Impact and wear resistant component, and method for producing the same

Abstract

A ripper shank as the impact and wear resistant component is made of a steel of a specific component composition which has a hardness of HRC 53 or more and HRC 57 or less. The steel includes a matrix including a martensite phase and a residual austenite phase, and first nonmetallic particles dispersed in the matrix and including at least one species selected from the group consisting of MnS, TiCN, and NbCN. The steel does not include a M23C6 carbide.

1 . An impact and wear resistant component made of a steel containing not less than 0.41 mass % and not more than 0.44 mass % C, not less than 0.2 mass % and not more than 0.5 mass % Si, not less than 0.2 mass % and not more than 1.5 mass % Mn, not less than 0.0005 mass % and not more than 0.0050 mass % S, not less than 0.6 mass % and not more than 2.0 mass % Ni, not less than 0.7 mass % and not more than 1.5 mass % Cr, not less than 0.1 mass % and not more than 0.6 mass % Mo, not less than 0.02 mass % and not more than 0.03 mass % Nb, not less than 0.01 mass % and not more than 0.04 mass % Ti, not less than 0.0005 mass % and not more than 0.0030 mass % B, and not less than 20 mass ppm and not more than 60 mass ppm N, with the balance consisting of iron and unavoidable impurities, and having a hardness of HRC 53 or more and HRC 57 or less,
 the steel including
 a matrix including a martensite phase and a residual austenite phase, and 
 first nonmetallic particles dispersed in the matrix and including at least one species selected from the group consisting of MnS, TiCN, and NbCN, 
 
 the steel not including a carbide represented as M 23 C 6  (where M represents the metallic elements constituting the steel). 
 
     
     
         2 . The impact and wear resistant component according to  claim 1 , wherein the steel further contains at least one species selected from the group consisting of not less than 0.05 mass % and not more than 0.20 mass % V, not less than 0.01 mass % and not more than 0.15 mass % Zr, and not less than 0.1 mass % and not more than 2.0 mass % Co. 
     
     
         3 . The impact and wear resistant component according to  claim 1 , wherein the matrix has a grain size number of 5 or more and 8 or less. 
     
     
         4 . The impact and wear resistant component according to  claim 1 , wherein the martensite phase constituting the matrix is a low temperature-tempered martensite phase. 
     
     
         5 . A method for producing an impact and wear resistant component, comprising the steps of:
 preparing a steel material made of a steel containing not less than 0.41 mass % and not more than 0.44 mass % C, not less than 0.2 mass % and not more than 0.5 mass % Si, not less than 0.2 mass % and not more than 1.5 mass % Mn, not less than 0.0005 mass % and not more than 0.0050 mass % S, not less than 0.6 mass % and not more than 2.0 mass % Ni, not less than 0.7 mass % and not more than 1.5 mass % Cr, not less than 0.1 mass % and not more than 0.6 mass % Mo, not less than 0.02 mass % and not more than 0.03 mass % Nb, not less than 0.01 mass % and not more than 0.04 mass % Ti, not less than 0.0005 mass % and not more than 0.0030 mass % B, and not less than 20 mass ppm and not more than 60 mass ppm N, with the balance consisting of iron and unavoidable impurities;   hot forging or hot rolling the steel material to obtain a formed body;   performing normalizing treatment on an entirety of the formed body by cooling the formed body from a temperature not lower than 945° C. and not higher than 1000° C. to a temperature not higher than a temperature corresponding to the M s  point of the steel; and   performing quench hardening treatment on the formed body having undergone the normalizing treatment and, thereafter, adjusting a hardness of the formed body to be HRC 53 or more and HRC 57 or less by heating the formed body to a temperature not lower than 150° C. and not higher than 250° C.   
     
     
         6 . The impact and wear resistant component producing method according to  claim 5 , wherein the steel further contains at least one species selected from the group consisting of not less than 0.05 mass % and not more than 0.20 mass % V, not less than 0.01 mass % and not more than 0.15 mass % Zr, and not less than 0.1 mass % and not more than 2.0 mass % Co. 
     
     
         7 . The impact and wear resistant component according to  claim 2 , wherein the matrix has a grain size number of 5 or more and 8 or less. 
     
     
         8 . The impact and wear resistant component according to  claim 2 , wherein the martensite phase constituting the matrix is a low temperature-tempered martensite phase. 
     
     
         9 . The impact and wear resistant component according to  claim 3 , wherein the martensite phase constituting the matrix is a low temperature-tempered martensite phase. 
     
     
         10 . The impact and wear resistant component according to  claim 7 , wherein the martensite phase constituting the matrix is a low temperature-tempered martensite phase.