The effect of the method for producing chromium-nickel stainless steel powders on the strain state and properties of the outer cage of a spherical hinge joint

The paper substantiates the relevance of studying powder metallurgy methods and efficiency of applying them to the production of spherical bearings of highly loaded spherical hinge joints. It proves that the force and work of deformation, as well as the kinetics of forming of the outer cage of a spherical hinge joint made of sintered corrosion-resistant chromium-nickel steels, are influenced by the chemical composition of powders and lubricants, the protective environment and the method of sintering, the microstructure and mechanical properties of the workpiece material. It is shown that the plastic properties of ring specimens under testing depend on the perfection of interparticle contacts, the presence and distribution of chromium oxides, forming schemes and workpiece porosity. The influence of the method for the production of stainless chromium-nickel powders on the density and mechanical properties of the sintered blanks is studied. A method is proposed for evaluating the strain state during radial deformation of ring specimens made of these steel powders and estimating the maximum allowable values of strain intensity below which no cracks are formed during cold forming of porous blanks. It is revealed that, to calculate the stress state and, accordingly, strain resistance in the cold forming of the outer cages of spherical hinge joints, made of sintered corrosion-resistant steels, it is possible to use the known constitutive equations if strain intensity does not exceed the experimentally obtained limit values. The feasibility of implementing the proposed method and selecting the process parameters of cold forming of spherical hinge parts made of chromium-nickel austenitic steels is substantiated.