High temperature embrittlement characteristics of continuous casting billet steel

High temperature embrittlement characteristics of continuous casting billet steel
Among the defects of continuous casting slab, various surface and internal cracks account for a considerable proportion. The occurrence of cracks is mostly related to the high temperature characteristics of steel and various mechanical behaviors during solidification. The high-temperature embrittlement characteristics of steel refer to the toughness characteristics or embrittlement tendency of high-temperature cast slabs.

The plasticity and strength changes of cast slabs at high temperatures can be divided into two embrittlement zones:
1. High temperature embrittlement zone in the range of 1300℃ to solidus temperature. The decrease in ductility in this zone is caused by the separation of the liquid phase film between the crystal grains, especially the sulfides FeS and MnS, as well as phosphorus and other easily segregated elements will promote the formation of this low melting point phase. Changes in carbon content will also reduce the ductility of steel in this zone.
2. The embrittlement zone of 700~900℃. For most steels, this is the temperature range where the γ-phase to α-phase transition occurs, and its degree can be controlled by various measures. When the billet is in this temperature zone, bending and straightening should be avoided.

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