INFLUENCE OF SULFUR AND PHOSPHORUS ON THE HOT DEFORMATION OF FE-CR 13-PERCENT HIGH-PURITY STEEL

A series of Fe-Cr13%-C high purity steels containing increasing volume fractions of Sulphur (30, 60 and 100ppm) and Phosphorus (30, 60 and 1 00ppm)were prepared in order to study their hot deformation properties by tensile tests at various strain rates (10(-1)s(-1) to 10(-4)s(-1)) and at temperatures from 700 degrees C to 1100 degrees C. It is obser ved that the hot ductility is lowered at 1000 degrees C with the addit ion of sulphur. However, this decrease is relatively small (about 30% for 100ppm of sulphur) and quite similar for all additions of sulphur. When phosphorus is added, the embrittlement is along the whole deform ed specimen. The usual criteria of ductility by parameter Z do not see m to be sufficient to describe this embrittlement.