The problem of Grade 4 network carbides and a small amount of eutectic carbides in Cr5 forged steel caused by improper post-forging heat treatment design can be solved by optimizing the heat treatment process. High-temperature normalizing is adopted to dissolve most carbides into the matrix, followed by rapid cooling using water-based or oil-based quenching media to ensure full austenite transformation, reduce precipitation of secondary carbides, thereby sufficiently refining the microstructure and avoiding the formation of network carbides. Ultimately, zero defect echoes and favorable bottom echoes are achieved in testing.
Prior to roll quenching and tempering, appropriate heat treatment processes can improve the grass-like echo defects of roll blanks. Aiming at the grass-like echo defects detected by ultrasonic testing in 70Cr5Mo steel roll blanks, this paper adopts post-forging heat treatment processes such as normalizing and spheroidizing annealing to refine the microstructure morphology of 70Cr5Mo steel blanks, obtain favorable microstructural features, and reduce or eliminate grass-like echoes in the blanks, so as to ensure no adverse effects on inspection and service performance.
As the core equipment of the forging industry, the fast forging hydraulic press plays an important role in promoting the upgrading of traditional industries and driving the coordinated development of upstream and downstream industrial chains.
