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、鍛造工藝。這是塑料模具工作零件製造過程中的重要環節。對於高（gāo）合金工具（jù）鋼的塑料模具，通常對材料碳化物分布等金相組織提出技（jì）術要求。此外，還應嚴格控製（zhì）鍛造溫度（dù）範圍，製定正確的加熱規範，采用正確的鍛造力（lì）法，以及鍛後緩冷或（huò）及時（shí）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、預備熱處理。應視塑料模（mó）具工作零件的材料和要求（qiú）的不同分別采用退火、正火或調質等預備熱處理工藝，以改善（shàn）組（zǔ）織（zhī），消除鍛造毛坯的組織缺陷，改善加工工藝性。高碳合（hé）金模具鋼經過適當的預備熱處理可消除網狀二次滲碳體或鏈狀碳化（huà）物，使碳化物球化、細化，推進碳化（huà）物分布均勻性（xìng）。這樣（yàng）有利於保證淬火、回火質量，提（tí）高模（mó）具壽命。

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、淬火與回火。這（zhè）是模具熱處理中（zhōng）的關鍵環節。若淬火加熱時產（chǎn）生過熱，不僅會使工件造成較大的脆性，而且在（zài）冷卻時容易引起變形和開裂，嚴重（chóng）影響模具（jù）壽（shòu）命。衝模淬火加熱時特別應注意防止氧化和（hé）脫碳，應嚴格控製熱處理工藝規範，在條件允許的情況（kuàng）下，可采用真空（kōng）熱處（chù）理（lǐ）。淬火後應及時回火，並根據技術要（yào）求采（cǎi）用不同的回火工藝。

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、消應力（lì）退火。塑料模具加（jiā）工零（líng）件後應進行消應力退火處理，具目的是消除粗加工所造（zào）成的內應力，以免淬火叫產生過（guò）大（dà）的變形和裂（liè）紋。對於精度要求高的模具，在磨削或電（diàn）加工後還需（xū）經過消應力回火處理，有利（lì）於（yú）穩定模具精度，提高使用壽命。

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.