PART 8: TECHNIQUE VARIABLES Key Notes: The mean of Weaving will increase the heat input, hence the Toughness will be reduced accordingly. The change from multi-pass to single-pass will reduce the toughness significantly, the deduction of R.O.L and omission of bead tempering concepts will reduce the weld metal’s mechanical in general.   Continue reading Welding Inspector & WPS (PART 8 – FINAL)

PART 7: ELECTRICAL CHARACTERISTICS VARIABLES Key Notes: * In case of WPS with CVN impact test and no PWHT requirement: As common sense dictates, the Welding inspector will take a look on Weld bead profile firstly. The increase of Weld bead (Width) or reduction of R.O.L (Run out length) which makes toughness deduction. From the Welding engineer point of views, the limitation of welding weaving bead should to be mentioned wisely as below example for SMAW:   Continue reading Welding Inspector & WPS (PART 7)

PART 6: GAS VARIABLES Key Notes: * The mixture of %Nitrogen in DSS welding shielding gas. Normally, the shileding gas used for DSS welding is Pure Argon (100% Ar) with the right techniques. But the Ferrite content (FN)  will be a big trouble to the Welding quality, however, the small quantity of %Nitrogen (2-5%) will help to protect the FN from over the range of (40-70 FN). Above information for your reference only, further discussion about the DSS/SS-welding metallurgy will be carried out in separated topic. * The deletion of backing purge when welding SS. “TIG (GTAW) welding of the … Continue reading Welding Inspector & WPS (PART 6)

PART 5: PRE-HEATING AND HEAT TREATMENT VARIABLES Normally, there’s no issue on this variable because almost the PWHT Heating devices are working in order with the correct set-up temperature range and monitoring/record system. EXAMPLE OF AN PWHT PROCEDURE: Continue reading Welding Inspector & WPS (PART 5)

PART 4: POSITION VARIABLES Key Notes: * For the ASME PQR running without CVN impact test: Any PQR position can qualified for ALL position. (QW 203) * For the ASME PQR running with CVN impact test: It’s advised to run PQR 6G (or 3G, 5G) position for qualifying all the positions of piping welding onsite/workshop. Hence, there will be no any issue later on. * For the AWS D1.1 PQR, to qualified all position, at least Three (3) PQR 2G/3G/4G qo be carried out as per Tab 4.1 But there’re still flexibility gap if the project can optimize the Rule of … Continue reading Welding Inspector & WPS (PART 4)