The service life of cemented carbide molds is related to the service conditions, design and manufacturing process, installation, use and maintenance of the molds. Therefore, to improve the service life of the molds, corresponding measures to improve these conditions need to be adopted. The main factors affecting the service life of the molds are described as follows.
(1) The influence of mold structure design on the service life of the molds The rationality of the mold structure has a great influence on the bearing capacity of the molds; unreasonable structure may cause serious stress concentration or excessive working temperature, thereby deteriorating the working conditions of the molds and causing premature failure of the molds. The mold structure includes the geometric shape of the working part of the mold, the size of the transition angle, the structure of the clamping, guide and ejection mechanism, the mold gap, the aspect ratio of the punch, the end face inclination angle, the opening of cooling water channels and assembly structures in the hot working molds, etc.
(2) The influence of cemented carbide mold materials on the service life of the molds The influence of mold materials on the service life of the molds is a comprehensive reflection of factors such as mold material type, chemical composition, organizational structure, hardness and metallurgical quality, among which the material type and hardness have the most obvious influence. The influence of mold material type on mold life is very large.
Therefore, when selecting mold materials, the mold materials should be reasonably selected according to the batch size of the parts. The hardness of the working parts of the mold also has a great influence on the life of the mold, but the higher the hardness, the longer the mold life. It can be seen that the hardness of cemented carbide molds must be determined according to the forming properties and failure forms, and the hardness, strength, toughness, wear resistance, fatigue resistance, etc. should be optimally matched to the forming requirements. The influence of the metallurgical quality of the material on the life of the mold cannot be ignored, especially high-carbon alloy steel, which has many metallurgical defects, which are often the root cause of mold quenching cracking and early damage to the mold. Therefore, improving the metallurgical quality of the material is also an important aspect of improving the life of the mold.
What is the fracture resistance strength of cemented carbide molds?
One-time brittle fracture resistance: The indicators that can characterize the one-time brittle fracture resistance of cemented carbide molds are one-time impact fracture work, compressive strength and bending strength.
Fatigue fracture resistance: It is characterized by the number of fracture cycles under a certain cyclic load or the load value that causes the specimen to fracture at a specified number of cycles. The cemented carbide mold can be reflected by several indicators such as small energy multiple impact fracture work or multiple impact fracture life, tensile and compressive fatigue strength or fatigue life, contact fatigue strength or contact fatigue life. Crack fracture resistance: When microcracks already exist in the cemented carbide mold, its fracture resistance is greatly weakened. Therefore, the various fracture resistances tested on smooth specimens cannot be used to evaluate the fracture resistance of the crack body. According to the theory of fracture mechanics, the fracture toughness index can be used to characterize the fracture resistance of the crack body.
Post time: Nov-12-2024
