Investigation of Tribological Behaviour of Nitrided and Coated AISI 4140 Steel (original) (raw)
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In the present study, samples made of AISI 4140 steel, pre-treated with plasma nitriding (PN) and coated with coatings like Titanium Nitride (TiN), Titanium Carbo Nitride (TiCN), Chromium Nitride (CrN), Aluminium Titanium Nitride (AlTiN) using Physical Vapour Deposition (PVD) technique, were investigated in terms of their dry and wet sliding wear behaviour. Wear tests, were performed with a pin-on-disc machine. The results of the duplex treated samples were compared with the conventional hard chrome coated AISI 4140 steel. The results showed improved wear properties of the duplex-treated specimens compared to the hard chrome coated AISI 4140 steel. TiCN coated and nitrided 4140 steel has shown the best performance among the investigated materials. Furthermore, the compound layer formed during nitriding was found to act as an intermediate hard layer leading to superior sliding wear properties. The improved performance of the duplex treated samples can be attributed to the presence of a nitrided subsurface. ARTICLE HISTORY
Tribological properties of plasma nitrided and hard coated AISI 4140 steel
Wear, 2001
In the present study, samples made of AISI 4140 steel pre-treated with plasma nitriding and coated with different PVD coatings (TiN, TiAlN and ta-C) were investigated in terms of their microhardness, surface roughness, scratch adhesion and dry sliding wear resistance. Wear tests, in which duplex-treated pins were mated to hardened ball bearing steel discs, were performed with a pin-on-disc machine. To examine the influence of the nitrided zone on the performance of the coating-substrate composite, coatings were deposited on hardened as well as on plasma nitrided samples, prepared under different nitriding conditions.
Wear and friction behaviour of duplex-treated AISI 4140 steel
Surface and Coatings Technology, 1999
In this study samples of AISI 4140 steel were pretreated by plasma nitriding and coated with two different physical vapour deposited coatings (TiN and TiAlN ). A hardened AISI 4140 sample and a coated sample were also included in the investigation. To examine the influence of the nitrided zone on the performance of the coating-substrate composite, two different nitriding conditions -a conventional 25% N 2 and an N 2 -poor gas mixture -were used. The specimens were investigated with respect to their microhardness, surface roughness, scratch adhesion and dry sliding wear resistance. Wear tests in which the duplex-treated pins were mated to hardened ball bearing steel discs were performed in a pin-on-disc machine under dry sliding conditions. Metallography, scanning electron microscopy and profilometry were used to analyse the worn surfaces in order to determine the dominant friction and wear characteristics of the samples investigated. The results show improved wear properties of the plasma-nitrided hard-coated specimens compared with uncoated and pre-hardened ones. Although previous investigations showed a negative effect of the compound layer, it was found that a precisely controlled plasma nitriding process can lead to a dense, uniform and highly adherent compound layer with a positive effect on the wear properties of pre-nitrided and hard-coated AISI 4140 steel. possibilities of using hard protective PVD coatings on 0257-8972/99/$ -see front matter
Tribological Performance of Plasma Nitrided Aisi 4140 Steel
Friction and wear characteristics of plasma nitrided discs in sliding wear contact against alumina were examined using a tribometer with a ball-on-disk configuration. The nitrided AISI 4140 samples were obtained by using the pulsed plasma nitriding process in a 1:4 H 2 -N 2 gas mixture at a temperature of 650K for 6h treatment time. Wear tests were performed at a sliding speed of 0.1 m.s -1 , 5 N load and 1000 m sliding distance. The tests were carried out at room temperature in air, without lubrication, by employing commercial alumina balls of 6 mm diameter as a static partner. A steady state friction coefficient of 0.87 was determined for this tribolgical pair. For comparison, the tribological behavior of substrate was also evaluated and a lower friction coefficient of 0.56 was found. The surface morphology and the topography of the wear scars have been determined by using both scanning electron microscopy and 3D stylus profilometry techniques. The wear resistance was evaluated by calculating the wear factor, k, considering than the volume is linearly proportional to the load and the sliding distance. Different wear mechanisms were detected such as abrasion, adhesion and oxidational wear for the pairs under study. Results have shown an improved wear resistance of the nitrided steel samples compared to the untreated ones.
2010
Mechanical behavior AISI H13 die steel substrates were low pressure gas nitrided to different thicknesses and hardness values. Nitrided and non nitrided samples were subsequently coated with bi-layer TiAlN/TiN to two different thicknesses. The hardness was measured across the coating thickness and observed to be higher when a thinner coating was deposited over nitrided substrates. The hardness behavior across relatively thin (3 μm) coatings was not affected by the nitrided surface hardness or thickness of the nitride layer in the range of values examined here (80-150 μm). On the other hand, the hardness behavior of thicker coatings (8um) was affected by the nitrided layer, as the thicker coatings were soft due to their columnar structure. The specific wear rate of the duplex coatings was affected by the coating thickness and hardness distribution across the coating system.
Wear, 1999
In our study, the friction and the wear behaviour of plasma and pulse plasma nitrided AISI 4140 steel was evaluated under dry sliding conditions, where hardened samples were used as a reference. The nitrided samples were fully characterised before and after the wear testing using metallographic, microhardness and surface examination techniques. After surface characterisation, dry sliding wear tests were performed on a pin-on-disc machine in which hardened ball bearing steel discs were mated to nitrided pins. The influence of sliding speed and contact load on the response of the surface treated pins was determined. The test results indicate, that the wear resistance of AISI 4140 steel can be improved by means of plasma and pulse plasma nitriding. However, compound layer should be removed from the nitrided surface to avoid impairment of the tribological properties by fracture of hard and brittle compound layer followed by the formation of hard abrasive particles. q 1999 Elsevier Science S.A. All rights reserved.
Behavior of the pulsed ion nitrided AISI 4140 steel/CVD TiN coatings as tribological pair
Thin Solid Films, 2000
The aim of the present investigation was to determine the effect of pulsed plasma nitriding process on the wear behavior of an AISI 4140 steel. Wear tests were performed using a ball-on-disc configuration with a linear sliding speed of 0.1 m s y1 , 5 N load and 700 m sliding distance. The tests were carried out at room temperature in air, without lubrication, by employing CVD TiN coated balls of 6 mm in diameter. The surface morphology and topography of the wear scars of samples and balls have been determined by using both scanning electron microscopy and three-dimensional stylus profilometry. Different wear mechanisms were detected such as abrasion, adhesion and oxidational wear for the pairs under study. Results have showed an improved wear resistance of the nitrided samples compared to the AISI 4140 steel samples. ᮊ
Materials
In this study, heat-treated and multisurface engineered DIN 1.2367 tool steel was subjected to room and elevated temperature wear tests, and the effect of nitriding on its tribological behavior was investigated. CrN, AlTiN, and CrN/AlTiN coatings with a total thickness of 2 µm were obtained by arc cathodic physical vapor deposition on conventional heat-treated and gas-nitrided steels. The white layer formed during nitriding was removed, and a diffusion layer (100 µm) was achieved in the cross section of the steel having a tempered martensitic matrix. The highest surface hardness was attained with an integral coating (CrN/AlTiN), and surface hardness increased even more after nitriding due to the formation of a multicomponent ceramic layer on top of the diffusion layer. The room temperature wear tests performed against an alumina counterpart revealed that (i) CrN/AlTiN-coated steel had the highest friction coefficient of 0.26, which further increased to 0.33 by nitriding due to the i...
Materials
Moving components of industrial machines and tools are subjected to wear and friction. This reduces their useful life and efficiency in running conditions, particularly at high temperatures. One of the most popular solutions is to apply an appropriate surface coating to the tribocouple’s base materials. In this study, tribometer experiments were used to evaluate the tribological performance of cathodic arc physical vapor deposited (CAPVD) AlCrN, TiSiN, CrTiN, and ZrN coatings on the gas nitrided AISI H13 tool steel to explore the effects of nitriding the steel on wear and friction behavior of these coatings at ambient and elevated temperatures. The coatings characterization is split into three main parts: mechanical, morphological, and chemical characterization. Nanoindentation has been used for mechanical characterization, thin film X-ray diffraction (XRD), and an energy-dispersive X-ray spectrometer mounted on a scanning electron microscope for chemical characterization, optical p...
Advanced Materials Research, 2011
Effects of wear testing temperature and sliding speed on the wear behavior of nitrided and untreated 31CrV3 steel were investigated. The specimens were tested at wear testing temperatures of 25°C and 500°C under a normal load of 15N at a sliding speed of 1m/s. The increase in the wear temperature from 25°C to 500°C led to a decrease in the wear rate and coefficient of friction of the nitrided steel samples. At 25°C, the wear resistance of the nitrided steel improved by 2.3 times compared to the untreated specimen. There was about 57 times improvement in wear resistance as the wear temperature increased to 500oC for the nitrided specimen. Scanning electron micrographs showed that the formation of compact and protective oxide layers on the worn surface of the nitrided steel was responsible for the improvement in the tribological behavior of nitrided steel at elevated temperatures. The effect of sliding speed on the wear of the samples was further tested at 500oC under a normal load of...