Title

IMPROVEMENT OF BOTH MECHANICAL PROPERTIES AND METALLURGICAL MICROSTRUCTURE OF WIRE ROD COLD HEADING STEEL BY APPLYING THERMO-MECHANICAL ROLLING

IMPROVEMENT OF BOTH MECHANICAL PROPERTIES AND METALLURGICAL MICROSTRUCTURE OF WIRE ROD COLD HEADING STEEL BY APPLYING THERMO-MECHANICAL ROLLING

Authorship

Cimolino, Maicol; Spadaccini, Andrea; Marzio, Sara

Cimolino, Maicol

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Spadaccini, Andrea

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Marzio, Sara

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DOI

10.5151/2594-5297-39723

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Abstract

Thermomechanical rolling of cold heading grades rolled in different conditions was industrially conducted in a last generation wirerod rolling mill. The results showed that the improvement of mechanical properties, and the trade-off between the necessary ductility prior to processing and the final characteristics reached after further thermal treatments can be attributed mainly to the grain refinement and microstructure modification. In these experiments, the decrease in ultimate tensile strength and the increase in ductility are obtained by lowering the finishing rolling temperature in the last passes of the sizing mill (Twin Module Block, or TMB), compared to traditional rolling, in a range of 780÷800 °C, where it is characterized by material deformation in the non-recrystallization region of austenite. Further investigations by the end user, who will test the coils made at different rolling temperatures, will be needed to confirm the encouraging results obtained on the as-rolled material.

Thermomechanical rolling of cold heading grades rolled in different conditions was industrially conducted in a last generation wirerod rolling mill. The results showed that the improvement of mechanical properties, and the trade-off between the necessary ductility prior to processing and the final characteristics reached after further thermal treatments can be attributed mainly to the grain refinement and microstructure modification. In these experiments, the decrease in ultimate tensile strength and the increase in ductility are obtained by lowering the finishing rolling temperature in the last passes of the sizing mill (Twin Module Block, or TMB), compared to traditional rolling, in a range of 780÷800 °C, where it is characterized by material deformation in the non-recrystallization region of austenite. Further investigations by the end user, who will test the coils made at different rolling temperatures, will be needed to confirm the encouraging results obtained on the as-rolled material.

Keywords

Thermo-Mechanical Rolling, Wire rod, Cold heading steel, C30B+CrTi, 30CrB3+Ti.

Thermo-Mechanical Rolling, Wire rod, Cold heading steel, C30B+CrTi, 30CrB3+Ti.