Maintenance and Reliability TABLE 3. Welding procedure specifications for the GTAW process Welding procedure specification no. Welding process GTAW Joint (QW-402) Joint design Corrosion-resistant weld overlay Root spacing Not applicable Backing Yes Backing material Base metal and weld metal Base metal (QW-403) P. no. P5A P. no. - Group no. 1 Group no. - Thickness range 8 mm Thickness range - Base metal groove Not applicable Base metal groove Not applicable Filler metal (QW-404) Specification no. (SFA) Barrier layer Subsequent layer AWS no. (Class) E-309 Nb E-347 F-no. 5 5 A-no. 8 8 Size of filler metals 3.15, 4φ 3.15, 4φ Fillet Not applicable Not applicable Electrode flux (class) Not applicable Not applicable Flux type Not applicable Not applicable Flux trade name Not applicable Not applicable Consumable insert Not applicable Not applicable Other Chemical composition Chemical composition Backing: Yes/No Yes Yes Backing material (type) Parent metal Weld metal Root spacing Not applicable Not applicable Maximum pass thickness: 0.5 in. (13 mm) (Yes) (No) No No Filler metal product form Not applicable Not applicable Supplemental filler metal Not applicable Not applicable Positions (QW-405) Position of groove All Welding progression Uphill Preheat (QW-406) Barrier overlay Weld overlay Preheat temperature: Minimum 125˚C 25˚C Interpass temperature: Maximum 175˚C 175˚C Preheat maintenance 250˚C Not applicable Other: Continuous or special heating, where applicable, should be recorded Method of applying heat for preheat and interpass temperature: Electric coil heating, which should be checked by a Thermapen PWHT (QW-407) Barrier overlay Weld overlay Temperature range Not required Not required Time range Not required Not required Soaking temperature Not required Not required Heating rate Not required Not required Cooling rate Not required Not required Method of heating Not required Not required Method of cooling Not required Not required 54 MAY 2021 | HydrocarbonProcessing.comhttp://www.HydrocarbonProcessing.com