JOURNAL OF MATERIALS SCIENCE LETTERS 22, 2 0 0 3, 691 – 693 High temperature resistance of a high nitrogen and low nickel austenitic stainless steel A. DI SCHINO, J. M. KENNY ∗ Materials Engineering Center, University of Perugia, Loc. Pentima Bassa 21, 05100 Terni, Italy E-mail: kenny@unipg.it M. BARTERI Centro Sviluppo Materiali, Via di Castel Romano, 00129 Rome, Italy Nitrogen alloyed austenitic stainless steels exhibit at- tractive properties such as high levels of strength and ductility, good corrosion resistance and reduced ten- dency to grain boundary sensitization [1]. The high austenitic potential of nitrogen in steel allows the reduc- tion of nickel content, offering additional advantages such as reduction of allergic risks and costs saving. The production of these low nickel steels is made possible by the addition of manganese which increases N solu- bility in the melt and decreases the tendency to Cr 2 N formation [2]. Moreover, since nitrogen increases the stability of the austenitic phase against martensite for- mation [3], nitrogen alloyed austenitic stainless steels can be strengthened by cold working without forma- tion of strain induced martensite. This results in higher mechanical properties and in a good balance between toughness and tensile properties. Specific potential applications of this new family of steels include automotive hose clamps, safety belt anchors, truck and bus frames, water supply and con- trol structures, sewage treatment plant structures, bulk solids handling equipment, magnetic ore separator screens, coal buckets and hopper cars. Moreover, stain- less steels have served successfully in many structural components in the transportation industry. In particular bus frames and bumpers can take advantage of the high strength of this new family of stainless steels. In previous reports we examined the influence of the grain size and of the chemical composition on the me- chanical, corrosion and wear resistance of this family TABLE I Chemical composition of the studied stainless steels (weight%) Cr Ni Mn Si Mo N P S C HN 16.5 1.07 11.4 0.12 1.0 0.30 0.022 0.003 0.037 T A B L E I I Room temperature yield strength ( R p02 ), tensile strength ( R m ) and fracture elongation ( A) of the HN steel R p02 (MPa) R m (MPa) A (%) HN 420 720 42 ∗ Author to whom all correspondence should be addressed. of steels [4, 5]. In this paper the mechanical, creep and corrosion properties of a high nitrogen stainless steel are studied at high temperatures. The chemical compo- sition of the steel (hereinafter HN) under consideration is shown in Table I and its room temperature mechani- cal properties are reported in Table II. In order to investigate the temperature effect on the tensile properties of the steel, 50 longitudinal ISO ten- sile specimens were cut from the material in the cold rolled and annealed state and tensile tests were carried out with a deformation rate of 3 mm/min over a tem- perature range from 600 ◦ C to 900 ◦ C. The temperature 0 50 100 150 200 250 500 600 700 800 900 1000 T (°C) R p02 (MPa) HN AISI 304 AISI 316 Fe 360 Figure 1 Temperature dependence of the yield strength of the HN steel in comparison to standard steels. 0 10 20 30 40 50 60 70 80 90 700 750 800 850 900 950 T (°C) Deflection (mm) HN AISI 304 AISI 409 AISI 321 Figure 2 Creep resistance of the HN steel (measured by means of SAG test) in comparison to standard stainless steels. 0261–8028 C  2003 Kluwer Academic Publishers 691