| 摘要 |
PURPOSE:To obtain a welded joint having high creep breakdown strength at elevated temps. by specifying the composition of deposited metal in the welded joint. CONSTITUTION:The welded joint consists of 0.02-0.08 C, 0.1-1.0 Si, 2-3 Mn, 33-42 Ni, 21-25 Cr, 0.8-1.7 Mo, 0.2-0.8 Nb by wt% and 1.5-2.0 (Mo+Nb), and if necessary, 0.1-0.5 Ti and 1.5-2.5 (Mo+Nb+Ti), and the balance Fe in the part where there is no dilution from the metallic members to be welded. Here, the more the C, the higher the high temp. strength, but the too much C results in decreased high temp. ductility and therefore its range is limited. With the Si in excess of the upper limit, high temp. cracking is liable to occur. The Ni is required in order to improve high temp. strength, but if it is above the upper limit, high temp. ductility degrades. The Mo raises high temp. strength and the same holds true of Nb, but above the upper limit, these will lower high temp. ductility. The Ti improves high temp. ductility and high temp. strength. |
