scholarly journals Heat Treatment Evaluation for the Camshafts Production of ADI Low Alloyed with Vanadium

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1036
Author(s):  
Eduardo Colin García ◽  
Alejandro Cruz Ramírez ◽  
Guillermo Reyes Castellanos ◽  
José Federico Chávez Alcalá ◽  
Jaime Téllez Ramírez ◽  
...  

Ductile iron camshafts low alloyed with 0.2 and 0.3 wt % vanadium were produced by one of the largest manufacturers of the ductile iron camshafts in México “ARBOMEX S.A de C.V” by a phenolic urethane no-bake sand mold casting method. During functioning, camshafts are subject to bending and torsional stresses, and the lobe surfaces are highly loaded. Thus, high toughness and wear resistance are essential for this component. In this work, two austempering ductile iron heat treatments were evaluated to increase the mechanical properties of tensile strength, hardness, and toughness of the ductile iron camshaft low alloyed with vanadium. The austempering process was held at 265 and 305 °C and austempering times of 30, 60, 90, and 120 min. The volume fraction of high-carbon austenite was determined for the heat treatment conditions by XRD measurements. The ausferritic matrix was determined in 90 min for both austempering temperatures, having a good agreement with the microstructural and hardness evolution as the austempering time increased. The mechanical properties of tensile strength, hardness, and toughness were evaluated from samples obtained from the camshaft and the standard Keel block. The highest mechanical properties were obtained for the austempering heat treatment of 265 °C for 90 min for the ADI containing 0.3 wt % V. The tensile and yield strength were 1200 and 1051 MPa, respectively, while the hardness and the energy impact values were of 47 HRC and 26 J; these values are in the range expected for an ADI grade 3.

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 647 ◽  
Author(s):  
Bingrong Zhang ◽  
Lingkun Zhang ◽  
Zhiming Wang ◽  
Anjiang Gao

In order to obtain high-strength and high-ductility Al–Si–Cu–Mg alloys, the present research is focused on optimizing the composition of soluble phases, the structure and morphology of insoluble phases, and artificial ageing processes. The results show that the best matches, 0.4 wt% Mg and 1.2 wt% Cu in the Al–9Si alloy, avoided the toxic effect of the blocky Al2Cu on the mechanical properties of the alloy. The addition of 0.6 wt% Zn modified the morphology of eutectic Si from coarse particles to fine fibrous particles and the texture of Fe-rich phases from acicular β-Fe to blocky π-Fe in the Al–9Si–1.2Cu–0.4Mg-based alloy. With the optimization of the heat treatment parameters, the spherical eutectic Si and the fully fused β-Fe dramatically improved the ultimate tensile strength and elongation to fracture. Compared with the Al–9Si–1.2Cu–0.4Mg-based alloy, the 0.6 wt% Zn modified alloy not only increased the ultimate tensile strength and elongation to fracture of peak ageing but also reduced the time of peak ageing. The following improved combination of higher tensile strength and higher elongation was achieved for 0.6 wt% Zn modified alloy by double-stage ageing: 100 °C × 3 h + 180 °C × 7 h, with mechanical properties of ultimate tensile strength (UTS) of ~371 MPa, yield strength (YS) of ~291 MPa, and elongation to fracture (E%) of ~5.6%.


Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 608
Author(s):  
Anastasiya Toenjes ◽  
Heike Sonnenberg ◽  
Axel von Hehl

The mechanical properties of heat-treatable aluminium alloys are improved and adjusted by three different heat treatment steps, which include solution annealing, quenching, and aging. Due to metal-physical correlations, variations in heat treatment temperatures and times lead to different microstructural conditions with differences in the size and number of phases and their volume fraction in the microstructure. In this work, the investigations of the correlation between microhardness measurements on micro samples and the conventional mechanical properties (hardness, yield strength and tensile strength) of macro samples and the comparability of the different heat treatment states of micro and macro samples made of a hardenable aluminium alloy EN AW-6082 will be discussed. Using the correlations between the mechanical properties of micro samples and macro samples, the size of the samples and, thus, the testing cost and effort can be reduced.


2013 ◽  
Vol 747-748 ◽  
pp. 390-397 ◽  
Author(s):  
Ji Lin Li ◽  
Yue Qun Ma ◽  
Rong Shi Chen ◽  
Wei Ke

The distribution of shrinkage porosities in sand cast Mg-Y-RE (WE54) alloy castings was characterized through density measurement and calculated by Archimedess principle. The effect of porosity on mechanical properties of sand cast WE54 alloy was investigated through tensile tests and microstructure observation. It was found that the shrinkage porosities distributed mainly in the middle of the plate where the liquid feeding was quite inconvenient. And the porosities were formed along grain boundaries when secondary phases formed at the end of solidification. Hardness tests showed that the vikers hardness declined linearly with increasing porosity volume fraction. While the tensile strength and nominal yield strength declined exponentially as the porosity volume fraction increased. Microstructure observation showed that the fracture cracks propagated along the grain boundaries where porosities and secondary phases gathering together in as-cast WE54 alloy. The tiny porosities distributed in the secondary phases were observed, which could reduce the tensile strength of cast specimens significantly. The heat treatment strengthening effects were significantly weakened by porosities, and even no heat treatment strengthening effect was detected when the porosity volume fraction was higher than 1%. The microstructure observation also proved that no heat treatment strengthening effect existed in samples containing porosities.


Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6667
Author(s):  
Huda Mohammed Sabbar ◽  
Zulkiflle Leman ◽  
Shazarel Shamsudin ◽  
Suraya Mohd Tahir ◽  
Che Nor Aiza Jaafar ◽  
...  

Direct solid-states, such as hot extrusion and equal channel angular pressing (ECAP), are alternative and efficient solid-state processes for use in recycling aluminium scrap. These processes utilise less energy and are eco-friendly. Ceramic particles such as ZrO2 are suggested as alternatives in the production of metal composites. This study investigated and optimised the effects of various parameters of reinforced ZrO2 nanoparticles on the mechanical and physical properties via response surface methodology (RSM). These parameters were the volume fraction (VF), preheating temperature (T), and preheating time (t). The effects of these parameters were examined before and after the heat treatment condition and ECAP. Each parameter was evaluated at varying magnitudes, i.e., 450, 500, and 550 °C for T, 1, 2, and 3 h for t, and 1, 3, and 5% for VF. The effect that process variables had on responses was elucidated using the factorial design with centre point analysis. T and VF were crucial for attaining the optimum ultimate tensile strength (UTS) and microhardness. Reducing VF increased the mechanical properties to 1 vol% of oxide. The maximum hardness of 95 HV was attained at 550 °C, 1.6 h, and 1 vol% ZrO2 with a density of 2.85 g/cm3 and tensile strength of 487 MPa. UTS, density, and microhardness were enhanced by 14%, 1%, and 9.5%, respectively. Additionally, the hot extrusion parameters and ECAP followed by heat treatment strengthened the microhardness by 64% and density by 3%. Compression pressure and extrusion stress produced in these stages were sufficient to eliminate voids that increased the mechanical properties.


2021 ◽  
Vol 7 (4) ◽  
pp. 49-67
Author(s):  
Nhuan Hoang ◽  
Thuc Phuong Nguyen Thi ◽  
Xuan Thi Hoang ◽  
Xuan Vinh Tran ◽  
Thi Tuyen Hoang

In the PWR pressure water reactor (PWR), stainless steel is used in many important parts in both primary and secondary water circuits. There are not enough necessary condition to experiment in extremly conditons of nuclear reactor, such as high temperature, high pressure in radiation environment in Vietnam. Therefore, in order to study the world's technology for evaluating metal materials, it is necessary to have basic research on SS304 stainless steel objects. This study deals with SS304L stainless steel, which is low carbon steel used in nuclear power plants. The material used in this work was stainless steel 304 with low C content (SS304L). AISI stainless steel 304L plates were cut by wire-cutting machine into standard specimens and then heat-treated under different conditions. Finally, the post-treated specimens were tested by Rockwell hardness tester, tensile strength tester, and Charpy impact tester to verify the mechanical properties. The results showed that when heating the specimens in the range of 300÷900oC, cooling in the furnace to the room temperature, the value of hardness changed insignificantly. When increasing heating temperature, the yield strength and ultimate tensile strength values of the specimens decreased while the relative elongation values were almost unchanged. It means that under tested heat treatment conditions, the higher the heating temperature is, the worse mechanical properties are. The reason for this might be the appearance of the brittle sigma phase. Heat treatment results of SS304 specimens with the normalizing conditions at 900oC also shows the possibility to remove the sigma phase in the steel composition.


Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2795 ◽  
Author(s):  
Alireza Vahedi Nemani ◽  
Mahya Ghaffari ◽  
Ali Nasiri

Wire arc additive manufacturing (WAAM) is known to induce a considerable microstructural inhomogeneity and anisotropy in mechanical properties, which can potentially be minimized by adopting appropriate post-printing heat treatment. In this paper, the effects of two heat treatment cycles, including hardening and normalizing on the microstructure and mechanical properties of a WAAM-fabricated low-carbon low-alloy steel (ER70S-6) are studied. The microstructure in the melt pools of the as-printed sample was found to contain a low volume fraction of lamellar pearlite formed along the grain boundaries of polygonal ferrite as the predominant micro-constituents. The grain coarsening in the heat affected zone (HAZ) was also detected at the periphery of each melt pool boundary, leading to a noticeable microstructural inhomogeneity in the as-fabricated sample. In order to modify the nonuniformity of the microstructure, a normalizing treatment was employed to promote a homogenous microstructure with uniform grain size throughout the melt pools and HAZs. Differently, the hardening treatment contributed to the formation of two non-equilibrium micro-constituents, i.e., acicular ferrite and bainite, primarily adjacent to the lamellar pearlite phase. The results of microhardness testing revealed that the normalizing treatment slightly decreases the microhardness of the sample; however, the formation of non-equilibrium phases during hardening process significantly increased the microhardness of the component. Tensile testing of the as-printed part in the building and deposition directions revealed an anisotropic ductility. Although normalizing treatment did not contribute to the tensile strength improvement of the component, it suppressed the observed anisotropy in ductility. On the contrary, the hardening treatment raised the tensile strength, but further intensified the anisotropic behavior of the component.


2007 ◽  
Vol 567-568 ◽  
pp. 337-340
Author(s):  
Klára Hanzlíková ◽  
Stanislav Vĕchet ◽  
Jan Kohout ◽  
Josef Zapletal

The structure of austempered ductile iron (ADI) matrix and consequently its mechanical properties are influenced by the heat treatment conditions, above all by the temperature and dwell length of isothermal transformation. The paper is focused on deeper understanding the interrelation between matrix mixture composition and static mechanical properties of ADI in dependence on the isothermal transformation dwell. Practical aim of the paper is to find the optimal isothermal transformation dwell range for ADI isothermally transformed at the temperature of 380 °C with emphasis on the level of static mechanical properties in tension. Microstructure and mechanical properties changes that proceed during isothermal transformation are observed and evaluated for the transformation dwells of 2, 5, 10, 25, 60, 120, 270, and 540 minutes.


2014 ◽  
Vol 59 (4) ◽  
pp. 1269-1273 ◽  
Author(s):  
R. Bogucki ◽  
K. Mosór ◽  
M. Nykiel

Abstract The influence of heat treatment on the microstructure and mechanical properties was studied in the Ti-10V-2Fe-3Al titanium alloy for two heat treatment schemes (α + β) and β + (β + α), which resulted in different morphologies of the α phase. Scheme I resulted in the α-phase of globular morphology, whose volume fraction did not change much during annealing. Scheme II led to obtaining a needle-like α-phase, whose amount increased together with heating time. The phenomenon of stress-induced martensitic transformation was observed in the material with needle-like morphology annealed for 15 and 30 min. Longer times of annealing effected in the decay of that transformation, provided the volume fraction of α-phase exceeded 50%.


Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1556
Author(s):  
Zhao Li ◽  
Run Wu ◽  
Mingwei Li ◽  
Song-Sheng Zeng ◽  
Yu Wang ◽  
...  

High boron steel is prone to brittle failure due to the boride distributed in it with net-like or fishbone morphology, which limit its applications. The Quenching and Partitioning (Q&P) heat treatment is a promising process to produce martensitic steel with excellent mechanical properties, especially high toughness by increasing the volume fraction of retained austensite (RA) in the martensitic matrix. In this work, the Q&P heat treatment is used to improve the inherent defect of insufficient toughness of high boron steel, and the effect mechanism of this process on microstructure transformation and the change of mechanical properties of the steel has also been investigated. The high boron steel as-casted is composed of martensite, retained austensite (RA) and eutectic borides. A proper quenching and partitioning heat treatment leads to a significant change of the microstructure and mechanical properties of the steel. The net-like and fishbone-like boride is partially broken and spheroidized. The volume fraction of RA increases from 10% in the as-cast condition to 19%, and its morphology also changes from blocky to film-like. Although the macro-hardness has slightly reduced, the toughness is significantly increased up to 7.5 J·cm−2, and the wear resistance is also improved.


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