Abstract: A specified metal member included among the components of a valve, coupling or like fluid handling part for use in piping and fluid control devices is made of an alloy comprising, in % by weight, 0.001 to 0.01% of C, up to 5% of Si, up to 2% of Mn, up to 0.03% of P, up to 100 ppm of S, up to 50 ppm of O, 18 to 25% of Cr, 15 to 25% of Ni, 4.5 to 7.0% of Mo, 0.5 to 3.0% of Cu, 0.1 to 0.3% of N, and the balance substantially Fe and other inevitable impurities, the alloy having a CRI (crevice corrosion resistance index) value in the range of 40?CRI?55, as determined from the expression CRI=[Cr]+4×[Mo]+30×[N] wherein the amount of alloy components present in combination in the alloy to ensure crevice corrosion resistance are expressed in % by weight.

Abstract: A fluid control device 1 comprises a metal body 2 having a fluid inlet channel 2a, a fluid outlet channel 2b and a communication channel 2c for holding the two channels in communication, and a metal slide member 3 vertically movable in a vertical passage 11 including the communication channel 2c for closing or opening the communication channel 2c with an end portion thereof. At least the end portion 3a of the slide member 3 is made of an alloy comprising, in % by weight, 0.001 to 0.01% of C, up to 5% of Si, up to 2% of Mn, up to 0.03% of P, up to 100 ppm of S, up to 50 ppm of O, 18 to 25% of Cr, 15 to 25% of Ni, 4.5 to 7.0% of Mo, 0.5 to 3.0% of Cu, 0.1 to 0.3% of N, and the balance substantially Fe and other inevitable impurities.

Abstract: A specified metal member (e.g., a bolt) 5 included among a plurality of components 2, 3, 4, 5, 6 of a fluid handling part and having a surface exposed on an exterior of the fluid handling part is made of an alloy comprising, in % by weight, 0.001 to 0.01% of C, up to 5% of Si, up to 2% of Mn, up to 0.03% of P, up to 100 ppm of S, up to 50 ppm of O, 18 to 25% of Cr, 15 to 25% of Ni, 4.5 to 7.0% of Mo, 0.5 to 3.0% of Cu, 0.1 to 0.3% of N, and the balance substantially Fe and other inevitable impurities.

Abstract: A pipe coupling 30 comprises a tubular body 31 for a pipe 32 to be inserted in through the rear end thereof, a front ring 33 and a back ring 34 to be fitted around the pipe 32 projecting from the rear end of the body 31, and a cap nut 35 for tightening up the front and back rings 33, 34 to fix the pipe 32 to the body 31. The back ring 34 is made of an alloy comprising, in % by weight, 0.001 to 0.01% of C, up to 5% of Si, up to 2% of Mn, up to 0.03% of P, up to 100 ppm of S, up to 50 ppm of O, 18 to 25% of Cr, 15 to 25% of Ni, 4.5 to 7.0% of Mo, 0.5 to 3.0% of Cu, 0.1 to 0.3% of N, and the balance substantially Fe and other inevitable impurities.