Influences of Thermomechanical Processing by Severe Cold and Warm Rolling on the Microstructure, Texture, and Mechanical Properties of an Equiatomic CoCrNi Medium-Entropy Alloy

Author(s):  
J. Saha ◽  
P. P. Bhattacharjee
2011 ◽  
Vol 64 (1) ◽  
pp. 57-62 ◽  
Author(s):  
Roberto Gerardo Bruna

It is well-known that variations in the thermomechanical processing can have a profound effect on the microstructure and mechanical properties of Low Carbon steels. Numerous studies have been published on the effect of composition, slab reheating temperature (SRT), hot rolling finishing temperature (FRT), coiling temperature after rolling (CT), amount of deformation during hot and cold rolling, and annealing temperature on the mechanical properties of LC steels. There are, however, some disagreements in the results presented in the literature. In this work the FRT and CT effects on the microstructure, recrystallization behavior and texture of LC steels rolled under hot and warm-rolling industrial conditions were investigated. The results in terms of the microstructure, crystallographic texture and properties are shown and discussed. In addition, this study will present the possible mechanisms responsible for the microstructure and mechanical properties observed.


2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Mandana Zebarjadi Sar ◽  
Silvia Barella ◽  
Andrea Gruttadauria ◽  
Davide Mombelli ◽  
Carlo Mapelli

Rolling temperature and rolling reduction intensively influence the formation of Luder lines and fluting marks in mild steels. They govern these effects through control of strain aging. In order to enhance the strain aging resistance and the consequent reduction of yield point elongation and fluting intensity, warm rolling without using the skin pass process is applied. The development of microstructure and crystallographic textures during deformation process and the determination of fluting intensity and mechanical properties consisting of tensile and formability properties in terms of different thermomechanical conditions (RT and RR%) were investigated in this study. These properties are determined through the use of bending, tensile tests, optical microscope, and EBSD analysis.


2020 ◽  
pp. 5-18
Author(s):  
D. V. Prosvirnin ◽  
◽  
M. S. Larionov ◽  
S. V. Pivovarchik ◽  
A. G. Kolmakov ◽  
...  

A review of the literature data on the structural features of TRIP / TWIP steels, their relationship with mechanical properties and the relationship of strength parameters under static and cyclic loading was carried out. It is shown that the level of mechanical properties of such steels is determined by the chemical composition and processing technology (thermal and thermomechanical processing, hot and cold pressure treatment), aimed at achieving a favorable phase composition. At the atomic level, the most important factor is stacking fault energy, the level of which will be decisive in the formation of austenite twins and / or the formation of strain martensite. By selecting the chemical composition, it is possible to set the stacking fault energy corresponding to the necessary mechanical characteristics. In the case of cyclic loads, an important role is played by the strain rate and the maximum load during testing. So at high loading rates and a load approaching the yield strength under tension, the intensity of the twinning processes and the formation of martensite increases. It is shown that one of the relevant ways to further increase of the structural and functional properties of TRIP and TWIP steels is the creation of composite materials on their basis. At present, surface modification and coating, especially by ion-vacuum methods, can be considered the most promising direction for the creation of such composites.


Author(s):  
Maruff Hussain ◽  
P. Nageswara rao ◽  
Dharmendra Singh ◽  
R. Jayaganthan ◽  
Sunkulp Goel ◽  
...  

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1094
Author(s):  
M. A. Lakhdari ◽  
F. Krajcarz ◽  
J. D. Mithieux ◽  
H. P. Van Landeghem ◽  
M. Veron

The impact of microstructure evolution on mechanical properties in superduplex stainless steel UNS S32750 (EN 1.4410) was investigated. To this end, different thermomechanical treatments were carried out in order to obtain clearly distinct duplex microstructures. Optical microscopy and scanning electron microscopy, together with texture measurements, were used to characterize the morphology and the preferred orientations of ferrite and austenite in all microstructures. Additionally, the mechanical properties were assessed by tensile tests with digital image correlation. Phase morphology was not found to significantly affect the mechanical properties and neither were phase volume fractions within 13% of the 50/50 ratio. Austenite texture was the same combined Goss/Brass texture regardless of thermomechanical processing, while ferrite texture was mainly described by α-fiber orientations. Ferrite texture and average phase spacing were found to have a notable effect on mechanical properties. One of the original microstructures of superduplex stainless steel obtained here shows a strength improvement by the order of 120 MPa over the industrial material.


2005 ◽  
Vol 475-479 ◽  
pp. 529-532
Author(s):  
Tae Kwon Ha ◽  
Hwan Jin Sung ◽  
Woo Jin Park ◽  
Sang Ho Ahn

The effect of warm rolling under various conditions on the microstructure and mechanical property was investigated using an AZ31 Mg alloy sheet. Several processing parameters such as initial thickness, thickness reduction by a single pass rolling, rolling temperature, roll speed, and roll temperature were varied to elicit an optimum condition for the warm rolling process of AZ31 Mg alloy. Microstructure and mechanical properties were measured for specimens subjected to rolling experiments of various conditions. Warm rolling of 30% thickness reduction per pass was possible without any side-crack at temperatures as low as 200oC under the roll speed of 30 m/min. The initial microstructure before rolling was the mixed one consisting of partially recrystallized and cast structures. Grain refinement was found to occur actively during the warm rolling, producing a very fine grain size of 7 µm after 50% reduction in single pass rolling at 200oC. Yield strength of 204MPa, tensile strength of 330MPa and uniform elongation of 32% have been obtained in warm rolled sheets.


Author(s):  
S.V.S. Narayana Murty ◽  
Sushant K. Manwatkar ◽  
P. Ramesh Narayanan

Microstructure plays an important role in obtaining the desired properties in metallic materials in general and aluminum alloys in particular. Mechanical properties of aluminum alloys can be significantly altered by changing the microstructure. No other alloy system can boast of as many temper conditions as aluminum alloys. With the progress in the understanding of microstructure–mechanical property relationships in these materials, “tailor made” alloys to meet specific demands are being industrially developed. The broad spectrum of aluminum alloys in wide range of temper conditions offer materials with widely varying mechanical properties for structural designers. In order to select aluminum alloys with the desired properties for the intended application, it is essential to understand the role of microstructure under actual service conditions. It is in this context “Metallography of aluminum alloys” becomes very important. This chapter provides an insight in to the microstructural evolution of aluminum alloys from the as-cast condition to the final product. Typical examples of microstructural evolution in different aluminum alloys under various thermomechanical conditions are presented here. An atlas of microstructures of commercial and experimental wrought and cast aluminum alloys is presented in an appendix to this book. This appendix includes optical photomicrographs of both cast and wrought alloys and scanning electron micrographs of polished surfaces as well as fracture surfaces of various aluminum alloys as well as transmission electron micrographs as separate annexure. Readers are encouraged to go through the optical microstructures and fractographs along with this chapter for better understanding of the evolution of microstructure as a function of alloying additions, thermomechanical processing conditions, and fracture behavior under tension.


2016 ◽  
Vol 16 (1) ◽  
Author(s):  
Ayu Rizeki Ridhowati ◽  
Eka Febriyanti ◽  
Rini Riastuti

Warm rolling is one of the thermomechanical method has several advantages such as produces high mechanical properties, but does not decrease % elongation and toughness value because partial recrystallization phenomenon that produces micron-sized new grain. This paper reports the results of an investigation carried out on the effects of holding time annealing to mechanical properties Cu-Zn 70/30 alloy. These alloy after homogenization process and quenched in the air then heated to temperature of 300°C, later the heated copper samples are warm rolled at 25%, 30%, and 35% reduction, after that heated at temperature 300°C and held during 120 minutes. Then sample is experienced rewarm rolling with reduction 25%, 30%, and 35%. The results obtained showed that the ultimate tensile strength and yield strength are higher proportional with the increasing of % reduction, their values are 501,1 MPa; 599,3 MPa; later decrease to 546, 5 MPa and to yield strength are 441,8 MPa; 466,1 MPa; then decrease to 458,6 MPa. Moreover hardness value increase proportional with % reduction such as 154 HV; 162 HV; after that decrease to 160 HV While, % elongation decreases inversely proportional with % reduction namely 12,4%; 8,2%; later increase to 11,2 %. It is caused of the partial recrystallization phenomenon as evidenced by the presence micron-sized.AbstrakWarm rolling merupakan salah satu metode termomekanik yang mempunyai beberapa keuntungan yaitu salah satunya menghasilkan sifat mekanik yang tinggi, namun tidak mengurunkan nilai keuletan karena adanya fenomena rekristalisasi parsial yang menghasilkan butiran baru berbentuk micron. Paper ini menjelaskan tentang hasil penelitian berupa pengaruh persentase reduksi terhadap sifat mekanis paduan Cu-Zn 70/30. Paduan Cu-Zn 70/30 setelah dilakukan proses homogenisasi dan didinginkan di udara lalu dipanaskan ke suhu 300°C, kemudian masing-masing dilakukan warm rolling dengan persentase reduksi sebesar 25%, 30%, dan 35% kemudian ditahan di suhu 300°C dalam waktu 120 menit. Selanjutnya sampel dilakukan rewarm rolling dengan persentase reduksi sebesar 25%, 30%, dan 35%. Hasil penelitian yang dilakukan antara lain nilai kekuatan tarik (UTS dan YS) yang semakin tinggi sebanding dengan peningkatan % reduksi warm rolling yaitu masing-masing untuk nilai UTS sebesar 501,1 MPa; 599,3 MPa; lalu menurun menjadi 546,5 MPa serta untuk nilai kekuatan luluh sebesar 441,8 MPa; 466,1 MPa; lalu menurun menjadi 458,6 MPa. Selain itu, nilai kekerasan meningkat sebanding dengan peningkatan % reduksi warm rolling masing-masing sebesar 154 HV; 162 HV; lalu menurun menjadi 160 HV. Sedangkan persentase elongasi semakin menurun berbanding terbalik dengan peningkatan % reduksi masing-masing sebesar 12,4%; 8,2%; lalu meningkat menjadi 11,2%. Hal tersebut disebabkan karena adanya fenomena rekristalisasi parsial yang dibuktikan dengan kehadiran butir kecil berukuran mikron.Keywords : Cu-Zn 70/30 alloy, warm rolling, anneal, % reduction, mechanical properties


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