In daily life, most of our common moulds are made of steel. When using mould steel, we will find that some defects will occur, which will cause the mould to be used normally, and even the manufactured workpiece will be deformed and used differently. Therefore, when using mould steel, we must understand its common defects and preventive measures.
1.Deformation
One of the reasons for the deformation of the material is the deformation caused by the manufacturer’s actual use of the mould material is not a special mould steel in order to reduce costs. The rigidity of the template is insufficient and the thickness is insufficient.
Preventive measures: ① When manufacturing precision and complex moulds, try to choose a mould steel with small carbide segregation, do not plan cheap, choose a steel with poor material produced by a small steel mill. ② Die steel with severe segregation of carbides must be reasonably forged to break the carbide ingots, reduce the level of uneven distribution of carbides, and eliminate the anisotropy of performance. ③ The forged mould steel should be quenched and tempered to obtain a uniform, fine and dispersed sorbite structure in carbide distribution, thereby reducing the deformation of the precision and complex mould after heat treatment. ④ For moulds that are large in size or cannot be forged, solid solution double refinement can be used to make the carbides fine, uniformly distributed, and rounded corners, which can reduce the heat treatment deformation of the mould.
2. Fracture
Due to improper temperature control, the material of the forging die has cracked. In this case, only the template must be changed. The cracking or even cracking of the template in production is often caused by the high hardness and excessive stress of the heat treatment of the selected material. Cracking is easy to occur during welding. In severe cases, cracking is easy to occur especially when welding Cr12 hard materials. The template has too much stress, and most of the impact cracks are at the sharp corners of the cavity. If it can still be used, it can be perforated and cut in I-shape, or it can be hugged around the template.
3.Wear
The hardness of the movable parts in the mould is not enough, there are sharp angles, improper selection of materials, etc. are also the causes of wear. For highly corrosive products and plastics with considerable hardness and fillers, the surface of the materials we choose should be resistant to corrosion and the surface hardness should be high.
4. Poor heat dissipation
The heat dissipation of the long core mould is very important. The selection of appropriate materials has a large gap between the appearance of the product and the output of the product. For example, beryllium copper and other materials containing beryllium and cobalt are selected. After heat treatment, they have higher strength, hardness, fatigue resistance, wear resistance and good heat transfer.