Improving Performance Of Engine Bush By Deep Cryogenic Treatment And Its Mechanism

Cryogenic treatment has wide application prospects not only in the fields of ferrous metal, nonferrous metal and alloy, but also in the fields of non-metal material, such as carbide, plastic material, metasilicate and so on. As a novel technique, cryogenic treatment has been used to improve the mechanical properties of materials and to prolong the life of tools and parts in the fields of machinery, aerospace, etc.In this thesis, the mechanical properties and microstructures of the Al-alloy based Engine Bush (Y-serial and Jingling-serial) and CSP steel (SPCC,SPHC) before and after deep cryogenic treatment are studied.The experimental results show that deep cryogenic treatment can obviously improve the hardness, strength of the bush Al alloys and the steel, which can be attributed to the fine precipitation of second phase particles and the grain preferred orientation. The relative experimental phenomena were explained and the mechanism was explored.The as-treated Al-alloy based engine bush and CSP steel show excellent performance in this thesis.