Archive for November, 2016

Practice has proved that the performance of punching die and the quality of life of the spread of heat treatment

Practice has proved that the performance and life of punching die heat treatment quality of the spread is very large. Statistical analysis of the reasons for the failure from the mold, punch punches are not due to thermal excitation die failure accounted for more than 40% “accident.” With the cracking deformation of the punch die working parts quenching, early fracture, and heat treatment-related links.

Quenching and tempering (1) Press Press. This is a critical step in the mold heat treatment. If the formation of overheating quenching, not only can make the workpiece to produce brittle, in the cooling process caused by the deformation and cracking, punch strictly affect the life of the mold. Mold Quenching Particular care should be taken to prevent oxidative decarburization, which must be strictly controlled by a typical heat treatment process, and in the case of a promise, a vacuum heat treatment can be selected. Quenching and tempering should be timely, according to the punching process of separation of the technical requirements.

(2) stress relief annealing. Stamping die punching parts of the work should be to eliminate the stress annealing roughing tool to remove the rough processing into internal stress, resulting in quenching deformation and cracking of large. High precision molds, grinding or eliminate stress after tempering needs, not conducive to mold accuracy, advanced life.

(3) punch forging process, it is an important part in the mold work. For high-alloy die steel, widely used in logistics such as metallographic structure of the carbonization process requirements. In addition, the temperature boundary should be strictly controlled, the exact heating protocol, the use of casting method is accurate, after the slow cold forging or timely annealing.

(4) trying to heat treatment. Different parts should be considered mold materials and the requirements of the working parts of the fire, normalizing, quenching and tempering of the heat treatment process, the organization changes to eliminate the billet organization perfect processing technology. Through the appropriate heat treatment to prepare to eliminate the two kinds of grid cementite or chain carbide, carbide ball, refine the high-carbon alloy steel carbide distribution balance, incitement. To ensure the quality of quenching and tempering, mold life.

2, punching machine processing quality
Mold parts surface quality is not wear-resistant and fracture-resistant power and mold resistance to adhesion is very closely related to a direct impact on the life of the mold. Surface roughness of the extreme value of the life of the mold a great impact, if the surface roughness value is too large, at work will produce stress components of the event, and its easy to crack between the peak and valley, corrosion-resistant die cost, Of the surface will directly affect its service life Therefore, precision molds, should pay attention to the following accidents:

Punching grinding, grinding and polishing, machining accuracy and machining accuracy, the smaller the surface roughness, die life and progress.

We should prevent the mold from working by leaving parts of the process traces of punch press the surface. Interlayer, crack, punch the impact of macro defects in the scar. These defects will have a career stress concentration, a source of failure, leading to early failure of the mold;

It is necessary to strictly control the grinding process conditions and process capability (such as grinding wheel hardness, grain size, cooling fluid, feed rate and other parameters);