An Investigation On Structure And Properties Of Cr-Ni-Mn-Mo Low Carbon High Alloy Steel

Microstructure, mechanical property, uniform corrosion resistance, and property of corrosive impact abrasion of CrNiMnMo liner steel with modification of nickel content and molybdenum content are studied by this paper. The choice of sample content hold the line with other alloys , add in 1.5 (wt) percent manganese and change the nickel content with 0.3(wt) percent and 0.5(wt) percent and modify the molybdenum with l.O(wt) percent and 0.8(wt) percent. CrNiMnMo liner steel of three variations of composition are melted, annealed, then quenched and tempered. Microstructure are analyzed by optical microscope, and hardness are tested by Rockwell hard tester and toughness were tested by impact-toughness tester at different heat treatment. The result indicates that microstructure of three LCHA would change at annealed state, but microstructure would maintain mainly as lath martensite at quenched—tempered state with the modification of nickel content and molybdenum content. The hardness of three liner steels keep above 48HRC, and the toughness keep above 50 J·cm^-2.Uniform corrosion resistance of three LCHA by the method of hanging thread. The result indicates that corrosion resistance of three liner steels are the level of even corrosion resistance.The impact corrosion and abrasion behavior of CrNiMnMo liner steel with different nickel and molybdenum content were tested by modified MLD-10 tester. Through the SEM observation of the worn surface, the subsurface optical metallographic analysis of the sample, and the SEM analysis of chemic component of worn surface, it is found that the impact corrosion and abrasion mechanism of CrNiMnMo liner steel with hardness above 48HRC and toughness above 48HRC is mainly micro-cutting, spalling of extruded harden edge, corrosion wear by the interactive work of corrosion and abrasion and fatigue spalling with superficial layer. Deforming layer of CrNiMnMo liner steel would form with shorter time and wear heavily as impact power increasing. Chemical component of worn surface is mainlyferrous oxide and chromium oxide.