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A reliable supplier of accurate high quality parts to myself and many other fabricators I know for a decade now. Pete Ellis Fabricator (via Google Reviews)

They supply us, celeritech.nl, for years and years of bends for headers and exhausts. Very happy with all the parts, the service and pricing. The variety in diameters, centerline radii, wall thickness and materials is enormous. Nice people, they respond to every technical question with tons of experience. Tjabring Snel Celeritech (via Google Reviews)

At Goodfabs we form many materials on a daily basis. The forming of some of the exotic materials such as Inconel, Titanium and Stainless steel requires an expertise. Exactly the expertise we have gained over all the years we have been active. Next to understanding the bend allowances in the materials we form, there is also a factor called ‘Springback’ we need to take into account. This springback occurs not only in the sheet metal forming, but also in the tube bending we perform on a daily basis. Understanding springback To understand this springback we need to go back to the basics of the materials and its properties. Each material has mechanical properties, those properties, to a great deal, inform of its behaviour and in which applications the material can be used. For example what temperatures the materials can be used in and – in the case of exhaust and performance engineering – whether the are suitable in hight temperature applications. One of the mechanical properties in materials is the tensile properties and tensile strength, when we put it simple: “this is the maximum load a material can support without breaking”. One of the other tensile properties is the Yield Strength, which simple put is the stress you can put on a material at which the material is starting to permanently deform and not return to its original position. How does this affect the bending materials? When a material is bent we basically compress the inside of the bend and stretch the outside of the bend. By doing this, a tension is created in the outer side of the material which could be referred to as strain (which is the relative change in length under the applied stress). The inside of the bend is actually compressed (which is why often you can see the inside of bends being rippled). Location of Neutral axis As mentioned, the Yield strength is only one factor which influences this behaviour. In our previous topic about bend allowance, we have discussed the neutral axis of the material. The location of this axis is different for each material and each thickness and is the location where (in theory) there are no stresses. If we consider that stresses are affecting the springback and the bending, this puts another piece to understanding this puzzle. The thicker the material, the more springback you are likely to face. This can be explained by the location of this neutral axis. When something is thicker, the distance to the neutral axis is actually longer which will result in a higher tensile stress due to the material being ‘stretched more’ on that location. Overbending Next to the above reasons, there are numerous of other factors which influence the behaviour of a material while it’s being bent or manipulated. To account for all of these, our experienced benders know exactly what percentage of overbending they need to apply to ensure the part is within the specification. Only by having this experience we can achieve the perfect results every single day and deliver custom hand fabricated pieces to the highest standards to our customers. If you have any bending requirements, feel free to contact us and one of our experts will get in touch with you shortly to discuss you project and what is possible.

At Good Fabs we are able to engineer things to the highest precision, together with Cavey Laboratories we were able to create a small, but life-saving link for those battling Covid-19. We rushed to the aid of Bucks Healthcare Trust to go into emergency production of a small but vital connector which joins ventilators to hospitals’ oxygen supplies. With supply chains stretched to breaking point by the current Covid-19 emergency, Bucks Healthcare Trust had managed to source much-needed intensive care ventilators but was dismayed to find the connectors to attach to the oxygen supply were missing, making them useless. When attempts to contact the manufacturer to get the vital connectors failed, the race was on to find a way around the problem. Cardiologist, and Chair of Medical Procurement at Stoke Mandeville Hospital Dr Andrew Money-Kyrle said it was a critical situation with patients needing ventilators to help them battle the virus, but the hospital had no way to connect its new ventilators to the oxygen system. Dr Money- Kyrle said: “At times like this, it seems miracles can happen. One of our volunteers, Jane Rampin of Resilience Health, put us in touch with the Neil Morgan, Managing Director of Good Fabs, which makes high- performance exhaust systems for Formula 1 cars and he leapt at the chance to help." The Trust’s head of Clinical Engineering, Stephen Squire then sent the only connector they had to Good Fabs’ Thame workshop. Mr Squire said Neil Morgan’s ‘can do’ attitude and highly skilled team of engineers and designers swung into action to produce a full set of technical drawings over the weekend. “Within 12 hours, Good Fabs had designed a prototype connector ready to go into production. At this point, Cavey Laboratories, a Formula 1 partner based in Guildford, were called on to take over the manufacture of the part,” Mr Squire said. Dr Money-Kyrle said the two companies worked flat out for four days to make the critical valves which were delivered to Stoke Mandeville on Friday, meaning the new ventilators were being used in intensive care wards in time for the expected surge in Covid-19 cases over the Easter weekend. “Our staff and clinicians are working round the clock to care for our community and battle this virus. This weekend, some of our wider community pulled together to help us,” Dr Money- Kyrle said. source: https://www.bucksherald.co.uk/health/coronavirus/local-firms-step-make-vital-part-missing-stoke-mandeville-hospital-ventilators-2537864

Unfortunately at GoodFabs we can’t always show what we are working on. That doesn’t mean we don’t do things with passion! Luckily sometimes (after approval of the customer) we are allowed to show what the entire team has accomplished. During the development phase of the 2019 BTCC racing season we were asked to design an equal length turbo exhaust system with a fully integrated heatshield to keep the heat inside the exhaust system. We were provided with the CAD of the full car outlining all the constraints we had to work with, and to be honest, it was a challenge with a very tight fit to some of the constraints. Fortunately our extensive tooling range for mandrel bending allowed us to come up with a design where the differences in length between the pipes only was 0.7mm, creating a perfectly balanced exhaust system. With the turbo system being very close to the engine itself and the need to allow for enough space to put a fully integrated heatshield around the system, our very skilled fabricators had to be able to work within the tightest areas to be able to weld this system including the short 4 into 1 collector with turbo V-Band ring and wastegate completely. Our years of experience in fabrication components with the highest level of detail ensured us that we could achieve what was needed. The integrated heat shield was made with dedicated tooling to follow the tight curvatures of the exhaust system with a constant clearance to allow a very snug fit for the insulation materials. The outer skin of the lightweight heatshield only had a thickness of 0.2mm while our uniquely designed shield pattern ensured the strength of the outer shield to be able to perform in the highest demanding conditions: RACING! Not only the primaries were a unique example of what can be achieved using the expertise at GoodFabs. The downpipe, cat, tailpipe and silencer were designed and fabricated to the highest standard without any compromise for the performance and clearances. Due to the BTCC regulations we had to keep a certain ground clearance without the loss of clearance to the undercar heat shield or flow through the tailpipe. With our experience in designing press tooling to create unique curving parts, the exhaust tailpipe was designed with an oval shape and corresponding curving transitions to allow for the underbody curvatures of the racecar. A performance catalyst and free flow exhaust silencer made this system to be one of the best performing systems on the field.

We've been told by our US-based tooling supplier that we probably have the largest amount of bend tooling outside the aerospace industry when it comes to mandrel bending exotic metal tube with a diameter between 1 and 3.5 inches and wall thicknesses from 0.5 - 1.5mm. For some diameters we have half a dozen mandrels allowing us to precision bend multiple wall thicknesses. When it comes to inconel 605, inconel 718, titanium (various grades) and SS 321 tube there isn't much ready made tube available for our bend tooling, so we form it ourselves from sheet. We've been doing this for F1 teams for over 35 years and their demands change every season. As a consequence we end up with more and more tooling, which is then available for everyone to use. So even if it's 304 stainless or aluminium that you are after download our tooling chart. You can even visit our online shop and get a quote for the materials and wall thicknesses that we tend to stock in sheet form. Alternatively call us on +44 1844 202850 or email jennie@goodfabs.com and we'll send you an A3 version to mount on the workshop wall! #MandrelBending #Inconel #Inconel625 #titanium #titaniumexhaust #stainlesssteel #Aluminum #aluminium #bending #outerdiameter #wallthickness

In collaboration with the Department of Materials Science and Metallurgy, University of Cambridge, Department of Earth Sciences and University of Oxford, the Department of Materials, Good Fabrications was able to investigate microstructural evolution in an aged Nickel superalloy for exhaust applications exposed to a Formula 1 racing environment. This has been examined using a range of advanced electron microscopy-based techniques, atom probe tomography and high-sensitivity laser ablation mass spectrometry. This study has characterised the formation and evolution of γ’’ precipitates during ageing in the nickel superalloy Inconel 625. Download the full paper here! #Inconel625 #oxidation #ageing

GoodFabs work closely with several F1 teams and engine builders to discuss how components can be manufactured most efficiently once CAD designs have been released. Force India is one of the teams who have worked closely with us since they entered Formula 1 in 2008. For example, in 2017 we worked together to fabricate the tailpipe for the VJM10, one of the team’s most successful cars to date. During the 2017 season the tailpipe was refined several times requiring detailed consultation to minimise weight and maximise performance without compromising the design. Bob Halliwell, Production Director at Force India said: “GoodFabs is one of our longstanding suppliers with whom we work closely to make sure that we optimise both technical and cost efficiency throughout the season. As the exhaust is an area that effects both performance and weight, it is useful to work with a company that has extensive and relevant experience in high level motorsport.” #fabrication #GoodFabs #ForceIndia #BobHalliwell #titanium #exhaust #Inconel #Formula1 #VJM10

In collaboration with the Department of Materials Science and Metallurgy, University of Cambridge, Department of Earth Sciences, University of Oxford, the Department of Materials, University of Oxford, Rolls Royce and Oak Ridge National Laboratory, Materials Science and Technology Division, Good Fabrications was able to investigate the oxidation response and microstructural evolution of an Inconel 625 alloy exhaust manifold exposed to a Formula 1 racing environment. This has been examined using a range of advanced electron microscopy-based techniques, atom probe tomography and high-sensitivity laser ablation mass spectrometry. The dynamic, corrosive gas conditions result in accelerated oxidation, with the inner exhaust surface also heavily contaminated by multiple species including Zn, P, K and Na. Nb carbides and Ti nitrides identified in stock control samples evolve into mixed (Ti, Nb)N species during exposure, decorated by smaller Mo, Si-rich precipitates. The exposed alloy component therefore reveals unique surface and subsurface features following in-service use. Download the full paper here! #inconel #oxidation #DidierDeLille

The terms used in metallurgy can be very complex. Welding terms are usually very specific and a lot of the terms are also misunderstood, below you can find some of the most common used ones and what they actually mean. Abrasive: Slag used for cleaning or surface roughening. Active Flux: Submerged-arc welding flux from which the amount of elements deposited in the weld metal is dependent upon welding conditions, primarily arc voltage. Adhesive Bonding: Surfaces, solidifies to produce an adhesive bond. Air Carbon Arc Cutting: An arc cutting process in which metals to be cut are melted by the heat of carbon arc and the molten metal is removed by a blast of air. Age hardening: Hardening by aging the material, for example: A material can become harder but more brittle over time. Aging: A change of material properties that happens at ambient (or close to) temperatures after hot working, heat treating quenching or cold working. Alloy: A metal composed of two or more chemical elements of which at least one is a metal. Alloy steel: Steel containing a significant quantity of alloying elements (other than carbon and small amounts of manganese, silicon, sulphur and phosphorus added to produce changes in mechanical or physical properties. Annealing: Heating metal to a suitable temperature followed by cooling to produce discrete changes in microstructure and properties. Arc Blow: The deflection of an electric arc from its normal path because of magnetic forces. Arc Cutting: A group of thermal cutting processes that severs or removes metal by melting with the heat of an arc between an electrode and the work piece. Arc Force: The axial force developed by an arc plasma. Arc Gouging: An arc cutting procedure used to form a bevel or groove. Arc Length: The distance from the tip of the electrode or wire to the work piece. Arc Time: The time during which an arc is maintained. Arc Voltage: The voltage across the welding arc. Arc Welding: A group of welding processes which produces coalescence of metals by heating them with an arc, with or without the application of pressure and with or without the use of filler metal. Arc Welding Deposition Efficiency (%): The ratio of the weight of filler metal deposited to the weight of filler metal melted. Arc Welding Electrode: A part of the welding system through which current is conducted that ends at the arc. Austenite: A solid solution of one or more alloying elements in the fcc structure of iron. Beach marks: Crack arrest ‘lines’ seen on fatigue fracture surfaces. Billet: A solid piece of steel that has been hot worked by forging, rolling or extrusion, often used for machining. Braze Welding: A method of welding by using a filler metal, having a liquidus above 840 °F (450 °C) and below the solidus of the base metals. Brittle fracture: Fracture precedes by little or no plastic deformation. Brittleness: The tendency of a material to fracture without first undergoing significant plastic deformation. Butt Joint: A joint between two members lying in the same plane. Carbide: a compound of carbon with metallic elements (f.d. tungsten, chromium). Carbon equivalent (CE): A ‘weldability’ value that takes into account the effect of carbon and other alloying elements on a particular characteristic of steel. Carbon steel: A steel containing only small quantities of elements other than carbon. Cast iron: Iron containing more than 2 percent carbon. Cast steel: Steel castings ,containing less than 2 percent carbon. Cleavage: Fracture of a crystal by crack propagation. Constitutional diagram: A graph showing the temperature and composition of limits of various phases in a metallic alloy. Crack initiator: Physical fracture which encourages a crack to start. Creep: Time dependent strain occurring under stress. Critical cooling rate: The maximum rate at which austenite needs to be cooled to ensure that a particular type of structure is formed. Crystalline: The general structure of many metals. Crystalline fracture: A fracture of a metal showing a grainy appearance. Decarburization: Loss of carbon from the surface of a ferrous alloy caused by heating. Deformation: General term for strain or elongation of a metal’s lattice structure. Deoxidation: Removal of oxygen from molten metals by use of chemical additives. Diffusion: Movement of molecules through a solid solution. Dislocation: A linear defect in the structure of a crystal. Ductility: The capacity of a material to deform plastically without fracturing. Elastic limit: The maximum stress to which a material may be subjected without any permanent strain occurring. Etching: Subjecting the surface of a metal to an acid to reveal the microstructure. Fatigue: A cycle or fluctuating stress conditions leading to a fracture. Ferrite: A solid solution of alloying elements in bcc iron. Fibrous fracture: A fracture whose surface is characterized by a dull or silky appearance. Filler Material: The material to be added in making a welded, brazed, or soldered joint. Fillet Weld: A weld of approximately triangular cross section that joins two surfaces approximately at right angles to each other in a lap joint, T-joint, or corner joint. Filter Plate: A transparent plate tinted in varying darkness for use in goggles, helmets and hand shields to protect workers from harmful ultraviolet, infrared and visible radiation. Flame Spraying: A thermal spraying process using an oxy-fuel gas flame as the source of heat for melting the coating material. Flammable Range: The range over which a gas at normal temperature (NTP) forms a flammable mixture with air. Flat Welding Position: A welding position where the weld axis is approximately horizontal and the weld face lies in an approximately horizontal plane. Friction Stir Welding: A solid-state welding process, which produces coalescence of material by the heat obtained from a mechanically induced rotating motion between tightly butted surfaces. The work parts are held together under pressure. Grain: An individual crystal in a metal or alloy. Grain growth: Increase in the size of the grains in metal caused by heating at high temperature. Grain orientation: The direction in which the grains of the material are pointing. Hardenability: The property that determines the depth and distribution of harness induced by quenching. Harness: Resistance of a metal to plastic deformation by indentation. This can be measures by Brinel, Vickers or Rockwell testing. Hot Crack: A crack formed at temperatures near the completion of weld solidification. Inclusion: A metallic or non-metallic material in the matrix structure of a metal. Initiation point: The point at which a crack starts. Joint: The junction of members or the edges of members that are to be joined or have been joined. Lamellar tear: A system of cracks or discontinuities, normally this is seen in a weld. Laser Beam Cutting: A process that severs material with the heat from a concentrated coherent beam impinging upon the work-piece. Laser Beam Welding: A process that fuses material with the heat from a concentrated coherent beam impinging upon the members to be joined. Leg of Fillet Weld: The distance from the root of the joint to the toe of the fillet weld. Lattice: A pattern (physical arrangement) or a metal’s molecular structure. Melting Range: The temperature range between solidus and liquidus. Micro cracks: Small ‘brittle’ cracks, normally perpendicular to the main tensile axis. Normalizing: Heating a ferrous alloy and then cooling in still air. Notch brittleness: A measure of the susceptibility of a material to brittle fracture at locations of stress concentration. Nitriding: Surface hardening process using nitrogenous material. Plasma Arc Cutting (PAC): An arc cutting process using a constricted arc to remove the molten metal with a high-velocity jet of ionized gas from the constricting orifice. Plasma Arc Welding (PAW): An arc welding process that uses a constricted arc between a non-consumable electrode and the weld pool (transferred arc) or between the electrode and the constricting nozzle (non-transferred arc). Shielding is obtained from the ionized gas issuing from the torch. Plastic deformation: Deformation that remains after release of the stress that caused it. Precipitation hardening: Hardening by managing the structure of a material, to prevent the movement of dislocations. Quench hardening: Hardening by heating and then quenching quickly, causing austenite to be transformed into martensite. Recovery: Softening of cold-worked metals when heated. Segregation: Non-uniform distribution of alloying elements, impurities or phases in a material. Soaking: Keeping metal at a predetermined temperature during heat treatment. Solid solution: A solid crystalline phase containing two or more chemical species. Solution heat treatment: Heat treatment in which an alloy is heated so that its constituents enter solid solution and then cooled rapidly enough to ‘freeze’ the constituents in solution. Strain aging: Aging induced by cold working. Strain hardening: An increase in hardness and strength caused by plastic deformation at temperatures below the recrystallization range. Stress-corrosion cracking: Failure by cracking under the combined action of corrosion and stress. Tempering: Supplementary heat treatment to reduce excessive hardness Temper brittleness: An increase in the ductile-brittle transition temperature in steels. Tensile Strength: The maximum stress a material subjected to a stretching load can withstand without tearing. Thermal Conductivity: The quantity of heat passing through a material. Thermal Spraying: A group of processes in which finely divided metallic or non-metallic materials are deposited in a molten or semi molten condition to form a coating. Thermal Stresses: Stresses in metal resulting from non-uniform temperature distributions. Thermionic: The emission of electrons as a result of heat. TIG Welding: See Gas Tungsten Arc Welding (GTAW). Toughness: Capacity of a metal to absorb energy and deform plastically before fracturing. Transformation temperature: The temperature at which a metal starts to exhibit brittle behaviour. Weldability: The capacity of a material to be welded under the fabrication conditions imposed into a specific, suitably designed structure and to perform satisfactorily in the intended service. Weld Bead: The metal deposited in the joint by the process and filler wire used. Welding Leads: The work piece lead and electrode lead of an arc welding circuit. Welding Wire: A form of welding filler metal, normally packaged as coils or spools, that may or may not conduct electrical current depending upon the welding process used. Weld Metal: The portion of a fusion weld that has been completely melted during welding. Weld Pass: A single progression of welding along a joint. The result of a pass is a weld bead or layer. Weld Pool: The localized volume of molten metal in a weld prior to its solidification as weld metal. Weld Puddle: A non-standard term for weld pool. Work hardening: Hardening of a material due to straining or cold working. #Materialproperties #terms #welding #metal #fabrication

Almost every exhaust system uses some form of a merge collector. The key role for this merge collector and the most obvious one is to combine the exhaust pipes of the different cylinder into one tailpipe, which could flow to the turbo or the tailpipe. A secondary role, not so obvious but equally – if not more – important is taking advantage of the exhaust gas dynamics and using the secondary exhaust tuning pulses as an advantage to the scavenging of the other cylinder exhaust pipes. There are different exhaust set-ups possible when combining (and merging) the cylinder exhaust pipes which is often called cylinder pairing by racing engine builders. The cylinder pairing is usually determined by the firing order where the aim would be to pair the even firing cylinders and the uneven firing cylinders to aid the scavenging in the paired cylinder exhaust pipe. Certain engines (for example motorbikes, see GF-moto.com) might prefer the merging of 4 exhaust pipes into 2 exhaust pipes into the tailpipe (also known as Tri-Y). Cylinder pairing sometimes you would want to pair 2 cylinders first to merge into the tailpipe later rather than 4 cylinders at once (often called 4 – 2 – 1 systems) or sometimes just need to pair all 4 straight into the tailpipe (often called 4 - 1 systems). When to use one or the other depends on the engine characteristics where even firing high engine speed engines often use 4 into 1 exhaust systems where some specific uneven firing orders or lower engine speed engines might prefer 4 into 2 into 1 exhaust systems. It is often said that the benefit of a decently designed collector is only noticeable below the peak torque engine speed of an engine, however nothing is less true. When designing an exhaust collector all aspects need to be taken into including the high engine speeds at which the engine might run. At these higher engine speeds flow separation could occur where you would reduce the hydraulic diameter of the pipe where the exhaust gasses flow into and reduce the engine peak power. In general it can be said that a 4 into 2 into 1 configuration would benefit the lower engine speed configurations where a 4 into 1 collector would benefit the engines with a higher engine speed. The collector diameter A well calculated collector merge diameter is very important in order not to create backpressure and restrict the flow of the exhaust. One would say: “to make sure it’s enough, I will make the pipe as big as possible”. This is not correct, to maximise the use of the paired scavenging effect, the exhaust gas velocity collector needs to be as large as possible without damaging the flow. In a similar way as calculating the exhaust primary diameters one can calculate the collector geometry. However, there are a couple of extra variables where you need to take into account pulses and any overlap on multi cylinder engines. If you want more information on this, you can always pre order our e-book or contact the office! #DidierDeLille #Exhaustdesign #collector #merge

In many racing series the regulations are constantly changing. This is also the case in the high performance racing series like NASCAR. The NASCAR Sprint Cup regulations for example make the routing of the exhaust system and its assembly quite a challenge, especially where a reduced weight of the exhaust system is needed while maintaining reliability. The regulations are quite open for development of the engine itself which often causes that the development of the exhaust system is pushed to the back of the queue. However the exhaust is one of the areas where a lot of performance is either gained or lost. The main goal for the perfect exhaust system is to reduce the pressure losses throughout the system to a minimum. Because of the ovalised sections in these NASCAR systems are constrained in the regulations this can cause a reduction of power if this is not designed properly. Some racing series have used these oval shapes on purpose with intentionally harming the performance of the engine to gain a performance somewhere else. This was the case in 2012 where we at the forefront of developing the exhaust for blown diffusers in Formula 1. When designing these ovalised shapes (and taking into account the regulations for cross sectional areas) the actual hydraulic diameter needs to be taken into account. This could increase the pressure losses considerably as the ovalised section can be relatively long. In most racing series the exhausts start out as a tubular (round) shape and maintain this shape up to the exit of the system. Because of the regulations in NASCAR this round shape changes to the ovalised regulated section at some point. To do this often a tapering transition piece is made by press forming the materials into the correct shapes. With every this change in geometry, the dynamics of the exhaust gas change (see our article about How exhaust gas dynamics work). Therfore these transition sections need to be carefully designed considering the crossectional area of every section throughout the system geometry changed to maximise the performance of the system. When the area change is too drastic there is a danger of having a flow separation on the walls causing turbulent areas and a very large pressure loss in this transitional section. At Goodfabs we have been serving NASCAR for decades now and have been closely creating development exhaust systems on the car and on the dyno to maximise the performance within the engine regulations. #NASCAR #Exhaustdesign