Forging defects
The purpose of forging is to press the intrinsic porosity defects of the steel ingot to make the structure dense and obtain a good metal flow line. The forming process is to make it as close as possible to the shape of the workpiece. The defects generated during forging mainly include cracks, internal forging defects, oxide scales and folds, unqualified dimensions, etc.
The main causes of cracks are overheating of the steel ingot during heating, too low forging temperature, and excessive pressure reduction.Overheating can easily cause cracks in the early stage of forging. When the forging temperature is too low, the material itself has poor plasticity, and the amount of pressure reduction during forging Tensile cracks, etc. In addition, cracks generated by forging are not easily cleaned in time or are not fully cleaned, which can easily cause cracks to expand further. The internal forging defects are mainly caused by insufficient pressure of the press or insufficient amount of pressure, the pressure cannot be fully transmitted to the core of the steel ingot, the shrinkage holes generated during the ingot are not fully pressed, and the dendritic grains are not fully broken Shrinkage and other defects. The main reason for the scale and folding is that the scale produced during forging is not cleaned in time and is pressed into the forging during forging, or it is caused by the unreasonable forging process. In addition, these defects are also likely to occur when the surface of the blank is bad, or the heating is uneven, or the anvil and the amount of reduction used are not suitable, but because it is a surface defect, it can be removed by mechanical methods. In addition, if the heating and forging operations are improper, it can cause the axis of the workpiece to be offset or misaligned. This is called eccentricity and bending in the forging operation, but these defects are correctable defects when the forging is continued.

The prevention of defects caused by forging mainly includes:

(1) Reasonably controlling the heating temperature to avoid over-burning and low temperature;

(2) Optimizing the forging process, many departments will sign the forging process and strengthen the forging process approval process;

( 3) Strengthen the process control of the forging, strictly implement the process, and do not change the forging parameters at will to ensure the continuity of the forging process.