Abstract: By changing the content of cobalt and the technology of postheat treatment the following subjects are studied:the hardness and redhaitlness,the age hardening mechanism of the surfacing metal of metal powder-cored wire which is a type of age hardening tool alloy for TIC surfacing. The results of the study show that the effects of cobalt content and postheat treatment on hardness and redhaxdness are notable. With the increasing of cobalt content in deposited metal the hardness and redhardness of surfacing metal rise apparently. The hardness of surfacing metal can go up to HRC 69.4 and remain above HRC 60 after heated at 650℃ for 6 hours. The optimum age technology is 560℃×2.5 h.