manual metal-arc welding

例句：

1. 1. This manual metal-arc welding machine is very efficient in cutting steel plates.
   这台手工金属弧焊机在切割钢板时非常高效。
2. 2. The construction workers used a manual metal-arc welding torch to repair the damaged roof.
   建筑工人使用手动金属弧焊枪来修复损坏的屋顶。
3. 3. Manual metal-arc welding is often used for joining heavy-duty materials, such as steelbeams and pipes.
   手动金属弧焊通常用于连接重型材料，如钢梁和管道。