welding repair procedure piping

Always mark root pass for DP (Die Penetrate) test in the case of critical welds (If time allows). (Ref : API582 Edi 2016 Para 9.8). In-service welding is a common industry practice in both the transmission and refining industry with the vast majority of these welds being deposited onto carbon steel […] Porosity 5. For stainless steel spool fabrication the floor will be covered with wooden planks or rubber. Lack of fusion 2. The ultrasonic examination area shall include the volume of the weld, plus 50 mm (2 in.) Our weld quality is tested on a per job basis by local inspection companies to ensure we meet the standards set out by our CWB Certified Div. Austenitic material including pipelines having austenitic weld overlay can be waived from hydrogen bake out. Two welding processes were selected for the investigation of weld repair procedures without PWHT: shielded metal arc welding (SMAW) and mechanised (machine) gas tungsten arc welding (GTAW). Back-welding may be used to repair minor leaks in solvent cemented or threaded joints. GTAW are particularly well suited to control dilution and do not typically introduce hydrogen into the weld deposit. For details, see Design Registration. Pipe Welding Procedures. Apply the entire roll over the pipe surface with at least 50% overlap for the entire pipe repair sectionin accordance to Engineering Calculation Report. We provide third party Inspection services to industry professionals across Canada. Cleaning.The immediate work area must be clean from all contaminants and this include… Lack of documentation which may lead to difficult in identifying metallurgy and welding requirements. Preheat applied was 150 degree Celsius as per WPS and temperature was monitored with the help of thermocouples. Following points should be considered while determining the extent of replacement. ≥1 ppmw total sulfide content and ≥20 ppmw free cyanide in the aqueous phase, and pH > 7,6; iv. 53 Ubi Avenue 1, #05-25 Paya Ubi Industrial Park, Singapore 408934, Crack (due to heat stress, solidification, hydrogen-induced). Accessibility issues/ Temperature of surroundings which makes the welding difficult. Welding of Large Diameter Pipelines: Design, Processes, Procedures Specifications for Welding Steel Water Pipe. How to qualify a WPS (Welding Procedure Specification) Welding Joint Efficiency; Magnetic particle examination (MT) What is the Welding Procedure Qualification Record (PQR)? This can typically be done using the original WPS. The procedures described are intended to be used only by qualified welders having adequate skill and experience in the practice of the appropriate welding and cutting methods for cast ferrous materials. MT (Magnetic Particle Testing) / LPT (Liquid Penetrate Testing) to be carried out on the beveled face of old pipeline portion before welding to ensure the joint is clear of all defects. For austenitic stainless steels, duplex stainless steels, and nickel alloys, digital hand-held contact thermocouples are preferred to avoid contamination from tramp elements, such as fluorides, chlorides, and sulfides which may be contained in the crayons. Some guidelines that can be followed for the selection of NDTs are. >50 ppmw total sulfide content in the aqueous phase; ii. PWHT requirement depends on three factors – Metallurgy, Thickness and Service. Where CE > 0.5, delaying final NDE for at least 24 hr should be considered to identify any delayed cracking. Location of site welds in any pipeline repair should be selected in such a way that it offers the most comfortable position for the welder. 5 materials is not permitted for applications in sour or hydrogen service or where the nominal chromium content of the material exceeds 1.25 %. The first step in all rehabilitation works is to ensure that all pipe surfaces have been rebuilt to even surface profile. Under the B31 Codes for Pressure Piping, Welding . If you are expecting delayed cracking and if time permits always plan for MPT of the welds after 72 hours of welding (in most of the cases not feasible). The main heating processes involved during the repair of pressure piping are usually Hydrogen Bake out, Preheating/ interpass heating and Post Weld Heat Treatment (PWHT). Hydrogen Bake out will be required if process stream contains hydrogen/ H2S with high temp (more than 200 degree Celsius or pressure). No one wants Incomplete Penetration! ASME B31.3 Process Piping Course 12. 4.2. The welding con-sumable should be selected to correctly match (or overmatch) the strength of the pipe. hot air (hot gas) welding, or extrusion welding techniques and joining by pipe threading are not recommended for pressure service. After painting, field inspection shall be offered for QC and the same shall be QC recorded in the prescribed format. When higher preheat is required by the applicable construction code (i.e. We work closely with Materials Testing Labs and 3rd Party Inspection agencies to ensure we deliver piping products in accordance with API and ASME. The weld repair is same as the original welding done as per WPS requirements By G.S.Crisi Date 10-08-2009 22:28 I personally don't like to use carbon gouging to repair defective welds. Safety.The repair welding location or area must be surveyed and all safety considerations satisfied. Figure 4: Checking temperature profile during stabilization treatment of SS321 (Austenitic) heater pipes with digital hand-held contact thermometer. Note: For new construction of pressure vessels, boilers, and pressure piping, refer to the Manufacturer section. Figure 9: LPT (Liquid Penetrate Testing) on the beveled face of old portion during the replacement of top portion of a tall column. Once established the excavation site must be clearly identified and marked out. Welding on metal that is wet is strictly prohibited; wet metal shall be heated until … Figure 8 : Improper weld joint design lead to cracks during solidification (Ref: Article 2.8, ASME PCC2 Edition 2015). Cleaning the repair area, (removal of paint grease etc). In most manufacturing environments we have specific WPSs for certain joint configurations, materials, and welding positions. WELDING PROCEDURE SPECIFICATION No. They are thus available to and for the use of NCPWB members only. (Ref : Article 2.8, ASME PCC2 Edition 2015). Fabrication and Installation BECHT ENGINEERING COMPANY, INC. Fabrication and Installation -5 Welder Qualification Welders are required to use an approved procedure in accordance with B&PV Code Section IX Prepare the welding procedure specification (WPS) • Essential variables (P-no., thickness, PWHT, etc.)

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