0 90 1 70 5 800 056 3 03 0 89 18 32 9 38 0 014 0 0028 0 98 2 00 3 900 049 3 09 0 92 18 12 12 60 0 025 0 0046 0 88 1 80 3 300 054 3 60 0 87 18 93 13 14 0 010 0 0039 0 78 1 60 3 800 060 3 93 0 83 18 01 13 27 0 014 0 0037 0 85 1 65 3 200 049 4 00 0 85 19 32 13 15 0 035 0 0096 0 85 1 60 3 65__________________________________________________________________________ the shape and size of the specimens were as previously explained with respect to the tensile test the compositions of the specimens ranges from the 18cr 10ni type to the 19cr 13ni type the oxidation weight loss is illustrated only in the drawing and numerical data therefor is omitted in these drawings black round dots represent data at 1200 u00b0 c triangle dots represent data at 1100 u00b0 c and white round dots represent data at 1000 u00b0 c as seen in these drawings both oxidation weight gain and weight loss remarkably increase at the si content range less than about 2 6 as stated previously there existed no austenitic stainless steels containing more than 2 5 si and ca the known austenitic stainless steels did not withstand cyclic heating to temperatures over 1100 u00b0 c but our study revealed the stainless steels become resistant to oxidation at temperatures over 1100 u00b0 c by combined addition of more than 2 56 si and a small amount of ca and this invention provides such steel materials the criticality.