Table 2 — Solidification Mode and Cracking of Sigmajig Samples Espy Equivalents Solidification Mode Total Crack Length Number of Cracks Alloy P + 0.2 S Creq Nieq Creq/ 21 42 85 21 42 85 21 42 85 Nieq mm/s mm/s mm/s mm/s mm/s mm/s mm/s mm/s mm/s 1 21.03 12.33 1.71 0.018 F F F 0 0 0 0 0 0 2 21.02 13.53 1.55 0.016 F D A 0 0 0 0 0 0 3 21.14 13.44 1.57 0.019 F F A 0 0 0 0 0 0 4 21.10 13.51 1.56 0.017 F F A 0 0 0 0 0 0 5 21.49 12.55 1.71 0.018 F F F 0 0 0 0 0 0 6 20.72 13.36 1.55 0.020 F A A 0 0 0 0 0 0 7 20.93 13.42 1.56 0.020 F A A 0 0 0 0 0 0 8 21.50 12.68 1.69 0.028 F F F 0 0 0 0 0 0 9 20.57 13.32 1.54 0.022 F F D 0 0 0 0 0 0 10 22.14 15.20 1.46 0.023 F A A 0 335 1137 0 8 24 11 20.83 13.90 1.50 0.023 F A A 0 0 0 0 0 0 12 19.45 12.06 1.61 0.019 F A A 0 0 0 0 0 0 13 21.01 13.82 1.52 0.023 F A A 0 0 0 0 0 0 14 21.47 12.76 1.68 0.021 F F F 0 0 0 0 0 0 30 20.31 11.29 1.80 0.021 F F A 0 0 85 0 0 7 31 22.65 15.81 1.43 0.024 F D D 0 0 0 0 0 0 32 21.23 13.39 1.59 0.027 F D A 0 55 104 0 2 4 33 25.51 23.53 1.08 0.021 A A A 1420 4463 2805 1 13 47 34 24.51 18.28 1.34 0.025 A A A 2460 3130 1844 2 2 44 35 23.33 14.20 1.64 0.032 D A A 1307 3134 2217 16 15 42 36 17.18 8.95 1.92 0.025 F F F 0 0 0 0 0 0 40 21.23 15.71 1.35 0.023 A A A 0 0 0 0 0 0 41 21.21 14.68 1.44 0.025 A — — 0 — — 0 — — 42 21.27 14.72 1.44 0.026 A — — 0 — — 0 — — 43 21.09 14.62 1.44 0.030 A — — 0 — — 0 — — 44 21.12 15.45 1.37 0.025 A — — 0 — — 0 — — 45 21.27 15.41 1.38 0.031 A — — 0 — — 0 — — 46 21.17 15.71 1.35 0.035 A — — 3824 — — 6 — — 47 21.10 15.65 1.35 0.033 A — — 569 — — 6 — — 48 21.04 15.39 1.37 0.025 A — — 0 — — 0 — — 49 20.98 14.57 1.44 0.030 A A A 905 384 1755 1 2 14 50 21.14 15.33 1.38 0.035 A — — 3340 — — 3 — — 51 20.96 14.73 1.42 0.032 A — — 0 — — 0 — — 52 20.96 14.16 1.48 0.032 A — — 225 — — 5 — — 53 20.94 14.32 1.46 0.035 A A A 229 347 541 7 2 7 54 20.40 15.57 1.31 0.037 A A A 4692 4690 5024 12 14 10 55 20.42 15.58 1.31 0.038 A A A 5907 5503 5907 3 18 3 56 21.40 13.86 1.54 0.032 F D A 0 181 657 0 3 10 57 21.42 13.96 1.53 0.039 F D A 0 983 4440 0 3 47 58 21.59 13.37 1.61 0.033 F D A 0 633 194 0 3 4 59 21.62 12.60 1.72 0.037 F D D 0 1154 798 0 3 4 dual solidification mode, which was not observed at 21 mm/s. At 42 mm/s travel speed, the critical Creq/Nieq for primary ferrite solidification shifts to approximately 1.75, compared to 1.55 for 21 mm/s. In the range of 1.55 to 1.75 Creq/Nieq a mix of primary ferrite, primary austenite, and dual solidification modes were observed. One alloy, 59, showed dual mode solidification at a Creq/Nieq of 1.73 with high impurity content, while alloys at equal Creq/Nieq and lower impurity content all exhibited primary ferrite solidification. A similar variation in solidification mode with increasing impurity content for constant Creq/Nieq, right at the transition from primary austenite WELDING RESEARCH to primary ferrite, was observed in the 21 mm/s diagram. In general, cracking was observed in alloys with primary austenite or dual solidification modes and impurity contents greater than approximately 0.02 wt-%. Some alloys with impurity content slightly above 0.02 wt-% and primary austenite solidification were crack free. One com- NOVEMBER 2016 / WELDING JOURNAL 413-s Solidification modes: A austenite, D dual (austenite and ferrite), and F ferrite.
Welding Journal | November 2016
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