Affiliation:
1. Steel Authority of India Limited
2. Rourkela Steel Plant
Abstract
The C, Mn and Si impart high strength to steels through solid solution strengthening. On hardening and tempering, these elements further increase the strength substantially by exploiting hardenability potentials. With this point in view, a microalloyed C-Mn-Si steel was designed to have elements in the range of C:0.24-0.28, Mn:1.30-1.50, Si:1.30-1.50, Cr.0.10-0.20, Ni:0.20-0.40, Mo:0.15-0.25, P:0.015max, S:0.010max and H:2ppm max. Aiming at this range of chemistry, steel was made in an electric arc furnace, refined in VAD and continuous cast to 170mm x 1160 mm slabs. Prior to hot rolling of the slabs, hot deformation and dilatation studies were carried out in a Gleeble-3500C system for simulating hot rolling and heat treatment schedules. Employing the designed parameters, the slabs were hot rolled to 5 mm x 1135 mm x 4600 mm plates, which were subsequently hardened and tempered to obtain hardness levels >460 BHN, YS >1300 MPa, UTS >1500 MPa, elongation >8% and reduction in area >25% in the material. The plates contained >95% martensite in the microstructure and observed to have adequately smooth surfaces free from defects such as holes, roll marks, scabs and rolled-in scale, etc.
Keywords: Hardening, Tempering, Quenching, Simulation, Strategic Application
Publisher
Trans Tech Publications, Ltd.
Subject
Mechanical Engineering,Mechanics of Materials,Condensed Matter Physics,General Materials Science
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