manual arc welding

例句：

1. 1. This manual arcwelding machine is very easy tooperate.
   这台手动电弧焊机很容易操作。
2. 2. Manual arc weldingis a common method for joining metal partstogether.
   手工电弧焊是一种常见的金属部件连接方法。
3. 3. The manual arc welding process requires special training and certification.
   手工电弧焊过程需要特殊的培训和认证。