Improvement of the Tribological Characteristics of AISI 8620, 8640 and 52100 Steels through Thermo-Reactive Treatments

Triani, Rafael Magalhães; Mariani, Fábio; Gomes, Lucas Fuscaldi De Assis; Oliveira, Paulo Gonçalves de; Totten, George E.; Casteletti, Luíz Carlos

doi:10.3390/lubricants7080063

Cited by 14 publications

(2 citation statements)

References 27 publications

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“…The ball-cratering test using a Calo (Surface Engineering Group, Department of Materials Engineering, Un Paulo, São Carlos, Brazil) with a fixed sphere was used to evaluate wear equipment configuration is shown in Figure 6. According to this test, the removed volume (V) of material can according to Equation 1, where d is the diameter of the caps measu microscopy, and R corresponds to the radius of the sphere [41][42][43]. F hardened spheres of AISI 52,100 steel with a diameter of 25.4 mm and hard were used.…”

Section: Vickers Microhardness and Wear Resistance Testsmentioning

confidence: 99%

“…Table 2 presents the chemical composition of the cast iron used determ emission spectrometry. According to this test, the removed volume (V) of material can be calculated according to Equation ( 1), where d is the diameter of the caps measured by optical microscopy, and R corresponds to the radius of the sphere [41][42][43]. For these tests, hardened spheres of AISI 52,100 steel with a diameter of 25.4 mm and hardness of 60 HRC were used.…”

Section: Chemical and Micrographic Analysis Of Samplesmentioning

confidence: 99%

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In-Situ Production of Metal Matrix Composites Layers by TIG Surface Alloying to Improve Wear Resistance of Ductile Cast Iron Using a Buffer-Layer and Post Weld Heat Treatment

et al. 2023

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A TIG surface alloying process was applied to modify the surface of ductile cast iron samples. Using this process, in-situ metal matrix composite (MMC) layers were produced on samples to improve their wear resistance. These layers were made by melting substrates and powders as additional material into this melt pool. The efficiency of preheating of the samples to prevent cold cracks during solidification was verified. Moreover, a buffer layer produced in situ to decrease the mismatches between the chemical and physical properties of the materials was also tested. Post-weld heat treatment (PWHT) was used to increase the tribological characteristics of the layers and eliminate adverse effects of the heat-affected zone (HAZ) created by the fusion of the substrate surface. The results showed that, in the samples without preheating, the formation of cold cracks occurred. Additionally, layers produced without a buffer layer showed defects, such as shrinkage and porosity. However, using both preheating and a buffer layer prevented cold cracks, discontinuities, shrinkage, and porosity defects in the layers. Furthermore, PWHT allowed for the transformation of brittle martensite into tempered martensite at the HAZ. MMC layers presented high hardness of up to 1230 HV and wear resistance up to 5.8 times greater compared to the substrate samples without layers.

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Section: Vickers Microhardness and Wear Resistance Testsmentioning

confidence: 99%

Section: Chemical and Micrographic Analysis Of Samplesmentioning

confidence: 99%

In-Situ Production of Metal Matrix Composites Layers by TIG Surface Alloying to Improve Wear Resistance of Ductile Cast Iron Using a Buffer-Layer and Post Weld Heat Treatment

et al. 2023

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Production of Niobium Carbide Layers on High‐Strength Bainitic Steels by Thermochemical Treatment of Thermoreactive Diffusion Followed by Austempering

Oliveira

Triani

Filho

et al. 2021

steel research int.

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High-strength bainitic steels obtained by the low-temperature austempering heat treatment belong to the third generation of advanced high-strength steels. These materials were developed through innovative heat treatments of low-alloy steels to meet demands of the automotive industry, such as increased resistance-to-weight ratio. [1] Steels obtained by low-temperature austempering, at just above the martensite start (M s ) temperature, are characterized by the presence of carbide-free bainite (CFB). Silicon contents around 1.2À1.5 wt% are normally used to suppress cementite formation, enriching the austenite in carbon, which becomes metastable at room temperature, allowing the transformationinduced plasticity (TRIP) effect. [2,3] It is important to highlight the effect of molybdenum and manganese, used to increase hardenability, and the addition of niobium to refine the austenitic grain and increase bainitic transformation rates. [4,5] Regarding the microstructural characteristics of high-silicon bainitic steels, the presence of granular and plate bainite favors high combinations of strength and toughness, making them attractive for applications in the railway sector [6,7] and in the manufacturing of precision gears, providing stress and distortion-free parts as no quench is used. [8,9] Therefore, surface hardening techniques are of great technological interest to increase component lifespan and decrease maintenance time. Studies show the efficiency of techniques such as shot peening, nitriding, and boriding thermochemical treatments for this purpose. [9][10][11][12] Another promising alternative is thermoreactive diffusion (TRD) treatment, which, as in the boriding treatment, can be directly incorporated into the austempering process without the need for a new heating step, as used, for example, in the case of tempering after quenching for saving time and energy. TRD in conjunction with the austempering treatment has already been successfully applied to vermicular and ductile cast iron, where, after removal from the TRD bath, samples were directly cooled and held at 300 C in the austempering salt bath. [13] The TRD process involves the production of hard and highly resistant carbide layers in ferrous alloys. This treatment utilizes a

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Boro-Austempering Treatment of High-Strength Bainitic Steels

Oliveira

Mariani

Casteletti

et al. 2020

J. of Materi Eng and Perform

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Improvement of the Tribological Characteristics of AISI 8620, 8640 and 52100 Steels through Thermo-Reactive Treatments

Cited by 14 publications

References 27 publications

In-Situ Production of Metal Matrix Composites Layers by TIG Surface Alloying to Improve Wear Resistance of Ductile Cast Iron Using a Buffer-Layer and Post Weld Heat Treatment

In-Situ Production of Metal Matrix Composites Layers by TIG Surface Alloying to Improve Wear Resistance of Ductile Cast Iron Using a Buffer-Layer and Post Weld Heat Treatment

Production of Niobium Carbide Layers on High‐Strength Bainitic Steels by Thermochemical Treatment of Thermoreactive Diffusion Followed by Austempering

Boro-Austempering Treatment of High-Strength Bainitic Steels

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