Evolution of phases during tempering of P91 steel at 760℃ for varying tempering time and their effect on microstructure and mechanical properties

Author(s):  
C Pandey ◽  
MM Mahapatra

In the present investigation, a systematic study has been undertaken with regard to the effects of tempering time on room temperature mechanical properties of P91 (X10CrMoVNNB9-1) steel. Samples cut from P91 (X10CrMoVNNB9-1) industrial pipe were normalized at 1040 ℃ for 40 min and then tempered at 760 ℃ for different tempering times starting from 2 h to 8 h. Detailed analysis of microstructure, particle size, inter-particle spacing, and secondary phase carbide particles of the tempered samples was conducted by secondary electron microscopy technique. Optical microscopy was also utilized to characterize the tempered samples and for the measurement of grain size. In order to reveal the various phases formed during tempering of P91 (X10CrMoVNNB9-1) steel, X-ray diffraction was carried out . To study the fracture surface morphology of tensile tested and impact tested specimen field-emission scanning electron microscopy was carried out. The effect of tempering time on the microstructural parameters revealed an increase in grain size up to 4 h of tempering and then decreased because of recrystallization. The coarsening of secondary phase carbide particles M23C6 was revealed with an increase in tempering time. As a consequence, yield strength, hardness, and ultimate tensile strength were observed to decrease with increase in the tempering time. However, a drastic change was observed in the yield strength, ultimate tensile strength, and toughness after tempering for 6 h. From the present study, it was concluded that optimum combination of yield stress, ultimate tensile strength, hardness, and toughness obtained after tempering at 760 ℃ for 6 h.

2016 ◽  
Vol 61 (2) ◽  
pp. 475-480
Author(s):  
K. Bolanowski

Abstract The paper analyzes the influence of different heat treatment processes on the mechanical properties of low-alloy high-strength steel denoted by Polish Standard (PN) as 10MnVNb6. One of the findings is that, after aging, the mechanical properties of rolled steel are high: the yield strength may reach > 600 MPa, and the ultimate tensile strength is > 700 MPa. These properties are largely dependent on the grain size and dispersion of the strengthening phase in the ferrite matrix. Aging applied after hot rolling contributes to a considerable rise in the yield strength and ultimate tensile strength. The process of normalization causes a decrease in the average grain size and coalescence (reduction of dispersion) of the strengthening phase. When 10MnVNb6 steel was aged after normalization, there was not a complete recovery in its strength properties.


2018 ◽  
Vol 37 (1) ◽  
pp. 97-103 ◽  
Author(s):  
Hansong Xue ◽  
Xinyu Li ◽  
Weina Zhang ◽  
Zhihui Xing ◽  
Jinsong Rao ◽  
...  

AbstractThe effects of Bi on the microstructure and mechanical properties of AZ80-2Sn alloy were investigated. The results show that the addition of Bi within the as-cast AZ80-2Sn alloy promotes the formation of Mg3Bi2 phase, which can refine the grains and make the eutectic phases discontinuous. The addition of 0.5 % Bi within the as-extruded AZ80-2Sn alloy, the average grain size decreases to 12 μm and the fine granular Mg17Al12 and Mg3Bi2 phases are dispersed in the α-Mg matrix. With an increase in Bi content, the Mg17Al12 and Mg3Bi2 phases become coarsened and the grain size increases. The as-extruded AZ80-2Sn-0.5 %Bi alloy has the optimal properties, and the ultimate tensile strength, yield strength and elongation are 379.6 MPa, 247.1 MPa and 14.8 %, respectively.


2013 ◽  
Vol 753 ◽  
pp. 473-476 ◽  
Author(s):  
Naoto Sakai ◽  
Kunio Funami ◽  
Masafumi Noda ◽  
Hisashi Mori ◽  
Kenji Fujino

In the present study, the grain refinement, grain growth behavior, and tensile properties of rolled and annealed AZX311 Mg alloys were investigated. The yield strength and ultimate tensile strength of the rolled material were 360 MPa and 370 MPa, respectively, and the total elongation was 5%. When annealing was performed at 423 K for 1hr, the yield strength and ultimate tensile strength were unchanged, but the elongation increased to 10%. Furthermore, the strength and elongation did not change for annealing temperatures of 473–673 K owing to Al2Ca precipitations.


2011 ◽  
Vol 682 ◽  
pp. 49-54
Author(s):  
Bin Chen ◽  
Chen Lu ◽  
Dong Liang Lin ◽  
Xiao Qin Zeng

The Mg96Y3Zn1 alloy processed by equal channel angular pressing has been investigated. It was found that the Mg96Y3Zn1 alloy processed by ECAP obtained ultrafine grains and exhibits excellent mechanical properties. After ECAP, the average grain size of Mg96Y3Zn1 alloy refined to about 400 nm. The highest strengths with yield strength of 381.45MPa and ultimate tensile strength of 438.33MPa were obtained after 2 passes at 623K. It was found that cracks were preferentially initiated and propagated in the interior of X-phase during the tensile test. As a result, the elongation of alloy is decreased with pass number increasing.


Author(s):  
Honggang Zhang ◽  
Jinhui Wang ◽  
Hongbin Ma ◽  
Yuan Yuan ◽  
Yongfeng Li ◽  
...  

Abstract The improvement of mechanical properties and the microstructure evolution through adding Sc to AZ61magnesium alloy were studied. The results indicated that the Mg17Al12 phase in the extruded AZ61 alloy was mainly distributed around the sub-structured and fine deformed grains, resulting in the nonuniform microstructure. The addition of Sc could effectively suppress the band-like precipitation of Mg17Al12 phase and improve the uniformity of microstructure. The grain sizes of the extruded alloys showed a trend of first decreasing and then increasing with the increase of Sc, which was mainly attributed to the secondary phase. The AZ61-0.5Sc alloy exhibited the best mechanical properties, its ultimate tensile strength and yield strength were 14.8MPa and 40.8MPa higher than those of the extruded AZ61 alloy, respectively, which was ascribed to the fine grains and abundant secondary phase in the alloy.


2016 ◽  
Vol 838-839 ◽  
pp. 392-397 ◽  
Author(s):  
Pavel Kusakin ◽  
Andrey Belyakov ◽  
Rustam Kaibyshev ◽  
Dmitri Molodov

The influence of thermo-mechanical treatment consisting of cold rolling followed by recrystallization annealing on the grain size and mechanical properties of a high-Mn TWIP steel was studied. An Fe-23Mn-0.3C-1.5Al TWIP steel (wt. %) was subjected to extensive cold rolling with a reduction of 80% (true strain of ∼1.6) and then annealed in the temperature interval ranging from 400 to 900 °C during 20 minutes. Recovery processes took place below 500 °C, partial recrystallization was evident at ~550°C and fully recrystallized structure evolved after annealing at 600 °C and higher. The static recovery resulted in a slight decrease in the yield strength from 1400 MPa to 1250 MPa and the ultimate tensile strength from 1540 MPa to 1400 MPa whereas the total elongation of 4% did not changed. The recrystallization development led to a drastic drop of strength and an increase in ductility. The yield strength of 225 MPa, the ultimate tensile strength of 700 MPa and the total elongation of 79% was obtained after annealing at 900 °C. Correspondingly, the grain size increased from 0.2 μm to 6.2 μm with increase in anneal temperature from 550 to 900°C.


2012 ◽  
Vol 503-504 ◽  
pp. 662-666
Author(s):  
C.H. Chen ◽  
Jian Xun Fu ◽  
Weng Sing Hwang

Adding small Ir element into Procelain Fusing Metal alloy can produce finer grains of PFM. Mechanical properties and dispersion of metal oxide can be improved by grain refining. In order to understand the effect of grain refining and mechanical properties by adding Ir into Au70.1-Ag12.4-Cu10.3-Pd6.2-Pt1-IrX alloy, series of experiments are carried out. There is an obvious effect of grain refining when adding 0.1wt% Ir into alloy. More than 0.1wt% Ir addition will no longer change the grain size obviously. Yield strength and Ultimate tensile strength are getting higher after adding more than 0.1wt% Ir. We found that these two mechanical properties will reach the maxima when 0.3wt% Ir added. And there is a little descent on mechanical properties when 0.5wt%, 0.7wt% of Ir existed in alloys.


2019 ◽  
Vol 34 (01n03) ◽  
pp. 2040035
Author(s):  
Xiang Cai ◽  
Yanxin Qiao ◽  
Baojie Wang ◽  
Huiling Zhou ◽  
Yuxin Wang

The influence of rolling on nanomechanical and mechanical behavior of Mg-7Li alloy was investigated by nanoindentation, tensile test and scanning electron microscopy (SEM), respectively. The [Formula: see text]-Mg phase elongated along the rolling direction and gradually cracked. As the rolling ratio increased from 3 to 10, the hardness of [Formula: see text]-Mg and [Formula: see text]-Li phase increased by 7.35% and 20.75%, respectively. The fracture of alloys changed from ductile fracture to quasi-cleavage fracture. The yield strength and ultimate tensile strength increased by 23 MPa and 12 MPa, respectively, while elongation reduced by 12.5%.


2011 ◽  
Vol 311-313 ◽  
pp. 1873-1878
Author(s):  
Shu Zhi Zhang ◽  
Fan Tao Kong ◽  
Yu Yong Chen ◽  
Shu Long Xiao ◽  
Chao Cao

Ti-47Al-2Cr-2Nb-Y alloy pancake were produced by hot-pack forging. The microstructure of as-forged Ti-47Al-2Cr-2Nb-Y alloy were investigated by optical microscopy and scanning electron microscopy, showing that the forged alloy was composed of fine γ grains and retain cast lamella colonies surrounded by elongated B2 phase. Tensile properties of the material showed that yield strength (YS) and ultimate tensile strength (UTS) were decreased from 500MPa and 612MPa at room temperature to 420 MPa and 462 MPa at 800°C, respectively. With the temperature increasing to 900°C, elongation reached 120%.


2020 ◽  
Vol 17 (6) ◽  
pp. 831-836
Author(s):  
M. Vykunta Rao ◽  
Srinivasa Rao P. ◽  
B. Surendra Babu

Purpose Vibratory weld conditioning parameters have a great influence on the improvement of mechanical properties of weld connections. The purpose of this paper is to understand the influence of vibratory weld conditioning on the mechanical and microstructural characterization of aluminum 5052 alloy weldments. An attempt is made to understand the effect of the vibratory tungsten inert gas (TIG) welding process parameters on the hardness, ultimate tensile strength and microstructure of Al 5052-H32 alloy weldments. Design/methodology/approach Aluminum 5052 H32 specimens are welded at different combinations of vibromotor voltage inputs and time of vibrations. Voltage input is varied from 50 to 230 V at an interval of 10 V. At each voltage input to the vibromotor, there are three levels of time of vibration, i.e. 80, 90 and 100 s. The vibratory TIG-welded specimens are tested for their mechanical and microstructural properties. Findings The results indicate that the mechanical properties of aluminum alloy weld connections improved by increasing voltage input up to 160 V. Also, it has been observed that by increasing vibromotor voltage input beyond 160 V, mechanical properties were reduced significantly. It is also found that vibration time has less influence on the mechanical properties of weld connections. Improvement in hardness and ultimate tensile strength of vibratory welded joints is 16 and 14%, respectively, when compared without vibration, i.e. normal weld conditions. Average grain size is measured as per ASTM E 112–96. Average grain size is in the case of 0, 120, 160 and 230 is 20.709, 17.99, 16.57 and 20.8086 µm, respectively. Originality/value Novel vibratory TIG welded joints are prepared. Mechanical and micro-structural properties are tested.


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