The production process of 42CrMo4 steel plate includes: electric arc furnace smelting, refining, pouring, slow cooling, steam stripping, heating, forging, normalizing and tempering.
The heat treatment process of 42CrMo4 steel plate is as follows: the steel ingot is not subjected to stress relief annealing after demoulding; heating before forging; forging process: 20% reduction, direct dial Φ580 mm x 6000 mm length; direct normalizing and quenching (water quenching and air quenching) after forging cold).
In order to determine the real reason for the brittle fracture of the 42CrMo4 steel plate during use, a sample analysis was carried out on the typical defects in the section of the core rod.
After low-power acid leaching, the zigzag slender cracks distributed at a certain distance from the sample surface or near the center of the 42CrMo4 steel plate sample are radially concentric or irregular in shape, which is a typical white spot crack defect.
