Effects of crack starter bead preparation in drop-weight test of nil-ductility transition temperature
- Ishikawajima-Harima Heavy Industries, Yokohama (Japan). Production Engineering Dept.
- Mitsubishi Heavy Industries Ltd., Kobe (Japan). Kobe Shipyard Machinery Works
- Babcock-Hitachi Corp., Kure (Japan)
- Univ. of Tokyo, Koshigaya (Japan)
The procedure for making crack starter weld deposits on drop-weight test (DWT) specimens was altered from two passes to one pass in about 1990. The effects of some parameters of crack starter weld process on drop-weight test results were studied. Results of this study indicated that length of overlap of the second pass and height of crack starter beads were most effective on mil-ductility temperature (T{sub NDT}). When overlap length and bead height of two-pass deposit were small enough, T{sub NDT} obtained by two-pass deposit became lower than one-pass T{sub NDT}, the discrepancy being by as much as 25 C. T{sub NDT} values for 24 Japanese steels were determined using two different DWT methods, one-pass deposit and two-pass deposit having small overlap length and bead height. The difference of T{sub NDT} depending on DWT method could be seen only for high-toughness low-alloy steel base metals. For other materials (i.e., low-to-medium-toughness low-alloy steel base metals, weld metals, and high-toughness carbon steels), T{sub NDT}s by two-pass and one-pass deposits were essentially the same. For lower-toughness steels, T{sub NDT}s by two-pass and one-pass deposits were essentially the same. For lower-toughness steels, T{sub NDT} was frequently lower than the temperature of ({sub v}T{sub cv} {minus} 33 C), and thus, the reference nil-ductility temperature (RT{sub NDT}) was determined from Charpy impact test results. These results can be taken as a way of interpreting the past toughness evaluations made for operating plants using the two-pass T{sub NDT}.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 355645
- Journal Information:
- Journal of Pressure Vessel Technology, Journal Name: Journal of Pressure Vessel Technology Journal Issue: 2 Vol. 121; ISSN 0094-9930; ISSN JPVTAS
- Country of Publication:
- United States
- Language:
- English
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