Abstract: Fe—Ni—Cr alloy contains, in mass, from 0.001% to 0.050% of C, from 0.18% to 1.00% of Si, from 0.20% to 0.80% of Mn, 0.030% or less of P, 0.0001% to 0.0020% of S, from 12% to 21% of Ni, from 18% to 24% of Cr, from 0.20% to 1.50% of Mo, 0.30% or less of Cu, from 0.10% to 0.70% of Al, from 0.10% to 0.70% of Ti, from 0.002% to 0.015% of N, from 0.0001% to 0.0010% of B, from 0.0002% to 0.0030% of O, 0.002% or less of Ca, and from 0.0010% to 0.0150% of REM in total, said REM being composed of one or more elements selected from among La, Ce and Y, with the balance being made up of Fe and unavoidable impurities, and which satisfies formulae 1 and 2. Formula 1: 0.575xNi+1.25xCr+3.43xMo-39xP-5.3xAl-641xREM-1018xO?20.0 Formula 2: 1.5xMn+41.3xSi+1469xS-1.67xAl-1.34xTi-150xO-620xREM?5.0.

Abstract: Alloy compositions, structures, and production methods for an appropriate slit cut surface shape improve productivity by increasing welding speed and stabilizing quality during high speed welding in Ti-containing Fe—Ni—Cr alloy production. The Ti-containing Fe—Ni—Cr alloy contains, hereinafter in weight %, C: 0.001 to 0.03%, Si: 0.05 to 1.25%, Mn: 0.10 to 2.00%, P: 0.001 to 0.030%, S: 0.0001 to 0.0030%, Ni: 15 to 50%, Cr: 17 to 25%, Al: 0.10 to 0.80%, Ti: 0.10 to 1.5%, N: 0.003 to 0.025%, 0: 0.0002 to 0.007%, Fe as a remainder, and inevitable impurities, and when the number and size of titanium nitrides contained in material are evaluated in a freely selected field of view of 5 mm2, the titanium nitrides having sizes of not more than 15 ?m are not less than 99.3% of total of the titanium nitrides.