Hot ductility behavior of medium carbon sulfur-containing alloy steel

Abstract

Sulfur-containing free-cutting steels are widely used because of their excellent processability. However, the crack problem of sulfur-containing steel during continuous casting production is still not solved. Therefore, this paper investigates the effect of sulfur content on the crack susceptibility or hot ductility of medium carbon alloy steel in detail. This research designed and produced four kinds of medium carbon alloy steel with different sulfur content. It also investigated the hot ductility of steel through a hot tensile test. This study focuses on the effect of sulfur content on the flow stress–strain curve, hot ductility curve, fracture morphology, and inclusions of the steel. The results show that the sulfur-containing steel has better hot ductility at low temperatures (750–900 °C) and worse hot ductility at medium temperatures (1000–1250 °C) compared to the sulfur-free steel. The difference is mainly related to the precipitation behavior of the MnS inclusions in the steel. The hot ductility behavior of medium-carbon sulfur-containing alloy steel grade is primarily related to DRX and the precipitation behavior of MnS inclusions.

Keywords

• Hot ductility
• Sulfur content
• Medium carbon alloy steel
• Brittle zone
• MnS inclusion