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In order to alleviate the shortage of global nickel resources, it is imperative to develop low nickel stainless steel. This paper presents a novel approach based on increasing nitrogen and reducing nickel for smelting economical stainless steel. Taking 06Cr19Ni10 stainless steel as the object, the test steels with different nitrogen and nickel content were smelted using vacuum induction furnace (ZG-0.01) under the laboratory conditions, and the effects of alloy content on microstructures, mechanical properties and corrosion properties of the economical stainless steel were investigated. The results show that the microstructure of the tested steel which nitrogen content 0~0.28% and nickel content 5.98~9.63% is still the single austenitic, and the grain size decreases as the nitrogen content increases. Nitrogen deteriorates the impact toughness of the tested steel, and the room temperature impact absorption energy is reduced from 267 J at the nitrogen content of 0 to 228 J at nitrogen content of 0.28%. Rockwell hardness, tensile strength and yield strength increase with the increase of nitrogen content. When the nitrogen content is 0.28%, the optimum mechanical properties of 06Cr19Ni10 steel are obtained. The Rockwell hardness is 95.4 HRB, the tensile strength is 814 MPa, the yield strength is 437 MPa, and the elongation after fracture is 52.5%. The degree of intergranular corrosion of the tested steel is reduced significantly with the increase of nitrogen content, from 0.023 μm to 0.008 μm. The experimental data prove that the composition design concept of increasing nitrogen and reducing nickel is feasible for smelting economical stainless steel.

Aqueous polyurethane(PU) polyols were synthesized from polyester polyol, toluene diisocyanate(TDI), dimethylolbutyric acid (DMBA) and diethanolamine(DEA). The structure of PU polyol and resulting polyurethane film were confirmed by the Fourier Transform Infrared Spectroscopy (FT-IR). The effects of NCO/OH and DMBA content on the particle size of PU polyol and resulting polyurethane films, which formed by the mixture of PU polyol and water-dispersible polyisocyanate, was investigated by dynamic light scattering analysis, dynamic mechanical analysis and measurement of the mechanical properties.The results show the increase in DMBA content or NCO:OH ratio may be used to decrease the particle size of aqueous polyurethane polyol, increase the Tg for two-component aqueous PU film and maybe adjust the mechanical properties of resulting film.