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Microsoft Word S0205 01 B DESCRIPTION OF INSTALLATION AND LAID DOWN FOR WELDED PIPE doc THANG LONG 2x300MW THERMAL POWER PLANT PROJECT Owner THANG LONG POWER PLANT JOINT STOCK COMPANY Owner Consultant FICHTNER GmbH ＆ Co KG EPC Contractor WUHAN KAIDI ELECTRIC POWER ENGINEERING CO , LTD EPC Engineering Designer SOUTHWEST ELECTRIC POWER DESIGN INSTITUTE CO , LTD Document Title DESCRIPTION OF INSTALLATION AND LAID DOWN FOR WELDED PIPE EPC Contract No 291210EPCTLP KD Design Stage DESIGN Document N.
THANG LONG 2x300MW THERMAL POWER PLANT PROJECT Owner THANG LONG POWER PLANT JOINT STOCK COMPANY Owner Consultant FICHTNER GmbH ＆ Co KG EPC Contractor WUHAN KAIDI ELECTRIC POWER ENGINEERING CO., LTD EPC Engineering Designer SOUTHWEST ELECTRIC POWER DESIGN INSTITUTE CO., LTD Document Title: DESCRIPTION OF INSTALLATION AND LAID DOWN FOR WELDED PIPE EPC Contract No : 291210/EPC/TLP-KD Design Stage: DESIGN Document No : Rev No : B 50-F416S- S0205-01 Modified according to Owner’s comments 10.Jan.2016 25 SEP 2015 First issue 张雄 李贵雷 李贵雷 徐明 Rev Date Description Prepared Checked Reviewed Approved CONTENTS 1.Forward 2.Material of welded steel pipe 3.Steel Pipe Welding and Installation Hydrostatic Test Pipe Laid Down Radiographic examination and supersonic examination 7 Construction Acceptance Forward This description declares the basic requirements and matters needed attention for welded steel pipes（including galvanized steel pipe） for which the design pressure is less than 1.6MPa during installation, laid down and construction period It consists of basic construction requirements for circulating pipes about welding, installation and water pressure test The detail construction procedure and ITP document can be referred to the rated document which is prepared by the construction department Material of welded steel pipe 2.1 Mechanical performance of steel products The mechanical performance and chemical component of welded steel pipe shall meet the requirement as follows Table 2-1 Tension limit of Mechanical performance（20℃） Min yield point Min relative extension Min impact strength fy percentage not less than (%) toughness N/mm2 N/mm2 % J Q235B 375~500 225 25 27 Q235A 370~460 205~235 25 ultimate strength fu Steel grade Steel products delivered to site shall be with factory verify conformity certificate In the event of uncertain mechanical performance, sample test shall be done 2.2 Steel pipe wall thickness Steel pipe wall thickness shall meet the requirement of design document (drawings for water supply and fire fighting department in which steel pipe is applied For example, fire water pipe, service water pipe, etc) The defect of steel plate shall not exceed the following limitation： Table 2-3 Acceptable defect limitation Thickness of steel plate（mm） < or = 10 > 10 Scratch marks depth Not more than 20% of plate Not more than 2mm thickness Crack Unallowable Unallowable Steel Pipe Welding and Installation 3.1 Electrode 3.1.1 E4301, E4303 type electrode will be adopted for manual welding，or H08A, H08MnA type electrode will be adopted for automatic welding 3.1.2 The electrode coating shall be oven, strong, and never been dampness damaged 3.1.3 The electrode shall melt evenly without splash during welding 3.1.4 The electrode without factory certificate qualification can not be used 3.2 Welding Technical Requirement 3.2.1 Impurities in the range of 100mm such as paint, rust, greasy dirt, mud, etc around the crater area shall be cleaned before welding 3.2.2 The pipe butted end shall be air cut to V-type groove according to design requirement Metal burr, residual, flash spot, melting wart, etc shall be cleaned completely in groove area before welding 3.2.3 Butt-welded without backing ring shall be adopted for all pipes 3.2.4 Longitudinal welded seam of butted pipe section shall be stagger arrangement The mutual stagger distance shall not be less than 100mm, and the longitudinal welded seam shall not be put at terminal point of pipe horizontal and vertical diameter, the longitudinal welded seam shall be put at point of 45°from vertical central line of the upper half circle in the pipe cross section, the space between two longitudinal welded seams shall not be less than 300mm 3.2.5 Welded seam shall be without sand hole, cavity, air hole or welding slag The outside surface of welded seam shall be regular squama scale 3.2.6 Welding slag, floating leather and scrap shall be cleaned by steel wire brush after welding work 3.3 Installation Technical Requirement 3.3.1 Coordinate, elevation and slope of pipes shall meet the design requirement 3.3.2 Installation error of pipe shall not exceed the following data 3.3.2.1 The allowable error of steel pipe diameter after processing will be ±0.001DN （nominal diameter, same as follows）.The diameter difference of the two adjacent pipe mouths shall not be more than 4mm 3.3.2.2 The ellipticity of pipe shall not be more than 9mm for DN2800 CW pipe, and not more than 6mm for DN1400CW pipe 3.3.2.3 When adjacent pipe section mouths are misfit mutually, the difference shall not exceed 1/4 of pipe wall thickness and not exceed 3mm If difference exceeds the allowable value, short pipe shall be added for connection, method of using strong external force or heating extension around pipe outside surface to reduce clearance is forbidden The length of short pipe will be more than or equal to 300mm when nominal diameter is more than or equal to 1000mm, and will be 200 to 300mm when nominal diameter is less than or equal to 1000mm 3.3.2.4 The deviant between central lines of pipe butted end shall not exceed regulation value as follows Table 3-1 Deviation Limitation Pipe diameter （mm） 10 Scratch marks depth Not more than 20% of plate Not more than 2mm thickness Crack Unallowable Unallowable Steel... adopted for all pipes 3.2.4 Longitudinal welded seam of butted pipe section shall be stagger arrangement The mutual stagger distance shall not be less than 100mm, and the longitudinal welded seam