The bend test is a simple and inexpensive qualitative test that can be used to evaluate both the ductility and soundness of a material. It is often used as a quality control test for butt-welded joints, having the advantage of simplicity of both test piece and equipment. No expensive test equipment is needed, test specimens are easily prepared and the test can, if required, be carried out on the shop floor as a quality control test to ensure consistency in production.
The outside of the bend is extensively plastically deformed so that any defects in, or embrittlement of, the material will be revealed by the premature failure of the coupon. The guided bend test is where the coupon is wrapped around a former of a specified diameter and is the type of test specified in the welding procedure and welder qualification specifications. As the guided bend test is the only form of bend test specified in welding qualification specifications it is the only one that will be dealt with in this article.
The strain applied to the specimen depends on the diameter of the former around which the coupon is bent and this is related to the thickness of the coupon 't', normally expressed as a multiple of 't' eg 3t, 4t etc.
The former diameter is specified in the test standard and varies with the strength and ductility of the material - the bend former diameter for a low ductility material such as a fully hard aluminium alloy may be as large as 8t. An annealed low carbon steel on the other hand may require a former diameter of only 3t. On completion of the test the coupon is examined for defects that may have opened up on the tension face. Most specifications regard a defect over 3mm in length as being cause for rejection.
For butt weld procedure and welder qualification testing the bend coupons may be oriented transverse or parallel to the welding direction.
Allseas wins removal contract for multiple North Sea installations
Below approximately 12mm material thickness transverse specimens are usually tested with the root or face of the weld in tension. Material over 12mm thick is normally tested using the side bend test that tests the full section thickness, Fig.
Where the material thickness is too great to permit the full section to be bent the specifications allow a number of narrower specimens to be taken provided that the full material thickness is tested. Conventionally, most welding specifications require two root and two face bend coupons or four side bends to be taken from each butt welded test piece.
The transverse face bend specimen will reveal any defects on the face such as excessive undercut or lack of sidewall fusion close to the cap.
The transverse root bend is also excellent at revealing lack of root fusion or penetration. The transverse side bend tests the full weld thickness and is particularly good at revealing lack of side-wall fusion and lack of root fusion in double-V butt joints. This specimen orientation is also useful for testing weld cladding where any brittle regions close to the fusion line are readily revealed.
Longitudinal bend specimens are machined to include the full weld width, both HAZs and a portion of each parent metal. They may be bent with the face, root or side in tension and are used where there is a difference in mechanical strength between the two parent metals or the parent metal and the weld. The test will readily reveal any transverse defects but it is less good at revealing longitudinally oriented defects such as lack of fusion or penetration.
Whilst the bend test is simple and straightforward to perform there are some features that may result in the test being invalid. In cutting the coupon from the test weld the effects of the cutting must not be allowed to affect the result. Thus it is necessary to remove any HAZ from flame cutting or work hardened metal if the sample is sheared.
It is normal to machine or grind flat the face and root of a weld bend test coupon to reduce the stress raising effect that these would have. Sharp corners can cause premature failure and should be rounded off to a maximum radius of 3mm. The edges of transverse bend coupons from small diameter tubes will experience very high tensile stresses when the ID is in tension and this can result in tearing at the specimen edges.
Weld joints with non-uniform properties such as dissimilar metal joints or where the weld and parent metal strengths are substantially different can result in 'peaking' of the bend coupon. This is when most of the deformation takes place in the weaker of the two materials which therefore experiences excessive localised deformation that may result in premature failure. A dissimilar metal joint where one of the parent metals is very high strength is a good example of where this may occur and similar peaking can be seen in fully hard welded aluminium alloy joints.From in-water surveys, propeller polishing and in-water hull cleaning, to complex class-approved permanent ship repairs propellers, rudders, thrusters, shell plates, sealswe are the one global resource you can truly rely on.
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What Are the Work Conditions for a Pipeline Welder?
We are our clients most valued and trusted resource through unrivaled service. Our Certifications See All. Ship Maintenance Ships husbandry, ship maintenance and inspection is provided by the Subsea Global Solutions on a world-wide basis. Read More. Marine Construction Subsea Global Solutions is recognized as a leader in all types of underwater construction.Pipeline welders have to work in all conditions, including rain and snow or even underwater.
When you work in pipeline welding, you go to where the jobs are. Oil and gas companies can't bring the pipelines in for repair, so you travel to the pipeline, whether it's in Alaskan ice, desert heat or underground. Welder working conditions are tough, but the pay reflects that. Wherever there are pipelines - oil industry, natural gas, water and sewer - there's a need for pipeline welding.
Professional welders may work on a assembling new pipes, or making repairs to old ones. A given job involves studying the pipeline or the specification, figuring out the dimensions of the weld and using arc welders or similar equipment to carry it out.
The work is less predictable than many welding careers because pipeline welders hop from job site to job site. If you don't want to travel a lot, this may not be the job for you.
Work hours for a welder often run into overtime. Workers in any branch of welding are at high risk for injury or illness. The intense light from arc welders and other equipment can damage your eyesight, the welding tools generate tremendous heat and there's a risk of inhaling gases or particles from the welding process.
You can reduce the risk by following safety procedures and wearing equipment such as protective lenses and heat resistant gloves. Pipeline welding takes this a step further and offers tougher welder working conditions than other welding gigs. Applying your welding skills underwater takes you into what's probably the most challenging pipeline welding environment.
Typically, you work in a dry chamber set up to house three welders without allowing water in. The chamber has to be pressurized to minimize pressure sickness, with fans pumping water in and out. If you have to work in the water, it's even tougher. Between bubbles and dim light, it's difficult to see what you're doing, and the water at the sea bottom is intensely cold. On the upside, the pay reflects the high level of risk.
Operating an arc welder is not something you want to do without training. Learning the secrets of pipeline welding typically involves a mix of technical education and on-the-job training. Welders typically start out as an apprentice or helper to an established welder who can show them the ropes. Alongside the hands-on work, you can take welding classes in various colleges, welding schools or the U. Classes dealing with blueprints, mechanical drawing, metallurgy and electricity are useful too.
So are computer classes, as pipeline welding jobs often use them. Once you acquire technical knowledge and skill, you can take certification classes to prove your ability. Fewer people have a taste for pipeline welding compared to other welding jobs. The trade-off for the tough work welder working conditions is that there's plenty of jobs available. If you grow tired of the work, welding skills and certifications can transfer to welding careers in other fields.
More challenging gigs, such as underwater welding, can pay considerably more. Fraser Sherman has written about every aspect of working life: the importance of professional ethics, the challenges of business communication, workers' rights and how to cope with bullying bosses. He lives in Durham NC with his awesome wife and two wonderful dogs.
You can find him online at frasersherman.
Skip to main content. References 5 U. About the Author Fraser Sherman has written about every aspect of working life: the importance of professional ethics, the challenges of business communication, workers' rights and how to cope with bullying bosses.Contact Us.
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Your Message. Pipeline Technique is a world leading provider of solutions to the oil and gas industry for the most demanding challenges in Welding, Non Destructive Examination and Field Joint Coating.
Pipeline Technique excels in the field of fabrication and construction in any condition, including Deep and Ultra-deep waters, Landlines, Subsea Production Systems and Drilling products.
We also specialise in value added products such as counterboring, pipe sorting and matching and research and development of processes and materials. We capitalise on our expertise and knowledge to safely and reliably deliver projects to tight fabrication schedules, virtually anywhere in the world.
Our combination of operational, engineering, project management, and hands-on experience is unrivalled, giving us a unique advantage. We take great pride in our workforce and assets, with whom we are able to safely deliver the highest quality services in the industry.
By any measure, to be and to be recognized as the best pipeline construction specialist contractor in the world, and in carefully selected segments and regions of the market. Our mission is to deliver projects safely, on time and within budget. To achieve this, we will operate at the forefront of industry technology capabilities, with a continuous drive for innovation and new product development solutions that will positively impact and add value to our clients.
Find out more about us and the unparalleled knowledge and experience we bring to our clients. Patrick was appointed Chief Executive Officer in April Until then he was the Chief Operating Officer since September Alan joined Pipeline Technique in January and has served in a number of roles including Commercial Manager and General Manager Gulf of Mexico before taking up the role of Group Commercial Manager midway through Alan joined Pipeline Technique in August as a document controller before joining the QHSE department in early gaining valuable experience with our site operations in various locations before progressing to the current role of Group QHSE Manager.
Safety-driven, creating a hazardous free environment for staff, subcontractors and clients.
Delivery of a compliant and effective management system meeting internal and client requirements. Pipeline Technique was founded in Today, Pipeline Technique is known across the globe as a leading contractor of pipeline, riser welding, subsea production systems and general fabrication and field joint coating services, specialising in tailored solutions for customers in the oil and gas industry.Patents Assigned to Allseas Group S. Guide device for welding curvilinear pipe surfaces.
Patent number: Abstract: Guide device for use in the processing, in particular welding, of curved surfaces, in particular pipe surfaces, comprising a flexible elongate body provided with a guide for processing means; tensioning means for tensioning the flexible body around the curved surface; wherein the flexible body is provided along its length with indicators arranged according to a determined pattern, this pattern being such that a determined position along the flexible body can be inferred on the basis of the detection of the indicators.
Type: Grant. Filed: March 4, Date of Patent: October 24, Assignee: Allseas Group S. Publication number: Type: Application. Publication date: July 11, Abstract: Guide device for use in the processing, in particular welding, of curved surfaces, in particular pipe surfaces.
A guide device includes a flexible elongate body provided with a guide for processing means and a tensioning means for tensioning the flexible body around the curved surface. The flexible body is provided along its length with indicators arranged according to a determined pattern, this pattern being such that a determined position of the guide device along the flexible body can be inferred on the basis of the detection of the indicators. Filed: April 18, Date of Patent: July 9, Abandonment and recovery system and method, and cable connector.
Abstract: A system for abandonment or recovery of a load, e. Filed: April 19, Date of Patent: November 24, Method and device for welding together two bodies. Abstract: A method and apparatus for welding together two pipes or plates. The bodies to be welded are placed mutually in line against each other while leaving clear a weld groove. The weld groove is filled with more than one welding layer by a welding torch moved in a longitudinal direction of the weld groove, and wherein two welding layers are laid in one welding pass by two welding torches placed successively at a predetermined fixed distance in the longitudinal direction of the weld groove, so that a time-saving is achieved in the welding process.
Filed: December 3, Date of Patent: May 18, Device and method for laying a pipeline on a seabed. Abstract: A device for laying a pipeline on a seabed. A vessel for laying a pipeline, which is fitted with a stinger for guiding a pipe string descending from the vessel and with a clamping structure for clamping the pipe string to the vessel, and support structure for supporting the part of the pipe string that extends between the surface and the seabed.
The support structure includes a cantilever structure, which is fixedly connected to the vessel, and clamping members that mate therewith. The clamping members engage the pipe string and transmit axial stresses from the pipe string to the vessel via the cantilever structure. Filed: November 13, Date of Patent: April 6, Inventor: Peter-Paul Maria Kuppers.
Method and apparatus for underwater connection of pipe pieces and bolt therefor. Abstract: A method and apparatus for connecting two pieces of pipe having flanges when the pipe pieces are located deep under a water surface. A movable bolt wrench is provided which has a number of wrenches mounted in a frame corresponding to the bolt holes on the flanges of the pipe pieces.Welded pipes are moving over the conveyor towards the aft.
There are three main ways that subsea pipe is laid -- S-lay, J-lay and tow-in -- and the pipelay vessel is integral to the success of the installation. Buoyancy affects the pipelay process, both in positive and negative ways.
In the water, the pipe weighs less if it is filled with air, which puts less stress on the pipelay barge. But once in place on the sea bed, the pipe requires a downward force to remain in place. This can be provided by the weight of the oil passing through the pipeline, but gas does not weigh enough to keep the pipe from drifting across the seafloor. In shallow-water scenarios, concrete is poured over the pipe to keep it in place, while in deepwater situations, the amount of insulation and the thickness required to ward of hydrostatic pressure is usually enough to keep the line in place.
While jumpers are typically short enough to be installed in sections by ROVs, flowlines and pipelines are usually long enough to require a different type of installation, whether that is tow-in, S-lay or J-lay. Tow-in installation is just what it sounds like; here, the pipe is suspended in the water via buoyancy modules, and one or two tug boats tow the pipe into place.
Once on location, the buoyancy modules are removed or flooded with water, and the pipe floats to the seafloor. There are four main forms of tow-in pipeline installation. The first, the surface tow involves towing the pipeline on top of the water. In this method, a tug tows the pipe on top of the water, and buoyancy modules help to keep it on the water's surface. Using less buoyancy modules than the surface tow, the mid-depth tow uses the forward speed of the tug boat to keep the pipeline at a submerged level.
Once the forward motion has stopped, the pipeline settles to the seafloor. Off-bottom tow uses buoyancy modules and chains for added weight, working against each other to keep the pipe just above the sea bed. When on location, the buoyancy modules are removed, and the pipe settles to the seafloor. Lastly, the bottom tow drags the pipe along the sea bed, using no buoyancy modules.
Only performed in shallow-water installations, the sea floor must be soft and flat for this type of installation. The term S-lay refers to the shape that the pipe forms between the vessel and the seabed as it is laid. The method is characterised by its fast installation process and its workability over a large range of water depths.
On board the pipelay vessel, pipe joints are assembled in a horizontal working plane the firing line. Pipe joints are welded together, inspected and then coated as they move through the various firing line work stations. As welding progresses, the pipeline is gradually lowered towards the seabed behind the vessel. During pipelay, the curvature of the upper section of the pipeline the overbend is controlled by the stinger, a steel structure with rollers protruding from the end of the firing line to prevent pipe buckling failure.
The curvature in the lower section the sagbend of the pipeline is controlled by pipe tensioners, caterpillar tracks that clamp the pipe. The amount of tension is one of the most important limiting factors in the capabilities of an S-lay vessel.
J-lay is used to install subsea rigid pipelines in deep water. With a J-lay system, pipe stalks, consisting of up to six pipes with a total length of 72m, are upended and welded to the seagoing pipe in a near vertical ramp. The ramp angle is adjusted so that it is in line with the pipe catenary hanging to the seabed to keep bending of the pipe to a minimum.
The J-lay method is very suitable for deepwater pipelaying because the pipe leaves the lay system in an almost vertical position and the pipeline is only bent once during installation at the seabed.
This reduced amount of bending is beneficial for installing pipelines that are sensitive to fatigue. Compared to other lay methods, J-lay has a relatively low production rate due to the single position welding of the pipe.
The J-lay method is less suitable for shallow waters as this requires a departure angle close to horizontal. Offshore Fleet. Tow-In Pipeline Installation While jumpers are typically short enough to be installed in sections by ROVs, flowlines and pipelines are usually long enough to require a different type of installation, whether that is tow-in, S-lay or J-lay.
Surface Tow Pipeline Installation Source: www. S-Lay Pipeline Installation The term S-lay refers to the shape that the pipe forms between the vessel and the seabed as it is laid.The automated welding system, Phoenixconsistently produces high quality welds to meet the ever-increasing requirements of the oil and gas industry with respect to weld strength overmatching, corrosion properties and impact toughness for heavy wall pipelines.
Allseas developed the concept inseeking to improve pipeline welding technology with the aim to provide assured quality of each and every pipeline weld. Phoenix — which has welded over 12, km of pipeline since its introduction in — has undergone several advancements including dual torch and triple torch arrangements, further optimising the system and increasing the weld speed on large diameter pipes. All the detailed engineering and development of the hardware and software is performed in-house, as is as the manufacturing of the system itself.
In this way, Allseas maintains full control over maintenance and project-specific modifications. Equipped with a colour camera and laser surface profiler, the tool takes visual weld inspection to the next level with pin-point accuracy. The camera captures defects such as misalignment, unsatisfactory weld penetration and porosity. Using the high quality images that appear on the computer screen, the inspector can examine the colour appearance of the weld and the condition of the surface.
The internal line-up clamp is an in-house designed hydraulic clamp with the purpose to reduce the global out of roundness of the pipe and reduce the required line-up time. The clamp fits two pipe sections together after they have been lined up. Uniquely, the clamp's hydraulic pressure can be regulated, and is substantial enough to alter the shape of the pipe end to optimise its circular shape. The maximum force per stamp can be set up to several tonnes so it can also be used for pipelines with heavy wall thicknesses.
The reduced out of roundness of the pipe improves the quality of the weld and line-up process, thus ensures fewer weld repairs. Learn more about Alleas' activitiesprojects and equipment.
Phoenix The automated welding system, Phoenixconsistently produces high quality welds to meet the ever-increasing requirements of the oil and gas industry with respect to weld strength overmatching, corrosion properties and impact toughness for heavy wall pipelines. Internal line-up clamp The internal line-up clamp is an in-house designed hydraulic clamp with the purpose to reduce the global out of roundness of the pipe and reduce the required line-up time.