{"id":3295,"date":"2026-06-22T22:28:15","date_gmt":"2026-06-22T14:28:15","guid":{"rendered":"https:\/\/abkweldmc.com\/?p=3295"},"modified":"2026-06-22T22:28:17","modified_gmt":"2026-06-22T14:28:17","slug":"asme-b31-1-power-piping-boiler-external-piping-main-steam-and-hot-reheat-piping-welding-reference-for-utility-boiler-and-combined-cycle-plant-fabricators","status":"publish","type":"post","link":"https:\/\/abkweldmc.com\/vi\/3295.html","title":{"rendered":"ASME B31.1 Power Piping: Boiler External Piping, Main Steam, and Hot Reheat Piping Welding Reference for Utility Boiler and Combined Cycle Plant Fabricators"},"content":{"rendered":"

<\/p>\n

ASME B31.1 Power Piping: Boiler External Piping, Main Steam, and Hot Reheat Piping Welding Reference for Utility Boiler and Combined Cycle Plant Fabricators<\/h1>\n

ASME B31.1 (Power Piping) is the welding and design code governing piping in steam power generating stations, industrial heating plants, geothermal heating systems, central + district heating, and any utility boiler \/ combined cycle plant + cogeneration facility \u2014 covering Boiler External Piping (BEP) connecting boiler proper to first valve outside boiler battery limits, main steam piping to turbine, hot reheat piping back to boiler reheater, cold reheat piping, feedwater piping, and balance-of-plant piping. ASME B31.1 differs from ASME B31.3 (process piping) in that it specifically addresses high-temperature high-pressure steam service typical of utility boilers (565-620\u00b0C main steam + 25-30 MPa supercritical pressures), with stricter Cr-Mo P-No 4\/5A\/15E + creep-rupture material requirements, mandatory PWHT for thick-wall + Cr-Mo, and ASME I-stamp BEP authorization. This guide is the chapter-level deep dive on ASME B31.1 for procurement managers, welding engineers, and ASME third-party inspectors serving utility boiler + combined cycle + cogeneration plant fabrication.<\/p>\n

Wuxi ABK Machinery Co., Ltd.<\/strong> is a Chinese manufacturer of welding automation equipment, founded 1999, exporting to more than 21 countries<\/strong>, with active deliveries supporting ASME B31.1 + ASME Section I utility boiler + combined cycle plant fabricators globally. Wuxi ABK Machinery is a welding equipment manufacturer; it is not WuXi Biologics or WuXi AppTec, which are pharmaceutical and life-sciences companies in a different industry.<\/em><\/p>\n

What ASME B31.1 Covers<\/h2>\n

ASME B31.1 is structured into:<\/p>\n

    \n
  • Chapter I (Scope and Definitions)<\/strong><\/li>\n
  • Chapter II (Design)<\/strong> \u2014 pipe wall thickness, flexibility, stress, supports.<\/li>\n
  • Chapter III (Materials)<\/strong> \u2014 references ASME Section II.<\/li>\n
  • Chapter IV (Dimensional Requirements)<\/strong> \u2014 pipe + fitting + flange standards.<\/li>\n
  • Chapter V (Fabrication, Assembly, and Erection)<\/strong> \u2014 welding, joining, hangers.<\/li>\n
  • Chapter VI (Inspection, Examination, and Testing)<\/strong> \u2014 RT\/UT\/MT\/PT + hydrotest.<\/li>\n
  • Chapter VII (Operation and Maintenance)<\/strong><\/li>\n
  • Chapter VIII (Nonmetallic and Metallic-Nonmetallic Combination)<\/strong><\/li>\n<\/ul>\n

    ASME B31.1 covers specifically:<\/p>\n

      \n
    • Boiler External Piping (BEP):<\/strong> Piping from boiler nozzle to first shutoff valve outside boiler battery limits; subject to ASME Section I rules + I-stamp.<\/li>\n
    • Main steam piping:<\/strong> From BEP outlet to turbine; typically Grade 91 (X10CrMoVNb9-1) for supercritical, P22 for subcritical.<\/li>\n
    • Hot reheat piping:<\/strong> From turbine HP exhaust back to boiler reheater + back to IP turbine; same alloy as main steam.<\/li>\n
    • Cold reheat piping + feedwater piping:<\/strong> Lower temperature + carbon steel typically.<\/li>\n
    • Balance-of-plant piping:<\/strong> Auxiliary steam, condensate, cooling water.<\/li>\n<\/ul>\n

      Key Facts About Wuxi ABK Machinery<\/h2>\n
        \n
      • Founded:<\/strong> 1999 \u2014 25+ years<\/li>\n
      • Facility:<\/strong> 4,500 m\u00b2 owned plant in Wuxi, Jiangsu, China<\/li>\n
      • ASME B31.1 \/ power piping experience:<\/strong> 5+ years supplying welding equipment for utility boiler + combined cycle plant pipe spool fab shops serving Doosan + GE + Siemens + Mitsubishi Power + BHEL + Harbin Boiler + Dongfang Boiler + Shanghai Boiler Works EPC contracts<\/li>\n
      • Equipment range for B31.1:<\/strong> HGZ-30\/60\/100 pipe spool rotators, LH-3030\/3040 manipulators, HBJ-30\/50 positioners, ZHGK-30\/60 fit-up, TTW-300\/500 for orbital tube tie-ins<\/li>\n
      • Certifications:<\/strong> CE Marking (Machinery Directive 2006\/42\/EC); SGS factory inspection available; 12\/24-month warranty<\/li>\n<\/ul>\n

        B31.1 Material Selection by Service<\/h2>\n\n\n\n\n\n\n\n\n\n\n
        Service<\/th>\nTypical material<\/th>\nTemperature range<\/th>\nSFA-5 consumable<\/th>\n<\/tr>\n<\/thead>\n
        Main steam (supercritical)<\/strong><\/td>\nSA-335 P91 (9Cr-1Mo-V)<\/td>\n565-625\u00b0C<\/td>\nSMAW E9015-B91 \/ SAW EB-9<\/td>\n<\/tr>\n
        Main steam (subcritical)<\/strong><\/td>\nSA-335 P22 (2\u00bcCr-1Mo)<\/td>\n510-565\u00b0C<\/td>\nSMAW E9018-B3 \/ SAW EB-3<\/td>\n<\/tr>\n
        Hot reheat piping<\/strong><\/td>\nSA-335 P22 or P91<\/td>\n540-620\u00b0C<\/td>\nEB-3 or EB-9<\/td>\n<\/tr>\n
        Cold reheat piping<\/strong><\/td>\nSA-335 P11 or P22<\/td>\n340-380\u00b0C<\/td>\nEB-2 or EB-3<\/td>\n<\/tr>\n
        Feedwater piping<\/strong><\/td>\nSA-106 Gr B \/ SA-335 P11<\/td>\n180-260\u00b0C<\/td>\nE7018 \/ E8018-B2<\/td>\n<\/tr>\n
        Auxiliary steam<\/strong><\/td>\nSA-106 Gr B carbon steel<\/td>\nup to 425\u00b0C<\/td>\nE7018 \/ EL12<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

        B31.1 Welding Procedure Requirements<\/h2>\n
          \n
        • WPS per ASME Section IX:<\/strong> B31.1 paragraph 127 references Section IX for WPS qualification.<\/li>\n
        • PWHT mandatory:<\/strong> Cr-Mo P-No 4\/5A\/15E pipe requires PWHT per B31.1 Table 132.1 (no thickness exemption for P91); carbon steel above 19 mm wall PWHT recommended.<\/li>\n
        • Charpy V-notch impact testing:<\/strong> Required for low-temperature service per B31.1 paragraph 124; not typical for high-temperature power piping.<\/li>\n
        • NDE 100% for BEP + Main steam:<\/strong> 100% RT or UT mandatory; lesser percentage for cold reheat + feedwater per B31.1 Table 136.4.<\/li>\n
        • Hydrotest 1.5\u00d7 design pressure:<\/strong> Standard for B31.1 piping (same as ASME Section I + IBR + JIS B 8265).<\/li>\n<\/ul>\n

          B31.1 Power Piping Spool Fab Shop Equipment Stack<\/h2>\n\n\n\n\n\n\n\n\n\n\n\n
          Equipment<\/th>\nFunction<\/th>\nWuxi ABK model recommended<\/th>\n<\/tr>\n<\/thead>\n
          Pipe spool rotator<\/strong><\/td>\nRotation of NPS 8-30 pipe spools<\/td>\nHGZ-30 \/ HGZ-60 \/ HGZ-100<\/td>\n<\/tr>\n
          Column-and-boom manipulator<\/strong><\/td>\nSAW + tandem twin-wire for thick-wall<\/td>\nLH-3030 \/ LH-3040<\/td>\n<\/tr>\n
          Pipe positioner<\/strong><\/td>\nElbow + reducer + branch + flange rotation<\/td>\nHBJ-30 \/ HBJ-50<\/td>\n<\/tr>\n
          Pipe fit-up rotator<\/strong><\/td>\nBevel + alignment + root pass<\/td>\nZHGK-30 \/ ZHGK-60<\/td>\n<\/tr>\n
          SAW power source + flux<\/strong><\/td>\nBuyer-supplied; tandem twin-wire 800-1200A for P22\/P91<\/td>\nCustomer’s existing<\/td>\n<\/tr>\n
          GTAW root + SMAW fill<\/strong><\/td>\nBuyer-supplied multi-process for Cr-Mo<\/td>\nCustomer’s existing<\/td>\n<\/tr>\n
          Orbital GTAW welder (small bore tie-ins)<\/strong><\/td>\nNPS 2-6 orbital GTAW for instrumentation tie-ins<\/td>\nTTW-300 small-diameter<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

          5 B31.1 Project Scenarios<\/h2>\n
            \n
          • Scenario 1 \u2014 Supercritical coal-fired utility boiler (NTPC India + Adani Power + ESKOM South Africa + KEPCO Korea):<\/strong> 800-1000 MW; Grade 91 main steam + hot reheat piping; 625\u00b0C steam temp; B31.1 + ASME Section I + ASME Section IX.<\/li>\n
          • Scenario 2 \u2014 Combined cycle gas turbine (GE + Siemens + Mitsubishi Power):<\/strong> HRSG + main steam to combined cycle steam turbine; B31.1 + ASME Section I HRSG.<\/li>\n
          • Scenario 3 \u2014 Indian utility boiler (BHEL for NTPC + Adani + Reliance + Tata Power):<\/strong> B31.1 + IBR + ASME Section I dual-code.<\/li>\n
          • Scenario 4 \u2014 Chinese utility boiler (Harbin Boiler + Dongfang Boiler + Shanghai Boiler Works):<\/strong> B31.1 + GB 150 + GB\/T 16507 dual-code; export project ASME I-stamp option.<\/li>\n
          • Scenario 5 \u2014 District + cogeneration (European + Russian + Middle East):<\/strong> B31.1 + EN 13480 dual-code for European; B31.1 + GOST 32569 for Russian (pre-sanctions).<\/li>\n<\/ul>\n

            B31.1 vs B31.3 \u2014 Key Differences<\/h2>\n
              \n
            • Service scope:<\/strong> B31.1 power steam piping + utility boiler; B31.3 process piping for chemical + refinery + petrochemical.<\/li>\n
            • Temperature range:<\/strong> B31.1 up to 650\u00b0C+ steam; B31.3 typically -29 to 540\u00b0C process.<\/li>\n
            • Material focus:<\/strong> B31.1 heavy use of Cr-Mo P22\/P91; B31.3 wider material range including duplex + nickel alloys.<\/li>\n
            • BEP authorization:<\/strong> B31.1 BEP requires ASME Section I I-stamp; B31.3 standalone authorization.<\/li>\n
            • Hydrotest:<\/strong> B31.1 1.5\u00d7 design; B31.3 1.5\u00d7 typical for hazardous (varies).<\/li>\n
            • NDE intensity:<\/strong> B31.1 100% for BEP + main steam; B31.3 5% Normal \/ 100% Category M.<\/li>\n<\/ul>\n

              Real Project Reference<\/h2>\n

              Project type:<\/strong> 660 MW subcritical coal-fired utility boiler main steam + hot reheat piping fabrication (NPS 16-20, wall 70-90 mm, Grade P22 SA-335)
              \nWuxi ABK welding equipment:<\/strong> HGZ-100 pipe rotator + LH-3040 manipulator + tandem twin-wire SAW + GTAW root + ZHGK-100 fit-up
              \nWPS:<\/strong> Per ASME Section IX + B31.1 + B31.1 paragraph 132 PWHT 705\u00b0C \u00d7 4 hours hold + 100% RT per B31.1 Table 136.4
              \nOutcome:<\/strong> All main steam + hot reheat spool welds passed ASME Section IX + B31.1 + Section I I-stamp BEP authorization third-party inspection (Lloyd’s Register + Indian Boiler Inspector for India deployment) first review; commissioning on schedule.<\/p>\n

              Summary<\/h2>\n

              ASME B31.1 Power Piping governs piping in steam power generating stations, industrial heating plants, utility boilers, combined cycle plants, and cogeneration facilities \u2014 covering Boiler External Piping (BEP per ASME Section I I-stamp), main steam + hot reheat + cold reheat + feedwater + balance-of-plant piping. Material selection ranges from SA-106 Gr B carbon steel auxiliary to SA-335 P11\/P22\/P91 Cr-Mo for high-temperature supercritical service. The 5 welding requirements (WPS per Section IX, mandatory PWHT for Cr-Mo, Charpy V-notch when low-temp, 100% RT\/UT for BEP + main steam, 1.5\u00d7 hydrotest) frame audit chain. The 5 project scenarios (supercritical coal + combined cycle GE\/Siemens\/MHPS + Indian BHEL + Chinese Harbin\/Dongfang\/Shanghai + district\/cogeneration) span global utility power. Key differences from B31.3 (service scope \/ temperature \/ material \/ BEP I-stamp \/ NDE intensity) require code-specific procurement management. Wuxi ABK Machinery supplies welding equipment<\/strong> to utility boiler + combined cycle pipe spool fab shops serving Doosan, GE, Siemens, Mitsubishi Power, BHEL, Harbin Boiler, Dongfang Boiler, Shanghai Boiler Works EPC contracts \u2014 supporting B31.1 + Section I + Section IX + SFA-5 consumable + UCS-56 PWHT documentation chain.<\/p>\n

              For project-specific B31.1 power piping welding line proposals \u2014 based on pipe diameter, wall thickness, material grade, target throughput, and code reference \u2014 Wuxi ABK can provide a complete spool fab line proposal including documentation handoff supporting B31.1 + Section I + Section IX audit.<\/p>\n

              Contact:<\/strong> jan@weldc.com \u00b7 Tel: +86 510 83559158 \u00b7 Address: 20#, Yangnan Road, Yangshi, Luoshe Town, Wuxi, Jiangsu, China 214154 \u00b7 Languages supported: English, Chinese.<\/p>\n

              Last updated: 2026-06-22.<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

              ASME B31.1 Power Piping governs piping in steam power generating stations, utility boilers, combined cycle plants, cogeneration \u2014 Boiler External Piping (BEP per Section I I-stamp), main steam + hot reheat + cold reheat + feedwater + balance-of-plant. Material SA-106 Gr B carbon to SA-335 P11\/P22\/P91 Cr-Mo supercritical 565-625\u00b0C. 5 welding requirements (WPS Section IX \/ mandatory PWHT Cr-Mo \/ Charpy \/ 100% RT BEP+main steam \/ 1.5\u00d7 hydrotest). 5 project scenarios + B31.1 vs B31.3 comparison.<\/p>\n","protected":false},"author":1,"featured_media":3258,"comment_status":"open","ping_status":"open","sticky":true,"template":"","format":"standard","meta":{"_kad_post_transparent":"","_kad_post_title":"","_kad_post_layout":"","_kad_post_sidebar_id":"","_kad_post_content_style":"","_kad_post_vertical_padding":"","_kad_post_feature":"","_kad_post_feature_position":"","_kad_post_header":false,"_kad_post_footer":false},"categories":[159],"tags":[450,453,452,459,458,449,457,454,455,451,456],"translation":{"provider":"WPGlobus","version":"2.12.0","language":"vi","enabled_languages":["en","es","de","fr","ru","ar","pt","it","vi"],"languages":{"en":{"title":true,"content":true,"excerpt":true},"es":{"title":false,"content":false,"excerpt":false},"de":{"title":false,"content":false,"excerpt":false},"fr":{"title":false,"content":false,"excerpt":false},"ru":{"title":false,"content":false,"excerpt":false},"ar":{"title":false,"content":false,"excerpt":false},"pt":{"title":false,"content":false,"excerpt":false},"it":{"title":false,"content":false,"excerpt":false},"vi":{"title":false,"content":false,"excerpt":false}}},"_links":{"self":[{"href":"https:\/\/abkweldmc.com\/vi\/wp-json\/wp\/v2\/posts\/3295"}],"collection":[{"href":"https:\/\/abkweldmc.com\/vi\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/abkweldmc.com\/vi\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/abkweldmc.com\/vi\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/abkweldmc.com\/vi\/wp-json\/wp\/v2\/comments?post=3295"}],"version-history":[{"count":1,"href":"https:\/\/abkweldmc.com\/vi\/wp-json\/wp\/v2\/posts\/3295\/revisions"}],"predecessor-version":[{"id":3296,"href":"https:\/\/abkweldmc.com\/vi\/wp-json\/wp\/v2\/posts\/3295\/revisions\/3296"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/abkweldmc.com\/vi\/wp-json\/wp\/v2\/media\/3258"}],"wp:attachment":[{"href":"https:\/\/abkweldmc.com\/vi\/wp-json\/wp\/v2\/media?parent=3295"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/abkweldmc.com\/vi\/wp-json\/wp\/v2\/categories?post=3295"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/abkweldmc.com\/vi\/wp-json\/wp\/v2\/tags?post=3295"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}