| The effects of boron and titanium on the hot ductility of 18Cr-8Ni austenitic stainless steel which was annealed at various soaking temperatures were investigated. Boron addition up to 54ppm increases hot ductility of this steel. Ti addition with small amount increases hot ductility slightly, however, more addition beyond 680ppm reduces its ductility significantly. The fracture crack by high temperature tension test was initiated and propagated mostly at r/δ-boundary or grain boundary. The cracks are, therefore, initiated and propagated earlier at the higher b-ferrite content. As δ-ferrite dissolution rate increases at lower soaking temperature within the range of 1230-1300℃, the hot ductility increases at lower soaking temperature. |
|
