PARTS FOR FLUID

摘要

Parts for a fluid for use in a piping and a device for controlling a fluid, such as a valve and a joint, wherein a metal member thereof specified in the specification comprises an alloy which has a chemical composition in wt %: C : 0.001 to 0.01 %, Si: 5 % or less, Mn: 2 % or less, P: 0.03 % or less, S: 100 ppm or less, O: 50 ppm or less, Cr: 18 to 25 %, Ni: 15 to 25 %, Mo: 4.5 to 7 .0 %, Cu: 0.5 to 3.0 %, N: 0.1 to 0.3 %, and the balance: substantially Fe and inevitable impurities, and exhibits a CRI (crevice corrosion resistance inde x) value of 40 <= CRI <= 55 in which CRI is determined from the following formula based on the contents in wt % of respective metals being added in combinatio n: CRI = [Cr] + 4 .times. [Mo] + 30 .times. [N]. The above parts have satisfactorily secure resistance to crevice corrosion.