The annex also serves another useful purpose. I find it the perfect location to list preheat and interpass requirements. Filler Metal If a filler metal is required, it must be listed in the WPS. Filler metals are grouped in a similar manner as base metals. Filler metals are grouped by F numbers by AWS and ASME; NAVSEA welding standards group the filler metals by A numbers. F numbers can be used for a couple of purposes. The F number is considered to be an essential variable for welder performance qualification and when qualifying the WPS. The F number is listed on the WPS, and the WPS is valid for all the electrodes contained within the F number group. That does not mean the welder can substitute one filler metal for any other filler metal within the same group; it simply means the WPS does not have to be requalified if the manufacturer decides to change from one filler metal to another within the same F number group. In addition to the filler metal F number, the specification and the classification are listed. Listing the specification and classification narrows the selection of filler metals the welder can use. An example might be useful to illustrate how the system works. Let’s look at the F number group F6 (there is no F6 in D1.1, so you can stop looking). F6 contains all ferrous filler metals not included in groups F1 through F5. F6 includes filler metals for GMAW, FCAW, GTAW, OFW, and SAW. It includes filler metals for carbon steels, and high-strength lowalloy, high-alloy, and heat-treatable low-alloy steels. It’s a trash heap of ferrous filler metals. You will find F6 filler metals listed in both ASME Section IX and AWS B2.1. It wasn’t always this way. Before the introduction of Standard Welding Procedure Specifications and the influence of ASME, F numbers were more specific. It used to be that in B2.1 the F numbers were also used to group filler metals, the alloy constituents, and the welding process. You might encounter an F10 filler metal when reviewing a WPS written in the 1970s or early 1980s. It was after 1984 that AWS B2.1 adopted the ASME F number groupings. A weld is a composition or alloy of the base metals being joined and the filler metal used. If you change the composition of either member being welded, there is a high probability the alloy composition of the completed weld can be changed even though the F number has not changed. A system of A numbers that applies only to ferrous metals was devised to address that problem. The A number reflects the chemistry of the completed weld. The WPS is only qualified for a weld with a specific A number when working with either ASME Section IX or AWS B2.1. A numbers are included in AWS D1.1 and D1.5 because those welding codes only apply to carbon- and low-alloy steels where the mechanical properties of the weld are not as likely to be affected by dilution if matching filler metals are used. The WPS also lists the appropriate filler metal diameters the welder is to use. Should a consumable insert be required, it is usually included along with the filler metal. Other things that might be included are the flux for SAW and any supplementary fluxes, filler metals, or powders used. Shielding Gas Gas tungsten arc, gas metal arc, and flux cored arc welding typically require a shielding gas to protect the molten weld pool from atmospheric gases. The gas may be an inert gas such Inspection Trends / Winter 2011 31 Table 1 — Example of the Welding Parameters Recorded in a PQR Procedure Qualification Data GF-F6P1-A 19-Oct-2010 Welding Parameters Side Pass Layer Class Diameter Volts Amps WFS Seconds Travel Heat Input Deposit Thk. PH/IPT A 1 Root E7OS-2 1⁄8 12 160 672 4.0 28800 3⁄16 81 A 2 2 E7OS-3 1⁄8 11 175 687 2.4 48090 1⁄4 108 A 3 3 E71T-1MJH4 0.045 26.5 200 299 302 5.8 55080 3⁄8 84 A 4 3 E71T-1MJH4 0.045 27 235 350 188 8.8 43377 3⁄8 145 A 5 3 E71T-1MJH4 0.045 27 235 350 198 9.0 42158 3⁄8 153 A 6 4 E71T-1MJH4 0.045 27 235 350 193 9.0 42140 1⁄2 220 A 7 4 E71T-1MJH4 0.045 27 230 350 208 8.8 42170 1⁄2 185 A 8 4 E71T-1MJH4 0.045 27 230 350 188 9.7 38607 1⁄2 204 A 9 4 E71T-1MJH4 0.045 27 238 350 246 7.6 50993 1⁄2 220 A 10 5 E71T-1MJH4 0.045 27 230 350 181 10.6 35125 3⁄4 243 A 11 5 E71T-1MJH4 0.045 27 230 350 212 9.1 41141 3⁄4 275 A 12 5 E71T-1MJH4 0.045 27 234 350 227 8.5 44818 3⁄4 258 A 13 5 E71T-1MJH4 0.045 27 239 350 236 8.1 47591 3⁄4 289 A 14 Cover E71T-1MJH4 0.045 26 199 305 314 6.3 49251 7⁄8 208 A 15 Cover E71T-1MJH4 0.045 26 200 305 274 7.2 43176 7⁄8 251 A 16 Cover E71T-1MJH4 0.045 26.6 200 305 310 6.4 49976 7⁄8 272 A 17 Cover E71T-1MJH4 0.045 26 205 305 260 7.6 41994 7⁄8 84 A 18 Cover E71T-1MJH4 0.045 26 199 305 284 7.0 44528 7⁄8 110
Inspection Trends - January 2011 - Winter
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