Corrosion resistant steel having good cold-workability and machinability

Abstract

Disclosed is a corrosion resistant steel suitable for the material of printer shafts. The steel has good machinability, corrosion resistance sufficient for ordinary indoor use without plating the product surfaces, and improved straightness after wire drawing and cold workability, and further, is less expensive. Alloy composition is, by weight percent, C: 0.005-0.200%, Si: up to 1.0%, Mn: up to 2.0%, P: up to 0.05%, Cu: up to 2.0%, Ni: up to 2.0%, Cr: 2.0-9.0%, one or both of Ti and Zr: [Ti%]+0.52[Zr%]=0.03-1.20%, one or both of S: 0.01-0.50% and Se:0.01-0.40%, N: up to 0.050% and O: up to 0.030%, and the balance of Fe and inevitable impurities, with the conditions of [S%]≧32[C%]/12, and 0<L ≦0.5, wherein L=4[C%]/([Ti%]+0.52[Zr%]). The inclusions therein are, Ti-based, Zr-based, or Ti—Zr-based compound or compounds containing C and one or both of S and Se.

1 . A corrosion resistant steel having good cold workability and machinability; characterized in that the steel consists essentially of the alloy components of, by weight percent, C: 0.005-0.200%, Si: up to 1.0%, Mn: up to 2.0%, P: up to 0.05%, Cu: up to 2.0%, Ni: up to 2.0%, Cr: 2.0-9.0%, one or both of Ti and Zr: [Ti%]+0.52[Zr%]=0.03-1.20%, one or both of S: 0.01-0.50% and Se:0.01-0.40%, N: up to 0.050% and O: up to 0.030%, and the balance of Fe and inevitable impurities, and that the steel contains, as the inclusions therein, Ti-based, Zr-based, or Ti—Zr-based compound or compounds containing C and one or both of S and Se in the conditions of [S%]≧32[C%]/12, and 0<L≦0.5, wherein L=4[C%]/([Ti%]+0.52[Zr%]).  
     
     
         2 . The corrosion resistant steel according to  claim 1 , characterized in that the steel has particularly good cold forgeability with the alloy composition satisfying the condition of 0<H≦0.5, wherein H=1.5([S%]+0.40[Se%])/([Ti%]+0.52[Zr%]).  
     
     
         3 . The corrosion resistant steel according to  claim 1 , characterized in that the steel has particularly good machinability in drilling with the alloy composition satisfying the condition of 0.5<H≦1.2, wherein H=1.5([S%]+0.40[Se%])/([Ti%]+0.52[Zr%]).  
     
     
         4 . The corrosion resistant steel according to one of  claims 1  to  3 , characterized in that the steel further contains, in addition to the above-defined alloy components, by weight percent, one or both of Mo: 0.1-4.0% and W: 0.1-3.0%.  
     
     
         5 . The corrosion resistant steel according to one of  claims 1  to  4 , characterized in that the steel further contains, in addition to the above-defined alloy components, by weight percent, at least one of Pb: 0.01-0.30%, Te: 0.005-0.100% and Bi: 0.01-0.20%.  
     
     
         6 . The corrosion resistant steel according to one of  claims 1  to  5 , characterized in that the steel further contains, in addition to the above-defined alloy components, by weight percent, at least one of Ca, Mg B and REM of 0.005-0.010%.  
     
     
         7 . The corrosion resistant steel according to one of  claims 1  to  6 , characterized in that the steel further contains, in addition to the above-defined alloy components, by weight percent, at least one of Nb, V, Ta and Hf of 0.01-0.50%.  
     
     
         8 . Shafts for printers and electric motors made of the corrosion resistant steel according to one of  claims 1  to  7 .