On 2018-08-08 14:48:54
How to prevent heat treatment deformation
The causes of deformation of precision and complex dies are often complex. If we master the deformation law and analyze the causes, we can reduce and control the deformation of dies by different methods. Generally speaking, the following methods can be adopted to prevent the heat treatment deformation of the precision and complex die.
1、 Reasonable material selection. For the precision and complex die, the micro deformation die steel with good material (such as empty quenching steel) should be selected. For the die steel with severe carbide segregation, the reasonable forging and tempering heat treatment should be carried out. For the large and non forging die steel, the solution and refining heat treatment can be carried out.
2、 The die structure design should be reasonable, the thickness should not be too different, the shape should be symmetrical, the deformation law should be mastered for the large deformation die, the machining allowance should be reserved, and the combined structure can be used for the large, precise and complex die.
3、 The precise and complex die needs to be heat treated in advance to eliminate the residual stress in the machining process.
4、 Choose heating temperature reasonably and control heating speed. Slow heating, preheating and other balanced heating methods can be adopted to reduce heat treatment deformation of precision and complex dies.
5、 On the premise of ensuring the hardness of the die, the pre cooling, staged cooling and quenching or temperature quenching process shall be adopted as far as possible.
6、 For the precision and complex mould, the vacuum heating quenching and the deep cooling treatment after quenching should be used as far as possible when the conditions permit.
7、 For some precise and complex dies, pre heat treatment, aging heat treatment and quenching, tempering and nitriding heat treatment can be used to control the accuracy of the dies.
8、 When repairing mold defects such as sand hole, air hole, wear, etc., cold welding machine and other repair equipment with small heat effect shall be selected to avoid deformation in the repair process.
In addition, the correct heat treatment process operation (such as plugging, binding, mechanical fixation, appropriate heating method, correct choice of cooling direction and moving direction in the cooling medium) and the reasonable tempering heat treatment process are also effective measures to reduce the deformation of the precision and complex mold.