回火的目的是什么,常用的回火操作有哪几种?
参考答案:
回火的目的:
1.获得工件所需的组织。
2.稳定尺寸。
3.消除淬火内应力。
回火的种类:低温回火;中温回火;高温回火
My parents ()in Hong Kong. They were born there and have never lived anywhere else.
A. live
B. lived
C. were living
D. will live
欲测知休克病人的准确体温最好采用
A.口腔测量B.腋下测量C.直肠测量D.腹股沟测量E.以上均正确