Non-Standard HIC and SSC Testing Under More Severe Test Conditions

2012 ◽  
Author(s):  
Tanja Schmidt ◽  
Thomas Haase ◽  
Christoph Bosch
Keyword(s):  
High Stress ◽  
Longitudinal Direction ◽  
Test Methods ◽  
Resistance Testing ◽  
Line Pipe ◽  
Bend Testing ◽  
Test Conditions ◽  
Challenging Environment ◽  
Steel Grades ◽  
Point Bend

The challenging environment appearing in recent and moreover future deep offshore explorations promoted the development of linepipe steel grades with reliable sour service resistance. Severe sour conditions such as the combination of elevated production temperature, increasing pipeline pressures and high stress loads initiated by modern laying methods or introduced during service are leading to increasing corrosion demands. Steel pipelines used for the transport of media containing wet Hydrogen Sulphide (H2S) are faced with the danger of the cracking phenomena HIC (Hydrogen Induced Cracking) and SSC (Sulphide Stress Cracking). To prove resistance to HIC and SSC, test specimens are typically tested according standardised test methods. The exposure of test specimens in a sour test solution to a H2S pressure of 1 bar for 96 h, as described in NACE TM0284 is used to prove HIC resistance. Commonly four-point bend testing as described in EFC publication no. 16 is performed for SSC resistance testing with the appliance of a specific load, typically 80% of the actual yield strength. Within this work HIC testing at test conditions representing higher H2S partial pressures (up to 5 bar) and longer test durations (up to 6 months) have been performed on seamless quenched and tempered line pipe steel of grade X65 and X70 produced by VALLOUREC & MANNESMANN TUBES by plug and continuous mandrel mill process. Beside material in as delivered condition also pre-strained material was tested. SSC four-point bend testing has been performed on specimens which were strained up to 10% of plastic strain in longitudinal direction.

Comparison Between Yield Strength Results Obtained From Methods Using Both Flattened and Non-Flattened Specimens

2020 ◽  
Author(s):  
Pratham Nayyar ◽  
Dimitris Dimopoulos ◽  
William Walsh
Keyword(s):  
Yield Strength ◽  
Large Diameter ◽  
Longitudinal Direction ◽  
Ring Expansion ◽  
Test Methods ◽  
Production Test ◽  
Pipe Axis ◽  
Line Pipe ◽  
Expansion Test ◽  
Weld Properties

Abstract Tensile properties of API 5L large diameter pipes are typically determined with the use of full thickness flattened strap samples extracted in the transverse direction with respect to the longitudinal pipe axis (TPA) [1, 2, 3, 4]. It has been well established that the process of sample flattening has a significant influence on determination of the yield strength of the pipe [5, 6]. The flattening process is sensitive to a number of variables such as method of flattening, equipment used, number/sequence of strokes, and operators conducting the flattening. As a result, issues with repeatability are frequently encountered and despite several efforts, the industry lacks any type of official standard for universal use. Historically, the industry has been focused on ensuring that the actual strength of pipes was safely higher than the specified minimum. Recently, there has been interest to also establish an upper limit on pipe strength particularly in the longitudinal direction with respect to the pipe axis (LPA) in order to avoid under matching between pipe and girth weld properties. These new requirements create the need for enhanced process control to minimize the variation due to flattening. Samples obtained from longitudinally welded (SAWL) and helically welded (SAWH) seam Grade X70M line pipe of various nominal wall thickness to diameter (t/D) ratios were flattened using different procedures, measured for curvature, and tensile tested, all in controlled laboratory environments with minimized repeatability variation. Special attention was given to the definition and measurement of different types of curvatures observed through the range of different t/D ratios and effort was made to assess criteria for curvature measurement prior to testing. Additionally, non-flattened specimens were tensile tested using round bar and full ring expansion test methods, and a comparison between the results obtained from both flattened and non-flattened specimen methods was made. The sample transverse yield strength results confirmed the expected variation between samples flattened by different methods. In addition, a much greater variation was observed when comparing the yield strength results between flattened and non-flattened samples. Considerations of extending the use of non-flattened specimens as a production test and benefits or limitations associated with such practice are discussed.

The practical implementation of DIN EN ISO 16891 “Test methods for evaluating the degradation of characteristics of cleanable filter media“/Die praktische Umsetzung der Norm DIN EN ISO 16891 „Prüfmethode zur Ermittlung der Abnahme der Wirksamkeit von abreinigbaren Filtermedien“

Gefahrstoffe ◽  
2019 ◽  
Vol 79 (05) ◽  
pp. 176-180
Author(s):  
F. Schmidt ◽  
J. Weimann ◽  
C. König
Keyword(s):  
Test Methods ◽  
Practical Implementation ◽  
Filter Media ◽  
Uniform Loading ◽  
Normal Filter ◽  
Current Form ◽  
Safety Aspects ◽  
Test Conditions ◽  
Chemical Ageing ◽  
Praktische Umsetzung

Summary DIN EN ISO 16891:2016 “Test methods for evaluating the degradation of characteristics of cleanable filter media“ is the first standard in Germany that takes into account the thermal and chemical ageing of the filter media and stipulates how they are to be tested. These normative specifications were to be implemented as part of a research project. However, the boundary test conditions proved to be general conditions and many other details were not described in the standard. This is why, as well as there being many safety aspects, the filter testing has so far only been partially implemented. Uniform loading of several samples at the normal filter flow velocities used in practice could not be implemented. Doubt exists with regard to the comparability of the results of the tests that were based on the standard in its current form at different test institutes.

Development of X90 and X100 Steel Grades for Seamless Linepipe Products

2014 ◽  
Author(s):  
Diana Toma ◽  
Silke Harksen ◽  
Dorothee Niklasch ◽  
Denise Mahn ◽  
Ashraf Koka
Keyword(s):  
Wall Thickness ◽  
Deep Water ◽  
High Strength ◽  
Oil And Gas Industry ◽  
Pipe Material ◽  
Line Pipe ◽  
Materials Development ◽  
Additional Tool ◽  
Technical Requirements ◽  
Steel Grades

The general trend in oil and gas industry gives a clear direction towards the need for high strength grades up to X100. The exploration in extreme regions and under severe conditions, e.g. in ultra deep water regions also considering High Temperature/High Pressure Fields or arctic areas, becomes more and more important with respect to the still growing demand of the world for natural resources. Further, the application of high strength materials enables the possibility of structure weight reduction which benefits to materials and cost reduction and increase of efficiency in the pipe line installation process. To address these topics, the development of such high strength steel grades with optimum combination of high tensile properties, excellent toughness properties and sour service resistivity for seamless quenched and tempered pipes are in the focus of the materials development and improvement of Vallourec. This paper will present the efforts put into the materials development for line pipe applications up to grade X100 for seamless pipes manufactured by Pilger Mill. The steel concept developed by Vallourec over the last years [1,2] was modified and adapted according to the technical requirements of the Pilger rolling process. Pipes with OD≥20″ and wall thickness up to 30 mm were rolled and subsequent quenched and tempered. The supportive application of thermodynamic and kinetic simulation techniques as additional tool for the material development was used. Results of mechanical characterization by tensile and toughness testing, as well as microstructure examination by light-optical microscopy will be shown. Advanced investigation techniques as scanning electron microcopy and electron backscatter diffraction are applied to characterize the pipe material up to the crystallographic level. The presented results will demonstrate not only the effect of a well-balanced alloying concept appointing micro-alloying, but also the high sophisticated and precise thermal treatment of these pipe products. The presented alloying concept enables the production grade X90 to X100 with wall thickness up to 30 mm and is further extending the product portfolio of Vallourec for riser systems for deepwater and ultra-deep water application [1, 3, 4].

Laboratory Tests

2019 ◽  
pp. 13-106
Author(s):  
John G. Bartlett ◽  
Robert R. Redfield ◽  
Paul A. Pham
Keyword(s):  
False Negative ◽  
Test Methods ◽  
Screening Tests ◽  
Resistance Testing ◽  
Sexually Transmitted ◽  
Molecular Tests ◽  
Testing Strategies ◽  
Resource Limited ◽  
Confirmatory Tests ◽  
Home Tests

This chapter covers the following topics: HIV viruses including viral variants (group O and group N); immune responses to HIV and detection markers; HIV serologic tests; initial tests to detect HIV antibody; confirmatory tests to detect antibody, antigen, or RNA; false-negative and false-positive results; testing strategies and algorithms; alternative testing strategies for resource-limited countries; home tests; tests that use oral fluids; molecular tests to detect and monitor HIV infection; kinetics of viral nucleic acid production (including qualitative and quantitative RNA tests); HIV DNA assessment; uses of viral load tests; rapid molecular tests; resistance testing (including purpose and scope); resistance test methods; tests for sexually transmitted infections (STIs); screening tests for other infectious agents; and recommended reading.

Research on Negative Skin Friction on Pile by a Simple Model Experiment

2014 ◽  
Vol 580-583 ◽  
pp. 693-696
Author(s):  
Ting Huang ◽  
Jin Hai Zheng ◽  
Wei Ming Gong
Keyword(s):  
Skin Friction ◽  
Model Test ◽  
Soil Surface ◽  
Test Methods ◽  
Negative Skin Friction ◽  
Experimental Scheme ◽  
Test Conditions ◽  
Surcharge Load ◽  
Conventional Test ◽  
Pile Model

Accompanied by the substantive construction of domestic ports, the negative skin friction on pile becomes a common problem. In order to provide references for the related experiment research in the future, the designs of model experiments reported in the literatures were emphatically analyzed and compared. Compared to conventional pile model test, the model test on negative skin friction on pile needs to apply load on soil surface and it is difficult to simulate large surcharge by conventional test methods. An experimental scheme which could produce large surcharge load by conventional test conditions is given in this paper. Pile stress, displacement of pile top and layered settlement of soil was tested under different surcharge level. The depth of neutral point and the group effect of NSF are discussed.

Research on Corrosive Sulfur and Temperature Effect in Transformer Oil

2011 ◽  
Vol 282-283 ◽  
pp. 492-496 ◽  
Author(s):  
Yi Hua Qian ◽  
Qi Tian Bao ◽  
Shun An Cao ◽  
Rui Liu
Keyword(s):  
High Temperature ◽  
Temperature Effect ◽  
Test Methods ◽  
Transformer Oil ◽  
Test Conditions ◽  
Typical Test

Failure in transformers could be caused by the corrosive sulfur in their oil. Preliminary studies on the test of corrosive sulfur in transformer oil and temperature are performed. The comparison among their results of their typical test methods for corrosive sulfur is discussed. It is illustrated that the corrosive-sulfur sensitivity is varied with the test conditions. Temperature is the important factor for the reaction of corrosive sulfur with copper. We have done experiments of specimen immersing and mercaptan content in oil, so we can confirm that high temperature enhances the reaction.

Effect of Stress Ratio on Fatigue Crack Growth in 95Pb-5Sn Solder

1999 ◽  
Vol 123 (3) ◽  
pp. 311-315 ◽  
Author(s):  
J. Zhao and ◽  
Y. Mutoh ◽  
T. Ogawa
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Crack Closure ◽  
Stress Ratio ◽  
High Stress ◽  
Growth Behavior ◽  
Crack Growth Behavior ◽  
Threshold Region ◽  
Test Conditions

The stress ratio effect on the fatigue crack growth behavior of 95Pb-5Sn solder has been investigated. It is found that both ΔJ and ΔK can correlate fatigue crack growth data well, which means that the crack growth behavior of the 95Pb-5Sn solder under the frequency of 10 Hz was dominantly cyclic dependent. The da/dN-ΔJ relationship can be expressed as: da/dN=1.1×10−11s˙ΔJ1.45. Low level of crack closure was found only in the near-threshold region. Except in this region, no crack closure was observed in the present test conditions. Both transgranular and intergranular fractures were observed on fracture surfaces: the former was dominant in most test conditions and the latter was dominant at the high stress ratio of 0.7. Striations and striation-like features were also found. Many slip bands and cavities along the grain boundary were observed on the crack wake and ahead of the crack tip in the high crack growth rate region.

Online Thermal Properties Database for Structure-Property Correlated Materials

2011 ◽  
Author(s):  
Ishan Srivastava ◽  
Timothy S. Fisher ◽  
Sudheera Fernando ◽  
Ann Christine Catlin ◽  
Puneet Gupta ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Thermophysical Property ◽  
Thermophysical Properties ◽  
Test Methods ◽  
Published Data ◽  
Online Database ◽  
Structure Property ◽  
Test Conditions ◽  
The World ◽  
Properties Of Materials

New data for thermophysical properties of materials are being discovered and measured routinely throughout the world, but sometimes conflicts exist in the published data from various sources. We introduce an online thermal properties database intended for use as a repository for experimentally obtained thermophysical properties of materials by researchers across the globe. This online database is a part of www.thermalhub.org, which is a NSF-funded cyber infrastructure initiative aimed at serving the global heat transfer community. The relevant details associated with an experiment, such as the material type and composition, the thermophysical property measured, the test methods employed, the test conditions of the experiment, the results of the experiments, the uncertainty associated with the experimental results, and the literature where the results are published, are included as fields in the online database. It is known that one thermophysical property can be tested by various methods whose results may differ. Similarly, one thermophysical property can be experimentally measured under varying test conditions to produce different results.

Qualification of TMCP Pipe for Severe Sour Service: Mitigation of Local Hard Zones

2019 ◽  
Author(s):  
B. D. Newbury ◽  
D. P. Fairchild ◽  
C. A. Prescott ◽  
T. D. Anderson ◽  
A. J. Wasson
Keyword(s):  
Oil And Gas ◽  
Steel Plate ◽  
Companion Paper ◽  
Test Methods ◽  
Pipe Material ◽  
Line Pipe ◽  
Hydrogen Damage ◽  
Current Test ◽  
Industry Practice ◽  
Sour Service

Abstract C-Mn steels are extensively used as line pipe material for sour service oil and gas applications, i.e. in the presence of hydrogen sulfide (H2S), because of their ease of fabrication, weldability and significantly lower cost compared to Corrosion Resistant Alloys (CRAs). However, use of C-Mn steel in sour conditions can be limited by its susceptibility to various hydrogen damage mechanisms such as sulfide stress cracking (SSC) and hydrogen induced cracking (HIC). Presently, there are several industry standards which provide guidelines for materials selection and qualification testing to ensure the integrity of carbon steel pipelines in sour service. In recent years, examples of line pipe susceptibility to SSC have occurred due to undetected Local Hard Zones (LHZs) produced during steel plate manufacture. A companion paper (Fairchild, et al, [1]) describes historical and one newly recognized root causes for LHZs. Due to this newly recognized root cause, the adequacy of the current industry practice for specifying and qualifying C-Mn line pipe for severe sour service should be evaluated. In this work, a new approach to monitoring steel plate manufacture during Thermo Mechanical Controlled Processing (TMCP) in order to manage LHZs is explained. Results from implementing this qualification approach will be discussed. In addition, several gaps were identified in the current test methods and various potential modifications to address these gaps were identified. Based on the results of these studies, recommendations to the test methods are made to improve the robustness in the materials qualification process used for sour pipeline projects.

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