| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing steel for a high-strength hollow spring having excellent resistance to hydrogen embrittlement.SOLUTION: This invention relates to a method for producing steel for a hollow spring, in which a seamless pipe containing prescribed components is subjected to heat treatment so as to satisfy the followings: quenching conditions (1) that express the equation (1) of 26,000≤(T1+273)×(log(t1)+20)≤29,000, in which 900°C≤T1≤1,050°C, 10 sec≤t1≤1,800 sec, T1 denotes the quenching temperature (°C), and t1 denotes the residence time (sec) in a temperature zone of 900°C and above; and tempering conditions (2) that express the equation (2) of 13,000≤(T2+273)×(log(t2)+20)≤15,500, in which T2≤550°C, t2≤3,600 sec, T2 denotes the tempering temperature (°C), and t2 denotes total time (sec) from initiation of heating to completion of cooling.SELECTED DRAWING: Figure 1 |
