Exploration of the Feasibility of Production Rolling an Optimum Aluminum Alloy System which has an as-Welded Yield Strength of 30ksi Minimum.

摘要

A high-strength weldable Al-Mg alloy, CS19, was fabricated into plate from large ingots on production rolling mills to evaluate feasibility. Plate in 6.3 mm (.250-in.) and 25.4 mm (1.0-in.) thicknesses was produced from two commercial sizes of ingot with no difference in product characteristics observed between plates fabricated from either size ingot. Tests on 25.4 mm thick CS19 plate and weldments showed it to have as-welded minimum yield strength of 207 MPa (30 ksi) and corrosion and fracture toughness equivalent to or better than 5456-H116 or H117 alloys. CS19 plate was shown to have more rapid rate of stress-corrosion crack growth than 5456 under some conditions but equal resistance to SCC initiation. The thinner plate and weldments had higher strength but lower toughness which was equivalent to that of 5456 of the same thickness. SCC resistance of the thinner plate and weldments was also good except for SCC resistance of weldments after thermal treatments simulating long service times. Greater strain in thinner plate produced an HAZ structure susceptible to SCC after thermal treatment. (Author)