Method of producing a structural member

摘要

PCT No. PCT/JP93/01137 Sec. 371 Date May 4, 1994 Sec. 102(e) Date May 4, 1994 PCT Filed Aug. 12, 1993 PCT Pub. No. WO94/05824 PCT Pub. Date Mar. 17, 1994 epsilon phase precipitates in the matrix having a composition of 0.07% or less carbon, 1 or less silicon, 1% or less manganese, 2.5 to 5% copper, 3 to 5.5% nickel, 14 to 17.5% chromium, 0.5% or less molybdenum, 0.15 to 0.45% niobium, by weight, and the balance composed substantially of iron, and comprising 6 to 30 vol % austenitic phase and the balance composed substantially of martensitic phase. In a method of producing a structural member in which first solution treatment is performed at 1010 DEG to 1050 DEG C. on a stainless steel having a composition described above and first aging treatment is performed at a temperature not lower than 520 DEG C. and not higher than 630 DEG C., second solution treatment is performed at 730 DEG to 840 DEG C., and then second aging treatment is performed at a temperature not lower than 520 DEG C. and not higher than 630 DEG C. or a structural member of any shape is fabricated by means of welding work before the second solution treatment. Also, a structural member is produced by performing first solution treatment at 1010 DEG to 1050 DEG C. on a stainless steel having a composition described above, performing aging treatment at a temperature not lower than 520 DEG C. and not higher than 630 DEG C., fabricating a structural member of any shape by means of welding work, heating the material at a rate of 100 DEG C./hour or lower, performing second solution treatment at 1010 DEG to 1050 DEG C., cooling the material in a furnace to room temperature at a cooling rate of 100 DEG C./hour or lower, performing aging treatment at a temperature not lower than 520 DEG C. and not higher than 630 DEG C., and cooling the material in a furnace to room temperature at a cooling rate of 100 DEG C./hour or lower.