metal sheath短语¹⁴⁴⁹⁷²⁺² 基本例句 金属外皮 With their tubular structure, metal cored wires carry the welding current through the outside metal sheath to the workpiece instead of through the entire cross section, as solid wires do. 因其筒状结构的特点，金属粉芯焊丝电流传输线路由实心焊丝的贯穿整个界面转变为仅仅沿薄金属外壁传输。 jdweld