Wear Behavior Of Stainless Steel Research Articles

Volume fraction effect of stainless steel on microstructure, interface, corrosion and wear behavior of stainless steel / aluminum bimetal composites

304 stainless steel (SS)/A356 aluminum bimetal composites were manufactured by vacuum-assisted melt infiltration casting successfully. SS chips with different volume fractions of 35%, 50%, 60%, and 65% were used in a composite structure. Low-cost, environmentally friendly production was achieved by using chips as reinforcing material. Dry sliding ball-on-disc tests were performed against Al2O3 ball under a load of 10 N. Potentiodynamic polarization analysis was carried out in 3.5% NaCl solution. θ (Fe4Al13) and η (Fe2Al5) phases developed at the SS/Al interfaces. Abrasive and adhesive wear predominated worn surfaces, whereas galvanic and pitting corrosion mechanisms originated during potentiodynamic polarization tests. Lower volume fractions of SS chips resulted in microploughing, while their higher amounts caused microcutting during sliding. Moreover, the samples containing 60% and 65% SS failed in the corrosion tests due to the lack of passivation. The most suitable SS ratio was determined to be 50%, considering microstructural, interfacial, tribological, and anti-corrosion features of SS/Al bimetal composites.

Wear Behaviors of Stainless Steel and Lubrication Effect on Transitions in Lubrication Regimes in Sliding Contact

The wear behavior of AISI304 stainless steel was investigated under dry, water-, and oil-lubricated conditions. A block-on-disk wear test was conducted in this work, since the test conditions could be controlled easily. For oil-lubricated contact, a significant amount of thin and elongated cutting chip-like debris was observed. This is attributed to the high lubricating effect of oil. Strain-induced martensitic (SIM) transformation was observed for all AISI304 blocks after the wear test, while AISI304 consisted of a single γ-austenite phase prior to the wear test. The Stribeck curve and the corresponding lubrication regimes were also considered to explain the wear behaviors and lubrication effect of AISI304. In comparison to the dry or water-lubricated conditions, which fall in the boundary lubrication regime at a low rotation speed, it is considered that the high viscosity of the oil-based lubricant causes the lubrication condition to enter the mixed lubrication regime early at a lower speed, thus reducing the specific wear rate over the 100–300 rpm range.

Friction and wear behavior of stainless steel fabricated by powder bed fusion process under oil lubrication

The friction and wear properties under oil lubrication of stainless steels fabricated through powder bed fusion (PBF) are investigated by changing the power of the infrared laser and the scan speed. The friction coefficient increases at the initial stage of friction. Thereafter, it decreases gradually and shows an almost constant value, irrespective of the material used. The specific wear rate increases with the mean friction coefficient over the entire test period. Among the PBF steels, sample D shows lower specific wear rates than the casting steel and has intermediate values of Vickers hardness and porosity.

Dry sliding wear behavior of SS316L composites containing h-BN and MoS2 solid lubricants

Mechanical properties and wear behavior of stainless steel supplemented with different solid lubricants were investigated. Hexagonal boron nitride (h-BN), molybdenum disulfide (MoS2), and a mixture of h-BN/MoS2 embedded in 316L stainless steels (SS316L/h-BN, SS316L/MoS2 and SS316L/h-BN/MoS2) were prepared by powder metallurgy method. Various solid lubricant contents (10, 15 and 20vol%) were mixed with 316L stainless steel powders and then sintered at 1200°C in H2 atmosphere for 60min. Dry sliding wear behavior of the composites was investigated using a pin-on-disc test rig at sliding speeds of 0.1 and 0.2m/s and an applied load of 3N. The experimental results showed that small boride phase and h-BN powder occupied the pores in the microstructure of the SS316L/h-BN composite, whereas the MoS2 second phase occupied the pores of the sintered 316L matrix in the microstructure of the SS316L/MoS2 composite. The addition of h-BN decreased the sintered density and hardness, whereas that of MoS2 produced the opposite effect. The results showed that the MoS2 composite had higher wear resistance than the h-BN composite, but the h-BN composite yielded better friction reduction. Furthermore, the addition of an h-BN/MoS2 mixture could promote the hardness and wear resistance of the composites. The incorporation of h-BN and MoS2 had the potential to provide friction reduction in SS316L composites as compared with sintered 316L stainless steel. The dry sliding wear process of stainless steel composites with added h-BN, MoS2 and h-BN/MoS2 involved adhesive wear, abrasive wear, oxidative wear and delamination wear mechanisms of the compacted layer.

Comparative Studies on Wear Behaviour of Sintered 316L Stainless Steels Loaded with h-BN and MoS<sub>2</sub>

Mechanical properties and wear behavior of stainless steel embedded with different solid lubricants were investigated. Hexagonal boron nitride (h-BN) and molybdenum disulfide (MoS2)-embedded 316L stainless steels (SS316L/h-BN and SS316L/MoS2) were prepared by powder metallurgy method. Various h-BN and MoS2 contents (10, 15 and 20 vol%) were mixed with 316L stainless steel powders and then sintered at 1200°C in H2 atmosphere for 60 min. The experimental results showed that small boride phase and h-BN powder occupied the pores in the microstructure of SS316L/h-BN composite whereas the MoS2 second phase occupied the pores of the sintered 316L matrix in the microstructure of SS316L/MoS2 composite. The addition of h-BN decreased the sintered density and hardness whereas that of MoS2 gave the opposite effect. Dry sliding wear behavior of composites was investigated by using pin-on-disc test rig at the sliding speeds of 0.1 and 0.2 m/s and the applied load of 3 N. The results showed that the MoS2 composites had higher wear resistance than the h-BN composite but the h-BN composite yielded a better friction reduction.

Wear behaviour of stainless steel sintered and alloyed with titanium, cobalt and molybdenum

In this study, a powder mixture was prepared by adding 1–3 wt-% of FeMo, FeTi and Co powders to the austenitic stainless steel powders and samples were produced by the powder metallurgy method. Attempts were made to establish correlations between the microstructure, hardness, toughness, and abrasive wear values of these samples. Wear resistance of the materials was measured by a two body pin-on-disk wear tester. SiC abrasive papers of 65 μm and 177 μm sizes were used as the abrasive media. Wear tests were performed at the loads of 10, 20, and 30 N at room temperature. They showed that the softer, base austenitic stainless steel exhibited higher mass loss than the alloyed samples. Furthermore, the abrasive wear resistance of the base austenitic stainless steel composites increased with increasing FeTi, FeMo,Co content. The wear rate with the 177 μm SiC abrasive paper increased more than that with the 65 μm SiC abrasive paper.

Abrasion resistance of stainless-steel composites reinforced with hard TiB 2 particles

AISI 304 stainless steel and composites reinforced with various volume fractions of TiB 2 particles were fabricated by hot-isostatic pressing. Pin-on-disc measurements were used to study the two-body abrasive wear behaviour of stainless steel and the composites. In the tests, the pin specimen was sliding against the counterpart disc bonded with an abrasive SiC paper of 240 grit size. The results showed that the wear resistance of 304 stainless steel generally increases with increasing TiB 2 content. This was due to the fact that the hardness of reinforcing TiB 2 particles was higher than that of SiC abrasives, leading to blunting of the abrasive particles. Scanning electron microscope observations revealed the presence of long continuous grooves on the surface of the stainless steel after sliding. By contrast, hard TiB 2 particles were observed to reside on the top surface of composites, thereby resisting the micro-cutting action of abrasive particles effectively.

Tribological behaviour of Ti6Al4V modified by surface treatments

At present, there are no good materials that can substitute ultra-high molecular weight polyethylene (UHMWPE), therefore the only way forward is to find a material for femoral heads with high wettability and hardness able to minimize the wear phenomena between metal and UHMWPE. In this work, the effects of surface treatments to improve the tribological behaviour of titanium alloy (Ti6Al4V) were studied. Ion implantation, CVD and PVD were the surface treatments investigated. Ti6Al4V modified and not modified samples were tested against γ-ray sterilized UHMWPE pins using a pin-on-flat wear test machine. The results have been compared with the wear behaviour of stainless steel (AISI 316L). Tests were carried out in accordance with ASTM F 732-82 practice, a specific wear test for materials used in total joint prostheses. Metal samples were characterized by SEM micrographs, roughness and hardness measurements, wettability and friction coefficient. UHMWPE wear rates were assessed by weighing the pins at intervals of 250 000 cycles and were expressed by linear regression analysis applied to the weight losses. Ion implantation of the titanium alloy results in lower wear of UHMWPE pins, in particular, chromium implantation is the most efficient among all surface treatments. A tentative explanation of the results is given.

The high temperature sliding wear of stainless steel in a CO 2 atmosphere—The effect of adding low concentrations of O 2

Sudden transitions in the friction and wear behaviour of stainless steel have recently been identified as a function of the sliding distance during high temperature sliding wear in CO 2. This work has studied the effect of making controlled additions of O 2 to CO 2 on such behaviour. The predominant effect is a significant fall in the number of cycles at which a severe-to-mild wear transition takes place, this being explained in terms of an increased rate of substrate hardening due to oxide inclusion into the subsurface layer. It is postulated that the enhanced rate of hardening is due to an acceleration in the linear oxidation rate of freshly revealed metal surface with increasing O 2 concentration. The present data are fitted to such a hypothesis on the basis of a previous model for the cycles to a transition; development of the previous model allows the fitting of the data with only one unknown parameter, the dissociation rate of CO 2. The best-fit value for this parameter is in reasonable agreement with that derived from existing linear oxidation data.