单项选择题
A.铬B.锰C.矾D.钛
A.0.85%~0.95% B.0.95%~1.05% C.1.05%~1.15% D.1.15%~1.25%
A.0.45% B.0.55% C.0.60% D.0.70%
A.进行热处理B.不进行热处理C.退火D.正火
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