back weld

例句：

1. 1. The engineer was able to perform a back weld on the damaged part of the pipe.
   这位工程师能够对管道受损的部分进行反向焊接。
2. 2. Back welding is often used in the repair of metal structures.
   反向焊接通常用于金属结构的修复。
3. 3. The process of back welding requires special tools and techniques.
   反向焊接的过程需要特殊的工具和技术。