When the mold parts produce these defects, they can not form a qualified fastener products, is bound to affect the production plan of the enterprise.
In order to prevent early failure of the mold, the effective extension of the life of the mold, mainly from the following aspects to take appropriate precautions.
First, the mold material
As the cold-work die unit to withstand greater compression, it should choose high strength, toughness, good wear resistance of high-performance mold material; due to the working conditions of the punch than the die more susceptible to eccentric force, so the convex Die material wear resistance should be selected higher than the die material.
Second, heat treatment
Die heat treatment, including: cold die billet forging after the timely tempering to refine the grain, roughing tempering to eliminate stress, electric spark, after the wire cutting to stress tempering. Experience shows that the mold diameter ≤ 80mm, bar should be used direct machining, no longer forging, but forging caused by improper forging, coarse grain, segregation and other defects.
Quenching cooling too fast and swimming temperature is too low, the mold is easy to produce quenching cracks. If the tempering temperature is too low, and not sufficient, will not be able to eliminate the residual stress during quenching, the mold to reduce the toughness, prone to early fracture.
Third, the mold design Cold-work die structure must have sufficient strength, stiffness, reliability and good orientation, but the mold structure is not reasonable will have a direct impact on the life of the mold. Working part of the mold should be designed to be large enough radius to avoid corner sharp corners of the stress concentration, the width of the ligament should be based on the rational design of metal flow to minimize friction, generally between 1.5-3.5.
Fourth, mold processing
In the touch cutting process, should take the following measures: Improve the surface roughness, grinding the formation of micro-cracks traces of the transition to be smooth, can not be machined marks and minor defects, to prevent the occurrence of stress concentration during the use of cracks . 【Suzhou Mold Casting】