Plane strain compression of high silicon steel

Abstract

A series of plane strain compression tests were conducted at room temperature on a high silicon steel to study the behaviour of this material owing to the similarity of this test with rolling. The tests were performed in a specially designed machine able to control the strain rate profile and the amount of deformation. The material was cast and hot rolled to a thickness of 4 mm from which the experimental samples were machined. Plane strain compression tests were carried out at three constant rates of strain (0·01, 0·1 and 1 s⁻¹) up to four levels of equivalent strain (0·15, 0·30, 0·45 and 0·60). ⁵⁷Fe Mössbauer spectroscopy analyses indicate that the degree of order of the material decreases with the amount of deformation until a strain of 0·45 is achieved; a further increase in strain augments the order of the material. It is found that the strain rate sensitivity close to yielding is negative, but converts to positive once a stain of ∼0·04 is surpassed. Microstructural analyses of deformed samples show that deformation is by twinning and shear. Electron backscattered diffraction analyses indicate that twinning occurs only at an early stage of deformation within grains with {111} planes parallel to the plane of deformation. Deformation twinning takes place in all grains at later stages of deformation.

Keywords:

• SILICON STEELS
• PLASTIC DEFORMATION
• TEXTURE
• MECHANICAL PROPERTIES
• ORDER
• 57FE MOSSBAUER SPECTROSCOPY
• TWINNING