Hot-forged wear-resistant powder meterials based on stainless steels of the austenitic class

Abstract

The microstructure, tribological and physicomechanical properties of hot-forged composites based on stainless steel of the austenitic class with additions of carbon, Cr 3 C 2 and MoS 2 are studied. The possibility is established of using these composites for powder structural articles resistant to wear and corrosion.Information about the preparation of dense wear-resistant materials based on stainless steels is very limited and it mainly concerns steels of the martensitic class, for whose preparation powder alloys of the corresponding composition or a mixture of iron powder with chromium-and carbon-containing components are used. As these components it is possible to use fine powders of chromium or chromium carbide and graphite [1,2]. Materials have also been studied [3-5] based on stainless steels of the austenitic class whose wear resistance is created by introducing solid additions to the charge (predominantly carbide additions) or by simultaneous use of carbide-forming elements and graphite. Typical for these materials is use during their preparation of fine (not more than 3-5 μm) additions of carbides or carbide-forming elements, and also of the method of single-stage compaction and sintering.We have prepared by single-stage compaction and sintering [6] composites resistant to wear and corrosion based on stainless steels of the austenitic class also containing inclusions of chromium carbide that markedly increase their wear resistance compared with known materials. In addition, apart from chromium carbide, within the composition of these materials there was some percentage of molybdenum disulfide that improves their tribological characteristics, in particular it reduces the friction coefficient especially in the absence of a lubricant.A disadvantage of the materials developed is their relatively low physicomechanical properties caused by porosity. In addition, porosity makes heat treatment difficult that is necessary in order to improve the physicomechanical and tribological properties of materials. In view of this a study was made of the possibility of preparing wear-resistant composites based on stainless steels by hot forging of porous billets. Thus, the aim of this research is to study structure formation during hot forging and heat treatment of wear-and corrosion-resistant materials based on stainless steel of the austenitic class grade Kh18N15 with different additions, and also to study the physicomechanical and tribological properties of composites.Composites based on steel Kh18N15 were studied with additions of 15% chromium carbide, 5% molybdenum disulfide, and 0.6% carbon, and also with additions of carbon alone (up to 1.4%). The standard was steel of the same grade without additions. Choice of objects was based on the results of work in [6][7][8].

Effect of chromium and manganese nitrides on the structure and properties of Kh18N15 powder stainless steel

“…It is established ( Table 3) that higher quenching temperatures increase the hardness of both materials from 20-22 HRC to 21-28 HRC. The bending strength of the materials based on stainless steel and containing nitride additions was 900-960 MPa after sintering and thermal treatment at 1050°C, which is 25 to 28% higher than the strength of Kh18N15-(10-15)% Cr 3 C 2 composites (650-770 MPa) [10].…”

Investigation of Thermomechanical Processing of Nb Microalloyed Steel Produced by Powder Metallurgy

“…This may cause a decrease in mechanical properties. Porous structure restricts the use of materials in high strength applications by causing the stresses increment [14]. It is indicated in the literature that the application of hot deformation to the materials produced by the powder metallurgy causes to exhibit better mechanical properties than the materials produced by the casting and forging method [15].…”