Effects of Residual Elements Arsenic, Antimony, and Tin on Surface Hot Shortness

Abstract

Scrap-based electric arc furnace (EAF) steelmaking is limited by a surface cracking problem in the recycled steel products, which is known as surface hot shortness. This problem originates from the excessive amount of copper (Cu) in the steel scrap, which enriches during the oxidation of iron (Fe) and consequently melts and penetrates into the austenite grain boundaries. In this article, the effects of arsenic (As), antimony (Sb), and tin (Sn) on surface hot shortness were investigated. A series of Fe-0.3 wt pct Cu-x wt pct (As, Sb, or Sn) alloys with x content ranging from 0.06 to 0.10 wt pct was oxidized in air at 1423 K (1150°C) for 60, 300, and 600 seconds inside the chamber of a thermogravimety analyzer (TGA) where heat is supplied through infrared radiation. Scanning electron microscopy (SEM) investigations show that (1) the presence of Sb and Sn results in severe grain boundary cracking, whereas the presence of As does not, (2) open cracks with Fe oxides were found beneath the oxide/metal interface in the Sb and Sn alloys, and (3) the oxide/metal interfaces for all As, Sb, and Sn alloys are planar. Penetration experiments of pure Cu and Cu-30 wt pct Sn liquid were also conducted in the chamber of a hot-stage confocal laser scanning microscopy (CLSM) in nonoxidizing atmosphere: (1) on the Fe-35 wt pct manganese (Mn) alloys to study the correlation between cracking and grain boundary characters, and (2) on the pure Fe substrates to exclude the bulk segregation effects of Sn on grain boundary cracking. It was found that grain boundary cracking rarely took place on low-energy grain boundaries. The results also suggest that the bulk segregation of Sn in the substrate is not necessary to promote significant grain boundary cracking, and as long as the liquid phase contains Sn, it will be highly embrittling.

Arsenic Removal from Arsenopyrite-Bearing Iron Ore and Arsenic Recovery from Dust Ash by Roasting Method

“…For example, arsenic reduces the quality of raw materials, affects the extraction of metal, interferes with the purity of the product, and poses serious environmental hazards [1]. Arsenic has an adverse effect on steel; for instance, the surface hot shortness increases, and the reduction of area and impact toughness decrease with the increase of arsenic content in steel [3][4][5][6]. Under the hot rolling or welding conditions, the arsenic in the steel leads to the increase in the content of arsenic at grain boundaries and the expansion of welding cracks [4,[7][8][9].…”

Improvement of hot ductility of C-Mn Steel containing arsenic by rare earth Ce

“…Consequently, the impurities are unavoidably accumulated in the steel scraps recycling. Once the impurities concentration exceeding a certain limit, they would considerably affect steel properties such as hot ductility deterioration [1], hot shortness [2].…”

Effect of Arsenic and Copper+Arsenic on High Temperature Oxidation and Hot Shortness Behavior of C–Mn Steel

“…[3][4][5][6][7][8][9][10] However, these studies almost focused on the copper content ranging from 0.25 wt% to 1.0 wt% instead of the lower copper content more commonly produced by electric furnaces, even the oxidation behavior and surface hot shortness of steels with the lower content of coexisted copper and arsenic. So far, Yin L. et al 11) has investigated the effect of 0.06 wt%-0.1 wt%As on oxidation behavior of Fe-0.3wt%Cu alloy in the (Received on January 2, 2016; accepted on March 17, 2016) To avoid surface hot shortness of C-Mn steels containing arsenic and copper + arsenic, high temperature oxidation behavior of the steels were systematically investigated. The results showed that the presence of arsenic and copper + arsenic accelerated oxidation degree of C-Mn steel.…”