The new 7CrMoVTiB10-10 (T 24) material for boiler waterwalls

摘要

Besides the main components such as headers, piping, superheaters and separators1 the waterwalls as flue gas-tight enclosure of the combustion chamber is of central importance for the design of a steam generator. The safety margins are more and more exhausted for the conventional materials, used so far for waterwalls1 by increasing operating pressures and temperatures to raise the efficiency of a power plant. The former safety margin of the waterwall materials might be recovered by the new material T 24 or 7CrMoVTiB10-10 (2,5Cr, 1 Mo, V, Ti, B). For this material creep rupture test results for test periods of up to about 100.000 h are already available. Test results of the base metal for tubes and pipes and the German qualification program which has been running for 4 years will be presented which includes qualification tests for TIG circumferential welds, SAW welds, creep rupture tests on welds, aging test on weld metal and test applications in power stations.