Microstructure and hardness of Pyrowear 53 steel after low-pressure vacuum carburizing at 921°C

Wojtyczka, Artur; Iżowski, Bartosz

doi:10.2478/amst-2019-0020

Cited by 3 publications

(3 citation statements)

References 7 publications

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“…Materials used for their production must have resistance for: abrasion, contact stress on the surface layer, bending strength at the tooth base, and also require properties to withstand cyclic variable loads in the core. Heavy duty gears used in aviation gearboxes are usually made from high-strength alloy steels like AMS 6308 [ 1 ] (the chemical composition of Pyrowear ® 53 is presented in Table 1 ). The AMS 6308 is a relatively new steel originally prepared for military products, but for about a dozen years, has been increasingly used in civil aviation.…”

Section: Introductionmentioning

confidence: 99%

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The Effect of Chip Binding on the Parameters of the Case-Hardened Layer of Tooth Surfaces for AMS 6308 Steel Gears Processed by Thermochemical Treatment

Fularski¹,

Filip

2021

Materials

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The following article describes influence of pressure welded or bound chips to the gear tooth flank and/or the tooth root on a carburized case and surface layer hardness of Pyrowear 53 steel gears, machined by Power Skiving method. This paper is focused only on one factor, the chips generated while forming gear teeth by power skiving, which could result in local changes in the carburized case parameters as a negatively affecting point of mechanical performance of the carburized case. The chips, due to the specifics of the power skiving process and the kinematics of tooth forming, could be subject to the phenomena of pressure welding or binding of chips to the tooth. During the carburizing stage of the downstream manufacturing processes, the chips form a diffusion barrier, which ultimately could result in localized changes in the carburized case. This work was an attempt to answer the question of how and to what extent the chips affect the case hardening. Performed simulations of chips by a generating cupper “spots”, mentioned in the study, represent a new approach in connection with minimization of errors, which could appear during carbon case depth and case hardness analysis for typical chips, generated during the machining process—assurance that a complete chip was bound to the surface. Hardness correlation for zones, where the chip appears with areas free of chips, gives simple techniques for assessment. Performed tests increased the knowledge about the critical size of the chip—1.5 mm, which could affect the case hardening. Obtained experimental test results showed that the appearance of chip phenomena on the gear tooth might have a negative impact on a carburized case depth and hardened layer.

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Section: Introductionmentioning

confidence: 99%

“…The AMS 6308 is a relatively new steel originally prepared for military products, but for about a dozen years, has been increasingly used in civil aviation. Due to the growing of industry interest, it has become the subject of scientific considerations, too [ 1 , 2 , 3 , 4 ].…”

Section: Introductionmentioning

confidence: 99%

The Effect of Chip Binding on the Parameters of the Case-Hardened Layer of Tooth Surfaces for AMS 6308 Steel Gears Processed by Thermochemical Treatment

Fularski¹,

Filip

2021

Materials

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“…The chemical composition of Pyrowear53 is presented in Table 1 [ 9 , 10 ]. The measured contents of the elements in Pyrowear53 are in accordance with the nominal composition of AMS 6308D.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of Impulse Carburization LPC Process

et al. 2021

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In the present work, Pyrowear53 steel was subjected to the impulse carburizing LPC process. After carburation, the material was quenched and tempered. Postprocessing analyses included the measurement of hardness, carbon content, residual austenite, and residual stresses. The results revealed that the thermochemical treatment resulted in the formation of an approximately 1200 µm wide carburized layer. The results of hardness, carbon content, and residual austenite measurement showed a continuous gradient (drop) in the measured values within the carburized layer. However, the results of residual stresses revealed the existence of a local extremum, namely, a zone with higher compressive stresses at the depth between 600 and 1000 µm. This was explained by a different temperature for initiation of martensite transformation as a function of carbon content. This difference resulted in the occurrence of two martensite expansion fronts at two different depths, resulting in an increase in compressive stresses at the noted depth range. Moreover, it was concluded that this region was present for material containing between 0.8 and 0.4 wt% carbon for Pyrowear53.

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Determination of the fracture toughness of carburized Pyrowear 53 steel for planetary gears by the small punch test method

Majchrowicz,

Romelczyk-Baishya,

Wieczorek-Czarnocka

et al. 2024

Arch. Civ. Mech. Eng.

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The aim of the current study was to determine the fracture toughness of different zones in carburized Pyrowear 53 steel using the small punch test (SPT) method. Firstly, Pyrowear 53 steel was quenched and tempered using different processing parameters to obtain core materials with varied microstructures and fracture toughness. The results obtained for the core material in standard fracture toughness tests were then compared with the SPT results, which allowed the determination of a formula correlating the fracture energy integral, JSPT, from the SPT with JQ integrals obtained from standardized compact tension specimens. In the next stage, Pyrowear 53 steel was carburized at 925 °C and divided into the following zones: (1) a carburized layer (up to 0.5 mm from the surface), (2) a transition layer (from 0.5 to 1.5 mm), and (3) a core zone (more than 1.5 mm). Each zone was characterized in terms of its microstructure and tensile properties using miniaturized test specimens. Finally, the fracture toughness values of the core zone (JSPT = 78–102 kJ/m2), the transition layer (JSPT = 71–80 kJ/m2), and the carburized layer (JSPT = 8.1–9.1 kJ/m2) were determined based on the obtained SPT results. It was shown that the use of such a relatively simple SPT method with the proposed energy-based approach seems to be a promising way of determining the fracture toughness of thin layers or local changes in the fracture behavior of surface-treated materials.

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Microstructure and hardness of Pyrowear 53 steel after low-pressure vacuum carburizing at 921°C

Cited by 3 publications

References 7 publications

The Effect of Chip Binding on the Parameters of the Case-Hardened Layer of Tooth Surfaces for AMS 6308 Steel Gears Processed by Thermochemical Treatment

The Effect of Chip Binding on the Parameters of the Case-Hardened Layer of Tooth Surfaces for AMS 6308 Steel Gears Processed by Thermochemical Treatment

Characteristics of Impulse Carburization LPC Process

Determination of the fracture toughness of carburized Pyrowear 53 steel for planetary gears by the small punch test method

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