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

Materials ◽  
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.

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

Coatings ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1130 ◽  
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.

scholarly journals Manufacturing Technology and Properties of Fe/TaC Metal Matrix Composite Coatings Produced on Medium Carbon Steel Using Laser Processing—Preliminary Study on the Single Laser Tracks

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5367
Author(s):  
Dariusz Bartkowski
Keyword(s):  
Laser Beam ◽  
Metal Matrix Composite ◽  
Matrix Composite ◽  
Laser Processing ◽  
Metal Matrix ◽  
Steel Substrate ◽  
Composite Coatings ◽  
Tantalum Carbide ◽  
Beam Power ◽  
Laser Beam Power

The paper presents study results of Fe/TaC metal matrix composite coatings produced on tool steel using laser processing of TaC pre-coat. The Fe/TaC coatings were produced in two steps. First, a pre-coat in the form of a paste based on tantalum carbide and water glass was made and then applied to the steel substrate. In the second step, the TaC pre-coat was remelted with steel substrate using a diode laser beam with a rated power of 3 kW. A constant scanning speed of the laser beam of 3 m/min and three types of laser beam power: 500 W, 800 W and 1100 W were applied. Tests were carried out on three different thicknesses of the TaC pre-coat: 30 µm, 60 µm and 90 µm. The influence of pre-coat thickness and laser beam power on the microstructure, chemical composition and microhardness were analyzed. A possibility of producing coatings with a characteristic composite structure was found, where the iron from the substrate became the matrix, and the introduced tantalum carbides—the reinforcing phase. It was found that too high power of the laser beam leads to complete melting of the introduced primary TaC particles. It was also found that the use of a thicker TaC pre-coat contributes to microhardness increase.

Modelling of the effects of laser modification of gas-nitrided layer

2017 ◽  
Vol 2 (88) ◽  
pp. 59-67 ◽  
Author(s):  
M. Kulka ◽  
D. Panfil ◽  
J. Michalski ◽  
P. Wach
Keyword(s):  
Laser Beam ◽  
Laser Processing ◽  
Nitrided Layer ◽  
Processing Parameters ◽  
Beam Power ◽  
Laser Modification ◽  
Gas Nitriding ◽  
Scanning Rate ◽  
Melted Zone ◽  
Laser Beam Power

Purpose: The effects of laser processing parameters on the dimensions of simple laser tracks, produced on the previously nitrided layer, were analysed. Design/methodology/approach: Gas nitriding is one of the most commonly used thermochemical treatment, resulting in many advantageous properties: high hardness, enhanced corrosion resistance, improved wear resistance and fatigue strength. However, an unfavourable increase in the thickness of compound zone (e + g’) close to the surface was observed after conventional gas nitriding. This was the reason for undesirable embrittlement and flaking of the layer. Therefore, a controlled gas nitriding was intensively developed, reducing the percentage of the most brittle e (Fe2-3N) iron nitrides. In this study, the hybrid surface layer was produced. The controlled gas-nitriding was followed by laser heat treatment (LHT). Laser modification was carried out using various laser beam powers and scanning rates. The dimensions of laser tracks (i.e. depths and widths of re-melted zone and heat-affected zone) were measured. Numerical methods were used in order to formulate a mathematical model. Findings: Laser processing parameters (laser beam power and scanning rate) influenced the microstructure obtained. The microstructure of laser modified nitrided steel with re-melting consisted of re-melted zone (MZ), heat-affected zone (HAZ), nitrided layer without visible effects of laser treatment and the substrate. The use of laser beam power of 0.26 kW resulted in only a partial re-melting of the compound zone. The two characteristic values of laser beam power were estimated. P0MZ corresponded to the laser beam power at which the re-melted zone disappeared (i.e. width and depth of MZ were equal to 0). P0HAZ was a value of laser beam power at which the effects of laser irradiation were invisible in microstructure (i.e. width and depth of HAZ were equal to 0). The model was proposed in order to predict the effects of LHT on microstructure. Research limitations/implications: The presented model was limited to the scanning rates in the range of 2.24-3.84 m/min. In the future research, this range should be exceeded, especially, taking into account the lower values of scanning rate. Practical implications: The presented model could be used in order to control the microstructure and properties of hybrid surface layers, obtained as a consequence of the controlled gas-nitriding and LHT. Originality/value: his work is related to the new conception of laser modification of nitrided layers. Such a treatment provided the hybrid layers of new advantageous properties.

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

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 608
Author(s):  
Aneta Bartkowska ◽  
Dariusz Bartkowski ◽  
Damian Przestacki ◽  
Jakub Hajkowski ◽  
Andrzej Miklaszewski
Keyword(s):  
Wear Resistance ◽  
Corrosion Resistance ◽  
Laser Beam ◽  
Diode Laser ◽  
Tool Steel ◽  
The Other ◽  
Beam Power ◽  
Other Hand ◽  
Laser Beam Power ◽  
Study Results

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.

Effects of Laser Processing Parameters on Grain Boundary Character Distribution and Corrosion Resistance of Austenite Stainless Steel

2007 ◽  
Vol 561-565 ◽  
pp. 2473-2476 ◽  
Author(s):  
Sen Yang ◽  
Hiroyuki Kokawa ◽  
Zhan Jie Wang
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Laser Processing ◽  
Processing Parameters ◽  
Laser Surface ◽  
304 Stainless Steel ◽  
Grain Boundary Character Distribution ◽  
Grain Boundary Character ◽  
Laser Surface Remelting ◽  
Character Distribution

In order to modify grain boundary character distribution (GBCD) and to improve intergranualr corrosion (IGC) resistance of 304 stainless steel, laser surface remelting experiments were conducted on 304 stainless steel using a 2kW CW Nd: YAG laser, and the effects of laser processing parameters on GBCD and corrosion resistance were investigated in detail under the optimal annealing condition (1220K 28h). The experimental results showed that combination of laser surface remelting and the following annealing treatment could change the GBCD remarkably and improve the IGC resistance of 304 stainless steel. However, there are no obvious effects of laser processing parameters on the final depth of the processed zone, although the depth of the molten pool increases with the increase of the laser output power or the decrease of the scanning velocity, and the subsequent GBCD and corrosion resistance.

Study on Behavior of Ni-Based and Fe-Based Hardfacing Alloys in Plant Valves with Laser Cladding

2011 ◽  
Vol 287-290 ◽  
pp. 2267-2270
Author(s):  
Ai Qin Xu ◽  
Ge Yan Fu ◽  
Chen Wang ◽  
Hui Zhang ◽  
Shuang Liu ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Laser Cladding ◽  
Laser Processing ◽  
Processing Parameters ◽  
Dense Microstructure ◽  
Wear And Corrosion ◽  
Wear And Corrosion Resistance

Two new kinds of Ni-based and Fe-based alloy power have been developed. Both kinds of power have been successfully coated by laser cladding on the surface of stainless steel as strengthening layers. The morphology and microstructure of these coatings have been analyzed by SEM and XRD, the mircohardness, wear and corrosion resistance of Ni-based and Fe-based laser cladding coatings have been measured respectively. The analysis reveals that both coatings with smooth and successive surfaces and homogeneous morphology have been obtained under the proper laser processing parameters; besides, Ni-based and Fe-based coatings have fine, well-proportioned and dense microstructure, and better joints with the substrates, respectively. So the results indicate that Ni-based and Fe-based alloys can supersede the cobalt-based alloys in the certain conditions.

Study on the Properties of the Laser Cladded Cobalt-Based Alloy Coating on T10 Tool Steel

2011 ◽  
Vol 464 ◽  
pp. 686-689
Author(s):  
Cheng Yun Cui ◽  
Xi Gui Cui ◽  
Yong Kong Zhang ◽  
Qian Zhao ◽  
Jin Zhong Lu
Keyword(s):  
Corrosion Resistance ◽  
Tool Steel ◽  
Co2 Laser ◽  
Steel Substrate ◽  
Cryogenic Treatment ◽  
Alloy Coating ◽  
Reinforced Composite ◽  
Maximum Value ◽  
Obvious Change ◽  
Continuous Co2 Laser

Co-based alloy coating was cladded on T10 tool steel by the powder feeding and continuous CO2 laser. The results showed that compared to the unreinforced T10 tool steel substrate, the microhardness of the Co-based reinforced composite was significantly enhanced and the maximum value was existed in the middle of the cladding coating. The corrosion resistance of the cladding coating was also improved. After cryogenic treatment, there is no obvious change for the structure of the cladding coating while the phase is transformed, leading to an increase in the microhardness of the cladding coating.

scholarly journals Microstructure and Corrosion Behavior of Ti-Nb Coatings on NiTi Substrate Fabricated by Laser Cladding

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 597
Author(s):  
Jie Hu ◽  
Yaojia Ren ◽  
Qianli Huang ◽  
Hao He ◽  
Luxin Liang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Laser Cladding ◽  
Laser Processing ◽  
Niti Alloy ◽  
Processing Parameters ◽  
Medical Applications ◽  
Strengthening Effect ◽  
Aggressive Environment ◽  
Metallurgical Bonding ◽  
Fine Microstructure

Ti-23Nb (at.%) coatings on an NiTi alloy with metallurgical bonding were prepared by laser cladding (LC) technology using Ti-Nb mixture powders. The effects of laser processing parameters on the microstructure and mechanical properties of the coatings were systematically investigated and the corrosion resistance of the coatings was assessed. The coatings were composed of TiNb, (Ti, Nb)2Ni, and β-Nb phases. The coatings increased the hardness of the NiTi alloy by a combined strengthening effect of the eutectics and fine microstructure. The corrosion resistance of the coated part was improved. The coatings with great corrosion resistance could keep the coated parts inert in an aggressive environment, and effectively restrain the release of toxic Ni ions, which means that the Ti-Nb alloy coatings are likely to be used as a biomaterial for medical applications.

scholarly journals Effect of Laser Processing Parameters on Microstructure, Hardness and Tribology of NiCrCoFeCBSi/WC Coatings

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6034
Author(s):  
Jelena Škamat ◽  
Olegas Černašėjus ◽  
Gulnara Zhetessova ◽  
Tatyana Nikonova ◽  
Olga Zharkevich ◽  
...  
Keyword(s):  
Power Density ◽  
Laser Processing ◽  
Steel Substrate ◽  
Pulsed Laser ◽  
Processing Parameters ◽  
Flame Spray ◽  
Spray Method ◽  
Pulsed Laser Processing ◽  
Thermally Sprayed ◽  
Sprayed Coatings

In the present study, pulsed laser post-processing was applied to improve the properties of the thermally sprayed NiCrCoFeCBSi/40 wt.% WC coatings. The powder mix was deposited onto a mild steel substrate by flame spray method and then the as-sprayed coatings were processed by Nd:YAG laser. The peak power density applied was between 4.00 × 106 and 5.71 × 106 W/cm2, and the laser operating speed ranged between 100 and 400 mm/min, providing processing in a melting mode. Scanning electron microscopy, energy dispersive spectroscopy, Knop hardness measurements, and “ball-on-disc” dry friction tests were applied to study the effect of the processing parameters on the geometry of laser pass and microstructure, hardness, and tribology of the processed layers. The results obtained revealed that pulsed laser processing provides a monolithic remelted coating layer with the microstructure of ultrafine, W-rich dendrites in Ni-based matrix, where size and distribution of W-rich dendrites periodically vary across remelted layer depth. The composition of W-rich dendrites can be attributed to a carbide of type (W, Cr, Ni, Fe)C. The cracks sensitivity of coatings was visibly reduced with the reduction of power density applied. The hardness of coatings was between ~1070 and ~1140 HK0.2 and correlated with microstructure size, being dependent on the processing parameters. The friction coefficient and wear rate of coatings during dry sliding were reduced by up to ~30% and up to ~2.4 times, respectively, after laser processing.

scholarly journals Corrosion Behavior of Selectively Laser Melted CoCrFeMnNi High Entropy Alloy

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1029 ◽  
Author(s):  
Jie Ren ◽  
Chaitanya Mahajan ◽  
Liang Liu ◽  
David Follette ◽  
Wen Chen ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Laser Processing ◽  
Electrochemical Impedance ◽  
Processing Parameters ◽  
High Entropy Alloy ◽  
Elemental Distribution ◽  
Powder Bed ◽  
High Entropy ◽  
Wide Range ◽  
Superior Corrosion Resistance

CoCrFeMnNi high entropy alloys (HEAs) were additively manufactured (AM) by laser powder bed fusion and their corrosion resistance in 3.5 wt% NaCl solution was studied by potentiodynamic polarization and electrochemical impedance spectroscopy tests. A systematic study of AM CoCrFeMnNi HEAs’ porosity under a wide range of laser processing parameters was conducted and a processing map was constructed to identify the optimal laser processing window for CoCrFeMnNi HEAs. The near fully dense AM CoCrFeMnNi HEAs exhibit a unique non-equilibrium microstructure consisting of tortuous grain boundaries, sub-grain cellular structures, columnar dendrites, associated with some processing defects such as micro-pores. Compared with conventional as-cast counterpart, the AM CoCrFeMnNi HEAs showed higher pitting resistance (ΔE) and greater polarization resistance (Rp). The superior corrosion resistance of AM CoCrFeMnNi HEAs may be attributed to the homogeneous elemental distribution and lower density of micro-pores. Our study widens the toolbox to manufacture HEAs with exceptional corrosion resistance by additive manufacturing.

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