scholarly journals Effects of Fine Precipitates on Austenite Grain Refinement of Micro-alloyed Steel during Cyclic Heat Treatment

2019 ◽  
Vol 59 (11) ◽  
pp. 2098-2104 ◽  
Author(s):  
Genki Saito ◽  
Norihito Sakaguchi ◽  
Munekazu Ohno ◽  
Kiyotaka Matsuura ◽  
Masayoshi Takeuchi ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Grain Refinement ◽  
Alloyed Steel ◽  
Cyclic Heat Treatment ◽  
Austenite Grain ◽  
Cyclic Heat ◽  
Micro Alloyed Steel

scholarly journals Wear-Resistance Improvement of 65Mn Low-Alloy Steel through Adjusting Grain Refinement by Cyclic Heat Treatment

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7636
Author(s):  
Ying Tong ◽  
Yu-Qing Zhang ◽  
Jiang Zhao ◽  
Guo-Zheng Quan ◽  
Wei Xiong
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Wear Resistance ◽  
Grain Refinement ◽  
Alloy Steel ◽  
Low Alloy Steel ◽  
Cyclic Heat Treatment ◽  
Average Grain Size ◽  
Cyclic Heat ◽  
Cyclic Quenching

Refined microstructures achieved by cyclic heat treatment significantly contribute to improving the wear resistance of steels. To acquire the refined microstructures of 65Mn low-alloy steel, first, the specimens were solid solution-treated; then, they were subjected to cyclic heat treatment at cyclic quenching temperatures of 790–870 °C and quenching times of 1–4 with a fixed holding time of 5 min. The mechanical properties of 65Mn low-alloy steel in terms of hardness, tensile strength, elongation and wear resistance were characterized. Afterwards, the effect of cyclic heat treatment on microstructure evolution and the relationships between grain refinement and mechanical properties’ improvement were discussed. The results show that the average grain size firstly decreased and then increased with the increase in the quenching temperature. Hardness increased with grain refinement when the temperature was lower than 830 °C. Once the temperature exceeded 830 °C, hardness increased with the temperature increase owing to the enrichment of carbon content in the martensite. With the increase in cyclic quenching times, hardness continuously increased with grain refinement strengthening. In addition, both tensile strength and elongation could be significantly improved through grain refinement. The relationships among wear loss, hardness and average grain size showed that wear resistance was affected by the synthesis reaction of grain refinement and hardness. Higher hardness and refined grain size contributed to improving the wear resistance of 65Mn low-alloy steel.

scholarly journals Challenging Ultra Grain Refinement of Ferrite in Low-C Steel Only by Heat Treatment

2020 ◽  
Vol 7 ◽  
Author(s):  
Myeong-heom Park ◽  
Akinobu Shibata ◽  
Nobuhiro Tsuji
Keyword(s):  
Heat Treatment ◽  
Plastic Deformation ◽  
Grain Size ◽  
Severe Plastic Deformation ◽  
Cyclic Heat Treatment ◽  
Austenite Grain Size ◽  
Fine Grained ◽  
Grain Sizes ◽  
Austenite Grain ◽  
Cyclic Heat

It is well-known that grain refinement is one of the most effective ways to improve strength of metals without addition of alloying elements. In order to obtain bulky metals having ultrafine grained (UFG) microstructures with average grain sizes smaller than 1 μm, severe plastic deformation (SPD) processes have made a great success. However, there are still big barriers to realize UFG metallic materials, especially UFG steels, in large scale industries, since severe plastic deformation processes usually need special techniques and equipment, and large deformation forces are required for heavy plastic deformations. Cyclic heat treatments to repeat martensitic transformation and austenitization have been known as a simple way to fabricate fine-grained austenitic structures in steels. In the present study, we tried to make final ferrite microstructures ultrafine in a low-C steel by means of the cyclic heat treatment. Evolution of microstructures during the cyclic heat treatment was systematically investigated, putting stress on the change of grain sizes of austenite and ferrite. The austenite grain size decreased with increasing the number of heat treatment cycles, and the minimum average austenite grain size obtained was 11 μm. By having furnace-cooling from austenite states with various grain sizes, ferrite microstructures with different mean grain sizes were fabricated. We could successfully obtain a fine-grained ferrite structure with a mean grain size of 4.5 μm and nearly a random texture through the heat treatment without deformation. Microstructural features and mechanical properties of the obtained fine-grained ferritic structures were investigated by scanning electron microscope/electron back-scattering diffraction measurements and a tensile test at room temperature. The specimens with ferrite + pearlite microstructure with the smallest average ferrite grain size of 4.5 μm managed both high strength (yield strength of 375 MPa and tensile strength of 500 MPa) and large tensile ductility (uniform elongation of 20% and total elongation of 39%) in the simple 2Mn-0.1C steel.

Grain Refinement of Ti-48Al-2Cr-2Nb Alloy by Heat Treatment Method

2012 ◽  
Vol 191 ◽  
pp. 221-234 ◽  
Author(s):  
Agnieszka Szkliniarz
Keyword(s):  
Heat Treatment ◽  
Grain Refinement ◽  
Treatment Method ◽  
Cyclic Heat Treatment ◽  
Treatment Processes ◽  
Multi Stage ◽  
Cyclic Heat ◽  
Treatment Procedures ◽  
Heat Treatment Method ◽  
Initial Heat

In this paper, the possibility of refining grain of Ti-48Al-2Cr-2Nb alloy in the processes of multi-stage heat treatment consisted of initial heat treatment, cyclic heat treatment and under-annealing was evaluated. Microstructural changes that take place during the particular heat treatment procedures were also described. It was demonstrated that due to the application of combined cyclic heat treatment and under-annealing almost 24-fold grain refinement in relation to the state after homogenising could be obtained. Probable mechanisms of grain refinement in the proposed heat treatment processes were also presented and influence of individual procedures of the proposed treatment on selected properties of the investigated alloy was described

Homology Analysis of Prior Austenite Grain Size of SAE52100 Bearing Steel Processed by Cyclic Heat Treatment

2013 ◽  
Vol 813 ◽  
pp. 116-119 ◽  
Author(s):  
Kazuaki Nakane ◽  
Katsuyuki Kida ◽  
Koshiro Mizobe
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Retained Austenite ◽  
Prior Austenite ◽  
Cyclic Heat Treatment ◽  
Austenite Grain Size ◽  
Austenite Grain ◽  
Cyclic Heat ◽  
Prior Austenite Grain Size ◽  
Prior Austenite Grain

Here, we introduce the mathematical methods to quantitatively evaluate the change of the tissue to quenching. SAE 52100 sample was repeatedly quenched and the influence of this cyclic heat treatment was investigated. The repeated quenching process increased the retained austenite content and had little influence on the materials hardness. The prior austenite grain size was decreased and consequently, refinement of the martensitic phase in the material occurred. The higher content of the retained austenite (higher fracture toughness) and the refinement of the microstructure accounted for the higher fatigue properties of the repeatedly quenched material. Here we use mathematical homology to quantify these features.

Oxidation resistance of TiAl alloy improved by hot-pack rolling and cyclic heat treatment

2021 ◽  
pp. 111196
Author(s):  
Tian Shiwei ◽  
He Anrui ◽  
Liu Jianhua ◽  
Zhang Yefei ◽  
Yang Yonggang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Oxidation Resistance ◽  
Tial Alloy ◽  
Cyclic Heat Treatment ◽  
Pack Rolling ◽  
Cyclic Heat ◽  
Hot Pack

scholarly journals Laser Powder Bed Fusion Processing of Fe-Mn-Al-Ni Shape Memory Alloy—On the Effect of Elevated Platform Temperatures

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 185
Author(s):  
Felix Clemens Ewald ◽  
Florian Brenne ◽  
Tobias Gustmann ◽  
Malte Vollmer ◽  
Philipp Krooß ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Crack Formation ◽  
Microstructural Analysis ◽  
Tensile Load ◽  
Grain Structure ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Cyclic Heat Treatment ◽  
Powder Bed ◽  
Cyclic Heat

In order to overcome constraints related to crack formation during additive processing (laser powder bed fusion, L-BPF) of Fe-Mn-Al-Ni, the potential of high-temperature L-PBF processing was investigated in the present study. The effect of the process parameters on crack formation, grain structure, and phase distribution in the as-built condition, as well as in the course of cyclic heat treatment was examined by microstructural analysis. Optimized processing parameters were applied to fabricate cylindrical samples featuring a crack-free and columnar grained microstructure. In the course of cyclic heat treatment, abnormal grain growth (AGG) sets in, eventually promoting the evolution of a bamboo like microstructure. Testing under tensile load revealed a well-defined stress plateau and reversible strains of up to 4%.

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