多元合金铸铁活塞环等温淬火与回火工艺研究

Study on Isothermal Quenching and Tempering Process of Multi-component Alloy Cast Iron Piston Rings

主要研究了多元合金铸铁活塞环等温淬火与回火工艺,分析了不同工艺下多元合金铸铁的显微组织及材料力学性能。结果表明,多元合金铸铁经等温淬火后,基体获得针状下贝氏体;在试验条件下,随着回火温度的升高,多元合金铸铁的硬度先上升后下降,其硬度在570℃回火时最高;在此温度回火过程中,含有Ti、W、Nb等金属元素的碳化物从基体析出,产生了析出强化的效果,使得多元合金铸铁活塞环抗弯强度达到1300 MPa,疲劳寿命得到了提高。

The isothermal quenching and tempering process of multi-component alloy cast iron piston rings was studied.The microstructure and mechanical properties of the multi-component alloy cast iron under different conditions were analyzed.The results show that after the isothermal quenching of the multi-component alloy cast iron, the acicular lower bainite is obtained in matrix; under the experimental conditions, with the increase of tempering temperature, the hardness of the cast iron increases firstly and then decreases, and the hardness of the alloy is the highest when tempering is at 570 ℃; in this temperature tempering process, the carbides containing Ti, W, Nb and other metal elements precipitate from the matrix,resulting in the precipitation strengthening effect, so that the bending strength of the alloy cast iron piston ring reaches 1300 MPa, and the fatigue life is improved.