Heat Treatment of Sintered Valve Seat Inserts

Gomes, Maurilio Pereira; Santos, Igor Passos dos; Couto, Camila Pucci; Betini, Evandro Giuseppe; Reis, L.A.M.; Mucsi, Cristiano Stefano; Colosio, Marco Antonio; Rossi, Jesualdo Luiz

doi:10.1590/1980-5373-mr-2018-0068

Cited by 4 publications

(1 citation statement)

References 25 publications

(23 reference statements)

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“…Electrical contact materials exhibiting high electrical and thermal conductivity as well as good wear behavior at elevated temperatures were prepared by infiltration of copper-based infiltrants into tungsten [ 20 ] and tungsten carbide [ 21 ]. In the automobile industry, copper infiltration is used for valve seat inserts in combustion engines in order to elevate the thermal conductivity of the material [ 22 , 23 ]. Seleznev and Roy-Mayhew [ 24 ] developed a method to create a bi-metal composite consisting of tool steel (H13 and 17-4PH) and copper by printing a steel preform with a porous infill by fused filament fabrication (FFF).…”

Section: Introductionmentioning

confidence: 99%

Impact of Particle Size Distribution in the Preform on Thermal Conductivity, Vickers Hardness and Tensile Strength of Copper-Infiltrated AISI H11 Tool Steel

et al. 2023

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Spontaneous infiltration of a porous preform by a metallic melt provides the potential of generating metal matrix composites (MMCs) with tailored combinations of material properties at low cost. The bulk of tool inserts for injection molding must sustain high mechanical and thermal loads and simultaneously exhibit high thermal conductivity for efficient temperature control of the mold insert. To fulfill these contradictory requirements, AISI H11 tool steel preforms were infiltrated by liquid copper. The impact of the fine powder fraction (0 wt.% to 15 wt.%) blended to a coarse H11 powder in the preform on thermal conductivity, Vickers hardness and tensile strength was elucidated. The thermal conductivity of the composites could be enhanced by a factor of 1.84 (15 wt.% fine powder) and 2.67 (0 wt.% fine powder) with respect to the sintered H11 tool steel. By adding 15 wt.% fine powder to the coarse host powder, the tensile strength and Vickers hardness of the copper-infiltrated steel were 1066.3 ± 108.7 MPa and 366 ± 24 HV1, respectively, whereas the H11 tool steel yielded 1368.5 ± 89.3 MPa and 403 ± 17 HV1, respectively. Based on the results obtained, an appropriate particle size distribution (PSD) may be selected for preform preparation according with the requirements of a future mold insert.

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Section: Introductionmentioning

confidence: 99%

Impact of Particle Size Distribution in the Preform on Thermal Conductivity, Vickers Hardness and Tensile Strength of Copper-Infiltrated AISI H11 Tool Steel

et al. 2023

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Influence of Heat Treatment Parameters on the Carbide Morphology of PM High‐Speed Steel HS 6‐5‐3‐8

Disch

Benito

Röttger

et al. 2023

steel research int.

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Cutting tools are commonly made of high-speed steel to simultaneously fulfill the requirements regarding hardness, strength, and toughness. The microstructure of high-speed steel alloys in as-cast condition is characterized by a microstructure consisting of a metal matrix and eutectic carbides. [1][2][3][4] The further manufacturing route of these materials comprises hot forming to break down the carbide network [1,2] and subsequent heat treatment. The behavior of the carbides during austenitization was examined in several publications. [3][4][5][6][7][8][9] Metastable carbides with the stoichiometry M 2 C (M¼ metal atoms, C ¼ carbon), which are present after casting, are transformed to carbides of the types MC and M 6 C with the transformation path of [3,[10][11][12] Dependent on the austenitization temperature and time and thus on the amount of dissolved carbides, different contents of retained austenite remain after quenching. [9] During typical subsequent tempering at temperatures where a secondary hardening effect occurs, retained austenite decomposes, and the precipitation of finely dispersed tempering carbides occurs. [13][14][15] Besides the conventional production route with casting and hot forming, alternative manufacturing processes like spray forming [16][17][18] or powder metallurgy (PM) with hot isostatic pressing are available. Several studies found that powder metallurgic high-speed steel exhibit higher toughness and better cutting performance compared to cast material. [19][20][21][22][23] In most cases, this is explained by the finer distribution, the isotropic properties, and the more regular shape of the eutectic carbides due to the rapid solidification of the powder particles during powder manufacturing. The carbides are affected in their type, [8] size, [5,24] and distribution [25] by the process variables during primary manufacturing and different heat treatments. Mishnaevsky et al. have shown that the fracture in tool steels typically starts in or along eutectic carbides. [26] It is, therefore, to be assumed that the morphology of the eutectic carbides must have an influence on the mechanical properties of high-speed steels.High-speed steel alloys typically exhibit a transformation gap in the isothermal time-temperature-transformation (TTT) diagram. The scientific consensus is that no transformation of the metastable austenite takes place in the temperature regime of the transformation gap. [27] Kešner et al. found that the size of carbides is affected by hardening in a salt bath under isothermal conditions at temperatures between 300 and 650 °C, which is in the temperature regime of the transformation gap of high-speed steels. [28] However, previous works have paid no attention to the effect of different heat treatment parameters on the shape of eutectic carbides. Our preliminary work shows that isothermal

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Derivation and validation of heat transfer model for Spark-Ignition engine cylinder head

Hassan

Razlan

Bakar

et al. 2023

Applied Thermal Engineering

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Heat Treatment of Sintered Valve Seat Inserts

Cited by 4 publications

References 25 publications

Impact of Particle Size Distribution in the Preform on Thermal Conductivity, Vickers Hardness and Tensile Strength of Copper-Infiltrated AISI H11 Tool Steel

Impact of Particle Size Distribution in the Preform on Thermal Conductivity, Vickers Hardness and Tensile Strength of Copper-Infiltrated AISI H11 Tool Steel

Influence of Heat Treatment Parameters on the Carbide Morphology of PM High‐Speed Steel HS 6‐5‐3‐8

Derivation and validation of heat transfer model for Spark-Ignition engine cylinder head

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