INVESTIGATION OF STRUCTURE AND SEVERAL PROPERTIES OF CARBON STEEL OF GRADE 50 DEFORMED BY DRAWING

Abstract

The continuous method of deformational nanostructuring is pre­sented. It consists of simultaneous applying of the tensile deformation by drawing, bending deformation while going via the rolls system and twisting deformation to the continuously moving wire. Combination of different kinds of deformation makes it possible to change in a wide range its mechanical properties matching high strength and ductility. The advantage of this scheme of deformational processing consists in arranging together tools which are used in metal ware manufacturing industrial processes as well as its simplicity and compatibility with rates at coarse and middle drawing processes. The scheme of the labo­ratory unit for the method implementation is considered. Wire from medium carbon steel of grade 50 was chosen as the object for inves­tigation because it is considered to be the needed kind of metal ware product. Chemical composition and mechanical properties of this wire are described. Experiments on investigation of the possibility for ultra­fine-grained structure formation effectiveness in carbon steel wire were conducted using the developed laboratory unit. Deformation modes and drawing route are given. Microstructure of the wire from medium carbon steel of grade 50 was studied after different kinds of deforma­tional processing in longitudinal and transversal cross-sections. Dur­ing experimental researches the effect of deformational processing on carbon steel wire microstructure was specified as well as its anisotropy in the cross section. The mechanical properties of the wire of grade 50 steel were studied after different kinds of deformational processing. The verification of these properties was carried out in accordance with the demands in current national wire standards. It was proved that car­bon steel wire mechanical properties matches well with norms set in GOST17305-91. Investigation results of microstructure and mechani­cal properties of the wire from medium carbon steel of grade 50 after different kinds of deformational processing show the perceptiveness of the chosen direction for combination of different kinds of deformation for ultrafine-grained structure formation in carbon steel wire.