Research on new rapid and deep plasma nitriding techniques of AISI 420 martensitic stainless steel

Wu, Kang; Liu, G.Q.; Wang, L.; Xu, Bin

doi:10.1016/j.vacuum.2009.12.001

Cited by 31 publications

(12 citation statements)

References 13 publications

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“…Investigations on deep nitriding were already carried out in the 1980s [6], when the nitriding plant technology was not yet sufficiently developed to enable controlled and reproducible nitriding treatments to be carried out in gas or plasma. For this reason, more recent investigations concern also nitriding processes for achieving high nitriding hardness depths [4,[7][8][9]. In [4] material-oriented two-stage processes for deep nitriding were developed with the aim of achieving high nitriding hardness depths with the highest possible strength.…”

Section: Of 12mentioning

confidence: 99%

Compound Layer Design for Deep Nitrided Gearings

Hoja

Steinbacher

Zoch

2020

Metals

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Deep nitriding is used to obtain a nitriding hardness depth beyond 0.6 mm. The long nitriding processes, which are necessary to reach the high nitriding hardness depths, mostly have a negative influence on the hardness and strength of the nitrided layer as well as on the bulk material. The compound layer often is considered less, because in most practical cases, it is removed mechanically after nitriding, to avoid spalling in service. However, in former investigations, it was shown, that thick and compact compound layers have the potential for high flank load capacity of gears. The investigations focus on the simultaneous formation of a high nitriding depth and a thick and compact compound layer. Beside the preservation of the strength, a challenge is to control the porosity of the compound layer, which should be as low as possible. The investigations were carried out using the common nitriding and heat treatable mild steel 31CrMoV9, which is often used for gear applications. The article gives an insight on the development of multistage nitriding processes studied by short- and long-term experiments aiming for a specific compound layer build-up with low porosity and high strength of the nitride layer and core material.

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Section: Of 12mentioning

confidence: 99%

Compound Layer Design for Deep Nitrided Gearings

Hoja

Steinbacher

Zoch

2020

Metals

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“…From an economic point of view, it not only reduces the cost, but also improves the surface properties of various steels in an environmentally friendly way. As an efficient and energy-saving thermochemical surface processing and modification technology, it has the advantages of a short processing time, low temperature, reduced brittleness of the nitriding layer, a reduction of work piece deformation and surface flexibility and toughness [9].…”

Section: Introductionmentioning

confidence: 99%

Low-Temperature Plasma Nitriding of 3Cr13 Steel Accelerated by Rare-Earth Block

You

Yan

et al. 2021

Coatings

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The plasma nitriding of 3Cr13 steel occurred at 450 °C for 4, 8 and 12 h in NH3 with and without rare earth (RE). The nitrided layers were characterized using an OM, SEM, TEM, XRD, XPS, microhardness tester and electrochemical workstation. The modified layer, with and without La, are composed of a compound layer and diffusion layer from surface to core. After the addition of La during nitriding, the maximum increase of layer thickness, mass gain and average microhardness was 15.6%, 35.8% and 212.50HV0.05, respectively. With the increase of the proportion of ε-Fe2-3N, the passivation zone of the corrosion resistance curve increases from 2.436 to 3.969 V, the corrosion current density decreases, the corrosion potential and pitting potential both increase, and, consequently, the corrosion resistance is significantly improved. Most of the surface microstructures of the nitrided layer was refined by the addition of La. The presence of La reduces the N content in the modified layer, which accelerates the diffusion of N atoms and, thus, accelerates the nitriding process.

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“…This steel category is largely employed in engineering components applied in aggressive environments. For example, AISI 420 martensitic stainless steel is commonly used in the fabrication of structural parts such as gears and shafts, automotive components, hydraulic turbine blades, oil and gas valves, pipes and chlorinated plastic injection molds, among others [1][2][3][4]. The large application field of martensitic stainless steels is mainly due to its ability of combining good mechanical properties and moderate corrosion resistance [5,6].…”

Section: Introductionmentioning

confidence: 99%