scholarly journals Investigation of short-term creep deformation mechanisms in MarBN steel at elevated temperatures

2018 ◽  
Vol 734 ◽  
pp. 491-505 ◽  
Author(s):  
A. Benaarbia ◽  
X. Xu ◽  
W. Sun ◽  
A.A. Becker ◽  
Mark A.E. Jepson
Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1310 ◽  
Author(s):  
Tai-Jung Wu ◽  
Chien-Chun Liao ◽  
Tai-Cheng Chen ◽  
Ren-Kae Shiue ◽  
Leu-Wen Tsay

T92 steel tubes have been widely applied in advanced supercritical boilers to replace Gr.91 tubes. Simulated samples with microstructures similar to those present in the heat-affected zone (HAZ) of a T92 steel weld were subjected to short-term creep tests in the study. T92 steel tubes were normalized at either 1213 K (L) or 1333 K (H) for 1 h, followed by tempering (T) at 1033 K for 2 h. After the normalizing and tempering treatments, the HT samples comprised finer precipitates but in greater numbers along the prior austenite grain boundaries (PAGBs) and martensite lath boundaries, as compared with those of the LT samples. The HAZ microstructures in the T92 steel welds were simulated by using an infrared heating system, which included over-tempering (OT, below AC1) and partial transformation (PT, slightly below AC3) zones. Martensite laths in the OT sample were more likely to be replaced by numerous cellular structures or subgrains together with spherodized carbides mainly located at the lath and austenite grain boundaries. Furthermore, coarser but fewer carbides were found along the refined lath and grain boundaries in the PT samples, in comparison with other samples in each group. Short-term creep tests showed that the PT samples were more likely to fracture than other samples in each group. Moreover, under the same testing conditions, the microstructures of T92 steel were more stable and resistant to degradation than those of T91 steel after welding or loading at elevated temperatures. Such events were responsible for higher creep resistance of the simulated T92 samples than that of the simulated T91 samples under the same creep-rupture conditions.


2018 ◽  
Vol 89 (8) ◽  
pp. 1522-1532
Author(s):  
Lingxiao Jing ◽  
Peng Hu Deng ◽  
Jing Zhao ◽  
Wang Ting ◽  
Jinhua Jiang ◽  
...  

Short-term creep experiments of composites of polyethylene reinforced with polyester fiber multi-axial warp knitted (MWK) fabrics were carried out for tensile and shear modes in three directions. This work primarily focuses on using the Burgers and Findley models to obtain parameters associated with stress level, temperature, and structure of MWK fabrics. Specifically, the material parameter A of the Findley model has higher values at elevated temperatures, which is contrary to the impact of fiber content along the loading direction. The material parameter n rises with an increasing temperature and is not affected by the fiber content. In terms of the Burger parameters, material parameters E1, E2, and η1 have a downside as temperature increases. The relationship of these parameters with fiber content is contrary to their relationship with temperature. There is no significant effect of temperature and fiber content on relaxation time, whereas there is an upward trend of relaxation time with increases in stress.


2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 39-40
Author(s):  
Kendi Tjardes ◽  
Katy Lippolis

Abstract One hundred four Angus calves were ranked by gender, BW, age, and dam parity, and assigned to 1 of 4 pre-weaning treatments: 1) nose flaps for 7-d prior to weaning (NF), 2) traditional weaning (TRAD), 3) traditional weaning and creep feed for 3-wk prior to weaning (TRADC), or 4) nose flaps for 7-d prior to weaning and creep feed for 3-wk prior to weaning (NFC). Cow-calf pairs were housed in dry lot pens on d -28. From d -21 to 0, calves in creep treatments were provided free choice access to creep feed. Nose flaps were placed on d -7, and calves were weaned on d 0. Calves were vaccinated and dewormed on d -21 and 0. There was no difference (P ≥ 0.97) in calf BW on d -28 or -21. During the 7-d period that nose flaps were placed, NFC calves had greater (P ≤ 0.0001) ADG than NF and TRAD calves, and tended to have greater (P ≤ 0.10) ADG than TRADC calves. At weaning on d 0, TRADC and NFC calves tended to have greater BW (P = 0.07) and had greater overall change in BW (P < 0.0001) during the pre-weaning period than TRAD and NF calves. Additionally, there was a greater (P ≤ 0.001) increase in BW of NFC and TRADC cows during the pre-weaning period compared to NF and TRAD cows. From d -21 to 0 there was no differences (P > 0.41) in plasma concentrations for Bovine Viral Diarrhea Virus (BVD). By d 14, the TRADC calves had the greatest plasma concentrations for BVD (P < 0.04). Therefore, providing short-term creep feed prior to placing nose flaps can improve pre-weaning calf and cow performance compared to traditional and nose flap weaning without creep feed supplementation, however, did not improve response to vaccination.


2021 ◽  
Vol 149 ◽  
pp. 106562
Author(s):  
Yidong Gan ◽  
Matthieu Vandamme ◽  
Yu Chen ◽  
Erik Schlangen ◽  
Klaas van Breugel ◽  
...  

2006 ◽  
Vol 519-521 ◽  
pp. 1041-1046 ◽  
Author(s):  
Brian Wilshire ◽  
H. Burt ◽  
N.P. Lavery

The standard power law approaches widely used to describe creep and creep fracture behavior have not led to theories capable of predicting long-term data. Similarly, traditional parametric methods for property rationalization also have limited predictive capabilities. In contrast, quantifying the shapes of short-term creep curves using the q methodology introduces several physically-meaningful procedures for creep data rationalization and prediction, which allow straightforward estimation of the 100,000 hour stress rupture values for the aluminum alloy, 2124.


2012 ◽  
Vol 73 ◽  
pp. 144-152 ◽  
Author(s):  
Shengzhi Li ◽  
Zumrat Eliniyaz ◽  
Lanting Zhang ◽  
Feng Sun ◽  
Yinzhong Shen ◽  
...  

2018 ◽  
Vol 25 (3) ◽  
pp. 713-722 ◽  
Author(s):  
Seen Chan Kim ◽  
Jae-Hyeok Shim ◽  
Woo-Sang Jung ◽  
Yoon Suk Choi

2010 ◽  
Vol 527 (29-30) ◽  
pp. 7505-7509 ◽  
Author(s):  
Huiran Cui ◽  
Feng Sun ◽  
Ke Chen ◽  
Lanting Zhang ◽  
Rongchun Wan ◽  
...  

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