CHARACTERISATION OF MILL SCALE FROM THE ROLLING MILL AND STUDIES ON UTILIZING IT FOR PRODUCTION OF STEEL BY POWDER METALLURGY ROUTE

Abstract

In this dissertation attempt has been made to reduce the Mill Scale received from "Bharat Rolling Mill, Muzaffamagar". The Rolling Mill Scale is reduced with carbon present in cast Iron. The mixture of rolling mill scale and Cast Iron powder-l00 mesh size were taken in 1:3.2 ratios in a graphite crucible and sealed with a refractory clay paste. Large numbers of pores were made on shielding surface to remove the gas generated during reduction. Then it was placed in the furnace and held at 950 °C for different time durations (7 to 21 hours) for reduction. This reduced mill scale powder was further reduced with hydrogen to investigate any improvement in characteristics with an aim to achieve P/M grade steel powder. The produced Iron powder was characterized by hydrogen loss value, chemical analysis, compressibility, apparent density, sieve analysis, Hall flow rate. Chemical analysis has been performed by AAS (Atomic absorption spectroscope) technique. The produced powder had as low as 0.018 % carbon and 0.238 % sulphur could be obtained from reduction carried at 950°C for 21 hours using cast iron powder. The sulphur got further reduced after reduction with hydrogen. The powder metallurgical characteristics of produced powder were also evaluated and documented in later part of the work. P/M grade characteristics of powder could be achieved only after treatment of powder with hydrogen.