Steel Authority of India

About: Steel Authority of India is a based out in . It is known for research contribution in the topics: Microstructure & Ultimate tensile strength. The organization has 797 authors who have published 661 publications receiving 9958 citations. The organization is also known as: SAIL.

Order hardening in nickel-molybdenum and nickel-tungsten alloys

Abstract: Order hardening characteristics were studied in Ni-20% Mo, Ni-25% Mo and Ni-20% W. They were processed through quench and reheat cycles and the progress of order hardening was monitored through microhardness measurements. A correlation with the microstructure as observed with polarized light microscopy and transmission electron microscopy was established. Among the various factors, such as degree of order, domain size, coherency strains and dislocations, which can contribute to strengthening, domain size seems to play a major role.

Light radiation pressure upon an optically orthotropic surface

Abstract: In this paper, we discuss the problem of determination of light radiation pressure force upon an anisotropic surface. The optical parameters of such a surface are considered to have major and minor axes, so the model is called an orthotropic model. We derive the equations for force components from emission, absorption, and reflection, utilizing a modified Maxwell’s specular-diffuse model. The proposed model can be used to model a flat solar sail with wrinkles. By performing Bayesian analysis for example of a wrinkled surface, we show that there are cases in which an orthotropic model of the optical parameters of a surface may be more accurate than an isotropic model.

Hydrogen sulphide resistance of high sulphur microalloyed steels

Abstract: Sulphide stress cracking (SSC) and hydrogen-induced blister cracking (HIBC) studies were conducted on a set of seven microalloyed steels to determine the effects of alloy additions and sulphide shape control on their H 2 S resistance. Two commercial steels with a sulphur level of 0.025% exhibited poor SSC and HIBC resistance when tested in H 2 S-containing acidic environments. A laboratory steel with 0.006% S (sulphide shape controlled) gave good SSC and HIBC resistance. High sulphur (0.025%) laboratory steels alloyed with copper, chromium, nickel, aluminium and molybdenum, and rare earth metal (REM) treated for sulphide shape control, gave an H 2 S resistance equal to or better than the low sulphur steel. Addition of copper, chromium and nickel lowered the corrosion rate and improved both the SSC and HIBC resistance. Further addition of 0.5% Al improved the SSC resistance, while addition of 0.3% Mo improved both the SSC and HIBC properties. The low sulphur steel had the lowest hydrogen concentration after exposure to H 2 S environments, while alloy additions and REM treatment lowered the amount of hydrogen absorbed by the high sulphur steels. Molybdenum addition seems to be a suitable method to make high sulphur microalloyed steels resistant to H 2 S environments.