Effect of heat treatment on changes in the properties of the surface layer of steel 12KhN3A during wear

1973 ◽  
Vol 15 (4) ◽  
pp. 356-358
Author(s):  
L. Ya. Oshinya ◽  
V. A. Grishko
Keyword(s):  
Heat Treatment ◽  
Surface Layer ◽  
Steel 12Khn3a

Laser Surface Modification of Borochromizing C45 Steel

2012 ◽  
Vol 57 (1) ◽  
pp. 211-214 ◽  
Author(s):  
A. Bartkowska ◽  
A. Pertek ◽  
M. Jankowiak ◽  
K. Jóźwiak
Keyword(s):  
Heat Treatment ◽  
Surface Layer ◽  
Surface Modification ◽  
Laser Power Density ◽  
Laser Surface ◽  
Laser Heat Treatment ◽  
Laser Surface Modification ◽  
Scanning Rate ◽  
Melted Zone ◽  
Laser Heat

Laser Surface Modification of Borochromizing C45 SteelIn this study the test results for borochromized C45 steel after laser surface modification were presented. Influence of laser heat treatment on the microstructure and microhardness of surface layer was investigated. The process of borochromizing consisted of chromium plating followed by diffusion boronizing. The laser heat treatment (LHT) of multiple tracks in the helical line was carried out with CO2laser beam. The technological laser TRUMPF TLF 2600 Turbo CO2of the nominal power 2.6 kW was applied. Borochromizing was carried out with laser power density q = 41.40 kW/cm2and at laser beam scanning rate v = 0.67 m/min and v = 2.016 m/min. Measurements of microhardness were conducted using the Vickers' method and Zwick 3212 B hardness tester. Microstructure observations were performed by means of an optical microscope Metaval Carl Zeiss Jena and scanning electron microscope Tescan VEGA 5135. After laser heat treatment with re-melting a three-zone layer was obtained, which included: re-melted zone, heat affected zone and a core. Influence of laser treatment parameters on thickness of melted zone and microstructure of the surface layer was tested. The microhardness tested along the axis of track of the surface layer after laser modification was about 800-850 HV. The results of tests showed influence of laser power density and scanning rate on microstructure and properties of borochromized layers.

THE INFLUENCE OF BORON IN THE SURFACE LAYER ON THE STRUCTURE AND THE TRIBOLOGICAL PROPERTIES OF IRON ALLOYS

Tribologia ◽  
2019 ◽  
Vol 288 (6) ◽  
pp. 73-80
Author(s):  
Aleksandra Pertek-Owsianna ◽  
Karolina Wiśniewska-Mleczko ◽  
Adam Piasecki
Keyword(s):  
Heat Treatment ◽  
Wear Resistance ◽  
Surface Layer ◽  
Steel Substrate ◽  
Eutectic Mixture ◽  
Iron Alloys ◽  
Boron Steel ◽  
Laser Alloying ◽  
Scanning Velocity ◽  
Steel Core

This paper presents two methods of introducing boron into the surface layer of iron alloys, namely diffusion boronizing by means of the powder method and laser alloying with a TRUMPF TLF 2600 Turbo CO2 gas laser. Amorphous boron was used as the chemical element source. As regards diffusion drilling, the influence of temperature and time on the properties of the layer was tested. During the laser alloying, the influence of the thickness of the boriding paste layer as well as the power and laser beam scanning velocity was determined. How the carbon content in steel and alloying elements in the form of chromium and boron influence the structure of the surface layer was tested. To achieve this object, the following grades of steel were used: C45, C90, 41Cr4, 102Cr6, and HARDOX boron steel. The microhardness and wear resistance of the obtained boron-containing surface layers were tested. A Metaval Carl Zeiss Jena light microscope and a Tescan VEGA 5135 scanning electron microscope, a Zwick 3212B microhardness tester, and an Amsler tribotester were used for the tests. The structure of the diffusion- borided layer consists of the needle-like zone of FeB + Fe2B iron borides about 0.15 mm thick, with a good adhesion to the substrate of the steel subjected to hardening and tempering after the boriding process. After the laser alloying, the structure shows paths with dimensions within: width up to 0.60 mm, depth up to 0.35 mm, containing a melted zone with a eutectic mixture of iron borides and martensite, a heat affected zone with a martensitic-bainitic structure and a steel core. The microhardness of both diffusionborided and laser-borided layers falls within the range of 1000 – 1900 HV0.1, depending on the parameters of the processes. It has been shown that, apart from the structure and thickness of the layer containing boron and microhardness, the frictional wear resistance depends on the state of the steel substrate, i.e. its chemical composition and heat treatment. The results of testing iron alloys in the borided state were compared with those obtained only after the heat treatment.

Semiporous Reinforcing Fillers for Composite Resins: I. Preparation of Provisional Glass Formulations

1976 ◽  
Vol 55 (5) ◽  
pp. 738-747 ◽  
Author(s):  
R.L. Bowen ◽  
L.E. Reed
Keyword(s):  
Heat Treatment ◽  
Surface Layer ◽  
Composite Resins ◽  
Porous Surface ◽  
Phase Separations ◽  
Reinforcing Fillers ◽  
Gradient Furnace ◽  
Polymeric Binders ◽  
Filler Particles ◽  
Glass Compositions

A conceptual means of obtaining improved bonding between filler particles and the polymeric binders of composites is presented. It involves preparing glass particles that separate into two interconnected vitreous phases when heated to an appropriate temperature, and then etching these to produce a porous surface layer. Candidate glass compositions were prepared and subjected to heat treatment in a gradient furnace. Compositions susceptible to phase separations were delineated.

Improvement of oxidation resistance of Si3N4 by heat treatment in a wet H2 atmosphere

2002 ◽  
Vol 17 (9) ◽  
pp. 2321-2326
Author(s):  
Young-Hag Koh ◽  
Hae-Won Kim ◽  
Hyoun-Ee Kim
Keyword(s):  
Heat Treatment ◽  
Surface Layer ◽  
Oxidation Resistance ◽  
Silicate Glass ◽  
Continuous Layer ◽  
Heat Treated

To improve the oxidation resistance of Si3N4 material, a dense and continuous layer, composed of small Y2Si2O7 crystallites and silicate glass, was formed on the surface. The surface layer was formed by exposing the specimens in a flowing H2 atmosphere containing 0.1% H2O at 1450 °C for 1 h. For the purpose of comparison, specimens of the same material were heat treated in air at 1450 °C for 1 h. Small equiaxed Y2Si2O7 crystallites were formed when the specimen was heat treated in the wet H2 atmosphere, while relatively large and elongated Y2Si2O7 crystallites developed when the specimens were heat treated in air. The oxidation resistance of Si3N4 material was improved remarkably by the heat treatment in the wet H2, while no improvement in oxidation resistance was observed from the specimen heat treated in air. The improvement was attributed to the retardation of the transport of oxidants through the dense and continuous layer formed on the surface.

scholarly journals Structural Changes of Nitrogen Ferrite After Aging in Temperature Interval up to 100 °С

2021 ◽  
Vol 44 (1) ◽  
pp. 28-33
Author(s):  
Tatyana MECHKAROVA ◽  
Yaroslav ARGIROV ◽  
Daniela SPASOVA ◽  
Aneliya STOYANOVA
Keyword(s):  
Heat Treatment ◽  
Surface Layer ◽  
Aging Process ◽  
Structural Changes ◽  
Electrochemical Corrosion ◽  
Micro Hardness ◽  
X Ray ◽  
Ferrite Structure ◽  
The Individual ◽  
Individual Grains

This paper aims to determine the extent of aging of nitrogen ferrite at temperatures below 100 °C and the structural and strength changes that occur in the process. The tests are carried out on samples of technically pure iron (Armco). The specimens are pre-deformed by tension and re-crystallisation heating to achieve a large-grain ferrite structure. A large-grained structure has been chosen to more accurately track the change in micro-hardness of the individual grains during the aging process. Nitric ferrite results from gas carbonitriding and subsequent hardening. Upon hardening, the samples are stored in a refrigerator, and then the surface layer formed is removed through electrochemical corrosion. Afterwards, aging heat treatment at temperatures below 100 °C is undertaken. After the aging process, micro-hardness of the individual grains is examined and X-ray structural analysis is performed.

scholarly journals Formation of a photocatalytic WO3 surface layer on electrodeposited Al–W alloy coatings by selective dissolution and heat treatment

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Shota Higashino ◽  
Masao Miyake ◽  
Takumi Ikenoue ◽  
Tetsuji Hirato
Keyword(s):  
Heat Treatment ◽  
Surface Layer ◽  
Selective Dissolution ◽  
Alloy Film ◽  
Light Illumination ◽  
Corrosion Resistant ◽  
Alloy Films ◽  
Visible Light Illumination ◽  
Self Cleaning ◽  
Surface Layer Formation

Abstract In this study, we explored the feasibility of WO3 surface layer formation on electrodeposited Al–W alloy coatings by selective dissolution and heat treatment, with the aim of providing corrosion-resistant Al–W alloy coatings with photocatalytic self-cleaning properties under visible light illumination. The selective dissolution of Al and oxidation of residual W was carried out by immersing Al–W alloy films in an aqueous solution of nitric acid. A nanostructured H2WO4·H2O surface layer was formed on the alloy film by this process. The H2WO4·H2O layer was dehydrated to WO3 by heat treatment, yielding a multilayered WO3/Al–W alloy film with an approximately 300 nm thick WO3 layer. The WO3/Al–W alloy film exhibited photocatalytic self-cleaning, as demonstrated by the photodegradation of stearic acid and methylene blue. We also confirmed that selective dissolution and heat treatment did not significantly diminish the corrosion resistance of the Al–W alloy films.

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