Determination of Critical Hydrogen Curves From Slow Bend Tests

2004 ◽  
Author(s):  
L. N. Pusseogda ◽  
A. Dinovitzer ◽  
D. Horsley
Keyword(s):  
Hydrogen Diffusion ◽  
High Strength Steels ◽  
High Strength ◽  
Hydrogen Diffusivity ◽  
Hydrogen Cracking ◽  
Cold Temperatures ◽  
Steel Strength ◽  
Delayed Cracking ◽  
Two Parameters ◽  
Welding Procedure

Recent trends in the pipeline industry are towards the use of high strength steels. As steel strength increases, the delayed hydrogen cracking propensity in the welds also increases. As welding is often completed during winter months, the cold temperatures must be considered in determining joining procedures that will avoid delayed hydrogen cracking. The Graville/BMT Fleet Technology Limited hydrogen diffusion and cracking models have been used successfully in the past to predict delayed cracking and to demonstrate how changes implemented in the welding procedure can minimize the risk of cracking. The two capabilities, hydrogen diffusion and cracking assessment, can be applied to the case of X100 pipe as well, provided the hydrogen diffusivity and the hydrogen cracking susceptibility curves are established for the materials of interest. These two parameters, the hydrogen diffusivity and the hydrogen cracking susceptibility curves are developed to examine the hydrogen cracking susceptibility of SMAW and GMAW welds in X100 pipe, and are the focus of the paper.

Numerical and Experimental Residual Stresses of Different Welded Joint Configurations in Heavy Wall

2020 ◽  
Author(s):  
Chiara Colombo ◽  
Stefano Monti ◽  
Mario Guagliano ◽  
Laura Vergani ◽  
Emanuele Fiordaligi ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Ad Hoc ◽  
High Strength Steels ◽  
High Strength ◽  
Thermal Treatments ◽  
Residual Stress Field ◽  
X Ray ◽  
Finite Element Software ◽  
Asme Code ◽  
Two Parameters

Abstract Refinery equipment subjected to high pressure is commonly made of Vanadium high strength steels (2¼Cr1Mo¼V), characterized by high allowable stress and low toughness in the as welded condition, leading to potential wall cracking before the application of thermal treatments. Therefore, the decision to perform specific thermal treatments after welding is of paramount importance. These thermal treatments, which are quite expensive and time demanding for the manufacturer, are still under discussion and not supported by evident scientific findings. The paper presents a numerical and experimental study on a plate-to-plate weld and on a nozzle-to-plate weld, created as ad-hoc mock-ups. Experimental residual stresses are collected by an X-ray diffractometer in the as welded configurations. These values are used to validate a complex 3D numerical model, implemented with the finite element software Abaqus and its AWI plugin. Finally, this validated model allows for the identification of joint criticality through two parameters: the volume of plasticized material per unit of welded length and the strain-based assessment according with ASME code. Their application as tools to compare the criticality of different welded geometries and the effect of thermal treatments on the residual stress field are discussed.

Weld Metal Hydrogen Cracking in Transmission Pipelines Construction

2010 ◽  
Author(s):  
Sheida Sarrafan ◽  
Farshid Malek Ghaini ◽  
Esmaeel Rahimi
Keyword(s):  
Weld Metal ◽  
Construction Projects ◽  
High Strength Steels ◽  
High Strength ◽  
Carbon Equivalent ◽  
Transverse Cracks ◽  
Diffusible Hydrogen ◽  
Hydrogen Cracking ◽  
Girth Welds ◽  
Welding Position

Developments of high strength steels for natural gas pipelines have been in the forefront of steelmaking and rolling technology in the past decades. However, parallel to such developments in steel industry, the welding technology especially with regards to SMAW process which is still widely used in many projects has not evolved accordingly. Decreasing carbon equivalent has shifted the tendency of hydrogen cracking from the HAZ to the weld metal. Hydrogen cracking due to its complex mechanism is affected by a range of interactive parameters. Experience and data gained from field welding of pipeline construction projects indicated that weld metal hydrogen cracking is related to welding position as it occurs more in the 6 o’clock position of pipeline girth welds. In this research an attempt is made to open up the above observation in order to investigate the contributory factors such as welding position and welding progression in terms of diffusible hydrogen and possibly residual stress considerations. It was observed that transverse cracks produced in laboratory condition may not be detected by radiography. But, the higher tendency for cracking at 6 o’clock position was confirmed through bend test. It is shown that more hydrogen can be absorbed by the weld metal in the overhead position. It is shown that welding progression may also have a significant effect on cracking susceptibility and it is proposed that to be due to the way that weld residual stresses are developed. The observations can have an important impact on planning for welding procedure approval regarding prevention of transverse cracking in pipeline girth welds.

Hydrogen cracking of high-strength steels during cathodic polarization in acid media

1974 ◽  
Vol 7 (6) ◽  
pp. 683-685
Author(s):  
F. F. Azhogin ◽  
E. V. Plaskeev ◽  
O. A. Gubenkova
Keyword(s):  
Cathodic Polarization ◽  
High Strength Steels ◽  
High Strength ◽  
Hydrogen Cracking ◽  
Acid Media

scholarly journals Multi-Pass Weld Hydrogen Management to Prevent Delayed Cracking

2000 ◽  
Author(s):  
A. Dinovitzer ◽  
B. Graville ◽  
A. Glover ◽  
N. Pussegoda
Keyword(s):  
Material Selection ◽  
Base Material ◽  
Carbon Equivalent ◽  
Hydrogen Cracking ◽  
Tensile Stresses ◽  
General Base ◽  
Delayed Cracking ◽  
Welding Procedure ◽  
Welding Processes ◽  
Procedure Development

The potential for weld hydrogen cracking, that can also manifest itself as delayed cracking due to formation well after weld deposition, is controlled by three factors: the presence of hydrogen, the susceptibility of the weldment microstructure and tensile stresses. The tensile stresses promoting hydrogen cracking may result from either welding residual stresses or construction or operations based stresses, while the susceptibility of a microstructure is a function of its carbon equivalent and cooling rate. Since all arc welding processes introduce hydrogen into welds to some extent, and in general, base material selection and weld stress levels are not controllable in welding procedure development, the prevention of hydrogen cracking must be accomplished through hydrogen management. This paper describes a means of considering the roles of welding procedure parameters (heat input, preheat, post-heat, inter-pass temperature and time, etc.) in the management of hydrogen in multi-pass welds to preclude delayed cracking. Some results obtained using a multi-pass weld hydrogen and thermal diffusion model are presented to demonstrate the models utility in understanding the effects of welding procedure parameter effects on the risk of delayed cracking.

scholarly journals Hydrogen Embrittlement and Diffusion in High Strength Low Alloyed Steels with Different Microstructures

2018 ◽  
Author(s):  
Marina Cabrini ◽  
Sergio Lorenzi ◽  
Diego Pesenti Bucella ◽  
Tommaso Pastore
Keyword(s):  
Hydrogen Embrittlement ◽  
Strain Rate ◽  
Hydrogen Diffusion ◽  
High Strength Steels ◽  
High Strength ◽  
Tempered Martensite ◽  
Hsla Steels ◽  
And Diffusion ◽  
Embrittlement Resistance ◽  
Hydrogen Embrittlement Resistance

<span lang="EN-US">The paper deals with the effect of microstructure on the hydrogen diffusion in traditional ferritic-pearlitic HSLA steels and new high strength steels, with tempered martensite microstructures or banded ferritic-bainitic-martensitic microstructures. Diffusivity was correlated to the hydrogen embrittlement resistance of steels, evaluated by means of slow strain rate tests.</span>

Studies of SCC and Hydrogen Embrittlement of High Strength Alloys Using Fracture Mechanics Methods

2005 ◽  
Vol 482 ◽  
pp. 11-16 ◽  
Author(s):  
Wolfgang Dietzel ◽  
Michael Pfuff ◽  
Guido G. Juilfs
Keyword(s):  
Plastic Deformation ◽  
Fracture Mechanics ◽  
Hydrogen Embrittlement ◽  
Hydrogen Diffusion ◽  
High Strength Steels ◽  
High Strength ◽  
Constant Load ◽  
Rate Of Change ◽  
Extension Rate ◽  
Hydrogen Atoms

Fracture mechanics based test and evaluation techniques are used to gain insight into the phenomenon of stress corrosion cracking (SCC) and to develop guidance for avoiding or controlling SCC. Complementary to well known constant load and constant deflection test methods experiments that are based on rising load or rising displacement situations and are specified in the new ISO standard 7539 – Part 9 may be applied to achieve these goals. These are particularly suitable to study cases of SCC and hydrogen embrittlement of high strength steels, aluminium and titanium alloys and to characterise the susceptibility of these materials to environmentally assisted cracking. In addition, the data generated in such R-curve tests can be used to model the degradation of the material caused by the uptake of atomic hydrogen from the environment. This is shown for the case of a high strength structural steel (FeE 690T) where in fracture mechanics SCC tests on pre-cracked C(T) specimens a correlation between the rate of change in plastic deformation and the crack extension rate due to hydrogen embrittlement was established. The influence of plastic strain on the hydrogen diffusion was additionally studied by electrochemical permeation experiments. By modelling this diffusion based on the assumption that trapping of the hydrogen atoms takes place at trap sites which are generated by the plastic deformation, a good agreement was achieved between experimentally obtained data and model predictions.

Pipeline In-Service Fillet Weld Inspection Delay Time

2006 ◽  
Author(s):  
A. Dinovitzer ◽  
Vlado Semiga ◽  
L. N. Pusseogda ◽  
Scott Ironside
Keyword(s):  
Delay Time ◽  
Hydrogen Diffusion ◽  
Time Estimate ◽  
Hydrogen Diffusivity ◽  
Hydrogen Cracking ◽  
Time To Peak ◽  
Novel Approach ◽  
Environmental Material ◽  
Delay Times ◽  
Weld Inspection

Traditionally, in-service welding procedures have been developed to minimize the risk of hydrogen cracking by considering the weldment cooling rate and chemistry to control the susceptibility of the resulting microstructure. To further ensure that weld hydrogen cracks do not enter service, weldment inspection is completed. The BMT Hydrogen Diffusion and Cracking Model has been used to develop a means of conservatively estimating the delay time for hydrogen cracking in multi-pass welds. The hydrogen cracking delay time estimate is developed based upon the Time To Peak Hydrogen (TTPH) concept that is evaluated numerically considering the hydrogen diffusivity in the weldment. CSA Z662 indicates that the pipeline operator should delay weld inspection until the risk of cracking is over. This requirement includes a suggested delay time of 48 hours after weld deposition. The BMT Hydrogen Diffusion Model and TTPH concept were used to define conservative inspection delay times for pipeline repair sleeve end circumferential fillet welds deposited in-service. This paper describes the investigation results and the effect of variations in welding, environmental, material and pipeline characteristics on the recommended inspection delay time. These delay times are compared to those recommended by CSA Z662 to illustrate this novel approach to establishing weldment inspection delay times.

Effect of Hot Dip Galvanizing on the Mechanical Properties of High Strength Steels

2014 ◽  
Vol 604 ◽  
pp. 12-15 ◽  
Author(s):  
Sirli Sepper ◽  
Priidu Peetsalu ◽  
Mart Saarna ◽  
Valdek Mikli ◽  
Priit Kulu
Keyword(s):  
Mechanical Properties ◽  
Structural Steel ◽  
High Strength Steel ◽  
Hydrogen Diffusion ◽  
High Strength Steels ◽  
High Strength ◽  
Bath Temperature ◽  
Zinc Bath ◽  
Batch Type ◽  
Pre Treatment

Present study focuses on investigating the hot dip galvanizing effect on the mechanical properties of high strength steel. The effect of chemical pre-treatment (hydrogen diffusion) and the effect of hot dip galvanizing temperature on mechanical properties was studied with high strength steel S650MC. Additional tests were made with widely used structural steel S355J2. A batch type hot dip galvanizing process was used and zinc bath temperature was 450 °C and 550 °C. Results of the study show the behaviour of high strength steel during hot dip galvanizing process.

Development of Innovative and Efficient Welding Technologies for Plates and Profiles Made of High Strength Steels Using the Example of the Production of Mobile Cranes

2012 ◽  
Vol 706-709 ◽  
pp. 2296-2301
Author(s):  
Arite Scharff
Keyword(s):  
Laser Beam ◽  
High Strength Steels ◽  
High Strength ◽  
Hybrid Welding ◽  
Plant Materials ◽  
Course Of Action ◽  
Welding Procedure

An investigation concerning laser beam – GMA – hybrid welding of high strength steels has been completed for a crane plant. Materials, welding procedure qualification tests and the course of action during welding a demonstrator were studied [1].

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