1994 Volume 12 Issue 4 Pages 534-538
The intergranular corrosion resistance in the bonded joint of austenitic stainless steel by diffusion bonding with an amorphus insert metal containing 1.5 mass% boron was investigated to clarifiy the optimum bonding condition on which austenintic stainless steel pipes are joined using a high speed diffusion bonding system. The copper-copper sulfuric acid test was conducted to evaluate the intergranular corrosion of bonded joints to be caused by the chromium depleted zone. The joints bonded on lower bonding pressure and shorter bonding time conditions were more sensitive to intergranular corrosion. The precipitats of the chromium boride and chronium carbo-boride, which cause the selective corrosion, were observed at the bonding layer on such bonding conditions. On the contrary, the joints bonded on higher bonding pressure and sufficient bonding time condition had no intergranular corrosion or had scarcely precipitates at the bonding layer. The optimum bonding condition to prevent the intergranular corrosion was obtained as the bonding temperature at 1473 K, the bonding pressure higher than 9.8 MPa and the bonding time longer than 180 s.
