scholarly journals Statistical analysis of 347 stainless steel and Hastelloy-X fatigue test results

1971 ◽  
Author(s):  
A.J. Mihanovich
Author(s):  
H. T. Harrison ◽  
Robert Gurdal

For Class 1 components, the consideration of the environmental effects on fatigue has been suggested to be evaluated through two different methodologies: either NUREG/CR-6909 from March 2007 or ASME-Code Case N-761 from August 2010. The purpose of this technical paper is to compare these two methods. In addition, the equations from Revision 1 of the NUREG/CR-6909 will be evaluated. For these comparisons, two stainless steel component fatigue test series with documented results are considered. These two fatigue test series are completely different from each other (applied cyclic displacements vs. insurge/outsurge types of transients). Therefore, they are producing an appropriate foundation for these comparisons. In general, the severities of the two methods are compared, where the severity is defined as the actual number of cycles from the fatigue tests, including an evaluation of the scatter, divided by the number of design cycles from the two methods. Also, how stable the methods are is being evaluated through the calculation of the coefficient of variation for each method.


1977 ◽  
Vol 99 (2) ◽  
pp. 264-271 ◽  
Author(s):  
J. F. Saltsman ◽  
G. R. Halford

As a demonstration of the predictive capabilities of the method of Strainrange Partitioning, published high-temperature, low cycle, creep-fatigue test results on AISI Types 304 and 316 stainless steel were analyzed and calculated cyclic lives compared with observed lives. Predicted lives agreed with observed lives within factors of two for 76 percent, factors of three for 93 percent, and factors of four for 98 percent of the laboratory tests analyzed. Agreement between observed and predicted lives is judged satisfactory considering that the data are associated with a number of variables (two alloys, several heats and heat treatments, a range of temperatures, different testing techniques, etc.) that are not directly accounted for in the calculations.


Author(s):  
Motoki Nakane ◽  
Yun Wang ◽  
Hisamitsu Hatoh ◽  
Masato Yamamoto ◽  
Akihiko Hirano ◽  
...  

Abstract Based on the world wide fatigue test database, The Design Fatigue Curve (DFC) Phase 1 and 2 subcommittees established in The Japan Welding Engineering Society (JWES) have been developed new design fatigue curves which are applied for the nuclear component materials, in air environment. The effects of the design factor, such as mean stress, size effect and surface finish, etc. on the fatigue curves are also discussed with the fatigue database in order to construct fatigue evaluation method for the new design fatigue curves. The subcommittees also have studied the applicability of newly developed fatigue evaluation method to the nuclear component materials. This paper reports the fatigue test results of machined finished small-scale test specimens which are used for the verification of proposed fatigue evaluation method. The materials subjected to the fatigue tests are austenitic stainless steel SUS316LTP, low-alloy steels SQV2A and SCM435H, and carbon steel STPT370. Specimens finished with lathe machining are subjected to the tests. The planed maximum height roughness of the specimen are 25 and 100 μm. The fatigue test results show that the surface finish effect on the fatigue strength in the high cycle region of the austenitic stainless steel can be negligible. On the other hand, fatigue strength of the carbon steel and low alloy steel is decreased as increasing the surface roughness of the specimen. Especially, decrease of fatigue strength for the specimens with more than 100 μm maximum height roughness is larger than that of conventional estimation. It is presumed that severe roughness introduced by lathe machining tends to behave as notches and increase the stress concentration at the specimen surface, and resulted in unexpected decrease of fatigue strength.


Author(s):  
Carol Johnston

The offshore environment contains many sources of cyclic loading. Standard design S-N curves, such as those in DNVGL-RP-C203, are usually assigned to ensure a particular design life can be achieved for a particular set of anticipated loading conditions. Girth welds are often the ‘weak link’ in terms of fatigue strength and so it is important to show that girth welds made using new procedures for new projects that are intended to be used in fatigue sensitive risers or flowlines do indeed have the required fatigue performance. Alternatively, designers of new subsea connectors, used for example in tendons for tension leg platforms, mooring applications or well-heads which will experience cyclic loading in service, also wish to verify the fatigue performance of their new designs. Often operators require contractors to carry out resonance fatigue tests on representative girth welds in order to show that girth welds made using new procedures qualify to the required design S-N curve. Operators and contractors must then interpret the results, which is not necessarily straightforward if the fatigue lives are lower than expected. Many factors influence a component’s fatigue strength so there is usually scatter in results obtained when a number of fatigue tests are carried out on real, production standard components. This scatter means that it is important first to carry out the right number of tests in order to obtain a reasonable understanding of the component’s fatigue strength, and then to interpret the fatigue test results properly. A working knowledge of statistics is necessary for both specifying the test programme and interpreting the test results and there is often confusion over various aspects of test specification and interpretation. This paper describes relevant statistical concepts in a way that is accessible to non-experts and that can be used, practically, by designers. The paper illustrates the statistical analysis of test data with examples of the ‘target life’ approach (that is now included in BS7608:2014 + A1) and the equivalent approach in DNVGL-RP-C203, which uses the stress modification factor. It gives practical examples to designers of a pragmatic method that can be used when specifying test programmes and interpreting the results obtained from tests carried out during qualification programmes, which for example, aim to determine whether girth welds made using a new procedure qualify to a particular design curve. It will help designers who are tasked with specifying test programmes to choose a reasonable number of test specimens and stress ranges, and to understand the outcome when results have been obtained.


Author(s):  
Osamu Watanabe ◽  
Bopit Bubphachot ◽  
Nobuchika Kawasaki ◽  
Naoto Kasahara

Crack initiation and propagation in creep-fatigue test were observed on semi-circular notched plates at elevated temperature by the CCD video camera. Test specimens are made of SUS304 stainless steel, and temperature is kept to be 550°C, and geometry of the semi-circular plate specimens are changed by diameter size of the hole. Photographs of all cycles were recorded to investigate crack initiation process in structural component having stress concentration and obtain number of cycle of crack initiation (Nc). The test results were compared with predictions by the Stress Redistribution Locus (SRL) method and the Neuber’s rule’s method.


2020 ◽  
Vol 2 (1) ◽  
pp. 5-8
Author(s):  
Arnas A.M Patonangi ◽  
Cahyono Cahyono ◽  
Muhlis Ruslan

Penelitian ini bertujuan untuk mengetahui apakah motivasi, kedisiplinan berpengaruh terhadap perilaku kerja, apakah motivasi dan kedisiplinan berpengaruh terhadap prestasi kerja, apakah perilaku kerja berpengaruh terhadap prestasi kerja, apakah motivasi berpengaruh terhadap prestasi kerja pegawai melalui perilaku kerja, serta apakah kedisiplinan berpengaruh terhadap prestasi kerja pegawai melalui perilaku kerja pada DKIPS Provinsi Sulawesi Barat. Teknik pengumpulan data melalui observasi, interview dan dokumentasi serta kuesioner. Sedangkan teknik analisis data yang digunakan adalah analisis statistic deskriptif, statistik infe-rensial, PLS (Partial Least Square), pengujian hipotesis. Hasil penelitian menemukan bahwa motivasi kerja berpengaruh positif dan signifikan terhadap perilaku kerja, Kedisiplinan berpengaruh positif dan signifikan terhadap perilaku kerja, Motivasi kerja berpengaruh positif dan signifikan terhadap prestasi kerja, Kedisiplinan berpengaruh positif dan signifikan terhadap prestasi kerja pegawai, Perilaku kerja berpengaruh positif dan signifikan terhadap prestasi kerja pegawai, hasil uji mediasi menunjukkan bahwa perilaku kerja dapat memediasi motivasi kerja terhadap prestasi kerja pegawai pada DKIPS Provinsi Sulawesi Barat, serta hasil uji mediasi menunjukkan bahwa perilaku kerja dapat memediasi disiplin kerja terhadap prestasi kerja pegawai pada DKIPS Provinsi Sulawesi Barat. This study aims to determine whether motivation, discipline affect work behavior, do motivation and discipline affect work performance, does work behavior affect work performance, does motivation affect employee performance through work behavior, and does discipline affect work performance through work behavior in West Sulawesi Province DKIPS. Data collection techniques through observation, interviews and documentation and questionnaires. While the data analysis technique used is descriptive statistical analysis, inferential statistics, PLS (Partial Least Square), hypothesis testing. The results found that work motivation has a positive and significant effect on work behavior, the discipline has a positive and significant effect on work behavior, work motivation has a positive and significant effect on work performance, the discipline has a positive and significant effect on employee work performance, work behavior has a positive and significant effect on employee work performance, mediation test results indicate that work behavior can mediate work motivation on employee work performance in DKIPS Province of West Sulawesi, and mediation test results indicate that work behavior can mediate work discipline towards employee work performance at DKIPS Province of West Sulawesi.


2014 ◽  
Vol 641-642 ◽  
pp. 427-433
Author(s):  
Shuang Cheng ◽  
Feng Lin ◽  
Pei Long Yang ◽  
Pei Ke Zhu ◽  
Jin Gen Deng ◽  
...  

This paper analyzed the corrosion environment of Missan oilfields and investigated the oilfield country tubular goods used in other similar oilfields. Summarized the effect of partial pressure ratio of H2S/CO2 and Cl-to the corrosion behavior of OCTG. This paper concluded the service condition, test results and anti-corrosion mechanism of carbon steel, low-chrome steel, modified martensitic stainless steel and nickel alloy. Finally arrived at conclusion that the nickel alloy can meet the requirement of Missan oilfields, some literature reported that the modified martensitic stainless steel can apply in H2S/CO2 environment. In the condition that be easy to replace the tubular, carbon steel and low-chrome steel tubular can meet the requirement with corrosion inhibitor.


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