Lower Bainite/Martensite Seamless Steel Pipe with High Strength and Toughness

摘要

A new type of seamless steel pipe with high strength and high toughness was developed. Only through air cooling (or air-cooling +low temperature tempering) after rolling, a duplex microstructure of lower bainite/martensite was obtained. The pipes could be used in solid materials transferring. The results showed that the mechanical properties of the seamless steel pipes was as following: σ_b > 1500MPa , σ_(0.2) > 900Mpa, δ_5 > 11% , ψ > 30% , A_(KV) > 45J and HRC > 45. Compared with that of the common seamless steel pipes, the service life of the carbide-free bainite/martensite seamless steel pipes could be increased obviously.