Extent of the softende zone at mig welds on 6xxx aluminium

摘要

The well known and simple "one-inch" rule for estimating the extent of the HAZ (heat-affected zone) adjacent to an aluminium weld is usually, but not aloways, adequate for practical design. In this paper we present an alternative and more scientific approach ("RD method") for use in situations where HAZ effects are significant and the one-inch rule too severe. Our method is based on the research of Robertson at Cambridge (reported at the 4th INALCO conference). It provides simple formulae covering three ranges of weld size: small, medium and big. For the small and big welds these are based directly on Robertson's work, using the heat-flow equations worked out by Rosenthal. Empirical formulae are then used to bridge the gap between small and big, i.e. for medium size welds. The paper goes on to compare our method with the one-inch rule, BS.8118 and the draft EC document. It is shown that the latter can be very pessimistic.