舰船拉杆用35CrMo钢带状组织消除热处理工艺研究

Study on Heat Treatment Technology of 35CrMo Steel Strip Structure Elimination for Ship Tie Rod

舰船拉杆用35CrMo钢棒料存在带状组织缺陷,导致拉杆加工成形后达不到要求的组织和力学性能指标。对35CrMo钢拉杆进行热处理试验,采用光学显微镜、万能试验机等研究了消除带状组织的扩散退火热处理工艺。结果表明,采用扩散退火控制钢材降温时的冷却速度,能使35CrMo钢冷却时的奥氏体均匀分解,消除因冷速不均所形成的铁素体和珠光体的多层带状缺陷。经热处理后的35CrMo钢,其组织和力学性能达到了设计标准。

Because 35CrMo steel bar material used for ship pull rod has banded structure defects, the microstructure and mechanical properties of the rod can not reach the required index after forming. The heat treatment of 35Cr Mo steel rod was carried out. Diffusion annealing heat treatment process for eliminating banded structure was studied by optical microscope and universal testing machine. The results show that, by using diffusion annealing to control the cooling rate of steel, the austenite of 35CrMo steel can be decomposed evenly, and the multilayer ribbon defects of ferrite and pearlite formed by uneven cooling rate can be eliminated. After heat treatment, the microstructure and mechanical properties of 35CrMo steel reaches the design standard.