{"id":846,"date":"2022-01-07T08:37:20","date_gmt":"2022-01-07T08:37:20","guid":{"rendered":"https:\/\/mewelding.com\/?p=846"},"modified":"2022-09-21T03:18:30","modified_gmt":"2022-09-21T03:18:30","slug":"wps-for-dissimilar-base-metal-thickness","status":"publish","type":"post","link":"https:\/\/mewelding.com\/wps-for-dissimilar-base-metal-thickness\/","title":{"rendered":"Practice Case 3 \u2013 WPS For Dissimilar Base Metal Thickness"},"content":{"rendered":"\n

This article discusses a few examples when the production weld comprises of dissimilar base metal thickness. What should the WPS for such production welds be like? How must the PQR for such welds look like? <\/p>\n\n\n\n

\"judging<\/figure>\n\n\n\n

Consider the following problem asked in Interpretation IX-13-09<\/a>.<\/p>\n\n\n\n

A WPS is qualified for a base metal thickness range of 13 mm to 25 mm. Can this WPS be used to weld a production joint involving a 10 mm thick member to 13 mm thick member?<\/p>\n\n\n\n

The answer given by the committee is a \u2018No\u2019. This is because doing so would be a direct violation of QW 202.4. The QW 202.4 states that the thickness of thinner member of the production joint shall satisfy the limits of QW 451.<\/p>\n\n\n\n

In this case, the thinner member is 10 mm thick, which is outside of the WPS range. Hence, a WPS qualified for 13 mm to 25 mm thickness range cannot be used to weld this joint.<\/p>\n\n\n\n

The question asked by the inquirer in Interpretation gives rise to a thought: what thickness of the test coupon would he have taken to qualify a range of 13 mm to 25 mm? The minimum values of the qualified ranges begin with 5 mm, in QW 451.1, for different thicknesses of test coupon.<\/p>\n\n\n\n

It might be that the inquirer\u2019s case involved impact test as a requirement. For such cases, supplementary variables come into play, and QW 403.6 becomes applicable. QW 403.6 says that 16 mm, or the actual test coupon thickness, whichever is less, is the minimum qualified thickness.<\/p>\n\n\n\n

If he used a 13 mm thick test coupon, the minimum qualified base metal thickness would be 13 mm. That explains the minimum value. However, if he used a 13 mm thick coupon, maximum qualified base metal thickness would be 26 mm (not 25 mm)!<\/p>\n\n\n\n

Perhaps the inquirer just asked a hypothetical question.<\/p>\n\n\n\n

Dissimilar Thickness In Welds Involving Cladding <\/h2>\n\n\n\n