Hot Pressing and Sintering of Tin—Stainless Steel Metallurgical System

Abstract

The effect of tin additions on the metallurgical properties of hot pressed and sintered stainless steel was investigated. Samples containing 0·25–10 wt-%Sn were hot pressed at a temperature of 650°C and a pressure of 85 MPa for 5 min. After hot pressing the specimens were heat treated at a temperature of 1150°C for 10 h under vacuum conditions. It was found that during hot pressing Ni-Sn intermetallic compounds were formed. These metastable compounds subsequently dissolved in the austenitic matrix during heat treatment at 1175°C. Addition of 10 wt-%Sn resulted in a saturated matrix and residual intermetallic compounds were located along the grain boundaries. This was observed by xray diffraction and metallographic analyses of the samples after hot pressing and heat treatment at 1175°C. The tin additions enhanced grain growth during heat treatment and grain size increased from ~17 to ~ 65 μm on raising the tin content to 10 wt-%. PM/0400