Nonlinear Wear Response of WC-Ni Cemented Carbides Irradiated by High-Intensity Pulsed Ion Beam

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
X. P. Zhu ◽  
F. G. Zhang ◽  
T. K. Song ◽  
M. K. Lei

Surface hardening on WC-Ni cemented carbides was achieved by high-intensity pulsed ion beam (HIPIB) irradiation, with formation of a binderless, densified, and “hilly” remelted top layer of a few μm in depth and a shock strengthened underlayer down to a hundred μm. The tribological behavior of the samples was studied under dry sliding against GCr15 bearing steel on a block-on-ring tribometer with 98 N and 0.47 m/s. The specific wear rate/wear resistance presented an exponential dependence on the surface hardness, in contrast to the commonly reported linear dependence of the specific wear rate or wear resistance on the hardness of WC based cemented carbides among both WC-Ni and WC-Co systems. The original samples underwent a severe abrasive wear due to the Ni binder micro-abrasion and WC grain fragmentation/pullout, whereas the irradiated samples began with a gradual abrasion of the binderless hard tops, followed by a mild abrasive wear accompanied by local adhesive wear. The wear resistance has been also compared with the reported data concerning the relative hardness of friction pairs in a value range of 2–7 on block-on-ring tribometer tests with the friction pairs of WC cemented carbides and steels in unlubricated condition. The nonlinear wear response is explained by the wear mechanism transition otherwise unobtainable in the case of the reported hardening by either lowering the binder content or refining the WC grains. It is revealed that the interfacial bonding enhancement of the WC/binder and the binder strengthening are pronounced for improving the wear resistance of the cemented carbides, by the effective suppressing of the WC grain fragmentation/pullout and binder micro-abrasion, even though they have limited contribution to the hardness enhancement.

2021 ◽  
Author(s):  
Safiye İpek Ayvaz ◽  
Mehmet Ayvaz

In this study, the effect of different counterparts on the wear resistance of AA6082 aluminum alloy was investigated. In tests using pin-on-disk method, 6 mm diameter Al2O3, 100Cr6 and WC-6Co balls were used as counterparts. The tests were carried out using 500 m sliding distance and 5N load. The lowest specific wear rate was measured as 7.58x10-4 mm3/Nm in WC-6Co / AA6082 couple, and the highest value was measured as 9.71x10-4 mm3/Nm in 100Cr6/AA6082 couple. In the Al2O3/AA6082 couple, the specific wear rate of the AA6082-T6 sample was determined as 8.23x10-4 mm3/Nm.While it was observed that the dominant wear type in the 100Cr6/AA6082 pair was abrasive wear, oxidation wear and oxide tribofilm were detected in the WC-6Co/AA6082 and Al2O3/AA6082 couple besides the abrasive wear.


2011 ◽  
Vol 121-126 ◽  
pp. 534-538 ◽  
Author(s):  
C. Anand Chairman ◽  
S.P. Kumaresh Babu

Three-body abrasive wear behavior of basalt–epoxy (B–E) and glass–epoxy (G–E) composites have been investigated using Dry sand rubber wheel abrasion resistance for various abrading distance, viz., 150, 300, 450 and 600m and different loads(22N and 32N) at 200 rpm. The weight loss and specific wear rate as a function of load and abrading distance were determined. The weight loss increases with increasing load and also with abrading distance while the specific wear rate decreases with increase in abrading distance and increases with the load. Better abrasion wear resistance was observed in B-E composite compared to G–E composite. Scanning Electron Microscope (SEM) is used to examine the abraded composite specimens and revealed that the more damage occur to glass fiber compared to basalt fiber. Also good interfacial adhesion was observed between epoxy and basalt fiber which leads to good abrasive wear resistance.


2020 ◽  
pp. 306-308
Author(s):  
V.S. Bochkov

The relevance of the search for solutions to increase the wear resistance of bucket teeth of excavating machine type front shovel is analyzed. The reasons for the wear of the teeth are considered. It is determined that when excavating machines work for rocks of VIII and IX categories, impact-abrasive wear of the inner side of the teeth and abrasive external wear occurs. It is proved that the cold-work hardening of Hadfield steel (the teeth material), which occurs during the excavating machine teeth work in the rocks of VIII and IX categories, reduces the impact-abrasive wear rate on the inner side of the teeth and does not affect the abrasive wear of the outer. The methods for thermomechanical treatment of the outer side of the excavating machine tooth is proposed. It can increase the wear resistance of Hadfield steel (110G13L) up to 1.7 times and lead to the self-sharpening effect of the tooth due to equalization of the wear rate of the outer and inner parts of the tooth. The efficiency factor of thermomechanical treatment to reduce the of abrasive wear rate of Hadfield steel is experimentally proved.


2012 ◽  
Vol 209 ◽  
pp. 143-150 ◽  
Author(s):  
Q.F. Wen ◽  
Y. Liu ◽  
Y.M. Wang ◽  
F.G. Zhang ◽  
X.P. Zhu ◽  
...  

Author(s):  
Gobinda C. Saha ◽  
A. Mateen ◽  
Tahir I. Khan

Abrasive and erosive wear of components and machinery is an ongoing challenge in the oil sands industry in northern Alberta, Canada. To improve the wear resistance by increasing surface hardness of steels, heat treatments and deposition of hard layers of metal alloys (such as stellite) by fusion welding techniques are traditionally used. However, these deposition techniques are not applicable to all shapes and add considerable weight to the final component. Thermal spraying techniques such as the use of high velocity oxy-fuel (HVOF) composite coatings based on WC-Co cermet system offer better wear resistance and greater flexibility in applications. This study presents work on two feedstock powders, namely nanocrystalline and microcrystalline WC-Co cermets, with identical matrix phase content: WC-17wt.%Co. The novelty of the research is that an engineered duplex Co coated WC-17wt.%Co cermet particle designed to withstand coating spalling under elevated loads as well as to limit abrasive debridement during wear is introduced for the first time to produce a more homogeneously-dispersed coating microstructure. The engineered particle has 6wt.% of the ductile phase material mixed into the core to insure that the reinforcement WC phase is discontinuous to limit the debridement during wear, while remainder (11wt.%) of the Co is applied as a coating on the particle to improve the ductility. The mechanical properties of the overall particle are further improved by controlling the size of the reinforcing phase (WC) in the matrix (Co). This resulted in a WC-17wt.%Co particle containing a characteristic WC grain in the order of 350 nm in the core with the Co outer coating of 1–2 μm thick, making the powder particle as nanocrystalline. HVOF deposited coatings of the nanocrystalline and microcrystalline powders were examined for microhardness, fracture toughness, sliding abrasion (ASTM G133-05) and dry-sand rubber wheel abrasion (ASTM G65-04) wear performance. The wear rate under various loads and sliding distances was studied. In both the coatings, it was found that the wear rate increased with increasing applied loads, while it decreased with increasing sliding distances. 3D surface analysis of the wear tracks using atomic force microscopy (AFM) revealed two distinctive mechanisms associated with the two coatings after abrasive wear. The improved wear resistance was attributed to the higher hardness value of the nanostructured WC-17wt.%Co coating. It was also found that the nanostructured WC-17wt.%Co coating has about twice the toughness of the conventional microstructured coating counterpart. The extent of the WC decarburization and the dissolution of Co in the coatings were also studied.


2019 ◽  
Vol 16 (5) ◽  
pp. 614-624 ◽  
Author(s):  
Sam Joshy ◽  
Jayadevan K.R. ◽  
Ramesh A. ◽  
Mahipal D.

Purpose In hot forging, a significant amount of forging force is used for overcoming frictional force at the die-billet interface. The high frictional force along with thermomechanical stress lead to wear, plastic deformation, mechanical fatigue and cracks, which reduce the service life of hot forging dies. Of all these different types of issues, wear is the predominant mode of failure in hot forging dies. This paper aims to describe mechanisms of wear transition in different loads at near forging temperature, occurring during sliding of chromium-based H11 tool steel specimens. Design/methodology/approach High temperature pin-on-disc tests are performed with pin specimens machined from bars of X38CrMoV5 steel, heat treated to surface hardness of 40-42 HRc. The disc is made of EN 31 steel with hardness of 60-62 HRc. Tests are performed at constant temperature of 500°C, and the normal load was varied from 20 to 70 N. Findings Scanning electron microscopy investigations on worn surface have revealed that wear is primarily due to abrasion and plastic deformation. The test results show an increasing trend in wear rate with increase in load up to 30 N, followed by a reversal in trend until 50 N. This transition in wear rate is caused by development of wear resistant layers, which are formed by compaction of wear debris particles on to the worn surfaces. These compact layers are found to be stable during load range from 40 and 50 N. However, with further increase in load, abrasive wear tracks are observed without any evidence of protective layers. As a result, there is an increase in wear rate with increase in loads above 50 N. In addition, plastic shearing was dominant over abrasive wear at this load regime. Originality/value The study on wear behaviour of H11 hot forging steel at 20 to 70 N will be an input to the research in hot forming industries.


2016 ◽  
Vol 68 (4) ◽  
pp. 476-481 ◽  
Author(s):  
Harun Mindivan

Purpose This study aims to investigate the microstructure and the abrasive wear features of the untreated and pack borided GGG 50 quality ductile iron under various working temperatures. Design/methodology/approach GGG 50 quality as-cast ductile iron samples were pack borided in Ekabor II powder at 900°C for 3 h, followed by furnace cooling. Structural characterization was made by optical microscopy. Mechanical characterization was made by hardness and pin-on-disc wear test. Pin-on-disc test was conducted on a 240-mesh Al2O3 abrasive paper at various temperatures in between 25 and 450°C. Findings Room temperature abrasive wear resistance of the borided ductile iron increased with an increase in its surface hardness. High-temperature abrasive wear resistances of the borided ductile iron linearly decreased with an increase in test temperature. However, the untreated ductile iron exhibited relatively high resistance to abrasion at a temperature of 150°C. Originality/value This study can be a practical reference and offers insight into the effects of boriding process on the increase of room temperature wear resistance. However, above 150°C, the untreated ductile iron exhibited similar abrasive wear performance as compared to the borided ductile iron.


2019 ◽  
Vol 71 (9) ◽  
pp. 1064-1071 ◽  
Author(s):  
Alagarsamy S.V. ◽  
Ravichandran M.

Purpose Aluminium and its alloys are the most preferred material in aerospace and automotive industries because of their high strength-to-weight ratio. However, these alloys are found to be low wear resistance. Hence, the incorporation of ceramic particles with the aluminium alloy may be enhanced the mechanical and tribological properties. The purpose of this study is to optimize the specific wear rate and friction coefficient of titanium dioxide (TiO2) reinforced AA7075 matrix composites. The four wear control factors are considered, i.e. reinforcement (Wt.%), applied load (N), sliding velocity (m/s) and sliding distance (m). Design/methodology/approach The composites were fabricated through stir casting route with varying weight percentages (0, 5, 10 and 15 Wt.%) of TiO2 particulates. The mechanical properties of the composites were studied. The specific wear rate and friction coefficient of the newly prepared composites was determined by using a pin-on-disc apparatus under dry sliding conditions. Experiments were planned as per Taguchi’s L16 orthogonal design. Signal-to-noise ratio analysis was used to find the optimal combination of parameters. Findings The mechanical properties such as yield strength, tensile strength and hardness of the composites significantly improved with the addition of TiO2 particles. The analysis of variance result shows that the applied load and reinforcement Wt.% are the most influencing parameters on specific wear rate and friction coefficient during dry sliding conditions. The scanning electron microscope morphology of the worn surface shows that TiO2 particles protect the matrix from more removal of material at all conditions. Originality/value This paper provides a solution for optimal parameters on specific wear rate and friction coefficient of aluminium matrix composites (AMCs) using Taguchi methodology. The obtained results are useful in improving the wear resistance of the AA7075-TiO2 composites.


Coatings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 660
Author(s):  
Qun Wang ◽  
Yingpeng Zhang ◽  
Xiang Ding ◽  
Shaoyi Wang ◽  
Chidambaram Seshadri Ramachandran

In order to investigate the effect of WC grain size on coatings’ properties and abrasive wear performance, a few WC-20Cr3C2-7Ni coatings with three different WC grain sizes were deposited by the high-velocity oxy-fuel (HVOF) thermal spray process. The phase compositions, microstructures, and mechanical properties of the coatings were investigated. Furthermore, the two- and three-body abrasive wear performances of the three coatings were tested by using SiC and SiO2 abrasives, respectively. The results show that all the three coatings were composed of WC, Cr3C2, and the Ni binder as well as the (W,Cr)2C phase. The abrasive wear resistance of the WC-20Cr3C2-7Ni coating monotonously increased with increasing WC grain size when the SiC abrasive was used in the two- and three-body abrasive wear tests. However, the wear resistance trend was reversed when the SiO2 abrasive was used in the three-body abrasive wear test. The specific wear rate of the WC-20Cr3C2-7Ni coating exposed to the SiC abrasive under the two-body abrasive wear test was the largest. The wear resistance of the coatings was more significantly affected by the hardness of the abrasive particles than the size of carbides present within the coating. The high hardness of SiC can cut both the carbide and the binder phase of the WC-based cermet coatings, resulting in a high wear rate, whereas the low hardness of SiO2 cuts and/or scratches the binder initially, and then it dislodges the carbides from the matrix. The dislodged carbides which were subsequently pulled out from the matrix by the repeated impact of the SiO2 abrasives result in a milder wear rate.


Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1805
Author(s):  
Yu ◽  
Zhang ◽  
Tang ◽  
Gao

(1) In order to improve the properties of antifriction and wear resistance of polyimide (PI) composite under high temperature conditions, (2) 3-Aminopropyltriethoxysilane (APTES) and Lanthanum (La) salt modifications were employed to manufacture poly-p-phenylenebenzobisoxazole (PBO)/PI composites with different interface properties. The representative ambient temperatures of 130 and 260 °C were chosen to study the friction and wear behavior of composites with different interface properties. (3) Results revealed that while both modification methods can improve the chemical activity of the surface of PBO fibers, the La salt modification is more effective. The friction coefficient of all composites decreases with the increase of sliding velocity and load at two temperatures, and the specific wear rate is increases. Contrary to the situation in the 130 °C environment, the wear resistance of the unmodified composite in the 260 °C environment is greatly affected by the sliding velocity and load, while the modified composites are less affected. Under the same test parameters, the PBO–La/PI composite has the lowest specific wear rate and friction coefficient, and (4) La salt modification is a more effective approach to improve the properties of antifriction and wear resistance of PI composite than APTES modification in high ambient temperatures.


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