Thermomechanical steels behaviors at semi-solid state

• Main Authors: Traidi, K., Favier, V., Lestriez, P., Debray, K., Langlois, L., Ranc, N., Saby, M., Mangin, P.
• Format: Conference Proceeding
• Language: English
• Subjects: Alloy steels; Forging; Melting points; Near net shaping; Porosity; Rheological properties; Semi-solid processing; Shrinkage; Solid state; Tensile tests; Thermomechanical properties; Thixoforming
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/1.4963418

Semisolid thixoforming is an intermediate process between casting and forging. The combination of the semi-solid state and globular microstructures leads to thixotropic properties of the material [1]. Thixoformingprocess presents several advantages such as energy efficiency, high production rates, smooth die filling, low shrinkage porosity, which together lead to near net shape capability and thus to fewer manufacturing steps than with classical methods. So far, there are only few applications of semisolid processing of highr melting point alloys [2]. Steel is a particularly challenging material to semi-solid process because of about 1400°C temperatures involved. Characterizing and modelling such semi-solid behaviour for steels is still challenging. The aim of the research work was to study the rheological properties of a suitable graded steel (LTT C38) designed for semi-solid processing. An experimental protocol was determined to characterize the thermomechanical behaviors and defect condition. Uniaxial tensile tests were carried out on semi-solid specimen having >0.8 solid fraction for different temperatures. The variation in both ductility and strength with temperature has been identified.