Forging defects and preventive measures of stainless steel die forgings
1. pit: local pit on the surface of stainless steel forging.
Causes: the billet is oxidized seriously or slag impurities are adhered to, and the oxide scale in the mold bore is not removed.
Preventive measures: control heating time, remove the serious oxide skin and sundries on the blank surface before use, and clean the oxide skin of die bore before final forging.
2. thickness difference: insufficient forging, making the stainless steel forging have larger dimension in the height direction.
Causes: the blank is overweight, the heating temperature is low, the hammer force is not enough to design the blank die bore is not good enough to fly the edge resistance is too large.
Preventive measures: not to make the blank volume too large, improve the final forging temperature, control the hammer weight and the number of blows, select the appropriate flying edge groove, reduce the flying edge resistance to repair the worn or deformed die bore in time.
3. insufficient size: the dimension of stainless steel forging is less than the negative tolerance.
Causes: the final forging temperature is too high or the shrinkage rate of the die is insufficient. The deformation of the die is adjusted improperly, and the forging parts are cut.
Preventive measures: reduce the final forging temperature, correct the shrinkage and repair the deformation die bore to adjust the cutting die reasonably, and eliminate the partial cutting of forgings.