a 1-in. (25.4-mm) thick cast plate were machined to represent the defective region. T e shape and size of the intentional defect (Fig. 1) is similar to a surface defect specifi ed by the AMS 2694A Weld Qualifi ca- tion Test Specimen standard. T e gage section location of the two types of specimens (full weld and partial weld) with respect to the location of the weld repair is shown in Fig. 2.
Table 1. Consensus Welding Parameters Used to Fabricate Weld Repair Specimens
Welding Process Weld Current Weld Polarity
Weld Amperage Weld Voltage Shielding Gas
Shielding Gas Flow Rate, cfh
Tungsten Electrode Diam., in.
Filler Metal Alloy Filler Metal Diameter, in.
GTAW AC EN (a)
15 – 30 Argon
20 – 30
1/16 – 1/8 AMS 4246 1/16 – 1/8
Preheat Temperature, °F 200 – 600 Interpass Temperature, °F
150
(a) 100 amps per 0.10-inch of material thickness
Fig. 2. The relative gage section location of test specimens with respect to location of weld repair is illustrated.
To assure proper location of the
artificial defects and identifica- tion of each test sample, the three metalcasting facilities followed a step-by-step procedure for ma- chining defects into the half-weld plates (Fig. 3) and full-weld plates (Fig. 4). T e process parameters used
for accomplishing the weld repairs were a consensus of the param- eters currently used by the foundry participants of the AFS-AMC program to make repair welds on E357-T6 sand castings (Table 1). All 30 sample plates were heat treated to a T6 condition using the same process parameters the castings used to determine the A and B design allowables. T ese were:
Solution Heat Treatment
• Solution temperature: 1,010F (543.3C)
• Time at temperature: 12 hours Quench
• Maximum quench delay: 15 seconds
• Quench media: Water • Quench media temperature: 90F ±10 (32.2C ±5.6)
• Maximum quench media tem- perature rise: 25F (13.9C)
Aging
• Room temperature aging time: 12-24 hours
• Aging temperature: 325F (162.8C) • Time at aging temperature: 12 hours.
Figs. 3-4. The half-weld (left) and full-weld (right) test plates ready for welding are pictured. Nov/Dec 2013 | METAL CASTING DESIGN & PURCHASING | 45
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