The effect of the rate of cooling on phase changes in the 1250-1000 deg C and 650-350 deg C temperature ranges and on the relative volume of ferrite in austenitic welds deposited with solid G23 12L and flux-cored T23 12 LRM3 wires

摘要

The prepared nomograms, accounting not only (as until now) for the effect of the chemical composition on the relative volume of ferrite, but also for the rate of cooling reflected by the time weld cooling, t = 1.1 t_(650-350), may be useful when designing a technology for the welding of steels resistant to corrosion. The investigation and its results showed a significant influence of the rate of cooling (especially within the 650-350 deg C range) on the relative volume of ferrite at ambient temperature. The investigative procedure revealed the significance of gamma -> alpha change occurring in this temperature range, and enable derivation of the technological parameters, linking the rate of weld cooling to the ferrite content, to be made. The nomograms were designed on the basis of the results of the investigation, and are an example of the technological approach to the problem of the effect of the rate of cooling on the content of ferrite. A design of a family of nomograms which would increase the accuracy of the determination of ferrite content within the whole range of Schaffler diagram, would require more extensive, and costly investigations into, among other things, the variation in the chemical composition of welds (Cr_(eq) -Ni_(eq)) = 6÷30.