Effect of Heat Treatment on Microstructures and Properties of N08020 Alloy Steel Pipes

The effects of different heat treatment processes on microstructure and properties of the N08020 alloy steel pipes are studied by optical microscope, tensile test machine, hardness tester and scanning electron microscope.The results show that there is some intermetallic phase precipitation existing in the hot extrusion pipe and after solid solution with 1 200℃ high temperature all intermetallic phases are dissolved;through cold rolling with large deformation and subsequent 1 000℃ heat treatment the average grain size is 22 μm in finished pipes with no intermetallic phase precipitation and then again through the stabilization treatment for 3 h with the precipitation of Nb(C, N) better comprehensive physical and chemical properties can be obtained.