scholarly journals A Numerical and Experimental Assessment of the Small Punch Creep Test for 316L(N) Stainless Steels

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1609
Author(s):  
Karl-Fredrik Nilsson ◽  
Daniele Baraldi ◽  
Stefan Holmström ◽  
Igor Simonovski
Keyword(s):  
Friction Coefficient ◽  
Creep Test ◽  
Equivalent Stress ◽  
Primary Creep ◽  
Creep Model ◽  
Strain Rates ◽  
Element Analysis ◽  
Small Punch ◽  
Deflection Rate ◽  
Small Punch Creep Test

This paper presents a finite element analysis of the small punch creep test for 316L(N), which is compared with experimental data for 650 and 700 °C. Special emphasis is placed on (i) assessing the influence of friction and (ii) comparing two different creep models: the simple Norton creep and the more general creep model. The computed normalized deflection rate versus time is almost identical for all cases, which allows for scaling of the results. The computed time to rupture increases linearly with the friction coefficient due to a reduction in the mean stress. There is a good overall agreement between the experimental values and the computed deflection rate for a friction coefficient of around 0.3. It is shown that the initial reduction in deflection rate is due to stress relaxation and homogenization, and is only marginally affected by primary creep hardening. The computed results are compared with the equivalent stress and strain rates in the recently published small punch standard (EN 10371). The computed von Mises stresses at minimum deflection decrease linearly with the friction coefficient but are consistently slightly higher than the equivalent stress in the standard. For the strain rates, the computed values are significantly higher than the equivalent values in the standard. The presented simulations give a deeper insight of the small punch creep and impact of key parameters such the friction coefficient and in general as a guidance to refinement and improvement of the empirically based formulae in the standard.

An Elastic-Plastic-Creep Finite Element Analysis for Small Punch Creep Test Specimens

2006 ◽  
Author(s):  
Xiang Ling ◽  
Yangyan Zheng ◽  
Zhengmai Qian
Keyword(s):  
Finite Element ◽  
Creep Test ◽  
Equivalent Stress ◽  
Creep Damage ◽  
Flow Rule ◽  
Element Analysis ◽  
Small Punch ◽  
Elastic Plastic ◽  
Plastic Creep ◽  
Small Punch Creep Test

An elastic-plastic-creep finite element model, incorporating a Von Mises plastic flow rule and a creep damage equation, was established based on the small punch creep test on Cr5Mo steel specimens at 550 °C and three different loads. Finite element analyses were performed to examine the variation of the central creep deflection and the creep strain with time and the evolution of creep damage. The sensitivity of the creep deflection and equivalent stress at the centre on the disc to mesh size is discussed. Numerical results presented in this paper confirm that the creep damage at the central part is high. The stress gradients are highest near the centre area of the specimen (from 0 to 1 mm). Therefore, accurate stress and strain can be obtained using refined meshes near the specimen center and coarse meshes in other places. The test results are in agreement with those of the numerical simulation and three different stages appearing in the curve of creep deflection, which are quite similar to those observed in conventional creep tests.

Analysis of Thick-Walled Pipeline Elements Operating in Creep Conditions

2015 ◽  
Vol 712 ◽  
pp. 63-68
Author(s):  
Przemysław Osocha ◽  
Bohdan Węglowski
Keyword(s):  
Finite Element ◽  
Test Data ◽  
Creep Test ◽  
Power Plants ◽  
Steam Pressure ◽  
Creep Model ◽  
Creep Process ◽  
Fe Model ◽  
Element Analysis ◽  
Wide Range

In some coal-fired power plants, pipeline elements have worked for over 200 000 hours and increased number of failures is observed. The paper discuses thermal wear processes that take place in those elements and lead to rupture. Mathematical model based on creep test data, and describing creep processes for analyzed material, has been developed. Model has been verified for pipeline operating temperature, lower than tests temperature, basing on Larson-Miller relation. Prepared model has been used for thermal-strength calculations based on a finite element method. Processes taking place inside of element and leading to its failure has been described. Than, basing on prepared mathematical creep model and FE model introduced to Ansys program further researches are made. Analysis of dimensions and shape of pipe junction and its influence on operational element lifetime is presented. In the end multi variable dependence of temperature, steam pressure and element geometry is shown, allowing optimization of process parameters in function of required operational time or maximization of steam parameters. The article presents wide range of methods. The creep test data were recalculated for operational temperature using Larson-Miller parameter. The creep strain were modelled, used equations and their parameters are presented. Analysis of errors were conducted. Geometry of failing pipe junction was introduced to the Ansys program and the finite element analysis of creep process were conducted.

A direct assessment of creep life based on small punch creep test

2019 ◽  
Vol 104 ◽  
pp. 102346 ◽  
Author(s):  
Jeong Hwan Kim ◽  
Uijeong Ro ◽  
Hoomin Lee ◽  
Seok Jun Kang ◽  
Byung Ho Lee ◽  
...  
Keyword(s):  
Creep Test ◽  
Creep Life ◽  
Small Punch ◽  
Direct Assessment ◽  
Small Punch Creep Test

Creep property measurement of service-exposed SUS 316 austenitic stainless steel by the small-punch creep-testing technique

2002 ◽  
Vol 17 (8) ◽  
pp. 1945-1953 ◽  
Author(s):  
Maribel L. Saucedo-Muñoz ◽  
Shin-Ichi Komazaki ◽  
Toru Takahashi ◽  
Toshiyuki Hashida ◽  
Tetsuo Shoji
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Creep Test ◽  
Creep Resistance ◽  
Creep Property ◽  
Creep Rupture ◽  
Secondary Creep ◽  
Small Punch ◽  
Uniaxial Creep ◽  
Small Punch Creep Test

The creep properties for SUS 316 HTB austenitic stainless steel were evaluated by using the small-punch creep test at 650 °C for loads of 234, 286, 338, 408, and 478 N and at 700 °C for loads of 199 and 234 N. The creep curves, determined by means of the small-punch creep test, were similar to those obtained from a conventional uniaxial creep test. That is, they exhibited clearly the three creep stages. The width of secondary creep stage and rupture time tr decreased with the increase in testing load level. The creep rupture strength for the service-exposed material was lower than that of the as-received material at high testing loads. However, the creep resistance behavior was opposite at relatively low load levels. This difference in creep resistance was explained on the basis of the difference in the creep deformation and microstructural evolution during tests. It was also found that the ratio between the load of small-punch creep test and the stress of uniaxial creep test was about 1 for having the same value of creep rupture life.

Study on size effect of Small Punch creep test

2018 ◽  
Vol 2018.24 (0) ◽  
pp. OS0710
Author(s):  
Ryota KANEKO ◽  
Yutaro NAKAYAMA ◽  
Ken-ichi KOBAYASHI ◽  
Yasuhiro YAMAZAKI
Keyword(s):  
Size Effect ◽  
Creep Test ◽  
Small Punch ◽  
Small Punch Creep Test

D122 Creep damage evaluation for high temperature units using small punch creep test

2012 ◽  
Vol 2012.17 (0) ◽  
pp. 131-132
Author(s):  
Toshimi KOBAYASHI ◽  
Toru IZAKI ◽  
Akihiro KANAYA ◽  
Junichi KUSUMOTO ◽  
Hajime WATANABE
Keyword(s):  
High Temperature ◽  
Creep Test ◽  
Creep Damage ◽  
Damage Evaluation ◽  
Small Punch ◽  
Small Punch Creep Test
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