40Cr are mainly used to manufacture various machine accessories and pipe accessories.
2. Seamless steel pipes for general purposes are also supplied according to chemical composition and mechanical properties and hydrostatic test. Seamless steel pipes bearing fluid pressure shall be qualified in hydrostatic test.
3. Special purpose seamless pipe is used for boiler, geological exploration, bearing, acid resistance, etc. Such as petroleum geological drilling pipe, cracking pipe for petrochemical industry, boiler pipe, bearing pipe and high-precision structural steel pipe for automobile, tractor and aviation.