Wear Of Stainless Steel Research Articles

Influence of atmospheric humidity and grain size on the friction and wear of high nitrogen austenitic stainless steel

Research on steels is still active and is motivated by the need to make further improvements in their properties. Among the different steel types, austenitic stainless steels possess good corrosion resistance and formability. However, they also have a relatively low yield strength. One method of increasing the yield strength is by alloying the steel with nitrogen. Such nitrogen-alloyed austenitic stainless steels exhibit attractive properties such as high strength and ductility, good corrosion resistance and reduced tendency to grain boundary sensitation [1]. The high austenitic potential of nitrogen allows the reduction of nickel content in steel. This offers additional advantages such as cost savings and makes the steel more suitable for stainless steel applications involving contact with human skin for people with nickel allergies. Due to the above-mentioned properties, in recent years significant efforts have been devoted to the production of high nitrogen austenitic stainless steels, and metallurgists have been very active in research concerning this class of steels. Particularly, considerable attention has been paid to solidification mechanisms and recrystallization processes [2–4]. Nitrogen in solid solution produces, in the austenitic stainless steel, many desirable properties: it stabilizes the austenite γ phase and increases the resistance to intercrystalline and pitting corrosion, but the most important property is the increase of the yield strength (RP0.2) without a corresponding decrease in ductility. There is another way of increasing the yield strength without severely affecting the ductility. This can be achieved by grain refining. Since austenitic stainless steels do not undergo phase transformation at typical annealing temperatures, the only way to refine the grain size is by recrystallization after cold rolling. An alternative way to obtain fine grains is by applying an austenite-martensite-austenite transformation. In previous publications [5, 6], we examined the influence of grain size and chemical composition on the mechanical properties and corrosion resistance of this family of steels.

Effects of grain size on the properties of a low nickel austenitic stainless steel

The effect of the grain size (varying in the range of 2.5–50 μm) on the mechanical properties and on the wear and corrosion resistance of a low nickel austenitic stainless steel is reviewed. In particular, the austenite-martensite transformation followed by annealing for martensite reversion in high nitrogen stainless steel is investigated. In order to study the effect of this thermo-mechanical process on grain refinement, the effect of cold reduction, annealing temperature and annealing times were analysed. After obtaining ultrafine grains, the effect of the grain size on the hardness and the tensile properties was evaluated and showed a Petch-Hall dependency in the fully analysed range (down to a 2.5 μm grain size).

Microvascular response of striated muscle to metal debris

Wear products of metal implants are known to induce biological events which may have profound consequences for the microcirculation of skeletal muscle. Using the skinfold chamber model and intravital microscopy we assessed microcirculatory parameters in skeletal muscle after confrontation with titanium and stainless-steel wear debris, comparing the results with those of bulk materials. Implantation of stainless-steel bulk and debris led to a distinct activation of leukocytes combined with a disruption of the microvascular endothelial integrity and massive leukocyte extravasation. While animals with bulk stainless steel showed a tendency to recuperation, stainless-steel wear debris induced such severe inflammation and massive oedema that the microcirculation broke down within 24 hours after implantation. Titanium bulk caused only a transient increase in leukocyte-endothelial cell interaction within the first 120 minutes and no significant change in macromolecular leakage, leukocyte extravasation or venular diameter. Titanium wear debris produced a markedly lower inflammatory reaction than stainless-steel bulk, indicating that a general benefit of bulk versus debris could not be claimed. Depending on its constituents, wear debris is capable of eliciting acute inflammation which may result in endothelial damage and subsequent failure of microperfusion. Our results indicate that not only the bulk properties of orthopaedic implants but also the microcirculatory implications of inevitable wear debris play a pivotal role in determining the biocompatibility of an implant.

Corrosion Wear of High Molybdenum and Nitrogen Stainless Steel for Biomedical Applications

The corrosion-wear property of high molybdenum and nitrogen stainless steel (UNS no. S32050) was investigated and compared with that of Ti, Ti6Al4V, CoCrMo, and 316L stainless steel used conventionally for biomedical applications. The corrosion resistance and corrosion-wear resistance of S32050 were examined using electrochemical methods. The stability of the passive film in a corrosion-wear system was evaluated. The corrosion-resistance of S32050 is as good as Ti alloys, because its passive film was enhanced due to the synergistic effect of the large amount of Mo and N addition. Therefore, it is predicted that S32050 can minimize the toxic effects by the released ions. The wear loss of UHMWPE (ultrahigh molecular weight polyethylene) to S32050 was less than that to Ti6Al4V and 316L stainless steel, and similar to the CoCrMo. There were no scratches on the S32050 surface after the corrosion-wear test. S32050 had a low current density and high pitting potential under wear and had corrosion-wear properties superior to Ti6Al4V and similar to the CoCrMo in Hank’s solution. S32050 with good corrosion-wear resistance could supplement the deficiencies of Ti alloys and CoCrMo. Thus, S32050 is considered to have the probability to be good metallic material for biomedical applications. © 2002 The Electrochemical Society. All rights reserved.

Sliding wear of austenitic and austenitic-ferritic stainless steels

The dry sliding behavior of a 304L austenitic stainless steel and a duplex 2205 austenitic-ferritic stainless was investigated. The evolution of wear was characterized by the existence of a sliding-distance transition. In particular, wear passed from delamination to tribo-oxidation, with a reduction in wear rate. The occurrence of such a transition was interpreted with reference to a theory of sliding wear based on the formation, by subsurface plastic deformation, of a tribological layer and its detachment during sliding. It has been found that the transition is controlled by the ability of the tribological system to form, on its outer part, a protective oxide-rich scale. This introduces a kinetic limitation, which is particularly important in the case of the duplex 2205, because of its lower ductility in comparison to the 304L steel. In this frame, the influence of sliding velocity, the particular frictional behavior, the role of chromium in the oxidative wear, and the surface temperature evolution during sliding could be explained.

Effects of processing and manufacturing of high nitrogen-containing stainless steels on their mechanical, corrosion and wear properties

The effects of N alloying through different processing and manufacturing routes on metallurgical, mechanical, corrosion and wear properties of high N-containing stainless steels have been studied. Nitrogen alloying has a well defined and marked improving effect on mechanical and corrosion properties of these steels until the solubility limit of N is reached and nitride precipitation exhibits its deleterious effects on these properties. It is also demonstrated that N alloying contributes significantly to sliding wear and cavitation erosion resistance of stainless steels. The processing and manufacturing technologies of high N-containing stainless steels are evaluated with main emphasis in P/M fabrication including solid-state nitriding of the metal powder.

Joint Second Prize Low Temperature Plasma Nitriding of 316 Stainless Steel – Nature of S Phase and Its Thermal Stability

Conventional plasma nitriding of stainless steels (at approximately 550°C) confers significant hardening of the treated case but at the expense of the corrosion resistance. Attempts have been made in the past decade to achieve combined improvements in wear and corrosion resistance of austenitic stainless steels (ASS) via low temperature thermochemical processes. However, varying degrees of success have been achieved in applications, which may be largely attributed to the lack of scientific understanding of the nature of the S phase and its thermal stability. The present work concerns two aspects of low temperature plasma nitriding of austenitic stainless steel: the study of the nature of the S phase and the thermal stability of the low temperature plasma nitrided layers on austenitic stainless steel. To achieve these tasks, systematic low temperature plasma nitriding of austenitic stainless steel has been carried out. The structure of the S phase was systematically investigated. The thermal stability of the low temperature plasma alloyed layers on stainless steel was studied employing both long term isothermal annealing and TEM in situ heating observations.

The wear and corrosion properties of stainless steel nitrided by low-pressure plasma-arc source ion nitriding at low temperatures

Low pressure plasma arc discharge-assisted nitriding of AISI 304 austenitic stainless steel is a process that produces surface layers with useful properties such as a high surface hardness of approximately 1500 Hv 0.1 and a high resistance to frictional wear and corrosion. The phase composition, the thickness, the microstructure and the surface topography of the nitrided layer, as well as its properties, depend essentially on the process parameters. Among them, the processing temperature is the most important factor for forming a hard layer with good wear and corrosion resistance. Nitriding austenitic stainless steel at approximately 420°C for 70 min can produce a thin layer of 7–8 μm with very high hardness and good corrosion resistance on the surface. The microstructure was studied by optical microscopy and both glancing angle and conventional Bragg–Brentano (θ–2θ) symmetric geometry X-ray diffraction (XRD). The formation of expanded austenite was observed. Measurements of the wear depths indicated that the wear resistance of austenitic stainless steel can be improved greatly by nitriding at approximately 420°C using low-pressure plasma-arc source ion nitriding.

The erosive wear of mild and stainless steels under controlled corrosion in alkaline slurries containing alumina particles

The erosive wear in an alkaline slurry containing alumina particles of three typical engineering materials, the mild steel BS 6323 (Fe-C), the AISI 410 stainless steel (Fe-Cr-C), and the AISI 304 stainless steel (Fe-Cr-Ni), was carried out, by means of rotating cylinder, three-electrode erosion-corrosion test, with a view to investigation into the roles of the typical elements and the mechanical and chemical properties in the erosive wear under simultaneous controlled corrosion. The total weight loss of erosion-corrosion was obtained by precision weighing and the result was compared and interpreted, for each material, by a full microscopical examination of the erosion-corrosion scars using scanning electron microscopy (SEM). It was found that the overall performance under erosion-corrosion in an descending order was the stainless steels AISI 304, AISI 410, and the mild steel, although the precise difference in performance was dependent upon the process conditions. Such a ranking of performance was not in total consistence with that expected only from the mechanical or the chemical property differences of the materials concerned. The individual contribution of each erosion and corrosion process was thus further separated through corrosion charge conversion using the Faraday's second law and the results were interpreted by discussion, on basis of the experimental and microscopical evidences, of the main factors that influenced the mechanical and wear behaviour, in conjunction with those influencing corrosion and passivity. Finally, schematic diagrams were proposed to outline the typical erosion and corrosion features thus obtained for all the three materials during erosion-corrosion.

Effects of yttrium and cerium additives in lubricants on corrosive wear of stainless steel 304 and Al alloy 6061

Effects of oxygen active elements, yttrium and cerium, as additives in commercial lubricants on corrosive wear were investigated. Sliding wear losses of stainless steel 304 and Al alloy 6061 lubricated by oil and thin grease respectively with and without yttrium or cerium additive in a corrosive environment were determined. Dilute H2SO4 solution (10% H2SO4) was used as the corrosive medium and added to the lubricants for the corrosive wear test. The wear test was performed on a pin-on-disc tribometer with the capability of measuring wear in lubricant. The disc was coiled with a copper tube, through which cooling water could pass, so that the wear losses respectively under cooling condition and non-cooling condition could be determined. The results showed that wear losses of the tested materials caused by synergistic attack of wear and corrosion can be effectively reduced by adding small amounts of yttrium or cerium to the lubricant. In addition, the effect of the additives was found more distinctive under the non-cooling condition. Worn surfaces were examined using SEM to clarify the wear mode and thus the wear mechanism.

Corrosion and wear of stainless steel reinforced with chromium aluminide particles: W.Moreira et al. (Carlos III University, Madrid, Spain.)

Sol–gel, homogeneous precipitation and hydrothermal synthesis are three different preparation techniques have been used as an attempt to synthesize nano-zirconium vanadate with properties suitable to be used as ion exchangers. The impact of the synthetic preparation variables such as the reactant concentrations, reaction temperature and reaction time on the ion exchange capacity of the produced ion exchanger has been considered for each preparation technique. One sample from each preparation technique having the largest ion exchange capacity has been selected to be physically and chemically characterized using various analytical techniques such as XRD, TGA, DSC, pH titration, FTIR and SEM in order to determine the properties of the ion exchanger produced from each technique. For all the studied ZrV samples it can be presumed that they have the ion exchange affinity sequences for alkali metal ions K > Na > Li, the order for the alkaline earth metals is Ba > Ca > Mg and their affinity for radioactive metals follow Cs > Sr. Moreover, the prepared materials are of high thermal and radiation stabilities. Also they have high chemical stabilities toward wide concentration ranges of acid, basic as well as polar solvents. It has been deduced from the X-ray analysis that ZrV produced from the sol–gel technique has an amorphous structural. While those produced from the homogeneous precipitation and hydrothermal synthesis techniques, in the nano-scale have semi-crystalline structural. Furthermore, SEM confirms that particle size of the all studied prepared ZrV samples have nano-diameters of range 50–60 nm. Specific surface area of the three different prepared ion exchangers are found to be equal to 187, 192 and 320 m2/g for sol–gel, homogeneous precipitation and hydrothermal, respectively. A tentative structural formula of Zr(OH)2(HVO4)2·2H2O has been proposed for all studied samples on the basis of on FTIR, DSC and TGA results.

High-temperature vapour-phase lubrication

Although it is recognised that the move towards cleaner burning, higher efficiency engines requires operating temperatures in excess of 500°C, there are currently few practical means available to achieve this. Therefore, the development of cleaner, more efficient engines requires the use of new lubrication technologies. Any potential lubricant and lubrication technology must address the changing needs of the original equipment manufacturers (OEMs). Specifically, this should include material and fuel compatibility, increased lubrication performance at elevated temperatures and pressures, ashless deposits, reduced particulate emissions, and biodegradability. Over the past six years, various organisations have addressed many of these needs and have successfully demonstrated the use of phosphate esters as candidate vapour phase (VP) lubricants. With the correct choice of lubricant, VP lubrication has been effective in reducing friction and minimising wear of ferrous-rich stainless and tool steels, alloys, ceramics and composites, at temperatures up to 670°C, under both sliding and rolling contact. This paper details the development of VP lubrication, and of sers some insights into materials and lubricant selection, and some examples of successful applications.

Effects of surface deformation on corrosive wear of stainless steel in sulfuric acid solution

Corrosive wear behaviors of austenitic, ferritic and duplex stainless steel in sulfuric acid solution were investigated. Transmission electron microscopy with energy dispersive X-ray, scanning electron microscopy, microhardness tester, etc. were used to study the mechanism of surface deformation of stainless steel after corrosive wear tests. The result indicated that the corrosive wear rate of austenitic stainless steel (ASS) was the highest and that of duplex stainless steel (DSS) was the lowest if the applied loads were higher than 25 N. Because martensitic transformation induced brittleness and increased corrosion rate of ASS surface, the corrosive wear rate of ASS increased largely though the surface microhardness of ASS was largely increased during corrosive wear under high loads. The corrosive wear rate of ferritic stainless steel (FSS) also increased largely under high loads though FSS had the best corrosive wear resistance under low loads. The corrosive wear rate of DSS had a linear relationship with loads. The abilities of surface deformation strengthening of two phases were very different. The investigation indicated that surface deformation strengthening of DSS with proper ratio of γ phase was one of the important methods to improve corrosive wear resistance of stainless steel.

Tribocorrosion d’un acier inoxydable en milieu marin artificiel

The friction and wear of stainless steels in sea-water environment is of prime interest for naval applications. The behaviour of the tribosystem alumina pin / 316L stainless steel disc in a 30g/l NaCl solution buffered at pH 8 exhibited the coupling between mechanical and electrochemical parameters. One objective of this study is to determine methods for the comprehension and interpretation of tribocorrosion tests. The friction coefficient is quite sensitive to the applied potential and it is particularly true around the free potential under friction. In our experimental conditions, sliding friction shifts the value of the free potential towards more cathodic value. This behaviour shows the sensibility of potential to frictional perturbation of the surface. In passive domain of materials, an increase of intensity is observed under friction. This evolution is due to depassivation / repassivation phenomena. The overall wear volume shows a dependence to the applied normal load and to the imposed electrochemical potential. Except for the beginning of the test, the evolution of wear is linear in time during a 5 hours test. The total wear, addition of mechanical and electrochemical wear, is investigated and an explanation of its global behaviour is proposed on the basis of an electrochemical and mechanical framework. This eroded volume can be principally attributed to corrosive mechanisms. A mechanical modelling related to evaluation of elasto-plastic pressure distribution is proposed and gives the stabilised wear regime. The experimental wear regime is in agreement with this model. The simplicity of this tribocorrosion system allows an automatic analysis and interpretation of tests results. Interactions between electrochemical and mechanical behaviour are studied. We can explain the mechanical wear by study of contact problem and electrochemical wear by analysis with Faraday law. Despite the great complexity of industrial problems (wear and corrosion of two antagonists,...), this method could be adapted to interpret various tribotest systems.

Effects of surface grinding conditions on the reciprocating friction and wear behavior of silicon nitride

The relationship between two significantly different surface grinding conditions and the reciprocating ball-on-flat friction and wear behavior of a high-quality, structural silicon nitride material (GS-44) was investigated. The slider materials were silicon nitride NBD 200 and 440C stainless steel. Two machining conditions were selected based on extensive machining and flexural strength test data obtained under the auspices of an international, interlaboratory grinding study. The condition categorized as “low strength” grinding used a coarse 80 grit wheel and produced low flexure strength due to machining-induced flaws in the surface. The other condition, regarded as “high strength grinding,” utilized a 320 grit wheel and produced a flexural strength nearly 70% greater. Grinding wheel surface speeds were 35 and 47 m s −1. Reciprocating sliding tests were conducted following the procedure described in a newly published ASTM standard (G-133) for linearly reciprocating wear. Tests were performed in directions both parallel and perpendicular to the grinding marks (lay) using a 25 N load, 5 Hz reciprocating frequency, 10 mm stroke length, and 100 m of sliding at room temperature. The effects of sliding direction relative to the lay were more pronounced for stainless steel than for silicon nitride sliders. The wear of stainless steel was less than the wear of the silicon nitride slider materials because of the formation of transfer particles which covered the sharp edges of the silicon nitride grinding grooves and reduced abrasive contact. The wear of the GS-44 material was much greater for the silicon nitride sliders than for the stainless steel sliders. The causes for the effects of surface grinding severity and sliding direction on friction and wear of GS-44 and its counterface materials are explained.

Acceleration of corrosive wear of duplex stainless steel by chloride in 69% H 3PO 4 solution

Plots of corrosive wear loss with load and anodic polarization curves during friction were examined for duplex stainless steel (DSS) in 69% H 3PO 4 solution with or without Cl − by a pin-on-ring apparatus. Morphology of tracks and debris was observed in a scanning electron microscope. Variation of Vicker hardness of worn surface was also tested. The defects in wear subsurface were analysed by means of the positron annihilation technique (PAT) and a transmission electron microscope (TEM). The results show that the acceleration of chloride on corrosive wear of the steel is due to the brittle-fracture of the worn surface.

An investigation of the corrosive wear of stainless steels in aqueous slurries

Pumping installations made of stainless steels have been widely used for transporting slurries in chemical process industry. However, knowledge of the attack of stainless steels due to corrosive wear in two-phase liquid-particle flow is still incomplete. This paper studies the behaviors and mechanisms of corrosive wear for two austenitic stainless steels, 24Cr-25Ni-4Mo and 18Cr-12Ni-2Mo, using a rotating disc apparatus made by the authors. The two components, wear by slurry abrasion and corrosion, within the corrosive wear process, are first examined individually. Then the synergistic effect between wear and corrosion is investigated. The research we have done shows that corrosive wear rate of samples is closely related to such factors as the solution, type of abrasive, flow velocity, impingement angle and temperature. In addition, a threshold of flow velocity exists which is called the breakaway velocity V k, above which the corrosive wear rate increases rapidly. The combined effects of abrasion and corrosion result in a total wear loss larger than the added effects of each process alone. An analytical model is developed which would help to reveal the mechanisms of the corrosive wear processes.

Wear of metal stirring rods in molten aluminium and suspensions of alumina particles in molten aluminium

The wear of stainless steel and titanium stirring rods in molten aluminium and a suspension of alumina particles in molten aluminium was studied. The known characteristic of more rapid wear by stainless steel than titanium was confirmed and the suspension of alumina particles was found to accelerate wear of both metals. Examination of worn specimens revealed that the stainless steel rods were separated from the liquid aluminium by a layer of iron, chromium and aluminium. Wear proceeded by the shedding of projections that formed on the layer into the liquid aluminium. Alumina particles accelerated wear by abrasion of the projections. The titanium was surrounded by a much thinner layer of titanium and aluminium mixture with no projections into the molten aluminium. The distribution of wear around the blades was controlled by the flow of liquid metal and of the alumina particles around each blade.

Effect of γ Phase on Corrosive Wear of Duplex Stainless Steel in Sulfuric Acid Solution

Abstract A modified pin-on-ring device was used to study corrosive wear of a duplex stainless steel (DSS) containing ferrite (α) and austenite (γ) phases in 1 mol/L sulfuric acid (H2SO4) at room te...

Corrosion Wear of Duplex Stainless Steels in Sulfuric Acid Solution Containing Chloride

Abstract The corrosion rate, wear rate, corrosion wear rate, variation of Vickers hardness of the worn surface, and the recovery time of passive film were determined for α + γ duplex stainless steel (DSS) in sulfuric acid (H2SO4) or H2SO4 + sodium chloride (NaCl) solution. In the chloride (Cl−) solution, the wear-induced corrosion and the corrosion-induced wear were ∼ 4% and 70% of the total damage, respectively. Damage was less in the absence of Cl−. Morphologies of tracks and debris also were observed. Results showed Cl− embrittled the worn surface of the metal.