Fatigue fracture of surface-modified layers in 18CrNiMo7-6 carburized steel

Zhang, Yue; Lu, Lijuan; Xu, Guoyan; Wang, Gang; Zhao, Minghao

doi:10.1016/j.engfailanal.2021.105839

Cited by 16 publications

(4 citation statements)

References 31 publications

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“…The carburized layer is mainly composed of AM, LB, and retained austenite (RA). RA appears as bright white small pieces under OM [9]. It can be observed that the transition layer is also composed of AM, LB, and RA.…”

Section: Resultsmentioning

confidence: 95%

Failure analysis of the piston used in a pneumatic down the hole impactor

Pan

Chen

et al. 2022

J. Phys.: Conf. Ser.

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In this paper, the failure mechanism of the piston in the pneumatic down the hole (DTH) impactor has been studied. Failed piston microstructure has been analyzed using the light optical microscopy (OM) and scanning electron microscope (SEM). Impact toughness test and the Rockwell hardness test were conducted. Results showed the following: a) The carburizing layer of IQCT failed piston is mainly composed of acicular martensite and lower bainite after the carburizing-tempering-isothermal quenching-cryogenic treatment-tempering (IQCT), and there are collapses on the impact side and outer surface of the piston, mainly fatigue failure. b) IQT failed piston samples are subject to carburizing-tempering-isothermal quenching-tempering treatment (IQT). The carburized layer is mainly composed of high-carbon martensite, carbide and retained austenite. The transition layer is still composed of lower bainite and acicular martensite, but the volume fraction of lower bainite increases significantly and the core is mainly composed of lower bainite. It has the best impact toughness, up to 61.5 J/cm2, which is mainly fatigue failure. c) OQT failed piston sample is subject to carburizing-tempering-oil quenching-tempering (OQT). The carburized layer is mainly composed of acicular martensite, the transition layer is composed of acicular martensite (AM) and lath martensite (LM), and the core is mainly composed of LM. The impact toughness of the sample is the worst. Therefore, fatigue fracture failure is caused.

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Section: Resultsmentioning

confidence: 95%

Failure analysis of the piston used in a pneumatic down the hole impactor

Pan

Chen

et al. 2022

J. Phys.: Conf. Ser.

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“…Owing to high-strength steel comprehensive mechanical properties, it is widely used for tools such as heavy-duty shafts, bearings, gearbox gears and sprockets (Zhang et al, 2022;Lu et al, 2019;Wang et al, 2020). However, hydrogen infiltration may occur during processes such as rust removal, oil removal, electroplating and gas carburization of high-strength steel (Wang et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

“…Owing to high-strength steel comprehensive mechanical properties, it is widely used for tools such as heavy-duty shafts, bearings, gearbox gears and sprockets (Zhang et al. , 2022; Lu et al, 2019; Wang et al , 2020).…”

Section: Introductionmentioning

confidence: 99%

Characterization of hydrogen embrittlement sensitivity of 18CrNiMo7-6 alloy steel surface-modified layer based on scratch method

Wang,

Wang

et al. 2024

ACMM

Self Cite

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Purpose The purpose of this paper is to assess the hydrogen embrittlement sensitivity of carbon gradient heterostructure materials and to verify the reliability of the scratch method. Design/methodology/approach The surface-modified layer of 18CrNiMo7-6 alloy steel was delaminated to study its hydrogen embrittlement characteristics via hydrogen permeation, electrochemical hydrogen charging and scratch experiments. Findings The results showed that the diffusion coefficients of hydrogen in the surface and matrix layers are 3.28 × 10−7 and 16.67 × 10−7 cm2/s, respectively. The diffusible-hydrogen concentration of the material increases with increasing hydrogen-charging current density. For a given hydrogen-charging current density, the diffusible-hydrogen concentration gradually decreases with increasing depth in the surface-modified layer. Fracture toughness decreases with increasing diffusible-hydrogen concentration, so the susceptibility to hydrogen embrittlement decreases with increasing depth in the surface-modified layer. Originality/value The reliability of the scratch method in evaluating the fracture toughness of the surface-modified layer material is verified. An empirical formula is given for fracture toughness as a function of diffused-hydrogen concentration.

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“…As Figure 2 shows, in different application scenarios, original billets are processed as different kinds of shaft parts, which can bear different working loads [ 9 ]. The strengthening process, which modifies the material, will have a large influence on the properties of the shafts [ 10 ]. In this respect, it is extremely necessary to study the mechanical properties of 42CrMo steel processed by RS.…”

Section: Introductionmentioning

confidence: 99%

Effect of Rotary Swaging on Mechanical Behaviors of Axle Steel Rod

Tian,

Xu,

Zheng

et al. 2024

Materials

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The short-chain forming process using rotary swaging (RS) is an important method of achieving the manufacturing of lightweight axles. Axle steel, like 42CrMo, is widely used in many types of axles and shafts; however, there is no existing research on rotary-swaged axle steel’s mechanical properties. It makes sense to carry out a comprehensive study on the effect of RS on the mechanical behaviors of axle steel rods. In this study, a 42CrMo steel rod was processed by RS through ten passes. The tensile properties, torsion properties, compression properties, and fatigue properties were tested. There was an overall improvement in the torsional and fatigue performance after RS. Combined with a finite element analysis (FEM), the uneven distribution of the dislocations and existence of the elongation material were inferred to have caused the different modes of the mechanical behaviors. Fracture surfaces were analyzed and the results showed that the fracture pattern had changed. There existed a competitive relation between the internal fatigue cracks and external cracks, which could be attributed to uneven strain hardening. This research proved the advantages of RS in the processing of axle parts, which mainly benefitted the torsional working conditions, and provided evidence for a new processing route for lightweight axles with RS.

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Fatigue fracture of surface-modified layers in 18CrNiMo7-6 carburized steel

Cited by 16 publications

References 31 publications

Failure analysis of the piston used in a pneumatic down the hole impactor

Failure analysis of the piston used in a pneumatic down the hole impactor

Characterization of hydrogen embrittlement sensitivity of 18CrNiMo7-6 alloy steel surface-modified layer based on scratch method

Effect of Rotary Swaging on Mechanical Behaviors of Axle Steel Rod

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