工艺参数变化对厚板硼钢热成形性能的影响

Effect of Process Parameter Changes on Hot Forming Performance of Thick Sheet Boron Steel

针对商用车厚板热成形难以淬透的关键问题,研究了热成形工艺参数的变化对6 mm厚板硼钢模压淬火后性能的影响。采用单一变量法,分别研究加热时间、淬火条件对板材压淬后性能的影响。实验结果表明,加热时间影响厚板硼钢奥氏体化比例,随着加热时间的延长,奥氏体化比例逐渐上升,在加热20 min时,厚料硼钢完全奥氏体化;淬火强度影响零件最终性能,单纯依靠模具水道冷却厚板,难以保证淬透性,采用模具水道冷却与模具表面开冷却水孔高压喷淋相结合的复合冷却方式,能够保证厚板硼钢的淬透性。对于6 mm厚的硼钢,采用20 min加热时间和模具水道+高压喷淋复合冷却的方式,厚板中部组织、硬度和力学性能指标满足要求。

Aimed at the key issue of difficulty in quenching during hot forming of thick sheets in commercial vehicles,it was studied that the effect of changes in hot forming process parameters on the properties of 6 mm thick boron steel after die press and quenching.The effects of heating time and quenching conditions on the properties of pressed and quenched sheets were studied respectively through the single variable method.The experimental results showed that the heating time affected the austenitizing ratio of thick boron steel.As the heating time prolonged,the austenitizing ratio gradually increased.After 20 minutes of heating,the thick boron steel sheet was completely austenitized.Quenching strength affected the performance of the final parts,and the relying solely on the mold water channel to cool thick sheets was difficult to ensure hardenability.Using a composite cooling method that combined water channel cooling and high-pressure spraying of cooling water from holes on the mold surface could ensure the hardenability of thick sheet boron steel.For 6 mm thick boron steel,a heating time of 20 minutes,and a combined cooling method of water channel cooling and high-pressure spraying of cooling water were used to meet the requirements for the structure,hardness,and mechanical performance indicators in the middle of the thick sheets.