A several time ago my company got the order for manufacturing inner casing for nuclear steam power plant. The material was different with the common steel we used. If usually we mostly working with low carbon steel, now we would weld alloy steel. Parts would be welded was casting part GX4CrNi 13 4 ( W. No 1.4317) and round bar X3CrNiMo 13 4 with diameter 60 mm. Design for welding K- joint , you can see on the left. To make round bar has a good shape, we make chamfer with milling process, beside the main reason that we couldn't do it by flame cutting. We had no experience how length the shrinkage after welding, so we put allowance 10 mm, on both of side. We had never experience for shrinkage of alloy weld, but this assumption was take from shrinkage on low carbon steel weld.
Welding process started with selection of filler metal, for root pass, we used Bohler EAS 2-1G, to get good root pass, and we fill with Bohler FOX CN 13/4 with SMAW process. Weld result then grinding smoothly, then we conducted penetrant test to check weld result. So far, result is good, and we also conducted Ultrasonic Test, even we know UT would not get optimum result due to alloy material properties constraint to reflect ultrasonic signal, it diverged, but we did it to prevent main defect inside of weld.
After welding, actually shrinkage is not too much, below 5 mm, however we put 10 mm allowance on both side, after consulted with designer, allowance was still enough for machining process.
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