保定市防撞墙模具厂

Use and maintenance of moulds

（1）模具的预热  HI3钢合金元素含量较高，导热性能较差，因此模具在工作前应充分预热。预热温度过高，模具在使用过程中温度偏高，强度下降，易产生塑性变形，造成模具表面塌陷；预热温度过低，模具开始使用时，瞬间表面温度变化大，热应力大，易萌生裂纹。综合考虑后H13钢模具的预热温度确定为250～300℃，既可降低模具与锻件的温差以避免模具表面出现过大的热应力，又有效地减少了模具表面的塑性变形。

(1) HI3 steel has high alloy element content and poor thermal conductivity, so the mould should be fully preheated before working. When the preheating temperature is too high, the mold temperature is on the high side, and the strength decreases. It is easy to produce plastic deformation and cause the surface of the mold to collapse. The preheating temperature of H13 steel die was determined to be 250 ~ 300 C after comprehensive consideration, which can not only reduce the temperature difference between die and forging to avoid excessive thermal stress on the die surface, but also effectively reduce the plastic deformation of the die surface.

（2）模具的冷却与润滑  为减轻模具的热负荷，避免模具温度过高，通常在模具工作的间歇对其进行强制性冷却，由此造成模具周期性的激热、激冷作用将会产生热疲劳裂纹。因此，模具使用结束后应缓慢冷却，否则将会出现热应力，从而引起模具的开裂失效。H13钢模具工作时可采用石墨含量为12％的水基石墨进行润滑，降低成形力，保证金属在型腔中正常流动和锻件顺利脱模；此外，石墨润滑剂还具有散热作用，可以降低H13钢模具的工作温度。

(2) In order to reduce the heat load of the mould and avoid the excessive temperature of the mould, the cooling and lubrication of the mould are usually forced to cool the mould intermittently. Thermal fatigue cracks will occur when the mould is periodically heated and cooled. Therefore, the mold should be slowly cooled after use, otherwise there will be thermal stress, resulting in cracking failure of the mold. The water-based graphite with 12% graphite content can be used to lubricate the H13 steel die when it is working, thus reducing the forming force, ensuring the normal flow of metal in the cavity and the smooth demoulding of forgings. In addition, the graphite lubricant has the function of heat dissipation and can reduce the working temperature of the H13 steel die.