scholarly journals Mechanical Properties of Nitrided Layer after Laser Modification

2021 ◽  
Vol 8 (1) ◽  
pp. 1-6
Author(s):  
Dominika Panfil-Pryka ◽  
Michał Kulka
Keyword(s):  
Wear Resistance ◽  
Friction Coefficient ◽  
Nitrided Layer ◽  
Wear Testing ◽  
Surface Layers ◽  
Laser Modification ◽  
Gas Nitriding ◽  
Large Fluctuations ◽  
42Crmo4 Steel ◽  
Hybrid Layers

The aim of this work was to study the microstructure and friction coefficient of hybrid surface layers, produced by a controlled gas nitriding and laser modification. Nitriding is well-known technique of thermo-chemical treatment, applied in order to produce the 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. 42CrMo4 steel was treated by composite technology of gas nitriding and laser hardening. The nitriding processes were carried out at temperature of 580 °C for 8h. Next, the nitrided layer was laser-modified using laser TRUMPF TruDiode 3006 with maximal power of 3 kW using the two laser beam powers (P): 0.53 kW and 0.62 kW. Then, the microstructure and properties of the laser-modified nitrided layers were investigated using optical microscopy, Vickers hardness tester and friction wear testing machine. The nitrided layers were subjected to wear tests using a ball-on-disc method at room temperature. The results showed that the microstructure of the produced hybrid layers consisted of the re-melted and heat-affected zones in which martensite mainly occurred. Additional laser treatment effectively increased the hardness, especially in heat-affected zone, as well as the depth of the hardened layer. The layer after modification laser hest tretment were good friction coefficien. The curve of the friction coefficient after the nitrided layer was characterized by large fluctuations. Compared with nitriding technology , the hybrid treatment technology can effectively increase the hardness and wear resistance of the 42CrMo4 steel surface. The effect of LHT on the tribological properties was ambiguous. Although the relatively low value of the average friction coefficient (0.46) was calculated for nitrided layer, the course of friction coefficient was characterized by large fluctuations and the extended grinding-in time. Simultaneously, the course of friction coefficient was very smooth after nitriding and LHT. However, the average friction coefficient were higher, obtaining 0.60 and 0.57 for the hybrid layers, produced using P=530 W and P=620 W, respectively. Keywords: Nitriding; Laser Heat Treatment; Microstructure; Wear Resistance; Microhardness

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

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.

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 The Effect of Laser Nitriding on Surface Characteristics and Wear Resistance of NiTi Alloy with Low Power Fiber Laser

2021 ◽  
Vol 11 (2) ◽  
pp. 515
Author(s):  
Hao Wang ◽  
Ralf Nett ◽  
Evgeny L. Gurevich ◽  
Andreas Ostendorf
Keyword(s):  
Surface Roughness ◽  
Wear Resistance ◽  
Friction Coefficient ◽  
Low Power ◽  
Fiber Laser ◽  
Niti Alloy ◽  
Nitride Layer ◽  
Wear Testing ◽  
Wear Loss ◽  
Laser Nitriding

The laser nitriding was performed in nitrogen gas at room temperature (20 °C) and low temperature (−190 °C) by a low power fiber laser to modify the wear and abrasion resistance of NiTi alloy. The surface roughness and element composition were analyzed by roughness device and energy-dispersive X-ray spectroscopy respectively. The results of roughness show that laser treatment can change the surface roughness due to the laser remelting. The effect of laser nitriding on the microhardness, friction coefficient, and worn scars of NiTi alloy was also studied, which shows that the microhardness of the NiTi alloy increases after laser nitriding. The optical microscope and scanning electron microscope were used to characterize the surface of NiTi alloy after wear testing to observe the microstructure of worn scars. The results show that the laser nitriding with different parameters can induce a nitride layer with different thicknesses and the higher energy deposition is the key factor for the formation of the nitride layer, which can decrease the friction coefficient and reduce wear loss during the application of NiTi alloy. The improvement of wear resistance can be attributed to the hard nitriding layer.

Surface Layers Produced by Modified Floe Ferritic Nitrocarburising

2015 ◽  
Vol 812 ◽  
pp. 253-258
Author(s):  
Andrea Szilagyine Biro ◽  
Endre Szabo ◽  
Miklos Tisza
Keyword(s):  
Wear Resistance ◽  
White Layer ◽  
Nitrided Layer ◽  
High Surface ◽  
Surface Hardness ◽  
Structural Steels ◽  
Surface Alloying ◽  
Tool Steels ◽  
Micro Hardness ◽  
Surface Layers

Ferritic nitrocarburising is a surface alloying heat treatment, which can provide to components high surface hardness, thus improved wear resistance. In structural steels the porosity of white layer has a key role in wear resistance: the porosity is undesirable. For tool steels the absence of white layer is undesirable. Floe process is one way to decrease the porosity of white layer. During our experiments we applied a modified Floe process on two different steels. The acontol of this process is simpler than conventional process. We measured the micro-hardness as a function of depth from the surface, and we made microscopic examination to analyse the structure of nitrided layer.

scholarly journals The Controlled Compound Layer of Ni-Coated Nitrided Pure Iron

Nanomaterials ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 31
Author(s):  
Qianqian Shen ◽  
Yu Zhang ◽  
Xuesha Li ◽  
Li Xiang ◽  
Chaoyin Nie
Keyword(s):  
Wear Resistance ◽  
Layer Thickness ◽  
Pure Iron ◽  
Nitrided Layer ◽  
Compound Layer ◽  
Wear Loss ◽  
Original Material ◽  
Ammonia Adsorption ◽  
Active Nitrogen ◽  
Gas Nitriding

In order not to sacrifice nitrided layer thickness and reduce brittle compound layer thickness, Ni-coated pretreatment was carried out with electrodeposition on a pure iron surface, followed by gas nitriding. The brittle compound layer thickness of duplex surface treated samples was reduced, and the nitrided layer thickness increased to 320 μm. The microhardness was 4 times harder, and the wear loss was reduced by 68% compared with the original material. The results indicate that Ni-coated pretreatment could effectively improve microhardness and wear resistance and realize the controlled microstructure of a brittle compound layer of pure iron without compromising nitrided layer thickness. Ni coating plays an important role in ammonia adsorption and decomposition, and in the transfer of active nitrogen atoms during nitriding.

Investigation of Gas Nitriding on Wear and Corrosion Behavior of 40Cr Steel

2011 ◽  
Vol 311-313 ◽  
pp. 674-678 ◽  
Author(s):  
Bing Ying Wang ◽  
Zhen Bo Hou ◽  
Wei Wang ◽  
Bin Zhao
Keyword(s):  
Wear Rate ◽  
High Speed ◽  
Nitrided Layer ◽  
Testing Machine ◽  
Test System ◽  
Wear Testing ◽  
Hardness Tester ◽  
Gas Nitriding ◽  
Wear And Corrosion ◽  
40Cr Steel

The influence of gas nitriding on the wear and corrosion resistance of 40Cr steel was investigated. Gas nitriding experiments were carried out at 550°C for 2h and 10h. The microstructure and hardness gradient were observed and analyzed through metallurgical microscope and micro hardness tester. The polarization curves were scanned by the M398 Corrosion Integrated Test System. Using MG-200 high speed friction and wear testing machine did end mill test and calculated the wear rate. By scanning electron microscopy (SEM) observationing the worn surface morphologies. The results show that after different nitriding time, the specimen surface forms with nitrided layer of different thickness, and changes with the hardness decreased with the penetration depth. Furthermore, the gas nitriding treatment may change the corrosion potential positively and reduce the density of the electric current of 40Cr steel. In addition, wear mechanism of the matrix is mainly adhesive wear, but after nitriding is mainly abrasive wear. The wear rate reduces significantly.

scholarly journals Laser Processing of Diffusion Boronized Layer Produced on Monel® Alloy 400—Microstructure, Microhardness, Corrosion and Wear Resistance Tests

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7529
Author(s):  
Aneta Bartkowska ◽  
Dariusz Bartkowski ◽  
Damian Przestacki ◽  
Mateusz Kukliński ◽  
Andrzej Miklaszewski ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Laser Beam ◽  
Scanning Speed ◽  
Substrate Material ◽  
Contact Method ◽  
Surface Layers ◽  
Laser Modification ◽  
Borided Layer ◽  
Diode Laser Beam ◽  
Boron Source

The paper presents the results of studies of microstructure, mechanical and physicochemical properties of surface layers produced by laser modification of the diffusion boron layer on Monel® Alloy 400. The diffusion boron layers were produced at 950 °C for 6 h. The gas-contact method was used in an open retort furnace. The process was carried out in a powder mixture containing B4C carbide as a boron source. The next stage was the modification of the boron layer with a diode laser beam of a nominal power of 3 kW. A constant power of 1400 W of the laser beam was used. The scanning speed was variable (successively 5 m/min, 25 m/min, 50 m/min). In order to determine the best parameters, single tracks were created, after which multiple tracks were prepared using previously selected parameters. It was found that both the diffusion borided layer and the laser modified layer had better properties than the substrate material. Both these processes contributed to an increase in corrosion resistance, hardness and wear resistance. It was also found that laser modification caused a slight deterioration of the properties in comparison with the diffusion borided layer. However, the laser modification process resulted in the production of a much thicker layer.

scholarly journals Study of the Effect of Gas Nitriding Time on Microstructure and Wear Resistance of 42CrMo4 Steel

2017 ◽  
Vol 08 (06) ◽  
pp. 493-507
Author(s):  
Mohamed Ali Terres ◽  
Lotfi Ammari ◽  
Abdelkarim Chérif
Keyword(s):  
Wear Resistance ◽  
Nitriding Time ◽  
Gas Nitriding ◽  
42Crmo4 Steel

A comparison of some properties of the computer controlled nitriding process versus carburizing

2021 ◽  
Vol 26 (1) ◽  
pp. 23-33
Author(s):  
Jan Senatorski ◽  
Paweł Mączyński ◽  
Jan Tacikowski
Keyword(s):  
Wear Resistance ◽  
Impact Strength ◽  
Process Control ◽  
Wear Testing ◽  
Gas Nitriding ◽  
Controlling Parameter ◽  
Key Factor ◽  
Computer Controlled ◽  
Nitriding Potential ◽  
Computerized System

A comparison is presented of the nitriding and carburizing processes. Traditional gas nitriding, despite its several advantages over carburizing, has still not achieved its due popularity. The key factor is inadequate process control. An industrial-scale computerized system, employing the nitriding potential as the fundamental controlling parameter, can produce repeatable, superior nitriding results, limiting layer brittleness and enhancing usable properties. Results obtained showed that nitriding layers match carburized layers in fatigue, while exceeding them in both impact strength and wear resistance. The superiority of the computer-controlled process over traditional nitriding is illustrated by results of wear testing. The advent of controlled nitriding makes this process a viable alternative to carburizing.

Frictional Temperature Field and Wear Behavior of Steel 52100 With Different Microstructures

1994 ◽  
Vol 116 (2) ◽  
pp. 255-259 ◽  
Author(s):  
You Wang ◽  
Mufu Yan ◽  
Xiaodong Li ◽  
Tingqun Lei
Keyword(s):  
Thermal Conductivity ◽  
Wear Resistance ◽  
Temperature Field ◽  
Wear Behavior ◽  
Temperature Fields ◽  
Wear Testing ◽  
Dry Sliding ◽  
Surface Layers ◽  
Close Relationship ◽  
Thermal Video

In this paper, the frictional temperature fields and the wear resistance of steel 52100 with different microstructures during dry sliding were studied by wear testing and computer simulation for thermometric data, which were real-time recorded by a thermal video system, using a mathematical model of frictional temperature field. The results show that the wear resistances of different microstructures are in close relationship with the temperature fields in surface layers during sliding. It is suggested that, because the different microstructures possess different thermal conductivities, the different microstructures will exhibit different frictional temperature fields, which will affect the wear resistances themselves. The less the thermal conductivity, the higher is the surface temperature during sliding, the lower is the wear resistance too.

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