Plastic mold processing is mainly divided into four links: forging process, preliminary heat treatment, quenching and tempering, stress relief annealing. Now let's introduce the points needing attention in each link.

1、锻造工艺。这是塑料模具工作零件制造过程中的重要环节。对于高合金工具钢的塑料模具，通常对材料碳化物分布等金相组织提出技术要求。此外，还应严格控制锻造温度范围，制定正确的加热规范，采用正确的锻造力法，以及锻后缓冷或及时退火等。

1. Forging process. This is an important link in the manufacturing process of plastic mold working parts. For the plastic mould of high alloy tool steel, technical requirements are usually put forward for the metallographic structure such as carbide distribution. In addition, the forging temperature range shall be strictly controlled, the correct heating specification shall be formulated, the correct forging force method shall be adopted, and the slow cooling or timely annealing after forging shall be carried out.

2、预备热处理。应视塑料模具工作零件的材料和要求的不同分别采用退火、正火或调质等预备热处理工艺，以改善组织，消除锻造毛坯的组织缺陷，改善加工工艺性。高碳合金模具钢经过适当的预备热处理可消除网状二次渗碳体或链状碳化物，使碳化物球化、细化，推进碳化物分布均匀性。这样有利于保证淬火、回火质量，提高模具寿命。

2. Prepare for heat treatment. Depending on the materials and requirements of plastic mold working parts, preliminary heat treatment processes such as annealing, normalizing or quenching and tempering shall be adopted respectively to improve the structure, eliminate the structural defects of forging blank and improve the processability. After proper preliminary heat treatment, high carbon alloy die steel can eliminate network secondary cementite or chain carbide, spheroidize and refine carbide and promote the uniformity of carbide distribution. This will help to ensure the quality of quenching and tempering and improve the service life of the die.

3、淬火与回火。这是模具热处理中的关键环节。若淬火加热时产生过热，不仅会使工件造成较大的脆性，而且在冷却时容易引起变形和开裂，严重影响模具寿命。冲模淬火加热时特别应注意防止氧化和脱碳，应严格控制热处理工艺规范，在条件允许的情况下，可采用真空热处理。淬火后应及时回火，并根据技术要求采用不同的回火工艺。

3. Quenching and tempering. This is the key link in die heat treatment. If overheating occurs during quenching and heating, it will not only cause great brittleness of the workpiece, but also easily cause deformation and cracking during cooling, which will seriously affect the service life of the die. Special attention shall be paid to prevent oxidation and decarburization during quenching and heating of die. The heat treatment process specification shall be strictly controlled. If conditions permit, vacuum heat treatment can be adopted. Tempering shall be carried out in time after quenching, and different tempering processes shall be adopted according to technical requirements.

4、消应力退火。塑料模具加工零件后应进行消应力退火处理，具目的是消除粗加工所造成的内应力，以免淬火叫产生过大的变形和裂纹。对于精度要求高的模具，在磨削或电加工后还需经过消应力回火处理，有利于稳定模具精度，提高使用寿命。

4. Stress relief annealing. Stress relief annealing treatment shall be carried out after plastic mold parts are processed, with the purpose of eliminating the internal stress caused by rough machining, so as to avoid excessive deformation and crack caused by quenching. For molds with high precision requirements, stress relief tempering treatment is also required after grinding or electrical machining, which is conducive to stabilizing the accuracy of molds and improving the service life.