welding on bottom

例句：

1. 1. The engineers used a special type of welding to join the metal plates together.
   工程师们使用一种特殊的焊接技术将金属板连接在一起。
2. 2. The construction workers are required tofollow strict safety guidelines during the welding process.
   建筑工人在焊接过程中需要遵循严格的安全指南。
3. 3. The weldingoperation was completed successfully without any incidents.
   焊接作业顺利完成，没有发生任何事故。