How to effectively extend the service life of the mold

When these defects occur in the mold parts, qualified fastener products cannot be formed, which will inevitably affect the production plan of the enterprise.

Precaution

In order to prevent the early failure of the mold and effectively prolong the service life of the mold, corresponding preventive measures are mainly taken from the following aspects.

1. Mold material

Since the cold work die bears a large unit extrusion force, high-performance die materials with high strength, good toughness and good wear resistance should be selected; since the working conditions of the punch are more susceptible to the eccentric force than the punch, The wear resistance of the die material should be selected to be higher than that of the die material.

2. Heat treatment

Die heat treatment includes: timely tempering of cold work die blank after forging to refine grains, tempering after rough machining to relieve stress, and low temperature tempering to relieve stress after EDM and wire cutting. Experience has shown that molds with a diameter of ≤ 80mm should be directly machined from bars without forging, because improper forging will cause defects such as overburning, coarse grains, and segregation.

If the quenching cooling speed is too fast and the swimming temperature is too low, the mold is prone to quenching cracks. If the tempering temperature is too low and insufficient, the residual stress in the quenching process will not be eliminated, the toughness of the mold will be reduced, and early fracture will easily occur.

3. Mold design The structure of the cold work mold must have sufficient strength, rigidity, reliability and good guidance, but the unreasonable structure of the mold will directly affect the service life of the mold. The working part of the mold should be designed with a large enough fillet radius to avoid stress concentration caused by the transition of sharp corners. The width of the ligament should be reasonably designed according to the metal flow conditions, and the friction force should be minimized to minimize the friction, generally between 1.5-3.5.

4. mold processing

During the cutting process of the mold tool, the following measures should be taken: improve the surface roughness, the micro-crack marks formed by grinding, the transition part should be smooth, and the tool marks and small defects should not be machined to prevent the occurrence of stress concentration during use. .