A new designed method for evaluating the repairability of a newly developed 5Cr5MoV cold working die steel

Casting defects seriously affect the service life of a cold working die for the automobile industry. For the newly developed cold working die steel, its repairability is a very important scientific and technical issue, especially how to evaluate its repairability is of great engineering value. In this work, the repairability of the newly developed 5Cr5MoV cold working die steel is investigated in detail by a newly designed method, defined as the round pit evaluation method. Experimental results show that the dimension of the round pit significantly influences the microstructure evolution and microhardness distribution in the repaired zone, i.e., the control of round pit dimension can regulate and control the performance matching between the repaired zone and the matrix. When the diameter of the round pit is controlled at about 20 mm, a better matching performance can be obtained. Finally, the round pit evaluation method was established based on a newly developed model of which a microhardness fluctuation coefficient was proposed and used to evaluate the repair effect.