Hydrogen-induced cracking along the fusion boundary of dissimilar metal welds

Cracking occurs due to a significant loss in ductility in the weld metal andor heat affected zone haz. Mills a model for heterogeneous nucleation along the fusion boundary is proposed key words dissimilarmetal welds epitaxial growth fusion boundary haz microstructure monel. Maintenance, repair and upgrade of pressure vessels. Lippold the susceptibility of dissimilar austeniticferritic combinations to hydrogeninduced cracking near the fusion boundary has been investigated key words hydrogen weld cracking dissimilar metal austenitic stainless filler metals. Friction stir weld technology development at lockheed. Us6892926b2 us10633,4 us633403a us6892926b2 us 6892926 b2 us6892926 b2 us 6892926b2 us 633403 a us633403 a us 633403a us 6892926 b2 us6892926 b2 us 6892926b2 authority us united states prior art keywords weld surface toughness discontinuity welding prior art date 20021011 legal status the legal status is an assumption and is not a. Recent experiences with cracking of load bearing dissimilar metal welds on subsea production systems. The morphology of the interface, is central to the susceptibility of the fusion zone, to hydrogenassisted cracking. Corrosion behavior of 316l and alloy 182 dissimilar weld.

Of the three, cracks are by far the most detrimental. May 19, 2009 susceptibility to hydrogen blistering and hydrogen induced cracking can be apportioned to the quality of the steel plate used. The sulphide stress cracking ssc behaviour of the dissimilar metal welded joint of x60 pipeline steel and inconel 625 alloy in h 2 s environment was investigated using constant load testing, weight loss testing and finite element analysis. Fusion boundary microstructure evolution associated with embrittlement of nibase alloy overlays applied to carbon steel. Doe office of fusion energy sciences, washington dc. Sohic is a type of cracking that can easily lead to failure and needs to be mitigated. Unfortunately, this book cant be printed from the openbook. An investigation of the susceptibility of fusion zone microstructures to hydrogen embrittlement in three dissimilar weld samples is presented. A paper titled analysis of hydrogen induced cracking along the fusion boundary of dissimilar metal welds published in the proceedings of the national conference on advances in joining technology, ncajt 2004 held on january 2324th 2004 at. Hydrogeninduced cracking hic refers to the internal cracks brought about by material trapped in budding hydrogen atoms. Factors influencing hydrogen induced cracking welding.

Published by welding technology institute of australia wtia, silverwater, nsw, australia, 1999. Hydrogen induced cracking in low strength steels, thammasat int. Cracking and hardness traverse near the fusion boundary source. Hydrogeninduced cracking hic in steel is a risk problem when steels are charged with hydrogen in service as in various hydrogen sulfide environments like sour oil and gas wells and some power plants. But this is not true in the case of dissimilar welds. Mitigating residual stresses is one of the most efficient ways to control hic. The objective was to determine if cracking near the fusion boundary of dissimilar metal welds could be caused by hydrogen absorbed during welding and to characterize the microstructures in which cracking occurred. Our last post factors influencing hydrogen induced cracking went over the factors that contribute to hydrogeninduced cracking. Weld cracking several types of discontinuities may occur in welds or heat affected zones. However, there is limited information about microstructureproperty relationships in dissimilar welds between austenitic and martensitic stainless steel by using duplex and austenitic stainless steel electrode. Having a low enough temperature is essential in creating stress induced. Normal epitaxial nucleation during solidification along the fusion boundary gives rise to grain boundaries that are continuous from the bm into weld metal across the fusion boundary.

O ur last post factors influencing hydrogen induced cracking went over the factors that contribute to hydrogeninduced cracking. Microstructure and properties of a dissimilar weld between. Fusion boundary microstructure evolution associated with. Nature and evolution of the fusion boundary in ferriticaustenitic dissimilar metal welds. Understanding hydrogen induced cold cracking in welds published on april 26, 2017 april 26, 2017 998 likes 49 comments. Most often, hydrogen picked up during the welding process is present in the form of moisture, which can come from humidity in the atmosphere or from the base material in the form of. I set out to get a better understanding of how this invisible gas could cause cracking in these high strength steel welds long after they. Apr 26, 2017 understanding hydrogen induced cold cracking in welds.

Lippold, a welding engineering professor at ohio state explains that there are three factors that. In the aswelded samples interfacial failure was dominant due to disbonding at the fusion boundary, whilst in overaged samples, failure occurred by linking cracks at m7c3 precipitates. Recent experience in dissimilar metal weld failures. Hydrogeninduced cracking along the fusion boundary of dissimilar metal welds rowe, m. An insitutracking observation was proceeded for evaluating corrosive progress at the fusion boundary by using a scanning electron microscope. Friction stir weld technology development at lockheed martin. Fusion boundary microstructure evolution associated. Secondly, whilst most occurrences of haz cracking occur in asformed microstructures this is not by any means always the case for weld metals since cracking is often.

It involves atomic hydrogen, which is the smallest atom, that diffuses into a metallic structure. Lu, tem observations of martensite layer at the weld interface of an a508iii to inconel 82 dissimilar metal weld joint, metall. Effective use of weld metal yield strength for hysteels. Corrosionpedia what is hydrogeninduced cracking hic. The investigation on destruction of the compressor in residue. Testing at the ohio state university using the delayed hydrogen cracking test dhct has concluded that this type of hac is strongly affected by the base metal filler metal combination, and by the welding and pwht procedures. Nature and evolution of the fusion boundary in ferritic. Dissimilar metal welds dmws or bimetallic welds refer to welds between two different metals. The dissimilar welded joint shows high ssc susceptibility, and the asymmetric stress concentration after corrosion is the prerequisite for. Causes of common problems encountered during welding of. Hydrogen cracking its causes, costs and future occurrence p h m hart weld metal hydrogen cracking in pipeline girth welds, proc.

The presence of hydrogen in the weld can cause significant quality and productivity issues, including stress in the microstructure of the base and weld metal that leads to hydrogen induced cracking. The welding journal, feb 1990, hydrogen induced cracking along the fusion boundary of dissimilar metal welds, m. Hydrogen induced cracking steel features, applications. Nature and evolution of the fusion boundary in ferriticaustenitic dissimilar weld metals, part 1nucleation and growth. A martensite boundary on the wrc1992 diagram journal. Also high strength structural steels which are welded are exposed to a certain hydrogen pickup which means a risk at fracture and blistering due to hic. Sulphide stress cracking behaviour of the dissimilar metal. How to avoid cracking in aluminum alloys the majority of aluminum base alloys can be successfully arc welded without cracking related problems, however, using the most appropriate filler alloy and conducting the welding operation with an appropriately developed and tested welding procedure is significant to success. Lippold, a welding engineering professor at ohio state explains that there are three factors that contribute to hydrogen induced cracking.

Semiannual progress report ending june 30, 2001, vol. Cracking along the fusion boundary of dissimilar metal welds. In situtracking evaluation for corrosion progress at. These controlling factors determine the microstructures that form at the fusion boundary. In the case of a crystal lattice becoming saturated or coming into contact with atomic hydrogen, many alloys and metals may. Martensite formed near the fusion boundary in all three filler metals.

Induction heating is a good option for minimizing hydrogen in. Martensite formation, which is commonly found at the interface between dissimilar welded joints, is particularly sensitive to hydrogen embrittlement 3. Hydrogeninduced cracking hic is a common issue when joining armored steel. The fusion boundary microstructure in dissimilar welds often possesses some unique features. The paper looks at the problem of hydrogen cracking both in general fabrication and with particular reference to. Hydrogen assisted crack in dissimilar metal welds for. The present work studied the corrosion property around the fusion boundaries of a dissimilar steel welded joint in aswelded condition and after postweld heat treatment pwht in h2s containing solution with different times. Another type of hydrogen corrosion, stressorientated hydrogen induced cracking sochic, is normally found in the base metal adjacent to the weld, where the stress point is highest due to the internal pressure of the. If you recall, we mentioned you need all three factors to be present in order to have hic. An understanding of the susceptibility of dissimilar metal fusion boundary microstructures to hydrogeninduced cracking will contribute to an understanding of defect formation in dis.

Nature and evolution of the fusion boundary in ferriticaustenitic dissimilar weld metals, part 1 nucleation and growth by t. Tensile residual stress mitigation using low temperature. C nature and evolution of the fusion boundary in ferriticaustenitic dissimilar metal welds part 1. Weld metal hydrogen cracking in pipeline girth welds, proc. Hydrogen induced cracking along the fusion boundary of dissimilar metal welds. Also called hydrogen assisted cracking or hydrogen cracking, it infests either the weld zone or the heat affected zone haz. They also reported the cracking or disbonding of dissimilar welds in service was associated with type ii boundary. Ranking the resistance of wrought superalloys to strainage cracking. Cracks did not extend into bulk weld metal with hardness less than 350 hv. Lippold, hydrogen induced cracking along the fusion boundary of dissimilar metal welds, welding research supplement 1999. Butt welds exhibit transverse cracks while fillet welds have longitudinal ones. Metallurgical characterization and testing of dissimilar metal welds.

The investigation on destruction of the compressor in. The welding journal, feb 1990, hydrogeninduced cracking along the fusion boundary of dissimilar metal welds, m. Fusion zone microstructure and subsea joint embrittlement twi. Lippold, hydrogeninduced cracking along the fusion boundary of dissimilar metal welds, welding research supplement 1999. Fusionboundary macrosegregation in dissimilarfiller metal alcu welds. Welds may contain porosity, slag inclusions or cracks. For further information contact manager repository services.

Azz wsi has over 30 years experience in the protection of vessels using the unifuse technology. An investigation of microstructureproperty relationships. In these reported instances, cracking occurred at the weld interface after the hubs. Hydrogen induced cracking of low strength steels in. Hydrogeninduced cracking along the fusion boundary of dissimilar metal welds journal article rowe, m. Cracking, or disbonding, along the fusion boundary in dissimilar metal welds has been a persistent problem, particularly in applications where austenitic alloys are clad on to structural steels for corrosion protection. An investigation of microstructureproperty relationships in. Pdf hydrogeninduced cracking along the fusion boundary. Dissimilar metal weld joints and their performance in nuclear. We utilize unifuse automated welding technology to structurally repair, upgrade and reinforce assets to deliver longterm, reliable performance, which is a key objective for the mechanical integrity of critical refinery components. If you need to print pages from this book, we recommend downloading it as a pdf. A paper titled analysis of hydrogen induced cracking along the fusion boundary of dissimilar metal welds published in the proceedings of the national conference on advances in joining technology, ncajt 2004 held on january 2324th 2004 at vasavi college of engineering, hyderabad. Whereas there are acceptable limits for slag inclusions and porosity in welds, cracks are never acceptable. It belongs to the class of physicsbased corrosion phenomena.

This is an interdendritic type of cracking mostly along observed along the weld centerline in very last stage of solidification primarily due to two factors a development of tensile residual stresses and b presence of low melting point phases in interdendritic regions of solidifying weld is called solidification cracking fig. In this study, microstructural and mechanical properties of a butt weld, joining two base metal alloys 617 and a387gr. Stress corrosion cracking in dissimilar metal welds with 304l stainless steel and alloy 82 in high temperature water tsungkuang yeha,c, guanru huanga, meiya wangb, chuenhorng tsaia,c adepartment of engineering and system science, national tsing hua university, 101, sec. We hope you will find this letter interesting and useful. Effect of welding process on the microstructure and. We will now go over how to prevent hic from happening.

Austenitic stainless steel and nickelbase alloys are generally used in dmws, and such alloys are employed in nuclear reactor components, plants of energy generation, chemical, and petrochemical industries due to their high corrosion resistance 2 7. In general, the susceptibility to hydrogeninduced cracking increases as the strength of the base metal increases. Welding journal presented here are the results from a series of experiments in which dissimilar metals welds were made using the gas tungsten arc welding process with pure argon or argon6% hydrogen shielding. May 05, 2012 cracking and hardness traverse near the fusion boundary source.

Microstructural and mechanical characterization of the. Different widths of fusion zones ob type ii boundary characteristic of dissimilar weld joints is served in the weld metal were relative to the different heat observed in parallel with the fusion boundary at the side of j. Hydrogeninduced cracking along the fusion boundary of dissimilar metal welds by m. Hydrogen induced cracking hic is a common form of wet h2s cracking caused by the blistering of a metal due to a high concentration of hydrogen. Us6892926b2 toughnessoptimized weld joints and methods. Fusion zone microstructure and subsea joint embrittlement. Pdf hydrogeninduced cracking along the fusion boundary of. Hydrogen induced cracking hic has been a persistent issue in welding of highstrength steels. Hydrogen induced cracking steel features, applications and. Recent experience with dissimilar metal weld dmw failures and evaluations includes. Induction heating is a good option for minimizing hydrogen. Presented here are the results from a series of experiments in which dissimilar metals welds were made using the gas tungsten arc welding process with pure.

The fusion zones of the three different joints were investigated in both aswelded and heattreated conditions. Metallurgical characterization, thermodynamic and kinetic simulations, and hydrogen charging experiments were conducted in an effort to identify the embrittlement mechanism and simulate the type of failures that occur in service under. Hydrogeninduced cracking an overview sciencedirect topics. Presented here are the results from a series of experiments in which dissimilar metals welds were made using the gas tungsten arc welding. The blistering damage tends to form parallel to the surface and to the direction of hoop stress. The effect of heat treatment on the embrittlement of. Factors influencing hydrogen induced cracking welding answers. Omar, effects of welding parameters on hard zone formation at dissimilar metal welds, research developments, 8693 1998. Hydrogeninduced cracking along the fusion boundary of dissimilar metal welds. Hydrogen induced cracking in weldments hydrogen induced cracking, also referred to in the litera ture as cold cracking, delayed cracking, underbead cracking and internal hydrogen embrittlement, is in general one of the most important potential sources of defects in welding hardenable. Hydrogen induced cracking the national academies press. Increasing application of these steels will require a better understanding of the issues associated with welds to dissimilar metals. Jp2000312969a jp11124793a jp12479399a jp2000312969a jp 2000312969 a jp2000312969 a jp 2000312969a jp 11124793 a jp11124793 a jp 11124793a jp 12479399 a jp12479399 a jp 12479399a jp 2000312969 a jp2000312969 a jp 2000312969a authority jp japan prior art keywords welded joint welding buttering outer surface welded prior art date.

Chen, microstructure and stress corrosion cracking behaviour of the weld metal in alloy 52a508 dissimilar welds, mater. Metallurgical characterization, thermodynamic and kinetic simulations, and hydrogen charging experiments were conducted in an effort to identify the embrittlement mechanism and simulate the type of failures that occur in service under cathodic protection. Mn type weld metals, in contrast to the haz situation, increasing heat input is not necessarily beneficial fig. Hydrogen induced cracking along the fusion boundary of dissimilar metal welds journal article rowe, m. Dissimilar joint resistance to hydrogenassisted cracking twi. Hydrogen cracking its causes, costs and future occurrence. Some data now exist in relation to weld metal hydrogen cracking in general fabrication and some of this has shown the situation is more complex than that of the heat affected zone. The embrittlement of the fusion boundary region of nibase alloy 625 overlay welds on aisi 8630 steel was evaluated. Hydrogen induced cracking in weldments hydrogen induced cracking, also referred to in the litera ture as cold cracking, delayed cracking, underbead cracking and internal hydrogen embrittlement, is in general one of the most important potential sources of. Modelling of carbon diffusion across the fusion boundary revealed the extent of phase precipitation during pwht. Stressoriented hydrogen induced cracking sohic is a common, insidious form of wet h2s cracking. Grain boundary character along intergranular stress corrosion crack paths in austenitic stainless alloys removed from hightemperature water service. Hydrogeninduced cracking along the fusion boundary of dissimilar. Hic usually occurs due to the effects of aqueous hydrogen charging of steel in wet h2s refinery process environments.

Hydrogen induced cracking in flux cored electrode welds. Preventing hydrogen induced cracking welding answers. Understanding hydrogen induced cold cracking in welds. Hydrogen induced cracking hic in the oil and gas industry. Ye, study of the martensite structure at the weld interface and the fracture toughness of dissimilar metal joints, weld. Lippold the susceptibility of dissimilar austeniticferritic combinations to hydrogen induced cracking near the fusion boundary has been investigated key words hydrogen weld cracking dissimilar metal austenitic stainless filler metals. Characterization on the gradient microstructure near the. Metallurgical factors influencing the susceptibility of. Cracking, or disbonding, along the fusion boundary in dissimilar metal welds has been a persistent problem, particularly in applications where austenitic alloys are clad on to structural steels. The results revealed that the fusion boundary was the worst region for corrosion resistance when comparing with other zones, and a broad boundary had a stronger resistance for hydrogen induced disbonding than a narrow one. Hydrogen induced cold cracking studies on armour grade.

Hydrogen induced cracking along the fusion boundary of dissimilar metal welds by m. Hydrogen induced cracking of low strength steels in geothermal fluids keith a. Hydrogen assisted crack in dissimilar metal welds for subsea service under cathodic protection dissimilar metal welds dmws are routinely used in the oil and gas industries for structural joining of high strength steels in order to eliminate the need for post weld heat treatment pwht after field welding. The type ii boundary has been investigated by nelson et al. Liu, hydrogen control in steel weld metal by means of fluoride additions in welding flux, welding research supplement 2000. Three different filler metals of ernicrmoco1, ernicr3, and er309l were used to perform welding. Hydrogen embrittlement is also referred to as hydrogeninduced cracking or hydrogen attack. Hydrogeninduced cracking along the fusion boundary of. Fusion welding was performed using gas tungsten arc welding. In his book welding metallurgy and weldability, john c.

Investigation of boundaries and structures in dissimilar. Tensile residual stress mitigation using low temperature phase transformation filler wire in welded armor plates x. Hydrogen induced cracking is an important issue in the welding industry. Hydrogen induced cracking hic occurs when carbon steel is exposed to hydrogen sulphide h 2 s and is the direct result of electrochemical corrosion reactions between the sour service or wet h 2 s environment. Microstructure and mechanical properties of dissimilar welds. Hydrogen induced cracking along the fusion boundary of dissimilar metal. In addition, the cracking in dissimilarmetal welded joints typically. It is one the most complex materials phenomena because hydrogen is very hard to detect, hence, structureproperty relations are often established on a phenomenological basis only. In addition, the cracking in dissimilarmetal welded joints typically occurred near the fusion bound ary fb either along the martensitic transition. In addition, dissimilar welding may form two types of highangle grain boundaries, type. Jun 02, 2012 different widths of fusion zones ob type ii boundary characteristic of dissimilar weld joints is served in the weld metal were relative to the different heat observed in parallel with the fusion boundary at the side of j. Hydrogeninduced cracking along the fusion boundary of dissimilar metal.