Effect of the technological conditions of frictional treatment on the structure, phase composition and hardening of metastable austenitic steel

Abstract

Abstract. The process parameters of the frictional treatment (indenter material, medium, load) of the 12Kh18N10T chromium-nickel austenitic steel have been optimized for the criteria of strain hardening and the quality of the surface being treated. The paper studies effect of the multiplicity of the frictional action of a synthetic diamond indenter at room temperature in an argon medium and the loading temperature ranging between -196 °C and +250 °C on the hardening, phase composition and fine structure of the surface layer of the steel. It has been found that the completeness of the strain-induced ´ martensitic transformation in the surface layer of the steel is strongly dependent on the multiplicity and temperature of loading and that the level of hardening rises with the multiplicity of action, but shows little dependence on the temperature of frictional treatment.

The formation of friction-induced nanocrystalline structure in submicrocrystalline Cu–Cr–Zr alloy рrocessed by DCAP

“…Tribological tests were carried out under sliding friction conditions following the scheme "plate (sample)indenter" with the latter made of VK-8 alloy and having a cylinder shape with diameter of 4 mm and a height of 4 mm on an experimental equipment described in [10,11]. The unlubricated friction was carried out in air at the load of 196 N and sliding velocity of 0.014 m / s; the number of cycles (double passes of the indenter) amounted to 1000, the sliding distance was 9 m. The friction force was continuously measured and recorded in the process of wear.…”

“…It is known that the values of the strain of surface layers of steels and alloys attained at SPD under friction are significantly higher than in the case of using bulk deformation methods [1 -5, 9]. In this case, a friction-induced nanocrystalline structure is formed, which suggests that due to the friction effect extremely high values of plastic deformation [10,11] are realized in a thin (up to 10 μm) surface layer of metallic materials. The current study uses the dynamic channel-angular pressing (DCAP) method based on the shock-wave loading technique [9], which makes it possible to deform materials at rates by six orders of magnitude higher than when using ECAP [2 -5].…”

Increasing the micromechanical and tribological characteristics of an austenitic steel by surface deformation processing

“…FT was performed with a hemispherical synthetic diamond indenter, with the hemisphere radius R=3 mm, in the non-oxidizing argon environment, with a load on the indenter P=294 N, the mean velocity of the reciprocating indenter V=0.05 m/s, the scan length l=29 mm, with a 0.1 mm displacement of the indenter per each double scan and the number of scans n=7. The use of a synthetic diamond indenter and the argon environment during FT provides severe strain hardening of metastable austenitic Cr-Ni steel in the absence of adhesive seizure typical of FT with indenters made of a W-Co hard alloy and finely dispersed boron nitride even in case a coolant is used [5]. Tribological testing was performed under conditions of sliding friction according to the pin-plate scheme on 03Cr16Ni14Mo3Ti steel specimens with a working area of 5.5×5.5 mm reciprocating on a 45 steel plate (50 HRC) with lubrication (I-30 industrial oil), under the loads P=392 and 588 N, with the average sliding velocity V=0.07 m/s, the friction path L=160 m, the travel length l=40 mm.…”

Improving the scratch test properties of plasma-nitrided stainless austenitic steel by preliminary nanostructuring frictional treatment

“…Nanostructuring frictional treatment preceding the operation of nitriding in electron beam plasma reduces the temperature of effective nitriding to 350 °С [4]. Besides, in the frictional treatment of austenitic Cr-Ni steel with an artificial diamond indenter in argon, simultaneously with effective hardening, low surface roughness (Ra ~0.1 µm) is achieved [5,6], this also being an important aspect in the implementation of finishing technologies.…”