Table 3 — Welding Parameters for GMAWCSC Sample 46 47 48 49 50 51 Arc Time Initial arc current (A) 40 50 60 65 70 77 Time (ms) 4 4 4 4 4 4 Mid arc current (A) 80 100 120 130 140 154 Time (ms) 4 4 4 4 4 4 End arc current (A) 40 50 60 65 70 77 Short Circuit Start short current (A) 40 40 40 40 40 40 Time Time (ms) 7 7 7 7 7 7 Mid short current (A) 40 40 40 40 40 40 Time (ms) 7 7 7 7 7 7 End arc current (A) 40 40 40 40 40 40 Ramp Rates Rise (A/ms) 250 250 250 250 250 250 Fall (A/ms) 250 250 250 250 250 250 Wire feeding Down wire feed 8 8 8 8 8 8 Rate speed (mpm) Delay before wire down (ms) 0 0 0 0 0 0 UP1 wire feed speed (mpm) 8 8 8 8 8 8 Delay before wire up (ms) 0 0 0 0 0 0 Up2 wire feed speed (mpm) 8 8 8 8 8 8 Arc length (mm) 0.7 0.7 0.7 0.7 0.7 0.7 Penetration delay (ms) 0 0 0 0 0 0 Start Sequence Preflow time (s) 0.5 0.5 0.5 0.5 0.5 0.5 Data Runin wire feed speed (mpm) 1.0 1.0 1.0 1.0 1.0 1.0 Process starting current (A) 50 50 50 50 50 50 Initial arc length (mm) 2.0 2.0 2.0 2.0 2.0 2.0 Preheat current (A) 60 60 60 60 60 60 Preheat timestart delay (ms) 50 50 50 50 50 50 Stop Sequence Stop arc length (mm) 2.0 2.0 2.0 2.0 2.0 2.0 Data Stop time (ms) 50 50 50 50 50 50 Arc stop current (A) 50 50 50 50 50 50 Postflow time (s) 0.5 0.5 0.5 0.5 0.5 0.5 Electrode Extension (mm) 16 16 16 16 16 16 Shielding Gas 75% Ar 75% Ar 75% Ar 75% Ar 75% Ar 75% Ar 25% CO2 25% CO2 25% CO2 25% CO2 25% CO2 25% CO2 Gas Flowing Rate (m3/h) 1.1 1.1 1.1 1.1 1.1 1.1 Travel Speed (mm/s) 15 15 15 15 15 15 Heat Input (J/mm) 56.3 74.8 90.6 99.5 107.1 119.5 distortion of the workpiece is visible, which probably can be minimized by using a stronger frame and heavier motors for the 3D printer system to allow the use of a metal fixture for clamping down the workpiece tightly before welding. Overall Composition of Cladding To prepare a sample for determining the overall chemical composition of the cladding, an eight-layer square cladding was made with the long serpentine motion pattern — Fig. 9A. As mentioned previously, the upper half of the cladding was cut off by electrical discharge machining (EDM), broken up into particles, and dissolved in various chemicals for chemical analysis. Table 4 — Dilutions in SingleBead Cladding Made by GMAWCSC and Conventional GMAW GMAWCSC Conventional GMAW Sample 46 47 48 49 50 51 53 54 55 Dilution 1 0.124 1.25 2.95 1.38 5.76 1.24 1.05 9.81 14.21 (%) 2 0.098 0.49 2.35 1.81 4.50 5.37 4.53 2.35 3 0.247 0.072 1.0 3.68 5.98 10.37 2.23 0.82 9.21 Average 0.16 0.6 2.1 2.29 5.41 5.66 2.60 4.33 11.71 As shown in Table 5, the overall composition of the cladding is 53.36 ± 2.80 wt-% Ni, 42.09 ± 0.93 wt-% W, 1.15 ± 0.003 wt-% C, 0.64 ± 0.004 wt- % B, 0.34 ± 0.01 wt-% Fe, and 0.33 ± 0.004 wt-% Si. Due to accumulation of errors, the summation of these concentrations is 97.91 wt-% instead of 100 wt-%, the difference being 2.09 wt-%. For simplicity, the composition will be taken as Ni-42.09W- 1.15C-0.64B-0.34Fe-0.33Si by wt-%, which implies the balance is 55.45 wt- % Ni (= 53.36 + 2.09). This composition is more reliable than that provided by the supplier of the welding wire. As shown in Table 1, the carbon content was not even measured. WELDING RESEARCH 458-s WELDING JOURNAL / DECEMBER 2016, VOL. 95
Welding Journal | December 2016
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