surface of weld overlay and back cladding翻译

surface of weld overlay and back cladding怎么翻译？
weld overlay 与 cladding经常混用，求高手指点具体含义。

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ASME IX里面的话 用词 是这样的：  weld overlay  堆焊。。。在一种材料上面 焊接，可以是耐腐蚀，可以是提高硬度  耐磨等。。
cladding   这是包覆  包覆铝  用的蛮多。。

niat8888，请告知ASME IX具体章节，谢谢！

二楼说的有点问题。。。
在AWS A3.0中，对于overlay和cladding的定义如下
overlaying----- A nonstandard term when used for surfacing
surfacing----- The application by welding, brazing, or thermal spraying of a layer, or layers, of material to a surface to obtain desired properties or dimensions, asopposed to making a joint. See also buildup, buttering, cladding, and hardfacing
也就是说   所谓overlay就是焊接表面（表面堆焊）的比较随意的说法
cladding-----A surfacing variation depositing or applying surfacing material usually to improve corrosion or heat resistance
表面处理/改性叫surfacing  意思就是balabala。。   通常也按功能分成buildup（以尺寸达标为目的），buttering（过渡堆焊），cladding（耐蚀/耐热堆焊）以及hardfacing（耐磨堆焊）
印象当中，ASME I和VIII-1都是根据这个来说明的

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在ASME IX中 用词。。。

overlay: a non‐standard term, used in Section IX, for surfacing.See also hard‐facing and corrosion‐resistant overlay.
overlay就是在ASME IX中就是 堆焊比较随意的说法。

overlay, corrosion‐resistant weld metal: deposition of one or more layers of weld metal to the surface of a base material in an effort to improve the corrosion resistance
properties of the surface. This would be applied at a level above the minimum design thickness as a nonstructural

component of the overall wall thickness. overlay, hard‐facing weld metal: deposition of one or more layers of weld metal to the surface of a material in an effort to improve the wear resistance properties of the surface. This would be applied at a level above the minimum design thickness as a nonstructural component of the overall wall thickness.