Authors: Erica Sampson Seetharaman Sridhar
Publish Date: 2014/07/11
Volume: 45, Issue: 5, Pages: 1769-1781
Abstract
Residual Cu in recycled steel scrap can cause hot shortness when the iron matrix is oxidized Hot shortness can occur directly after the solid steel is formed from continuous casting as the steel undergoes a cooling process known as secondary cooling where water is first sprayed on the surface to promote cooling This is followed by a radiant cooling stage where the steel is cooled in air to room temperature This investigation examines the roles of water vapor Si content temperature and the presence of Sn in a Fe02 wt pct Cu005 wt pct Ni alloy on oxidation separated Cu and Cu inducedhot shortness during simulations of the secondary cooling process The secondary cooling from 1473 K 1200 °C resulted in a slight increase in liquid quantity and grain boundary penetration as compared to the isothermal heating cycles at 1423 K 1150 °C due to the higher temperatures experienced in the nonisothermal cycle The addition of water vapor increased the sample oxidation as compared to samples processed in dry atmospheres due to increased scale adherence scale plasticity and inward transport of oxygen The increase in weight gain of the wet atmosphere increased the liquid formation at the interface in the nonSi containing alloys The secondary cooling cycle with water vapor and the effect of Sn lead to the formation of many small pools of Curich liquid embedded within the surface of the metal due to the Sn allowing for increased grain boundary decohesion and the water vapor allowing for oxidation within liquidpenetrated grain boundaries The presence of Si increased the amount of occlusion of Cu and Fe significantly decreasing the quantity of liquid at the interface and the amount of grain boundary penetration
Keywords: