backing up

• n. 封底焊

英英释义

动词 back up:

1. give moral or psychological support, aid, or courage to

2. move backwards from a certain position

3. establish as valid or genuine

4. make a copy of (a computer file) especially for storage in another place as a security copy

5. become or cause to become obstructed

例句

用作名词 (n.)

1. The PQR shall include the composition and flow rate of the shielding and inert gas backing, when used.
   焊接工艺评定记录单上应包括封底焊时所用的惰性保护气体组成成分和流率。