Structure and properties of sintered corrosion-resistant steel manufactured from electroerosive powders

Corrosion-resistant steels are characterized by several very valuable properties, thereby they are effectively used in different industries [1–3]. The sintering technology of corrosion-resistant steels has several features which are stipulated by high chromium affinity to oxygen and, respectively, by necessity of use of deeply dried protective media and high temperatures. Single and dual extrusion and sintering within the temperature range 1150–1300 °С are the most frequently applied technological procedures for manufacture of powder corrosion-resistant steels [4–8]. The properties of powder corrosion-resistant steels are generally determined by their porosity, thereby corrosion-resistant steels which are applied at present time are characterized by lower strength (by 10–30 %), plasticity (by 2–3 times) and impact toughness in comparison with the corresponding properties of cast steels. It restricts their application area. Porosity of corrosion-resistant steels has negative effect on corrosion resistance. This problem can be solved owing to use of the spark plasma sintering technology which allows to decrease porosity in sintered alloys to 1 % [9–14]. Additionally, presence of large amount of expensive chromium in corrosion-resistant steels is considered as one of the main problems of their recycling [15–17]. This problem can be solved via comminution of wastes and their secondary use. The existing industrial comminution technologies are characterized by large-scale production facilities, high energy consumption and environmental problems. So, electroerosion method seems to be one of the prospective and not applied industrially technologies for comminution of any conductive material at present time [18, 19]. At present time there are no scientific-technical developments for use of waste particles of corrosion-resistant alloys (which were dispersed by electroerosion) as charge material for manufacture of sintered products from these wastes. Conduction of complex theoretical and experimental investigations is required for these purposes. It will help to solve the problem of porosity decrease for sintered corrosion-resistant alloys and saving the expensive chromium. The aim of this research was examination of structure and properties of sintered samples produced in butyl alcohol and fabricated from corrosion-resistant powders subjected to electroerosion. Obtaining of the new relationships and interactions between composition, structure and properties of sintered corrosion-resistant alloys (from one side) and sintering technology for powder materials fabricated via electric dispersion of 12Kh13 steel wastes are estimated as novelty of this research. To solve the above-noted problem of obtaining low-cost porous-free microstructure of corrosion-resistant steels, the prospective technologies of electroerosion dispersion and spark plasma sintering will be applied. Structure and properties of sintered corrosion-resistant steel manufactured from electroerosive powders