What is the method of surface corrosion treatment for 40 Cr seamless steel pipe?

Chemical composition and mechanical properties of 40Cr seamless steel pipe: carbon 0.37-0.45%, silicon 0.17-0.37%, manganese 0.5-0.8, chromium 0.8-1.1%. Annealing hardness: less than 207 HBS; normalizing hardness: less than 250 HBS; tempering treatment: sample; diameter: 25 mm, 850 degree quenching, heating, oil quenching, 520 degree tempering: tensile 1000 MPa, yield 800 MPa, extension 9%, section shrinkage 45%, impact toughness 588.3 kJ / m2.
Due to different manufacturing processes, it can be divided into hot-rolled (extruded) seamless steel pipe and cold drawn (rolled) seamless steel pipe. Cold drawn (rolled) pipe is divided into two kinds: round pipe and special-shaped pipe.

The surface treatment of 40Cr seamless steel pipe is one of the key factors to determine the service life of pipeline anticorrosion, which is the premise of the solid combination of anticorrosive coating and seamless pipe. It is verified by the research organization that the service life of the anticorrosive coating depends on the coating type, coating quality, construction environment and other factors, and the influence of the surface treatment of 40Cr seamless steel pipe on the service life of the anticorrosive coating accounts for about 50%. Therefore, the surface treatment method of the steel pipe shall be continuously improved in strict accordance with the requirements of the anticorrosive coating specification on the steel pipe surface.