WELDER QUALIFICATION (For Detail Ref. ASME SEC IX)
1.) PRESSURE PARTS
Welders must be qualified and welder’s identity card must be provided for each category of welding. Before welder selection the concerned welding engineer must review his IBR certificate and his previous experience certificates etc. as preliminary qualifying document. A person without above data should not be allowed for welder
test.
(a) Welders qualified for higher grade material is qualified for all material up to that Grade. Means a welder qualified in Carbon steel material is qualified for carbon steel material only. He needs additional qualification for T-11, T-22, T-91, T-23 etc. A welder qualified in higher category like in T-22 is qualified for all material up to T-22.
Separate qualification required for T- 91 materials.
(b) For IBR welder qualification welders must be tested at 6G position, means 45 0 to the horizontal X axis. There are 5 positions from 1 G, 2G, 5G & 6 G depend upon the orientation of work piece. A welder qualified in 6G will be qualified for all positions welding.
After the root welding, physical inspection to be carried out for proper uniform penetration maximum up to 1.5 mm , lack of fusion , excess penetration ,surface porosity, root under cut etc. If we observe any of the above defects, that welder should not be permitted to continue the test. A welder qualifying in preliminary visual inspection must finish the hot pass and finish welding and that test piece must be marked with letter punching as per welder code and must send for Radiography test. Welder will pass the test based on the radiography result with zero defects.
An identity card must be issued to that welder who passed the test as specified above. This test can be conducted with boiler tubes with 44.5 NB X 4.5 mm thick, for carbon steels and super heater tubes of 38.1 ODX 5.5mm thick tubes. This qualification is for tube minimum up to welded size and maximum diameter will be unlimited.
(c) Thickness range qualification is 2 X thickness of weld test coupon and if the thickness of test coupon is above 13 mm, the range qualified will be unlimited.
(d) Weld Position Details and Range qualified. Annexure- VI
2.) NON PRESSURE PARTS
Welders must be qualified and welders identity card must be provided for each category of welding. Before welder selection the concerned welding engineer must
review his previous experience certificates as preliminary qualifying document. A person without above data should not be allowed for welder test.
(a) Welders qualification separately required for Structure and piping as per Annexure –Ref. QW- 461.9. Welders separate qualification required for Fillet welding & Groove
welding. Fillet welding test qualification can be done by i). Micro etching followed with visual examination. Cut the fillet welded test coupon with grinding and the face
can be cleaned with diluted Nitric Acid and can check for the following.
(i) Complete fusion and freedom from linear indications > 0.8mm will not be acceptable.
(ii) Concavity and convexity >1.5 mm not acceptable.
(iii) Lug length difference > 3mm is not acceptable.
(b) Structure welder qualification in Groove welding can be qualified by i) Visual Inspection, Bend Test or RT.
c) Thickness range qualification is 2 X thickness of weld test coupon and if the thickness of test coupon is above 13 mm, the range qualified will be unlimited.
(d) Weld Position Details and Range qualified. Annexure- VI
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