Introduction
Hot forging is a process carried out at temperatures above the recrystallization temperature of the metal billet.
Main Characteristics
Reduced deformation resistance, thereby decreasing the forging force required for billet deformation and significantly reducing the tonnage requirements of forging equipment;
Transformation of the as-cast structure of steel ingots—during hot forging, through recrystallization, the coarse as-cast structure is transformed into a new fine-grained structure, and defects in the as-cast structure are reduced, improving the mechanical properties of the steel;
Enhanced plasticity of steel, which is particularly important for high-alloy steels that are brittle and difficult to forge at low temperatures.
Process Flow
Different forging methods have different process flows. Among them, hot die forging has the longest process flow. The general sequence is as follows:
Billet cutting
Billet heating
Roll forging for pre-forming
Die forging and forming
Trimming
Punching
Straightening
Intermediate inspection—checking dimensions and surface defects of forgings
Heat treatment of forgings—to eliminate forging stress and improve metal machinability
Cleaning—primarily removing surface oxide scale
Straightening
Final inspection—general forgings require visual and hardness inspection; important forgings also require chemical composition analysis, mechanical property testing, residual stress inspection, and non-destructive testing
Author: Wang Bo