Browsing by Author "Coward, M. D."

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    Measurement of thermal cycles in the weld heat affected zone of mild steel
    (College of Aeronautics, 1967-09) Coward, M. D.; Apps, R. L.
    The thermal cycles in the mild steel parent plate adjacent to a bead on plate weld have been measured for heat inputs of 108, 54 and 42 kJ/inch, by means of embedded thermocouples connected to high response automatic recorders. The results show that decreasing the heat input increases the cooling rate and decreases the width of the heat affected zone. For thermal cycles in which the peak temperatures reached 900°C or above, two points of inflection have been noted in the temperature ranges 400° - 600°C and 950° - 1200°C. The inflection in the lower temperature range, which has been observed by other workers, has been attributed to latent heat from the exothermic transformation of austenite to ferrite. The higher inflection point, not previously reported, has been tentatively related to the solidification in the weld pool and the release of the latent heat of fusion.
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    Welding embrittlement of the parent plate outside the visible heat affected zone region
    (College of Aeronautics, 1968-04) Coward, M. D.
    Enbrittlement of steels outside the visible heat affected zone region due to plastic straining from the weldment and subsequent ageing has been reported by several authors. The problem is reviewed in this Note and an attempt made to detect this region in a semi-killed mild steel by means of a micro hardness testing survey taken at regular intervals in a direction away from the veld fusion boundary. Recommendations for future work in understanding the magnitude of this Problem particularly in multi stressed welded joints are given.