レーザ表面改質した Alloy 600の耐食性

抄録

Intergranular corrosion (IGC) and intergranular stress corrosion cracking (IGSCC) of the laser-modified surface of Alloy 600 containing 0.04%C or 0.06%C have been investigated. YAG (Yttrium-Aluminum-Garnet) laser beam was used as a heat source for melting or alloying of the surface of the thermally sensitized Alloy 600. The resistances of IGC and IGSCC were evaluated by Streicher test and creviced bent beam test in high temperature water, respectively. The results obtained are as follows: (1) The IGC and IGSCC resistances of the laser-melted surface of Alloy 600 depend on carbon content of the base metal. (2) In the case of 0.04%C Alloy 600, corrosion resistance slightly increases by laser surface melting. And in the case of 0.06%C Alloy 600, corrosion resistance decreases by laser surface melting. (3) The IGC and IGSCC resistances of the sensitized 0.06%C Alloy 600 remarkably increase by the laser surface alloying, in which Cr, Mo, Ti, Nb-rich filler wires are used.