铍青铜可采用()强化。
参考答案:固溶时效
Do you know what ___ while you were away from home?
A.had happened
B.was happened
C.has happened
D.happened
GB151规定符合附录C的奥氏体不锈钢焊接钢管不得用于介质毒性程度为高度危害的换热器。