Influence of temperature and duration on the nitriding behavior of 40Cr low alloy steel in mixture of NH3 and N2

Shen, Hongyu; Wang, Liang

doi:10.1016/j.surfcoat.2019.124953

Cited by 23 publications

(4 citation statements)

References 32 publications

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“…The formation of nitrides is influenced by process parameters, such as the nitrogen content [9]. A high nitrogen content can lead to the formation of a compound layer that has a higher hardness than the diffusion zone [10] and can reduce adhesive wear according to Terres et. al [11].…”

Section: Introductionmentioning

confidence: 99%

Metal-Containing Diamond-Like Carbon Coatings with Increased Temperature Stability for Wear Protection of Nitrided Hot Forging Dies

Behrens,

Bräuer,

Brunotte

et al. 2023

MSF

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In cold forging processes, diamond-like carbon (DLC) coatings have become established as a wear protection for forging dies, featuring high hardness and advantageous friction properties. This counteracts the particular critical abrasive tool wear and increases tool life. A major disadvantage of DLC coatings is their low thermal stability. In this study, the influence of metallic elements (niobium, tungsten and chromium) in the treatment atmosphere of the coating process is investigated with the aim of increasing the temperature resistance of the DLC coating and enabling its application as a wear-protection measure for hot forging dies. Preliminary studies were carried out to investigate the influence of different treatment atmospheres on wear-reducing properties such as high hardness and coating adhesion depending on prior nitriding processes. The most promising metal-doped DLC coating, with 30 % tungsten in the treatment atmosphere, was used in serial forging tests. At a blank temperature of 1,200 °C and a moderate count of 100 forging cycles, wear was reduced by up to 60 % compared to the nitrided reference tool.

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Section: Introductionmentioning

confidence: 99%

Metal-Containing Diamond-Like Carbon Coatings with Increased Temperature Stability for Wear Protection of Nitrided Hot Forging Dies

Behrens,

Bräuer,

Brunotte

et al. 2023

MSF

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“…Nitriding process is well-known as a technique of surface treatment that improves the mechanical properties of metallic materials [1]. The most common methods of nitriding are as follows: controlled gas nitriding [2][3][4][5][6], plasma nitriding [7][8][9][10][11][12], and low-pressure gas nitriding [13,14]. Controlled gas nitriding and low-pressure gas nitriding is commonly used for constructional and tool steels.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Temperature Distribution during Laser Heat Treatment of Gas-Nitrided 42CrMo4 Steel on the Microstructure and Mechanical Properties

et al. 2020

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A gas-nitrided layer was produced on the toughened 42CrMo4 low-alloy steel using the changeable nitriding potential in order to limit the thickness of a brittle ε zone. The microstructure consisted of the compound ε + (ε + γ’) zone and diffusion zone (nitric sorbite with γ’ precipitates). Such a layer was subjected to laser heat treatment with or without remelting. The single laser tracks were formed using various laser beam powers (in the range of 0.234–0.624 kW) and scanning rates (in the range of 2.24–3.84 m·min−1) and the same laser beam diameter (2 mm). The microstructure of laser-modified nitrided layer usually consisted of re-melted zone (MZ) with coarse-grained nitric martensite Feα’ and possible ε precipitates, heat-affected zone (HAZ) with fine-grained nitric martensite Feα’ and γ’ precipitates and diffusion zone with nitric sorbite and γ’ precipitates. Sometimes, the compound zone was partially re-melted and an amount of iron nitrides remained in the MZ. Only one laser track was characterized by the different microstructure, consisting of the compound ε + (ε + γ’) zone, HAZ with fine-grained nitric martensite Feα’ and γ’ precipitates and diffusion zone with nitric sorbite and γ’ precipitates. This laser track was formed without visible effects of remelting. The effect of temperature distribution during laser heat treatment of gas-nitrided 42CrMo4 steel on the microstructure and mechanical properties was studied. The equations developed by Ashby and Esterling were used in order to determine the temperature distribution along the axis of each laser track. Taking into account the temperature profiles, it was possible to calculate the depths of MZ and HAZ. These predicted values were compared to those-measured based on the microstructure observations, obtaining good compatibility. The microstructure of the produced surface layers influenced the mechanical properties such as hardness and Young’s modulus. The hardness of MZ was higher than that of ε zone and lower than that of ε + γ’ zone when compared to nitrided layer. Whereas Young’s modulus of MZ was significantly higher than those characteristic of the compound zone in gas-nitrided layer (both ε and ε + γ’ zone) and similar to that of HAZ. The laser heat treatment (LHT) without remelting resulted in the similar hardness and slightly higher Young’s modulus of ε zone in comparison with the nitrided layer. Simultaneously, such a treatment of the nitrided layer did not influence the hardness and the Young’s modulus of ε + γ’ zone considerably. The hardness of HAZ was higher than that of MZ and that of the same area of diffusion zone in the nitrided layer because of the presence of fine-grained nitric martensite with γ’ precipitates after laser quenching.

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“…When the temperature of the workpiece surface is uniform, the uneven hardness of the nitrided layer and uneven nitriding layer depth are reduced. 13 However, when the temperature difference between the workpiece surface and the core is large, nitrogen atoms are diffused into the core, thereby increasing the nitride layer thickness. 14 Therefore, it is very important to control the temperature distribution of the heated workpiece during the induction heating process.…”

Section: Introductionmentioning

confidence: 99%

Experimental and numerical study of the effect of coil structure on induction nitriding temperature field

Song

Guan

et al. 2020

Advances in Mechanical Engineering

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The axial and radial temperature distributions of an induction heating workpiece considerably impact the subsequent nitriding process. To obtain a satisfactory temperature distribution, an equal pitch coil, a variable pitch coil, and a variable radius coil were designed. Furthermore, an induction heating model that exhibits electromagnetic and temperature field coupling was established; thus, the effects of the current density and frequency on the heating efficiency and temperature distribution of the workpiece were analyzed and compared. In addition, an induction heating experiment was conducted to verify the model. According to the numerical results, the variable radius coil can reduce the axial temperature difference in comparison with equal pitch coil and variable pitch coil. Hence, the workpiece heated using the variable radius coil can achieve a better temperature distribution when compared with those heated by the equal pitch coil and variable pitch coil, with appropriate current density and current frequency values.

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Influence of temperature and duration on the nitriding behavior of 40Cr low alloy steel in mixture of NH3 and N2

Cited by 23 publications

References 32 publications

Metal-Containing Diamond-Like Carbon Coatings with Increased Temperature Stability for Wear Protection of Nitrided Hot Forging Dies

Metal-Containing Diamond-Like Carbon Coatings with Increased Temperature Stability for Wear Protection of Nitrided Hot Forging Dies

The Effect of Temperature Distribution during Laser Heat Treatment of Gas-Nitrided 42CrMo4 Steel on the Microstructure and Mechanical Properties

Experimental and numerical study of the effect of coil structure on induction nitriding temperature field

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