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.

Weldability and Microstructural Aspects of Shielded Metal Arc Welded HSLA-100 Steel Plates

Abstract: HSLA-100 steel with 14 mm thickness in quenched and tempered condition was shielded metal arc welded (SMAW) with 2 kJ/mm heat input using basic flux coated filler rods without any pre or post welding heat treatments. The steel was found to be welded satisfactorily in this condition without developing any defect. Optical microscopy studies revealed typical cast dendritic structure in the weld metal and coarse bainite in grain-coarsened area of the heat-affected zone (HAZ). Transmission electron microscopy (TEM) study confirmed incidence of mixed structure of martensite laths and bainite in weld metal, while, it was mainly of bainite laths in HAZ with evidence of martensite–austenite (M–A) constituent and massive ferrite. The yield strength (YS), ultimate tensile strength (UTS) and Charpy V-notch (CVN) impact energy of the weld metal (YS-695 MPa, UTS-842 MPa and CVN-105 J at –50°C) and HAZ (YS-790 MPa, UTS-891 MPa and CVN-130 J at –50°C) were found satisfactory although HAZ properties were inferior to the base metal properties. The hardening of HAZ was not very significant in this steel under the present welding condition.

Strain energy based low cycle fatigue damage analysis in a plain C-Mn rail steel

Abstract: Strain-controlled low cycle fatigue tests were performed on 60 kg/m 90-UTS plain C-Mn rail steel with fully pearlitic microstructure. Analysis of hysteresis loop shape and properties revealed that the steel deviated from the ideal Masing type material behaviour to a little extent. To evaluate the fatigue damage in rail steel, energy-based analytical approach proposed by Morrow based on Masing hypothesis was employed. The Morrow energy model resulted in reasonably good approximation of both average plastic strain energy and fatigue life in comparison to experimentally observed values. In addition to that the plastic strain energy density (ΔWp) was correlated to fatigue life (2Nf) through a simple power law and very well represented by Coffin-Mansion type relationship similar to conventional strain-life (Δep – 2Nf) relationship. Finally, the concept of fatigue toughness, an energy parameter, was introduced to life prediction in rail steel which was proved to be a suitable and reliable alternative to strain-life approach in fatigue damage evaluation with high degree of accuracy.

Effect of Inclusions and Microstructural Characteristics on the Mechanical Properties and Fracture Behavior of a High- Strength Low- Alloy Steel

Abstract: The strength and toughness properties of hot-rolled plates from three commercial heats of a high-strength low-alloy steel were investigated with respect to their intrinsic microstructural and inclusion characteristics. One heat was argon purged and contained relatively higher carbon and sulfur, whereas the other two heats, with lower carbon and sulfur levels, were sulfide shape controlled. The study revealed that although yield and tensile strengths specific to a heat were unaffected by testing direction, the anisotropy in tensile ductility was greater in steels with stringered sulfides. Despite similar grain sizes in all the steels, Charpy shelf energy and impact transition temperature were significantly affected by pearlite content and sulfide morphology and to a lesser extent by pearlite banding. The modification of stringer sulfides to tiny lenticular/globular oxysulfides resulted in considerably higher shelf energies, lowering of impact transition temperatures, and minimal anisotropy of impact properties. The macroscopic appearance of splitting on the fracture surfaces of transverse Charpy specimens associated with low impact energies confirmed failure by a low-energy mode. The presence of pancake-shaped ferrite grains and fractographic evidence of inclusion stringers inside furrows identified their role in accentuating the splitting phenomenon.