Microstructural and Mechanical Properties of B-Cr Coatings Formed on 145Cr6 Tool Steel by Laser Remelting of Diffusion Borochromized Layer Using Diode Laser

The paper presents study results focused on the microstructural, mechanical, and physicochemical properties of B-Cr coatings obtained by means of modification of diffusion borochromized layers by diode laser beam. The studies were conducted on 145Cr6 tool steel. Diffusion borochromized layers were produced at 950 °C in powder mixture containing boron carbides as a source of boron and ferrochrome as a source of chromium. In the next step these layers were remelted using laser beam. Powers: 600, 900, and 1200 W were used during these processes. The microstructure, microhardness, chemical composition, as well as wear and corrosion resistance of newly-formed B-Cr coatings were determined. As a result of laser beam interaction, the diffusion borochromized layer was mixed with the steel substrate. The study showed that too low laser beam power causes cracks in the newly formed B-Cr coating, and on the other hand, too higher laser beam power causes deep remelting resulting in the loss of microhardness. The reduced corrosion resistance in comparison with diffusion borochromized layers was caused by occurrence cracks or deep remelting. For B-Cr coatings produced using laser beam power 600 W, a small decrease in wear resistance was observed, but note that this coating was much thicker than diffusion borochromized layers. On the other hand, laser beam power of 1200 W caused a significant decrease in wear resistance. Newly formed B-Cr coatings had an advantageous microhardness gradient between the layer and the substrate.

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Production and Properties of FeB-Fe2B-Fe3(B,C) Surface Layers Formed on Tool Steel Using Combination of Diffusion and Laser Processing

Coatings ◽

10.3390/coatings10111130 ◽

2020 ◽

Vol 10 (11) ◽

pp. 1130 ◽

Cited By ~ 1

Author(s):

Aneta Bartkowska

Keyword(s):

Wear Resistance ◽

Corrosion Resistance ◽

Laser Beam ◽

Tool Steel ◽

Laser Processing ◽

Steel Substrate ◽

Beam Power ◽

Slight Reduction ◽

Laser Beam Power ◽

Study Results

The paper presents the study results of laser remelting diffusion boronized layers produced on CT90 tool steel. A diffusion boronized layer was produced at 950 °C in a powder mixture containing boron carbide as a source of boron. A needle-like microstructure of iron boride was obtained. After diffusion boronizing, the specimens were subjected to laser processing, which was carried out using a diode laser with a nominal power of 3 kW. Three laser beam power values were applied (600, 900, and 1200 W). The aim of the study was to investigate the microstructure, microhardness, chemical, and phase composition as well as the wear and corrosion resistance of newly formed FeB-Fe2B-Fe3(B,C) layers. As a result of the laser beam interaction, the needle-like borides occurring in the subsurface zone were remelted, and three characteristic areas were obtained: the remelted zone, the heat-affected zone, and the substrate. The properties of newly formed layers have improved in comparison to diffusion boronized layers (except for corrosion resistance). It should be noted that using the highest laser beam power contributed to a slight reduction in wear resistance. Both the reduced corrosion and wear resistance were caused by greater remelting of the steel substrate and thus by the increased iron content in the formed layer.

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Surface condition, microstructure and microhardness of boronized layers produced on Vanadis-6 steel after modification by diode laser

Archives of Mechanical Technology and Materials ◽

10.1515/amtm-2017-0011 ◽

2017 ◽

Vol 37 (1) ◽

pp. 70-75 ◽

Cited By ~ 1

Author(s):

Aneta Bartkowska ◽

Peter Jurči ◽

Dariusz Bartkowski ◽

Damian Przestacki ◽

Mária Hudáková

Keyword(s):

Laser Beam ◽

Diode Laser ◽

Heat Affected Zone ◽

Surface Condition ◽

Beam Power ◽

Laser Surface Modification ◽

Laser Beam Power ◽

Study Results ◽

Diffusion Boriding ◽

Two Phases

AbstractThe paper presents the study results of surface condition, microstructure and microhardness of Vanadis-6 tool steel after diffusion boriding and laser modification by diode laser. As a result of diffusion boriding the layers consisted of two phases: FeB and Fe2B. A bright area under the continuous boronized layers was visible. This zone was probably rich in boron. As a result of laser surface modification of boronized layers, the microstructure composed of three zones: remelted zone, heat affected zone and the substrate was obtained. The microstructure of remelted zone consisted of boron-martensite eutectic. The depth of laser track (total thickness of remelted zone and heat affected zone) was dependent on laser parameters (laser beam power density and scanning laser beam velocity). The microhardness of laser remelting boronized layer in comparison with diffusion boronized layer was slightly lower. The presence of heat affected zone was advantageous, because it allowed to obtain a mild microhardness gradient between the layer and the substrate.

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Characteristics of Cr-B Coatings Produced on Vanadis® 6 Tool Steel Using Laser Processing

Materials ◽

10.3390/ma14102621 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2621

Author(s):

Aneta Bartkowska

Keyword(s):

Corrosion Resistance ◽

Tool Steel ◽

Laser Processing ◽

Chemical Elements ◽

Steel Substrate ◽

Processing Parameters ◽

Beam Power ◽

Laser Beam Power ◽

High Microhardness ◽

The Impact

The paper presents the results of a study of the microstructure, chemical composition, microhardness and corrosion resistance of Cr-B coatings produced on Vanadis 6 tool steel. In this study, chromium and boron were added to the steel surface using a laser alloying process. The main purpose of the study was to determine the impact of those chemical elements on surface properties. Chromium and boron as well as their mixtures were prepared in various proportions and then were applied on steel substrate in the form of precoat of 100 µm thickness. Depending on the type of precoat used and laser processing parameters, changes in microstructure and properties were observed. Coatings produced using precoat containing chromium and boron mixture were characterized by high microhardness (900 HV0.05–1300 HV0.005) while maintaining good corrosion resistance. It was also found that too low laser beam power contributed to the formation of cracks and porosity.

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Influence of Laser Cladding Parameters on Microstructure, Microhardness, Chemical Composition, Wear and Corrosion Resistance of Fe–B Composite Coatings Reinforced with B4C and Si Particles

Coatings ◽

10.3390/coatings10090809 ◽

2020 ◽

Vol 10 (9) ◽

pp. 809 ◽

Cited By ~ 1

Author(s):

Dariusz Bartkowski ◽

Aneta Bartkowska ◽

Adam Piasecki ◽

Peter Jurči

Keyword(s):

Wear Resistance ◽

Corrosion Resistance ◽

Chemical Composition ◽

Laser Beam ◽

Laser Cladding ◽

Scanning Speed ◽

Powder Mixtures ◽

Wear And Corrosion ◽

Study Results ◽

Wear And Corrosion Resistance

The paper presents the study results of a laser cladding process of C45 steel using powder mixtures. The aim of this study was to investigate the microstructure, X-ray diffraction (XRD), chemical composition (EDS), microhardness, corrosion resistance and wear resistance of the newly obtained coatings. Modified coatings were prepared using laser cladding technology. A 1 kW continuous wave Yb:YAG disk laser with a powder feeding system was applied. Two different powder mixtures as well as various laser beam parameters were used. The first powder mixture contained Fe–B, and the second mixture was Fe–B–B4C–Si. Two values of laser beam power (600 and 800 W) and three values of scanning speed (600, 800, and 1000 mm/min) were applied during the studies. As a result of the influence of the laser beam, the zones enriched with modifying elements were obtained. Based on the results of XRD, the presence of phases derived from borides and carbides was found. In all cases analyzed, EDS studies showed that there is an increased content of boron in the dendritic areas, while there is an increased silicon content in interdendritic spaces. The addition of B4C and Si improved properties such as microhardness as well as wear and corrosion resistance. The microhardness of the coating increased from approx. 400 HV to approx. 1100 HV depending on the laser parameters used. The best corrosion resistance was obtained for the Fe–B–B4C–Si coating produced using the highest laser beam scanning speed. An improvement in wear resistance can be seen after wear tests, where the weight loss decreased from about 0.08 g to about 0.05 g.

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Microstructure and wear resistance of gas-nitrided steel after laser modification

Journal of Achievements of Materials and Manufacturing Engineering ◽

10.5604/01.3001.0010.7984 ◽

2017 ◽

Vol 1 (85) ◽

pp. 12-20

Author(s):

D. Panfil ◽

M. Kulka ◽

P. Wach ◽

J. Michalski

Keyword(s):

Wear Resistance ◽

Laser Beam ◽

Nitrided Layer ◽

Beam Power ◽

Surface Layers ◽

Laser Modification ◽

Gas Nitriding ◽

Laser Heat ◽

Laser Beam Power ◽

Hybrid Layers

Purpose: The aim of this work was to study the microstructure and wear resistance of hybrid surface layers, produced by a controlled gas nitriding and laser modification. Design/methodology/approach: Nitriding is well-known method of thermo-chemical treatment, applied in order to produce surface layers of improved hardness and wear resistance. The phase composition and growth kinetics of the diffusion layer can be controlled using a gas nitriding with changeable nitriding potential. In this study, gas nitriding was carried out on 42CrMo4 steel at 570°C (843 K) for 4 hours using changeable nitriding potential in order to limit the thickness of porous e zone. Next, the nitrided layer was laser-modified using TRUMPF TLF 2600 Turbo CO2 laser. Laser tracks were arranged as the multiple tracks with scanning rate vl=2.88 m/min and overlapping of about 86% using the two laser beam powers (P): 0.21 kW and 0.26 kW. Microstructure was observed by an optical microscope. Phase composition was studied using XRD. Hardness profiles in the produced hybrid layers was determined using a Vickers method. Wera resistance tests were performed using MBT-01 tester. Findings: Gas nitriding resulted in formation of compound zone, consisting of e nitrides close to the surface and a zone, composed of e + g' nitrides. Below the white compound zone, the diffusion zone occurred with nitric sorbite and precipitates of g' nitrides. In the microstructure after laser heat treatment (LHT) of nitrided layer, the zones were observed as follows: the re-melted zone (MZ) with e nitrides, nitric martensite and non-equilibrium FeN0.056 phase, the heat-affected zone (HAZ) with nitric martensite and precipitates of g' phase and the diffusion zone (DZ) without visible effect of laser treatment. Laser beam power influenced the depth of MZ and HAZ, so the thickness of hardened zone. The hardness of MZ was slightly decreased compared to the hardness of compound zone after gas nitriding. However, the significant increase in hardness was observed in HAZ. The formation of hybrid layers advantageously influenced the tribological properties. The laser-heat treated nitrided layers were characterized by improved wear resistance compared to the only gas-nitrided layer. Research limitations/implications: The effect of LHT on the microstructure and properties of gas-nitrided layer was limited to the two laser beam powers. In the future research, this range should be exceeded, especially, taking into account the lower values of laser beam power. It will result in laser modification without re-melting. Practical implications: The selection of suitable LHT parameters could provide the hybrid layers of modified microstructure and improved wear resistance. Originality/value: This work was related to the new concept of modification of nitrided layer by laser heat treatment.

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Microstructure, Microhardness, Corrosion Resistance and Chemical Composition of Mo, B and Mo-B Coatings Produced Using Laser Processing

Materials ◽

10.3390/ma13153249 ◽

2020 ◽

Vol 13 (15) ◽

pp. 3249 ◽

Cited By ~ 3

Author(s):

Aneta Bartkowska ◽

Dariusz Bartkowski ◽

Mikołaj Popławski ◽

Adam Piasecki ◽

Damian Przestacki ◽

...

Keyword(s):

Corrosion Resistance ◽

Laser Beam ◽

Cross Sections ◽

Steel Substrate ◽

Scanning Speed ◽

Beam Power ◽

Laser Alloying ◽

Properties Of Coatings ◽

Study Results ◽

Steel Substrates

The paper presents study results of laser alloying of CT90 tool steel with an applied pre-coat of boron, molybdenum or a mixture of these elements. Pre-coats were applied on steel substrates in the form of a paste. The aim of the study was to investigate the microstructure, chemical and phase composition, microhardness and corrosion resistance of these newly-formed coatings. The laser alloying process was carried out using a diode laser with a nominal power of 3 kW. In this study a laser beam power of 900 W and a scanning speed of 48 mm/s were used. As a result of the laser beam action, the presence of three areas was observed in cross-sections of specimens: a remelted zone, a heat affected zone and the substrate. The properties of coatings enriched with both molybdenum and boron were better than those of the steel substrate, but only the use of a Mo-B mixture resulted in a significant improvement in microhardness and corrosion resistance.

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MILNE CMV

Alloy Digest ◽

10.31399/asm.ad.ts0111 ◽

1961 ◽

Vol 10 (11) ◽

Keyword(s):

Fracture Toughness ◽

Wear Resistance ◽

Corrosion Resistance ◽

High Temperature ◽

Tensile Properties ◽

Tool Steel ◽

Compression Strength ◽

Heat Treating ◽

Medium Carbon ◽

Temperature Performance

Abstract Milne CMV is a 5% chromium, medium-carbon hot work tool steel, having high compression strength, wear resistance, and corrosion resistance. This datasheet provides information on composition, hardness, and tensile properties as well as fracture toughness and creep. It also includes information on high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: TS-111. Producer or source: A. Milne & Company (Distributor).

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