焊接通用要求
Welding procedure together with the relevant procedure qualification and non-destructive testing procedure shall be provided for pressure vessels.
Heat treatment procedure may be indicated in the welding procedure or submitted as separate documents.
Welding procedure and welder’s qualification shall be according to ASME code.
Welding shall be performed by qualified welders using qualified procedures and test and inspection shall be performed by qualified inspectors using qualified procedures, according to applicable ASME code.
The identification of the welders must be applicable for the following critical piping:
∙HP steam pipe (from(SH) outlet to ST HP stop valve);
∙Low temperature reheat steam pipe (from ST HP exhaust to (RH) inlet);
∙High temperature reheat steam pipe (from (RH) outlet to ST RSV).
The welding material shall be similar to the mother material according to applicable code.
Welding plant and ancillary equipment shall be in accordance with the appropriate parts of BS 638 or equivalent international standard.
The area of the temporary welded attachments shall be examined according to applicable code if the parts will be used as removed.
The material composition to be welded shall be according to applicable material code.
Preheat condition for shop and field welding shall be in accordance with applicable code.
NDT of castings, wrought products and welding shall be carried out in accordance with the applicable material code/standard or British Standard. NDE procedure for the owner’s witness ite ms shall be submitted for approval.
SNT-TC-1A shall be applied for NDE operator/inspector qualification. NDE operator shall be Level I, and inspector shall be Level II.
During the detailed design stage, the boiler manufacturer shall submit for approval the welding procedure specification (WPS) and procedure qualification records (PQR’s) and heat treatment procedure for the critical components which are listed below.（卖方负责自己供货范围内焊缝）
HP steam pipe (from (SH) outlet to ST HP stop valve);
Low temperature reheat steam pipe (from ST HP exhaust to (RH) inlet);
High temperature reheat steam pipe (from (RH) outlet to ST RSV).
Special consideration for field welding of any P-92 materials shall be taken. Field welding of this material shall be limited as much as possible.
Welding field procedures shall be according to ASME Code (without stamp).
焊接材料的选择应根据钢的化学成分、力学性能、使用工况条件和焊接工艺评定的结果选用。
焊接材料（焊丝、焊条、焊剂、钨棒、氩气、氧气和乙炔等）的质量应符合ASME标准。
焊接工程中使用的进口焊接材料应符合设计要求和工艺技术要求。
无焊接工艺评定（PQR）和焊接工艺规程（WPS）不能开始焊接生产，编制《焊接工艺规程》及其它焊接技术和生产用文件。
其它项目的焊接工艺评定可以转移到本项目，工艺评定必须覆盖本项目钢材的所有材质、规格、焊接位置及其它，当设计要求和母材有冲击韧性要求时，工艺评定应做冲击试验。
焊接坡口形式、对接间隙及坡口内、外边缘20mm附近无裂皮、重皮、坡口破损和毛刺等，按照ASME标准要求执行。
焊缝尺寸必须符合设计要求和相应的规范、标准要求。
焊缝表面应成型美观，波纹均匀，焊缝边缘应圆滑过渡到母材，焊缝及焊缝附近的飞溅物必须清理干净，严禁油漆掩盖飞溅及焊渣。
外观检查参照ASME 要求。
焊接接头的热处理按照ASME相关要求执行。
受压件焊接接头无损检验标准按照ASME相关标准执行。
焊接接头的光谱分析按照ASME的规定执行。
焊接接头的硬度检验：可取样的焊接接头采用台式硬度仪，按照ASME规定执行，其余焊接接头采用便携里氏硬度仪，按照ASME的规定执行。
硬度检验在焊后热处理完成后进行。
金相检验按照ASME执行。
焊接设备、热处理设备、无损检测设备、工器具及仪表应定期检查，需要计量的部分应定期校验。
焊接环境、焊接人员资质按照ASME规定执行。