Model for estimation of thermal history produced by a single pass underwater wet weld
By: Jay F. Dill
Contributors: Naval Postgraduate School (U.S.) 
Publisher: Naval Postgraduate School; Available from National Technical Information Service
Published: 1997
Place of publication: Monterey, Calif; Springfield, Va
Language: eng
Number of pages: 53
Description: Thermal history calculations for single pass underwater wet weldments were made by solving the appropriate      beat transfer equations using the three- dimensional Crank-Nicholson finite difference method. The Adams      approach, which defines the fusion line temperature as a boundary condition, was adopted. Tsai and      Masubuchi's semi-empirical correlation, defining the surface heat transfer coefficient of underwater weldments,      was used to determine the heat loss through the surface of the welded plate. As expected, the calculated cooling      rates in heat affected zones (HAZs) of underwater wet welded ferritic steels were found to be somewhat faster      than equivalent cooling rates calculated for the same weldments generated in air. However, the effect of water      temperature on cooling times in the HAZ between 8000 and 5000C (the parameter conventionally used to      measure the cooling rate in the HAZ ) was found to be minimal. These calculations suggest that HAZ      microstructure of underwater wet welded ferritic steels should be independent of water temperature. This      prediction was confirmed by microstructural studies of samples of ASTM A516 grade 70 steel which were      underwater wet welded at water temperatures of 31 degrees, 10 degrees and 30 degrees C respectively and for      which suggest that HAZ microsructures were obtained in each case.
Notes: "December 1997."

Thesis advisor(s): A.G. Fox.

Thesis (M.S. in Mechanical Engineering) Naval Postgraduate School, December 1997.

Includes bibliographical references (p. 51)

Approved for public release; distribution unlimited.

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dk/dk cc:9116 7/10/98.