Combination Of Wear Resistance Research Articles

Assessment of the tribological and wear performance of new duplex AlTiN-based coating systems at high temperatures when threading super duplex stainless steel

During machining, a significant amount of energy is transferred at the cutting interfaces (tool/chip and tool/workpiece) to perform a cut. Tribology is the science of how surfaces interact when cutting metal, describing the physics and mechanics characterized by high loads and temperatures at the cutting interface. This paper explains how to determine the energy consumption required to make a cut, considering different combinations of cutting tool/coated surface and the wear characteristics of each one. Moreover, this paper finds the correlation produced by the effect of the heavy-load high-temperature on the friction condition between the interactive surfaces. Based on these findings, cutting tests (threading operations) were conducted to verify the tool wear mechanisms of the different AlTiN-based coatings, the amount of energy each consumed to perform the cut, and their tribological behaviour. The cutting test confirmed the tribometer simulation result. The AlTiNOS + WC/C coating demonstrated the minimum coefficient of friction in both the experimental and simulation analyses, while the AlTiNOS + TiB2 coating possessed a better combination of wear resistance and mechanical properties.

Austempering and Cryogenic treatment of Vanadium modified Carbidic Ductile Iron

ABSTRACT Conventional Austempered Ductile Irons (ADI) are lacking in adequate wear resistance. Introduction of hard alloy carbide phase in the microstructure by strong carbide formers imparts wear resistance. Deep cryogenic treatment subsequent to austempering is another way to improve the wear resistance without a major reduction in toughness. The present study encompasses the microstructural evolution following deep cryogenic treatment and the resultant bulk hardness, Charpy impact toughness and dry sliding wear of two vanadium contained (0.1% and 0.3%) carbidic austempered ductile irons. The irons were austempered at two temperatures viz. 3000 C and 3500 C for 30, 45, and 60 minutes and which is accompanied at −1960 C either by deep cryogenic treatment or air-cooled. EDS & XRD (X-ray Diffraction), Optical and Scanning Electron Microscopy analysis have characterized the microstructural features. Increase in vanadium content and cryo-treatment result in a prominent combination of wear resistance and impact toughness.

Performance of a Matrix Type High Speed Steel after Deep Cryogenic and Low Tempering Temperature

A matrix type high speed steel YXR3 designed for a combination of wear resistance and toughness is investigated for its mechanical properties after hardening by deep cryogenic treatment follow by tempering. The deep cryogenic quenching carried out at -200 °C for 36 hours and the single step tempering results in an obvious improvement in wear resistance while balancing the toughness, comparing with the conventional quenching followed by a double tempering treatment. The quantitative image analysis reveals little difference in the MC carbide size distribution between tempering at different temperatures. The synchrotron high energy XRD confirms the MC type carbide with some evolution in its orientation together with tempered martensite approaching the BCC structure at higher temperatures. In contrary to the conventional quenching and tempering, the lowest tempering temperature at 200 °C yields a moderate drop in hardness with increase in surface toughness proportionally while exhibiting exceptional wear resistance. Such thermal cycle can be recommended for the industry both for the practicality and improved tool life.

UDDEHOLM VIKING

Abstract Uddeholm Viking is a medium-carbon, chromium-molybdenum-vanadium, alloy cold-work tool steel that is characterized by an excellent combination of wear resistance and toughness required for chipper-knives and for heavy-duty blanking and forming. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on heat treating and surface treatment. Filing Code: TS-807. Producer or source: Uddeholms AB (a voestalpine company).

Improvement of wear resistance in a pearlitic rail steel via quenching and partitioning processing

Improvement of wear resistance and mechanical performance of rails used in heavy-haul railway are essential to reduce railroad maintenance costs. A novel heat treatment based on quenching and partitioning (Q&P) processing was proposed to improve the wear resistance of a hypereutectoid pearlitic rail. 50% of austenite was transformed into martensite under an interrupted quenching from full austenitization temperature to 140 °C. A multiphase microstructure resulted from the quenching and partitioning process, consisting of tempered martensite, bainite, retained austenite, and pearlite colonies. The partitioning step was performed in the range of 350–650 °C. Microstructure characteristics were investigated using scanning electron microscopy, microhardness measurements, X-ray and electron backscattered diffraction. Uniaxial tensile and pin-on-disc tests were also performed to evaluate the mechanical properties and wear resistance. The best combination of wear resistance and mechanical performance was obtained in samples partitioned at 450 and 550 °C, which may be applied in the railway industries.

Heat treatment effects on tribological characteristics for AISI A8 tool steel and development of wear mechanism maps using K means clustering and neural networks

Viking steel classified under AISI A8 cold working tool steel is widely used for heavy duty blanking and forming operations. The excellent combination of wear resistance and toughness make this material superior when compared to other tool steels in such applications. This cold working tool steel is easy to machine and gives excellent mechanical properties upon proper heat treatment. The heat treatment carried out with air and oil as quenching media at various conditions of temperature and time are discussed. Optical microscopy and hardness tests are performed on the heat-treated specimens. The samples with best results from each group are selected for further analysis. The tribological properties of these specimens are analysed with the help of wear tests conducted on pin on disc tribometer under different load and velocity levels. The data obtained from these experiments are used to find out the coefficient of friction and wear rate. The experimental results are used to develop wear mechanism maps with the help of K means clustering analysis and probabilistic neural networks. A novel approach based on clustering analysis is proposed as the analysis of wear data and wear mechanism maps are developed using with neural networks for tool steel. The data analysis is correlated with the scanning electron microscopic observations and the results are discussed.

BÖHLER K490 MICROCLEAN

Abstract Böhler (or Boehler) K490 Microclean is a PM cold work tool steel that has a combination of wear resistance and high toughness. It is made by powder metallurgy. This datasheet provides information on composition, physical properties, hardness, and elasticity. It also includes information on wear resistance as well as heat treating and powder metal forms. Filing Code: TS-740. Producer or source: Böhler-Uddeholm North America. See also Alloy Digest TS-734, February 2016.

Wear resistance of TiN(Ti2N)/Ti composite layer formed on C17200 alloy by plasma surface Ti-alloying and nitriding

The duplex treatment of plasma Ti-alloying and plasma nitriding was applied on the surface of C17200 alloy to improve its wear resistance. C17200 substrate was alloyed with Ti using double glow plasma alloying to form a Ti-alloyed layer in its surface, and then treated by plasma nitriding to make a TiN(Ti2N) alloying layer based on the Ti-alloyed surface. The microstructure and formation mechanism were studied by using GDOES, XRD and SEM. The hardness, tribological property and electrical conductivity of C17200 alloy after plasma alloying and nitriding were investigated by mean of micro-hardness tester, friction and wear testers as well as impedance analyzers. Modulus of elasticity and the adhesive strength of TiN(Ti2N)/Ti composite layer were evaluated by nano-indenter and scratch tester. The result shows that a TiN(Ti2N)-Ti-Be-Cu composite layer with a thickness of 27μm is formed in the C17200 surface and is mainly composed of TiN, Ti2N, Cu(Ti) solid solution, etc. The composite alloying surface consists of the hard TiN(Ti2N)-rich layer on the top surface and Ti-Cu-Be diffusion layer, showing a strong adhesive strength with the C17200 substrate and a little decrease in the modulus of elasticity. A certain amount of Cu and Be together with TiN/Ti2N exists in the outmost, resulting in a better combination of wear resistance and conductive performance.

Measurement of Cobalt Gradient in Functionally Graded WC-Co Composites

Functionally graded WC-Co (FG WC-Co) offers superior combination of wear resistance, fracture toughness, and strength, and provides superior engineering performance over conventional homogeneous WC-Co. The cobalt gradient structure of the FG WC-Co, including the thickness of the gradient zone and the cobalt concentration distribution, have the great influence on its engineering performances. Measurement of cobalt gradient of the FG WC-Co was studied in this paper using an energy dispersive spectroscopy (EDS) technique. The result shows that the rectangular area scanning mode of EDS is suitable for evaluating the cobalt content distribution quantitatively in the FG WC-Co. Based on the cobalt content distribution curve, the thickness and the amplitude of cobalt gradient in the FG WC-Co can be measured easily.

Impact of tool wear on joint strength in friction stir spot welding of DP 980 steel

Friction stir spot welding has been shown to be a viable method of joining ultra high strength steel, both in terms of joint strength and process cycle time. However, the cost of tooling must be reasonable in order for this method to be adopted as an industrial process. Recently a new tool alloy has been developed, using a blend of polycrystalline cubic boron nitride (PCBN) and tungsten rhenium (W–Re) in order to improve the toughness of the tool. Wear testing results are presented for two of these alloys: one with a composition of 60% PCBN and 40% W–Re, and one with 70% PCBN and 30% W–Re. The sheet material used for all wear testing was 1·4 mm DP 980. Lap shear testing was used to show the relationship between tool wear and joint strength. The Q70 tool provided the best combination of wear resistance and joint strength.

Effect of heat treatment on microstructure and mechanical properties of Cr–Mo steels (FMU-226) used in mills liner

To improve mechanical properties specifically wear resistance and impact toughness of Cr–Mo steels, the specimen were subjected to austempering and martempering processes, and the results were compared with the common cycle used in industry (compressed air cooling). After the accomplishment of austenization process, the specimens were quenched in salt bath at 300 °C and 200 °C in austempering and martempering processes, respectively, for 2, 8, 30, and 120 min and then cooled down to room temperature in still air. Microstructure of the specimens was studied using optical microscopy (traditional black and white etching as well as color etching), scanning electron microscopy (SEM) as well as X-ray diffraction (XRD). Mechanical properties of the austempered and martempered specimens were investigated by measuring the hardness, impact toughness and wear resistance. Results shown that the samples austempered for 2 h have demonstrated the best impact toughness, while the samples martempered for 2 h have presented the highest values of wear resistance. In addition using salt bath instead of compressed air, leads to a better combination of wear resistance and toughness.

Advances in the Development of Carbidic ADI

Carbidic ADI (CADI) is a new type of Austempered Ductile Iron containing free carbides in the microstructure, providing a particular combination of wear resistance and impact toughness. In this work, four CADI variants were evaluated, in which carbides were promoted by alloying with chromium. Tests performed under the low stress abrasion condition imposed by the ASTM G65 standard show that CADI can increase the wear resistance up to 100 % when compared with conventional ADI austempered at the same temperature. The carbide content must be higher than 10 % to promote a considerable reinforcing effect. However, at this carbide content level, the impact toughness varies between 7 and 11 J/cm2 for unnotched samples. These values are much lower than those of conventional ADI, but higher than those of other abrasion resistant materials, like white irons. Some CADI variants were also evaluated in field tests, producing abrasion under either low stress or high stress conditions. For this purpose, two CADI prototype parts were studied: screw segments for animal food extruders (low stress abrasion) and wheel loader bucket edges (high stress abrasion). The results gathered showed that CADI behaves satisfactorily under low stress abrasion, but the performance is not so good under high stress conditions. To analyze the differences in the abrasion response, scratch tests were performed in order to evaluate the interaction between the abrasive tip and the microstructure.

TLP M4

Abstract TLP M4 is a powder metallurgy produced high-speed tool steel with a combination of wear resistance, high impact toughness, and transverse bend strength. This datasheet provides information on composition, physical properties, and hardness as well as fracture toughness. It also includes information on high temperature performance and wear resistance as well as heat treating. Filing Code: TS-586. Producer or source: Timken Latrobe Steel.

A Novel Polyamide 12/Al-Cu-Fe Quasicrystal Composite

ABSTRACTThe tribological and mechanical properties of a novel polyamide 12 (PA12)/Al-Cu-Fe quasicrystal (QC) composite were systematically studied to accelerate efforts to develop a useful, melt-processable, and wear-resistant polymer composite. The wear and friction properties were characterized using a pin-on-disk configuration and the static and dynamic mechanical properties were investigated using dynamical mechanical analyzer, tensile tester, and an impact tester. Further, the melt processability of the composite was studied using a Haake torque rheometer and a dynamic rotational rheometer. The results suggest that PA12/QC composite can be melt-processed into a wear-resistant material with enhanced mechanical properties for applications where combinations of wear resistance and good mechanical properties are required. The static mechanical properties of the composite were found to be consistent with the Halpin-Tsai equation and agreement was observed between the measured viscoelastic properties and theoretical predictions of Burgers' and Eilers' models.

VANADIS 23

Abstract Vanadis 23 is a Cr-Mo-W-Va alloyed high-speed steel made by powder metallurgy. The tool steel offers an excellent combination of wear resistance and toughness. This datasheet provides information on composition, physical properties, hardness, and elasticity as well as fracture toughness. It also includes information on heat treating, machining, and surface treatment. Filing Code: TS-561. Producer or source: Uddeholm Corporation. See also Alloy Digest TS-552, March 1997.

Some observations on the fracture of austempered ductile iron

There is extensive work on the fracture of steel with ferrite or/and austenite structure, but little on crack propagation in austempered ductile iron (ADI) whose microstructure also comprises austenite and ferrite (in the form of bainitic ferrite) but with graphite nodules in the matrix. Because of its good combination of wear resistance and toughness, and its low density and low cost (compared with forge steel), ADI has been widely used for various kinds of engineering components, such as gears, crankshafts, vehicle components, sprockets, cutting and digging tools etc. The matrix of ADI can withstand a certain amount of deformation before fracture during tensile or impact testing; for example, the elongation of ADI (grade 1050/700/7 to ASTM Standard) can reach 7--10% during tensile testing. However, the graphite nodules in the matrix cannot deform and hence are barriers to matrix deformation and give rise to crack initiation. In addition, carbides may precipitate in the bainitic ferrite laths or at the ferrite/austenite interfaces and these may also influence the fracture of ADI and produce characteristic features.

Dry sliding wear behaviour of polyamide 66 and polycarbonate composites

A study has been made of the reciprocating dry sliding wear behaviour of polyamide 66 and polycarbonate containing glass fibres, ultra high molecular weight polyethylene (UHMWPE) and polytetrafluoroethylene (PTFE/2% Si oil). Studies have been conducted at sliding loads of 2 kg and 10 kg at an average velocity of 0.33 m s −1 against a hardened stainless steel counterface with a surface roughness of 0.3 μm. It has been shown that additions of 10–15% of filler/reinforcement lead to greatly improved sliding wear behaviour. PTFE/2% Si oil filled polyamide 66 has been shown to have the best overall wear performance whilst the high glass filled variants of polyamide 66 and polycarbonate have the best combination of wear resistance and mechanical strength. These findings are discussed with reference to composite constitution and properties, thermal effects and counterface interactions. Explanations are advanced to account for the differences in behaviour inter alia the composite materials.

Effect of Heat Treatment on Wear Resistance and Impact Strength of High Chromium White Cast Iron

Martensitic chromium white cast irons find extensive industrial applications for resisting wear coupled with impact forces. Out of the several possible heat treatments for developing a martensitic chromium white cast iron, the arrested cooling heat treatment offers the best combination of wear resistance and impact strength, providing properties comparable to that of the standard Ni-Hard type 4 alloy.

Heat Treatments of Chromium-Manganese White Cast Irons for an Optimum Combination of Wear Resistance and Impact Strength

As cast microstructures of chromium-manganese white cast iron containing about 2.5 % carbon, 0.7 % silicon, 4.5 % manganese and 11.5 % chromium reveal discontinuous plate like eutectic carbides embedded in a mainly austenitic matrix[1](Fig.1). This austenitic matrix accounts for a higher impact strength and a lower wear resistance. It has been reported elsewhere [2] that a martensitic matrix containing uniformly distributed fine alloy carbides exhibits a very good wear resistance, but lower impact strength.

AL TECH NAVAHO

Abstract AL TECH NAVAHO is an air-hardening punch and die steel with lower carbon than most cold-work steels; this provides an optimum combination of wear resistance and toughness for difficult cold-work applications. It also is used for abrasive hot-work requirements. This steel offers relatively favorable size stability and exceptional secondary hardness characteristics. NAVAHO has a broad application range from shear blades and punches to molds for plastics ad hot-work tooling. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance as well as forming, heat treating, and machining. Filing Code: TS-421. Producer or source: AL Tech Specialty Steel Corporation.