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这是一种复合的化学热处理工艺,可用来提高马氏体时效钢制造的各种航空和火箭零件及压力铸造用压模部件的强度性能。过去报道的钢件渗铬的渗剂成份含铬粉为25~75%,含Al_2O_3为70~20%,含NH_4Cl为5%。这种渗剂成份从保证耐热性和耐磨性的观点看是有前途的。但是,马氏体时效钢用这种渗剂在1050~1100℃渗铬时,由于沿奥氏体晶粒边界形成网状碳化物,且晶粒尺寸增大,会使心部性能明显变脆,因而使马氏体时效钢的使用性能大大降低。
This is a composite chemical heat treatment process that can be used to improve the strength properties of various aerospace and rocket components manufactured by martensitic aged steel and die-cast components for pressure casting. It is reported in the past that the penetrating agent for chromizing steel contains 25-75% of chromium powder, 70-20% of Al 2 O 3 and 5% of NH 4 Cl. This penetration agent composition is promising from the standpoint of ensuring heat resistance and abrasion resistance. However, when maraging steel is infiltrated with chromium at 1050-1100 ° C by this infiltrating agent, reticular carbides are formed along the grain boundaries of austenite and the grain size is increased, so that the core performance becomes markedly brittle , Thus greatly reducing the serviceability of martensitic aging steel.