scholarly journals Effect of cold-rolling on mechanical properties of Haynes 25 cobalt-based superalloy

10.30544/248 ◽  
2017 ◽  
Vol 23 (1) ◽  
pp. 31-45 ◽  
Author(s):  
Padina Ajami Ghaleh Rashidi ◽  
Hossein Arabi ◽  
Seyed Mehdi Abbasi

Effect of cold-rolling and annealing time on the microstructure, hardness and the tensile properties of Haynes 25 superalloy at room-temperature and 760 °C were investigated in this research. Hot-rolled and solutionized alloy of Haynes 25 was subjected to cold-rolling with different amounts of reductions, i.e. 5%, 10%, 20%, 30% and 35%. After that, all cold-rolled samples were annealed at 1230 °C for a period of time from 2 to 120 min. Microstructural analysis showed that for annealing time range from 30 to 120 min, the rate of grains coarsening remained approximately stable in all cold-rolled samples. On the other hand, the hardness results showed that expected decreasing trend of hardness did not occur after annealing of the cold-rolled samples at 1230 °C; on the contrary, hardness increased moderately in the range time from 10 to 120 min. Tensile properties after annealing of the cold-rolled samples at room temperature and 760 °C decreased. Loss of the tensile properties can be related to the high annealing temperature. According to the experimental results, decreasing trend of tensile properties and increasing trend of hardness is linked to the formation of hcp phase after annealing at 1230 °C for 30 min. Even though the hcp phase is a hard phase, the interface between fcc and hcp phases provides suitable sites for crack nucleation and propagation.

10.30544/231 ◽  
2016 ◽  
Vol 22 (4) ◽  
pp. 221-236
Author(s):  
Padina Ajami Ghaleh Rashidi ◽  
Hossein Arabi ◽  
Seyed Mehdi Abbasi

In this research, the effect of cold rolling, annealing time and temperature on microstructure and hardness were studied in L-605 superalloy. A cast bar of L-605 alloy was hot rolled at 1200ºC. As the following, it was solutionized at 1230 ºC for 1 hour and finally was cold rolled by different amounts (i.e. 5-35 percent thickness reduction). The cold-rolled samples were heat treated for different times (i.e. 2-120 min.) at temperature range of 1068-1230 ºC in order to study their recrystallization behavior. The results of microstructural analysis indicated that static recrystallization is responsible for microstructural refinement and coarsening, so that an increase in the amounts of cold rolling resulted in a fully recrystallized microstructure at lower temperature. This analysis also indicated that annealing temperature is more effective than annealing time in grain growth. Microstructural evaluation as well as showed that carbides such as M7C3 and M23C6 which have been reported in some literature were not observed during rolling or annealing in this research. It is perhaps due to usage of high annealing temperatures or possibly due to their very low contents which was not possible for us to evaluate their formation with conventional methods. Hardness results revealed that higher annealing temperature lead to lower hardness values as expected.


2011 ◽  
Vol 312-315 ◽  
pp. 51-55
Author(s):  
A. Shokohfar ◽  
S. M. Abbasi ◽  
Ali Yazdani ◽  
Behnam Rabiee

In this study, cold rolling and annealing are used to refine the austenite grains of 301 austenitic stainless steel. The 301 austenitic stainless steel was cold rolled for 70 and 90% strain and then annealed. Effects of cold rolling factors and temperatures and annealing times on microstructure, hardness and tensile properties have been studied.


Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 5975
Author(s):  
Jae-Hwan Kim ◽  
Jong-Min Jung ◽  
Hyunbo Shim

The tensile properties and damping capacity of cold-rolled Fe–20Mn–12Cr–3Ni–3Si alloys were investigated. The martensitic transformation was identified, including surface relief with a specific orientation and partial intersection. Besides, as the cold rolling degree increased, the volume fraction of ε-martensite increased, whereas α’-martensite started to form at the cold rolling degree of 15% and slightly increased to 6% at the maximum cold rolling degree. This difference may be caused by high austenite stability by adding alloying elements (Mn and Ni). As the cold rolling degree increased, the tensile strength linearly increased, and the elongation decreased due to the fractional increment in the volume of martensite. However, the damping capacity increased until a 30% cold rolling degree was approached, and then decreased. The irregular tendency of the damping capacity was confirmed, depicting that it increased to a specific degree and then decreased as the tensile strength and elongation increased. Concerning the relationship between the tensile properties and the damping capacity, the damping capacity increased and culminated, and then decreased as the tensile properties and elongation increased. The damping capacity in the high-strength area tended to decrease because it is difficult to dissipate vibration energy into thermal energy in alloys with high strength. In the low-strength area, on the other hand, the damping capacity increased as the strength increased since the increased volume fraction of ε-martensite is attributed to the increase in the damping source.


Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2757 ◽  
Author(s):  
Ning Cui ◽  
Qianqian Wu ◽  
Zhiyuan Yan ◽  
Haitao Zhou ◽  
Xiaopeng Wang

In this paper, the microstructure, deformability, tensile properties, and phase hardness of the Ti–43Al–2Cr–0.7Mo–0.1Y alloy with a high β phase content were investigated. Microstructural analysis showed that the β phase precipitated not only at the colony boundaries but also inside the lamellae due to its high content. A high-quality forging stock was prepared through one-step noncanned forging. The total deformation reached above 80%, suggesting that the alloy has good hot deformability compared to other TiAl alloys. The deformed microstructure was composed of fine and equiaxed grains due to dynamic recrystallization. The high β phase content was shown to contribute to the decomposition of the initial coarse lamellae. Tensile testing showed that the alloy has good room-temperature ductility, even if the β phase content reaches above 20%. This is inconsistent with a previous study that showed that a large amount of the hard β phase is detrimental to the room-temperature ductility of TiAl alloys. Nanoindentation testing showed that the hardness of the β phase in the current alloy is about 6.3 GPa, which is much lower than that in the Nb-containing TiAl alloys. Low hardness benefits the compatible deformation among various phases, which could be the main reason for the alloy’s good room-temperature ductility. Additionally, the influence of various β stabilizers on the hardness of the β phase was also studied. The β phase containing Nb had the highest hardness, whereas the β phase containing Cr had the lowest hardness.


2012 ◽  
Vol 706-709 ◽  
pp. 2693-2698 ◽  
Author(s):  
A. Arlazarov ◽  
M. Gouné ◽  
O. Bouaziz ◽  
A. Hazotte ◽  
F. Kegel

The study about the influence of intercritical annealing time on a cold rolled 0.1%C – 4.6%Mn (wt.%) steel was performed. The tensile tests show an interesting balance between strength and ductility especially after 7 hours annealing at 670°C. A part of this good result can be explained by the presence of rather high fraction of metastable austenite at room temperature. On the other hand a very complex microstructure combining lath-like and polygonal features was observed making the interpretation complicated.


2018 ◽  
Vol 921 ◽  
pp. 231-235
Author(s):  
Ke Bin Sun ◽  
Yan Feng Li ◽  
Ye Xin Jiang ◽  
Guo Jie Huang ◽  
Xue Shuai Li ◽  
...  

Copper foils with 91% cold rolled deformation annealed at temperature between 140°C and 170 °C.The microstructures were observed by EBSD. The mechanical properties were measured at room temperature by tensile test machine and the fracture morphologies observed by SEM. After annealed at 150 °C, recrystallization begins to occur, while the elongation increases evidently and tensile strength decreases sharply. When the temperature rises to 170 °C, recrystallization is complete and the grain starts to grow. When the foils are annealed at 140 °C, it exhibits a strong cold rolling textures characterized by Brass {011}<211> and Cu {112}<111>. After annealed at 170 °C, there are olny weak Brass {011}<211> texture.


2020 ◽  
Vol 56 (1) ◽  
pp. 89-97
Author(s):  
I. Angela ◽  
I. Basori ◽  
B.T. Sofyan

Al-brass alloys (Cu29.5Zn2.5Al wt. %) were produced by gravity casting and homogenized at 800?C for 2 h, resulting in a binary phase morphology identified as cubic ? and martensitic ?? phases through X-ray diffraction (XRD). Samples were then subsequently cold rolled and annealed at 150, 300, 400, and 600?C for 30 minutes. Visible traces of slip, intersecting slip bands, and shear bands were observed in microstructure images of the samples after each progressive deformation stage. Deformation-induced martensites were present after 20 % cold rolling. Higher thickness reduction resulted in simultaneous strain hardening of the phases. Low temperature annealing slightly increased microhardness, of both ? and ??, due to the formation of precipitates. SEM-EDX analysis showed that no solute segregation was found in annealed samples. Annealing at higher temperature resulted in conventional softening. Recrystallized equiaxed ?? phase grains were visible after annealing at 600?C.


2019 ◽  
Vol 113 ◽  
pp. 106578 ◽  
Author(s):  
Praveen Sathiyamoorthi ◽  
Peyman Asghari-Rad ◽  
Jae Wung Bae ◽  
Hyoung Seop Kim

2007 ◽  
Vol 546-549 ◽  
pp. 311-314 ◽  
Author(s):  
Da Quan Li ◽  
Qu Dong Wang ◽  
Wen Jiang Ding

Microstructure and tensile properties of AZ31 rolled at different temperatures were characterized. Rolling of extruded AZ31 plates was carried out at room temperature, 573K, 623K and 673K. Cold rolling of extruded AZ31 plates was difficult due to the poor formability at room temperature. And deformation twinning plays an important role in rolling of AZ31 alloy at room temperature. The microstructural analysis showed that the nucleation of dynamic recrystallization (DRX) occurred at 573K, DRX was almost completed at 623K and grain growth was determined at 673K. The ultimate tensile strength (UTS) as large as 377MPa was achieved after rolled at 573K. And the anisotropy in strength was obviously examined due to the rolling texture. The anisotropy reduced as rolling temperature increasing from 573K to 673K and this may be attributed to the completion of DRX.


Sign in / Sign up

Export Citation Format

Share Document