Tribological Evaluation of Boride Layers Formed on an AISI M2 Steel Substrate by the Powder Packing Method (original) (raw)
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Production and characterization of boride layers on AISI D2 tool steel
Vacuum, 2010
a b s t r a c t AISI D2 is the most commonly used cold-work tool steel of its grade. It offers high hardenability, low distortion after quenching, high resistance to softening and good wear resistance. The use of appropriate hard coatings on this steel can further improve its wear resistance. Boronizing is a surface treatment of Boron diffusion into the substrate. In this work boride layers were formed on AISI D2 steel using borax baths containing iron-titanium and aluminium, at 800 C and 1000 C during 4 h. The borided treated steel was characterized by optical microscopy, Vickers microhardness, X-ray diffraction (XRD) and glow discharge optical spectroscopy (GDOS) to verify the effect of the bath compositions and treatment temperatures in the layer formation. Depending on the bath composition, Fe 2 B or FeB was the predominant phase in the boride layers. The layers exhibited ''saw-tooth'' morphology at the substrate interface; layer thicknesses varied from 60 to 120 mm, and hardness in the range of 1596-1744 HV were obtained.
Tribological properties of oxidised boride coatings grown on AISI 4140 steel
Materials Letters, 2006
In this study, we investigated the wear behaviour of borided and borided + short-duration oxidized AISI 4140 steel. Boronizing was carried out in a slurry salt bath consisting of borax, boric acid and ferro silicon. Also, short-duration oxidizing treatment was applied to borided steel to produce glass-like boron oxide layer. The short-duration oxidizing was performed at 750°C for 3 min. Optical and scanning electron microscope (SEM) cross-sectional examinations of borided layer revealed a needle-shaped morphology. The presence of non-oxide boride type ceramics FeB and Fe 2 B formed on the surface of steel substrate was confirmed by classical metallographic technique and X-ray diffraction (XRD) analysis. The hardness of borides formed on the surface of steel substrate and unborided steel substrate were 1446-1690 HV 0.1 and 280 HV 0.1 , respectively. The wear behaviour of borided steel were characterised by using a pin-on-disc technique. The borided and short-duration oxidized steels, in the form of pins were allowed to slide against a hard AISI 440C stainless steel disc (63 HRc). The sliding velocity of 1 m s − 1 for borided and short-duration oxidized steel and the nominal load on the pin was 20 N. The highest wear rates were observed on disc slide against the base steel, whilst the lowest wear rates occurred during sliding against the borided and short-duration oxidized steel surfaces. It was observed that the friction coefficient of unborided (hardened + tempered) and borided steels ranged from 0.50 to 0.60, but after short-duration oxidizing, the friction coefficient of borided steel was dropped to 0.12.
Dry sliding wear behavior of borided hot-work tool steel at elevated temperatures
Surface and Coatings Technology, 2017
In the present study, the surface of AISI H13 hot-work tool steel was borided with EKabor II powders using powder pack-boriding method. The process was carried out at 800, 900 and 1000 °C temperatures for 2, 4 and 6 h periods. The wear tests were carried out using a ball-on disc tribometer at room temperature and 500 ºC on borided and untreated AISI H13 hot-work tool steel. Scanning electron microscope (SEM), optical microscope, 3D profilometer, X-Ray diffraction analysis and micro-hardness tester were used in the evaluation of micro-structure and wear data. The increase in the boriding temperature and boriding period led to increased thickness and hardness of the boride layer. Boriding at 800 °C resulted with formation of Fe 2 B, Mn 2 B, Cr 5 B 3, phases, while FeB, Fe 2 B, Mn 2 B, and Cr 5 B 3 boride phases occurred at 900 and 1000 °C. Dominant wear mechanisms were microcrack-induced plastic deformation during high temperature wear tests; oxidation and microcrack formation during room temperature wear tests; and oxidation and severe plastic deformation for the untreated specimen.
Characterization and wear performance of boride phases over tool steel substrates
Advances in Mechanical Engineering, 2016
This research work was conducted to characterize boride phases, obtained from the powder-pack process, on AISI H13 and D2 steel substrates, and investigate their tribological behavior. The boriding was developed at a temperature of 1273 K with an exposure time of 8 h. X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were conducted on the borided material to characterize the presence of the FeB, Fe2B, and CrB phases and the distribution of heavy elements on the surface of the substrates. The adherence of the boride layers was evaluated, in a qualitative form, through the Daimler-Benz Rockwell-C indentation technique. Sliding wear tests were then performed using a reciprocating wear test machine. All tests were conducted in dry conditions at room temperature. A frequency of 10 Hz and 15-mm sliding distance were used. The applied Hertzian pressure was 2.01 GPa. Scanning electron microscopy was used to observe and analyze the wear mechanisms. Add...
Journal of Materials Processing Technology, 2000
In this study, the wear behaviour of the borided and carburized AISI 1020 and 5115 steels are investigated. Some of the samples prepared from test materials are carburized and some borided. The microstructure, worn surface and hardness distribution of the samples are examined. After and before wear testing, the surface phases of the treated samples are determined by X-ray diffraction method. Fe 2 B phase is obtained on the borided surface. The wear tests are conducted with plate-on-disc sample con®guration under dry sliding conditions. The wear behaviour and friction characteristics of the samples are determined as a function of sliding distance and the load. The results are compared with each other. It is observed that the weight loss of the borided AISI 1020 steel is lower than that of carburized AISI 5115 steels.
Electrochemical boriding and characterization of AISI D2 tool steel
Thin Solid Films, 2011
D2 is an air-hardening tool steel and due to its high chromium content provides very good protection against wear and oxidation, especially at elevated temperatures. Boriding of D2 steel can further enhance its surface mechanical and tribological properties. Unfortunately, it has been very difficult to achieve a very dense and uniformly thick boride layers on D2 steel using traditional boriding processes. In an attempt to overcome such a deficiency, we explored the suitability and potential usefulness of electrochemical boriding for achieving thick and hard boride layers on this tool steel in a molten borax electrolyte at 850, 900, 950 and 1000°C for durations ranging from 15 min to 1 h. The microstructural characterization and phase analysis of the resultant boride layers were performed using optical, scanning electron microscopy and X-ray diffraction methods. Our studies have confirmed that a single phase Fe 2 B layer or a composite layer consisting of FeB + Fe 2 B is feasible on the surface of D2 steel depending on the length of boriding time. The boride layers formed after shorter durations (i.e., 15 min) mainly consisted of Fe 2 B phase and was about 30 μm thick. The thickness of the layer formed in 60 min was about 60 μm and composed mainly of FeB and Fe 2 B. The cross sectional micro-hardness values of the boride layers varied between 14 and 22 GPa, depending on the phase composition.
Investigation of wear behavior of borided AISI D6 steel
Materiali in tehnologije, 2016
We have investigated the effect of the boriding process on the wear behavior of AISI D6 steel. The boride layer was characterized by light microscopy, X-ray diffraction and micro-Vickers hardness testing. The X-ray diffraction analysis of the boride layers on the surface of the steels revealed the existence of the FeB, Fe2B, CrB and Cr2B compounds. Depending on the chemical composition of the substrates, the boride-layer thickness on the surface of the AISI D6 steel was found to be 164.42 μm. The hardness of the boride compounds formed on the surface of the steels ranged from 1672 HV0.05 to 2118 HV0.05, whereas the Vickers hardness value of the untreated steels was 584 HV0.05. The wear tests were carried out using a ball-disc arrangement under dry-friction conditions at room temperature with an applied load of 10 N and a sliding speed of 0.3 m/s for a sliding distance of 1000 m. It was observed that the wear rate of the borided and unborided AISI D6 steel ranged from 1.28 × 10-6 to 81.2 × 10-6 mm 3 /Nm.
Some mechanical properties of borided AISI H13 and 304 steels
Materials & Design, 2007
In the present study, mechanical properties of borides formed on AISI H13 hot work tool and AISI 304 stainless steels have been investigated. Both steels have high chromium content and have a widespread use in the engineering application. Boriding treatment was carried out in slurry salt bath consisting of borax, boric acid, and ferrosilicon at temperature range of 800-950°C for 3, 5, and 7 h. X-ray diffraction analysis of boride layers on the surface of steels revealed various peaks of FeB, Fe 2 B, CrB, and Ni 3 B. Metallographic studies showed that the boride layer has a flat and smooth morphology in the 304 steel while H13 steel was a ragged morphology. The characterization of the boride layer is also carried out by means of the micro-hardness, surface roughness, adhesion, and fracture toughness studies.