scholarly journals Short-Term Characterization of Spherical 100Cr6 Steel Samples Using Micro Compression Test

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 733 ◽  
Author(s):  
Heike Sonnenberg ◽  
Brigitte Clausen

For the establishment of a novel development process of new structural materials, short-term characterization methods capable of testing hundreds of spherical micro samples are needed. This paper introduces a compression test on spherical micro samples as a short-term characterization method to investigate the elastic-plastic deformation behavior. To demonstrate the potential of this newly developed method, the micro compression test is performed with a maximum loading of 300 N on 100Cr6 (AISI 52100 bearing steel) samples, with a diameter of 0.8 mm, in 15 different heat treatment conditions. The austenitizing temperature is varied between 800 and 1150 °C. Tempering of the samples is carried out in a differential scanning calorimetry process with temperatures of 180, 230 and 300 °C. Out of force-displacement curves and stress-strain relations, so-called descriptors (characteristic values) which are sensitive to the applied heat treatment can be extracted. The change of mechanical properties due to heat treatment and the resulting microstructure is presented by the trend of a stress descriptor in dependence of austenitizing and annealing temperature, which can be compared to the trend of the tensile strength as a material property obtained by conventional tensile tests. The trend of the descriptor determined in the compression test on spherical samples indicates the validity of this approach as a short-term characterization method.

2011 ◽  
Vol 465 ◽  
pp. 459-462 ◽  
Author(s):  
Lin Wang ◽  
Luen Chow Chan ◽  
Ting Fai Kong

The microstrctural evolution pre and post heat treatment is critical to achieve a successful product for metal forming process. This paper aims to investigate the microstructual effect of the magnesium alloy tubes undergone various heat treatment conditions to achieve material homogenization. The heat treatment conditions under various periods of time (1, 2, 6, 12 and 30 hours) at 400 °C were employed to investigate the microstructural effect on hydroforming magnesium tubes. The greatly reduced impurity embedded in grain boundaries and more uniform grain sizes do indicate the improvement of material strength and ductility. To validate the conclusion, corresponding tensile tests at the different temperatures (20 °C and 200 °C) were carried out. The increased engineering strain in two directions (hoop and longitudinal) implies that the microstructural evolution is unquestionably useful to enhance the ductility of the magnesium tubes. Subsequently, the tubes after optimal heat treatment condition at 400 °C for 6 hours were used to further carry out the thermal hydroforming process for validation. The defect-free hydroformed tubes were produced under the same working condition, which is unable to be achieved for tubes without the heat-treatment process.


2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Arash Badakhsh ◽  
Kay-Hyeok An ◽  
Chan Woo Park ◽  
Byung-Joo Kim

Herein, simplified time-efficient production of AlN-coated SiC (SiC@AlN) ceramic powder was practiced. Short-term vibratory ball milling with high frequency was employed to integrate the microsize particles. Also, paraffin as a significant phase change material (PCM) was reinforced using the manufactured SiC@AlN in order to enhance the thermal conductivity (TC) and stability of the final composite. Various characterization methods were used to clarify the changes in particle size of the biceramic powder as well as the thermal features of the paraffin-based composite. Manufactured SiC@AlN was found to be the most effective in the improvement of interfacial adhesion of composite components and the subsequent enhancement of TC, compared with singular ceramic powders as the reinforcing agents. Also, differential scanning calorimetry (DSC) indicated a very slight increase in latent heat of the fabricated composite PCM.


Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 918
Author(s):  
Julia Osten ◽  
Benjamin Milkereit ◽  
Michael Reich ◽  
Bin Yang ◽  
Armin Springer ◽  
...  

The mechanical properties after age hardening heat treatment and the kinetics of related phase transformations of high strength AlZnMgCu alloy AA 7068 were investigated. The experimental work includes differential scanning calorimetry (DSC), differential fast scanning calorimetry (DFSC), sophisticated differential dilatometry (DIL), scanning electron microscopy (SEM), as well as hardness and tensile tests. For the kinetic analysis of quench induced precipitation by dilatometry new metrological methods and evaluation procedures were established. Using DSC, dissolution behaviour during heating to solution annealing temperature was investigated. These experiments allowed for identification of the appropriate temperature and duration for the solution heat treatment. Continuous cooling experiments in DSC, DFSC, and DIL determined the kinetics of quench induced precipitation. DSC and DIL revealed several overlapping precipitation reactions. The critical cooling rate for a complete supersaturation of the solid solution has been identified to be 600 to 800 K/s. At slightly subcritical cooling rates quench induced precipitation results in a direct hardening effect resulting in a technological critical cooling rate of about 100 K/s, i.e., the hardness after ageing reaches a saturation level for cooling rates faster than 100 K/s. Maximum yield strength of above 600 MPa and tensile strength of up to 650 MPa were attained.


2014 ◽  
Vol 59 (4) ◽  
pp. 1637-1640 ◽  
Author(s):  
J. Dworecka ◽  
E. Jezierska ◽  
K. Rozniatowski ◽  
W. Swiatnicki

Abstract The aim of the work was to produce a nanobainitic structure in the commercial bearing steel - 100CrMnSi6-4 and to characterize its structure and mechanical properties. In order to produce this structure the austempering heat treatment was performed, with parameters that have been selected on the basis of dilatometric measurements of phase transformation kinetics in steel. The heat treatment process was performed in laboratory as well as in industrial furnaces. The obtained structure was characterized using transmission electron microscopy. In order to investigate the effect of the microstructure parameters on the material’s mechanical properties, the hardness, impact strength and static tensile tests have been conducted.


2010 ◽  
Vol 44-47 ◽  
pp. 2385-2389 ◽  
Author(s):  
Fei Ming Xie ◽  
Yan Lin Wang ◽  
You Yang Xiang ◽  
Qing Zhang

The influence of microstructure in GCr15 bearing steel by the different heat treatment conditions was studied, and the influence regular pattern of recrystallization percentage in GCr15 bearing steel by the different deformation amount, deformation temperature and dwell time after rolling was also analyzed. The research results show that when the deformation temperature and deformation amount under certain conditions, the recrystallization percentage of deformed austenite in GCr15 bearing steel increases as the dwell time after rolling increases, and the austenitic grain is also grow up; The uniformity of deformed austenite organization is influenced greatly by the different deformation amount, deformation temperature and dwell time after rolling, when the deformation temperature is 950 °C, the deformation amount is 45% and the dwell time after rolling is 100 S, the recrystallization percentage can up to 84.57%.


2016 ◽  
Vol 877 ◽  
pp. 400-406 ◽  
Author(s):  
Hannes Fröck ◽  
Matthias Graser ◽  
Benjamin Milkereit ◽  
Michael Reich ◽  
Michael Lechner ◽  
...  

Precipitation hardening aluminium alloys are widely used for automotive applications. To enhance the application of aluminium profiles, improved formability is needed. Tailor Heat Treated Profiles (THTP) with locally different material properties attempt to increase formability e.g. in bending processes. Tailoring of local properties is obtained by a local short-term heat treatment, dissolving the initial precipitate state (retrogression) and still allowing subsequent ageing. In the present study, the dissolution and precipitation behaviour of the aluminium alloy EN AW-6060 T4 was investigated during heating with differential scanning calorimetry (DSC). Heating curves from 20 to 600 °C with heating rates of 0.01 up to 5 K/s were recorded. Interrupted heat treatments with different maximum temperatures were performed in a deformation dilatometer. Immediately afterwards, tensile tests were carried out at room temperature. The course of the recorded mechanical properties as a function of the maximum temperature is discussed with regard to the dissolution and precipitation behaviour during heating. Finally, the aging behaviour of the investigated alloy was recorded after different typical short-term heat treatments and is discussed with reference to the DSC‐curves. The correlation of the microstructure and the mechanical properties enables the derivation of optimal parameters for the development of THTP through a local softening.


2017 ◽  
Vol 17 (3) ◽  
pp. 222-228 ◽  
Author(s):  
E. Türedi ◽  
M. Yilmaz ◽  
V. Senol

Abstract AISI 52100 bearing steels are commonly used in applications requiring high hardness and abrasion resistance. The bearing steels are working under dynamic loads in service conditions and their toughness properties become important. In order to provide the desired mechanical properties, various heat treatments (austenizing, quenching and tempering) are usually applied. In this study, AISI 52100 bearing steel samples were austenized at 900°C for ½ h and water quenched to room temperature. Then tempering was carried out at 795°C, 400°C and 200°C for ½ h. In order to investigate the effect of heat treatment conditions on wear behavior, dry friction tests were performed according to ASTM G99-05 Standard with a ‘ball-on-disk’ type tribometer. The samples were tested against steel and ceramic counterparts using the parameters of 100 m distance and 30 N load and 0.063 m/s rotational speed. After wear test, the surface characterization was carried out using microscopy. Wear loss values were calculated using a novel optical method on both flat and counterpart specimens.


2021 ◽  
Vol 11 (20) ◽  
pp. 9682
Author(s):  
Heejeong Kim ◽  
Jungyu Park ◽  
Sangmin Shin ◽  
Seungchan Cho ◽  
Junghwan Kim ◽  
...  

A metal matrix composite was developed through a unique liquid pressing infiltration process to study the wear mechanism of a TiC reinforced AISI 1020 steel matrix. The microstructure, hardness, and wear behaviors of the TiC/AISI 1020 composite were compared with commercial AISI 52100 bearing steel. Microstructural analysis showed that there were no defects, such as pores or agglomeration of reinforcement particles, and about 60% of the volume of TiC was uniformly dispersed. In the case of the AISI 52100 alloy, the hardness was 62.42 HRC, which was similar to the 62.84 HRC value of the as-cast TiC/AISI 1020 composite. After the quenching heat treatment, the Rockwell hardness of the composite increased to 76.64 HRC, which was attributed to the martensitic transformation of the AISI 1020 matrix. As a result of the pin-on-disc wear test with high contact pressure, the wear width of AISI 52100 was 2937 μm, which was approximately 4.3 times wider than that of the heat-treated metal matrix composite (682 μm). The wear depths of AISI 52100 and the heat-treated composite were 2.6 μm and 0.5 μm, respectively, indicating that TiC/AISI 1020 exhibited excellent wear resistance compared with bearing steel. Improved wear resistance of the TiC/AISI 1020 composite originates from uniformly distributed TiC, with an increase in the hardness due to the heat treatment.


Author(s):  
Osita Obiukwu ◽  
Henry Udeani ◽  
Progress Ubani

The effect of various heat treatment operations (annealing, normalizing, tempering) on mechanical properties of 0.35% carbon steel was investigated. The change in the value of endurance limit of the material as a result of the various heat-treatment operations were studied thoroughly. It was found that the specimens tempered at low temperature (200°C) exhibited the best fatigue strength. Microscope was used to characterize the structural properties resulting from different heat treatment processes. The results from the tensile tests impact tests and hardness tests showed that the mechanical properties variate at every heat-treatment conditions. The microstructure of differently heat-treated steels was also studied.


2020 ◽  
pp. 096739112095407 ◽  
Author(s):  
Ali Shaan Manzoor Ghumman ◽  
Mohamed Mahmoud Nasef ◽  
M Rashid Shamsuddin ◽  
Amin Abbasi

Sulfur-based polymers are unique renewable materials that are receiving a growing attention. The utilization of elemental sulfur with a variety of monomers in their preparation in the absence of solvents using the inverse vulcanization are granting them green nature and unique properties. Several characterization techniques have been used to evaluate the properties of sulfur-based polymers. However, the complex structure and lack of solubility undermine the applicability of some standard characterization techniques in the usual manners. This article reviews the characterization methods used for the evaluation of various properties of sulfur-based polymers such as chemical, morphological, structural, thermal, rheological and mechanical properties, all of which vary depending on the type of comonomer involved in the reaction and heat treatment conditions. The successful applications of different characterization techniques including Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, nuclear magnetic resonance (NMR), scanning electron microscopy/X-ray energy dispersion (SEM-EDX), X-ray diffraction (XRD), mechanical tester, rheometer, thermal gravimetric analyzer (TGA) and differential scanning calorimetry (DSC) are discussed. The challenges to the evaluation of the properties of sulfur-based polymers and the innovative applications of the conventional techniques to overcome them are also deliberated.


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