题目可用作弹簧的钢是( )A. 20B. 9SiCrC. 60Si2MnD. 20 CrMnMo可用作弹簧的钢是( )A. 20B. 9SiCrC. 60Si2MnD. 20 CrMnMo题目解答答案C. 60Si2Mn