Spring steel, spring, and manufacturing method of spring

Abstract

A spring steel contains, in terms of mass %, C: 0.35% or more and 0.55% or less, Si: 1.60% or more and 3.00% or less, Mn: 0.20% or more and 1.00% or less, Cr: 0.10% or more and 1.50% or less, Ni: 0.05% or more and 0.30% or less, and Cu: 0.05% or more and 1.00% or less, and substantially does not contain V, the remainder being Fe and unavoidable impurities.

1 . A spring steel containing, in terms of mass %, C: 0.35% or more and 0.55% or less, Si: 1.60% or more and 3.00% or less, Mn: 0.20% or more and 1.00% or less, Cr: 0.10% or more and 1.50% or less, Ni: 0.05% or more and 0.30% or less, and Cu: 0.05% or more and 1.00% or less, and substantially does not contain V,
 the remainder being Fe and unavoidable impurities.   
     
     
         2 . The spring steel according to  claim 1 , wherein Ni is 0.18% or more in terms of mass %. 
     
     
         3 . The spring steel according to  claim 1 , wherein Ni is 0.18% or more and 0.25% or less in terms of mass %. 
     
     
         4 . The spring steel according to  claim 1 , wherein Mn is 0.45% or more and 0.65% or less in terms of mass %. 
     
     
         5 . The spring steel according to  claim 1 , wherein Cu is 0.20% or more and 0.30% or less in terms of mass %. 
     
     
         6 . The spring steel according to  claim 1 , wherein Ti is 0.030% or more and 0.100% or less in terms of mass %. 
     
     
         7 . The spring steel according to  claim 1 , wherein B is 0.0010% or more and 0.0050% or less in terms of mass %. 
     
     
         8 . The spring steel according to  claim 1 , wherein Cu is 0.10% or more and 0.50% or less and Ni is 0.18% or more and less than 0.30% in terms of mass %. 
     
     
         9 . The spring steel according to  claim 1 , wherein Cu is 0.20% or more and 0.30% or less and Ni is 0.18% or more and 0.25% or less in terms of mass %. 
     
     
         10 . A spring manufactured using the spring steel according to  claim 1 . 
     
     
         11 . A method for manufacturing a spring, comprising:
 forming a spring steel into a shape of a spring, wherein   the spring steel comprises, in terms of mass %, C: 0.35% or more and 0.55% or less, Si: 1.60% or more and 3.00% or less, Mn: 0.20% or more and 1.00% or less, Cr: 0.10% or more and 1.50% or less, Ni: 0.05% or more and 0.30% or less, and Cu: 0.05% or more and 1.00% or less, and substantially does not contain V, and   the remainder of the spring steel being Fe and unavoidable impurities.   
     
     
         12 . The method according to  claim 11 , further comprising:
 performing hot setting on the spring steel, which has been formed into a coil shape and subjected to heat treatment; and   performing warm shot peening on the spring steel after the hot setting.   
     
     
         13 . The method according to  claim 11 , further comprising:
 performing warm shot peening on the spring steel, which has been formed into a coil shape and subjected to heat treatment; and   performing hot setting on the spring steel after the warm shot peening.   
     
     
         14 . The method according to  claim 11 , further comprising:
 performing low-temperature annealing at 430° C. for 20 minutes;   performing hot setting on the spring steel, which has been formed in a coil shape and subjected to heat treatment; and   performing warm shot peening on the spring steel after the hot setting.   
     
     
         15 . The method according to  claim 11 , further comprising:
 performing low-temperature annealing at 400° C. for 20 minutes;   performing hot setting on the spring steel, which has been formed in a coil shape and subjected to heat treatment; and   performing warm shot peening on the spring steel after the hot setting.   
     
     
         16 . The method according to  claim 11 , further comprising:
 performing hot setting on the spring steel, which has been formed in a coil shape and subjected to heat treatment at 150° C. or higher and 400° C. or lower; and   performing warm shot peening on the spring steel after the hot setting.   
     
     
         17 . The method according to  claim 11 , further comprising:
 performing hot setting on the spring steel, which has been formed in a coil shape and subjected to heat treatment; and   after the hot setting, performing warm shot peening on the spring steel at 150° C. or higher and 400° C. or lower.   
     
     
         18 . The spring steel according to  claim 1 , wherein Ni is 0.18% or more and Cu is 0.20% or more and 0.30% or less in terms of mass %. 
     
     
         19 . The spring steel according to  claim 1 , wherein Cu is 0.20% or more and 0.30% or less, Ti is 0.030% or more and 0.100% or less and B is 0.0010% or more and 0.0050% or less in terms of mass %. 
     
     
         20 . The spring steel according to  claim 19 , wherein in terms of mass %:
 C is 0.45% or more and 0.53% or less,   Si is 1.90% or more and 2.05% or less,   Mn is 0.45% or more and 0.65% or less,   Cr is 0.25% or more and 0.40% or less,   Ni is 0.18% or more and 0.25% or less,   Ti is 0.050% or more and 0.095% or less,   B is 0.0013% or more and 0.0035% or less,   P is 0.010% or less,   S is 0.010% or less and   V is 0.03% or less.