Application of ultrasonic testing method for determining defects of hot-deformed powder materials

Don state technical University, Rostov-on-don, Russia

^* Corresponding author: aquavdonsk@mail.ru

Abstract

The article is devoted to the analysis of elastic and plastic characteristics of composite materials during hot stamping. The purpose of this work is to offer optimal conditions for hot plasticity of composite porous material with determination of temperature conditions of hot stamping excluding the appearance of defects in the structure. Production of details of the difficult form by method of hot stamping from preparations of the cylindrical form is followed by development of barrel on a peripheral surface. Sludge sintered porous blanks, and sediment compact material, accompanied by a nonuniform height lateral deformation. In connection with the action of friction forces on the contact surfaces, this leads to the formation of a “barrel”. The heterogeneity of the deformed state is associated with the appearance of tangential tensile stresses on the free surface of the workpiece. If they exceed some critical degree of transverse deformation, cracks appear on the side surface, which leads to gas saturation (oxidation) of the inner layers of the forging, to the ingress of grease into them and its pressing into the volume of the part during hot stamping. In the end, this significantly reduces the properties of hot-stamped parts. Conclusion: the methods of determining the elastic characteristics depending on the geometric parameters of the workpieces, the applied strain energy, body density and temperature dependence of the plasticity characteristics of the hot deformation of the powder material are сonsidered.