Precision Mould Reduce Heat Treatment Deformation

It can be said that the rapid development of Precision Mould manufacturing industry mainly benefited from the innovation of CNC milling technology. From the traditional milling machine to the three-axis machining center, and then to today's five-axis high-speed milling, making no matter how complex three-dimensional parts of the processing can almost become a reality, the hardness of the material is no longer a problem. The main cavity of the Precision Mould is machined by CNC milling.

Heat treatment deformation is the main drawback of the Precision Mould processing process. Precise complex Precision Moulds are often scrapped by heat treatment deformation, and the deformation of complex precision Precision Moulds has been the key problem in heat treatment production.

Precision Mould deformation after heat treatment is generally considered to be caused by cooling, which is not correct. Precision Mould, especially the complex Precision Mould, the correct processing of the Precision Mould on the deformation of the Precision Mould often have a greater impact on some of the Precision Mould heating process can be clearly seen, the heating speed is faster, often produce large deformation.

Any metal heating should be inflated, because the steel in the heating, the same Precision Mould, the various parts of the uneven temperature (ie, uneven heating) will inevitably lead to expansion of the various parts of the Precision Mould inconsistency, resulting in heating Uneven internal stress. In the steel transformation point below the temperature, uneven heating mainly produce thermal stress, more than the phase transition temperature heating uneven, but also produce tissue transformation of the unequal, both produce tissue stress. Therefore, the faster the heating rate, the greater the difference between the Precision Mould surface and the heart temperature, the greater the stress, the greater the deformation of the Precision Mould after heat treatment.

In the process of quenching, the temperature difference caused by the inconsistency of the heating and cooling speed of the Precision Mould section makes the volume shrinkage and unevenness of the parts of the Precision Mould section, and the unevenness of the tissue transformation, which causes the "tissue stress" and the inside and outside the Precision Mould Temperature difference caused by thermal stress. When the internal stress exceeds the yield limit of the Precision Mould, it will cause the Precision Mould deformation or fragmentation!

In the heat treatment of the Precision Mould there is no shortage of sophisticated Precision Mould, so the need for processors have the right way.

1. Reasonable selection. For the complex density of the Precision Mould to choose a good quality micro-deformation of abrasive steel, carbide segregation serious abrasive steel forging and quenching and tempering treatment of large or can not forge the abrasive steel for solid solution double fine heat treatment.

2. Precision Mould design should be reasonable, symmetrical shape, the larger Precision Mould to master the law of deformation, reserved processing margin, large and sophisticated complex Precision Mould can be used in composite structure.

3. This kind of Precision Mould should be pre-heat treated.

4. Reasonable choice of heating temperature and control the temperature, can be taken to slow heating, preheating and other methods of equal heating to reduce the Precision Mould heat treatment deformation.

5. Conditions permitting, try to use vacuum heating quenching and quenching after cryogenic treatment.

In addition, the correct heat treatment process operation and reasonable tempering heat treatment process is to reduce the precision of complex Precision Mould deformation of the limited measures.