Closure to “Discussion of ‘Influence of Microstructure and Heat-Treatment on Impact and Creep Properties of a Low Alloy CrMoV Turbine Steel’” (1967, ASME J. Eng. Power, 89, p. 246)

1967 ◽  
Vol 89 (2) ◽  
pp. 246-246
Author(s):  
K. Relander ◽  
T. Geiger
Keyword(s):  
Heat Treatment ◽  
Creep Properties ◽  
Turbine Steel

Influence of Microstructure and Heat-Treatment on Impact and Creep Properties of a Low Alloy CrMoV Turbine Steel

1967 ◽  
Vol 89 (2) ◽  
pp. 238-246 ◽  
Author(s):  
K. Relander ◽  
T. Geiger
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Lower Bainite ◽  
Mechanical Tests ◽  
Creep Ductility ◽  
Creep Properties ◽  
Microstructural Effects ◽  
Turbine Steel ◽  
Vanadium Carbides ◽  
The Impact

This investigation concerns the strongly scattering mechanical properties of a 17 MoV 84 creep resistant steel. Emphasis is laid on the effect on microstructure of heat-treatment. The mechanical tests made after various austenitizing treatments, cooling rates, and tempering temperatures revealed that a complex relationship existed between the mechanical properties and microstructure in the steel precipitation hardened by vanadium carbides. In spite of constant tensile strength, the impact and creep properties in the steel therefore differ widely, due to relatively small microstructural effects. The study shows that the microstructural constituents, i.e., martensite, lower bainite, upper bainite in aciculare and globulare forms, as well as pre-eutectoid ferrite, all influence the room temperature ductility in a similar way to the creep ductility. However, in the case of creep strength, similar microstructural constituents have almost the reverse effect. As a result of these contrasting effects, it is not possible to obtain good ductility and creep properties at the same time. Any heat-treatments recommended can therefore only be a compromise between the properties desired.

Effect of Heat Treatment on the Creep Properties of Ti-22Al-27Nb/TiB Composite

2007 ◽  
Vol 345-346 ◽  
pp. 545-548
Author(s):  
Satoshi Emura ◽  
Masuo Hagiwara
Keyword(s):  
Heat Treatment ◽  
Intermetallic Phase ◽  
Powder Metallurgy Method ◽  
Ingot Metallurgy ◽  
Creep Properties ◽  
Matrix Microstructure ◽  
Heat Treated ◽  
The Matrix ◽  
Annealing Heat Treatment ◽  
Annealing Heat

A TiB particulate-reinforced Ti-22Al-27Nb (mol%) alloy, based on the orthorhombic intermetallic phase, was prepared using gas atomization powder metallurgy method. In the as-atomized condition, extremely fine TiB particulates of less than 1-μm diameter and 5-μm length were dispersed in the matrix. After annealing heat treatment (heat treated at 1423 K with subsequent furnace cooling), this composite exhibited a lamellar matrix microstructure and showed better creep properties than a composite produced using conventional ingot metallurgy method, with coarse TiB particulates of 5-μm diameter and 40-μm length. Coarsening of the matrix microstructure and growth of TiB particulates occurred after annealing heat treatment at higher temperature (ca. 1473 K). Creep-resistance improvement was also observed, which seemed to be mainly attribute to the effect of the matrix microstructure. From measurements of stress components and activation energy, all composites showed an identical creep mechanism: dislocation-controlled creep.

scholarly journals Influence of Heat Treatment on Long Term Creep Properties of 9Cr–W–Mo–V–Nb Steel

2010 ◽  
Vol 96 (4) ◽  
pp. 172-181
Author(s):  
Satoshi Obara ◽  
Takashi Wakai ◽  
Tai Asayama ◽  
Yoshiyuki Yamada ◽  
Takanori Nakazawa ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Creep Properties ◽  
Term Creep

Effect of Heat Treatment on the Creep Properties of Zr-1Nb-0.12O Nuclear Cladding Tubes

2015 ◽  
Vol 1102 ◽  
pp. 3-6
Author(s):  
In Won Kim ◽  
Sun Ig Hong
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Size Control ◽  
Creep Life ◽  
Creep Tests ◽  
Creep Properties ◽  
Instantaneous Strain ◽  
Grain Size Control ◽  
One Step ◽  
The One

Creep properties of one-step and two-step annealed Zr-1Nb-0.12O cladding tubes were studied. Creep tests were carried out at 450~500 °C with the applied stress between 80MPa and 120MPa The creep rates of the two-step annealed Zr-1Nb-0.12O alloy were found to be slower than those of the one-step annealed Zr-1Nb-0.12O alloy. The creep rate decreased with increase of grain size with annealing for Zr-1Nb-0.12O at intermediate temperatures, suggesting the creep resistance can be enhanced by the grain size control. The creep life of two-step annealed Zr-1Nb-0.12O increased over the one-step annealed Zr-1Nb-0.12O by the factor of 18~20 despite the greater initial instantaneous strain.

Influences of Heat Treatment on Microstructure and Creep Properties of Ti6Al4V Alloy

2009 ◽  
Vol 610-613 ◽  
pp. 658-662
Author(s):  
Su Gui Tian ◽  
Xian Yu Bao ◽  
Zhong Gang Zhao ◽  
Yang Liu ◽  
Li Qing Chen ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Strain Rate ◽  
Local Region ◽  
Experimental Results ◽  
Creep Life ◽  
Creep Properties ◽  
T6 Heat Treatment ◽  
Microstructure Observation ◽  
Creep Curves ◽  
The Matrix

By means of the measurement of creep curves and microstructure observation, the influence of T6 heat treatment on the microstructure and creep properties of the wrought Ti-6Al-4V the alloy has been investigated. The experimental results showed that the microstructure of the wrought alloy consists of the strip-like +  phases, which results in the alloy displaying a higher strain rate and shorter creep life under the test condition of 575 MPa and 400°C. After T6 treatment, the creep life of the alloy at same conditions enhanced to 548 h from 66 h. Microstructure of T6 treated alloy consisted of the primary  and /phases, and signification amount of the bundle-likephase precipitated along the different orientations in the grains, this is a main reason of enhancing creep life of the alloy. During forging, the denser dislocation rows were activated in the local region of the matrix in the alloy. During creep, the deformed mechanism of the alloy was the double orientations slip of <a> and <a+c> dislocations activated on the pyramidal planes in  phase.

Failure Analysis of T91 Finishing Superheater Tube Bursting for Improper Initial Microstructure and their Life Evaluation

2012 ◽  
Vol 557-559 ◽  
pp. 187-190
Author(s):  
Jie Ouyang ◽  
Xue Xia Xu ◽  
Yan Ting Feng ◽  
Xiao Guang Niu ◽  
Guang Zong Yan ◽  
...  
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Failure Analysis ◽  
Standard Heat Treatment ◽  
Creep Properties ◽  
Initial Microstructure ◽  
Superheater Tube ◽  
Life Evaluation ◽  
Creep Rupture Test ◽  
Test Result

The failure analysis was performed for T91 finishing superheater bursting tube. It is concluded that improper initial microstructure resulted from non-standard heat treatment contributes to poor creep properties at high temperature and subsequent tube bursting. In addition, life evaluation was carried out on the basis of creep-rupture test result of experimental steel with similar improper microstructure. It is in accordance with the practical condition and provides significant guidance for safety and operation supervision.

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