Effect by Spheroidization Anneal Cooling Rate on Microstructure and Hardness of 23CrNi3Mo Alloy Pipe for Drilling Tool Service

To solve the problem of high cold-rolling deformation resistance of the 23CrNi3Mo alloy pipe for drilling tool service, a study is made, which involves spheroidization annealing of the tube so as to reduce the hardness of the alloy.Revealed, with the help of scanning electron microscope(SEM)and the characteristics like hardness, are the regularity of the microstructure evolution and the change of hardness of the 23CrNi3Mo alloy tube as spheroidization annealed.Relevant test results show that as being spheroidization annealed at 680℃, the 23CrNi3Mo alloy has its microstructure getting into granular carbides, and along with reduction of the cooling rate, diameter of the carbide is getting bigger and bigger;and that after spheroidization annealed, the said alloy has its hardness remarkably reduced, and in turn the required cold-rolling deformation is obtained.