ON A PROPRIETERY STAINLESS STEEL.

Abstract

The physical, mechanical and welding properties of a proprietery staihless steel of the following composition were studied:C 0·25; Si 0·1-2·0; Cu 0·05-4·5; Ni 1-7; Cr 16-30; W 0·2-8·0%. One or more of the following optional element may be present: V 1·0; Co 1·0; Al 1·0; Ti 1·0%. In the experiment, the steels were divided into the four grtoups: martensitic, ferritic, austenitic and austeno-ferritic, according with the different proportions of Ni and Cr within the patented range and to each of which 1-8% W was added. From the result of the experimgnt it was concluded that, besides its high strength and at elevated and room temperatures, it has excellent corrosion resistance to dilute sulphuric, hydrochloric, sulphurous, nitric, phosphoric, oxalic, tartaric, acetic and formic acids. Steels containing 18% Cr, 7% Ni and 5-8% W may be favorably used for handling such solution as ferric chloride or sea water plus hydrogen peroxide, which will cause pitting. As, for the resistance to infergranular corrosion, the addition of W alone is, not so efficient as that of Ti or Cr, but rather Si or Ti should be accompanied for this purpose.