Electron Beam Welding Joint Design And Function

July 8, 2024, 3:52 pm

The step typically is on the order of 0. Narrow welds for a limited heat input minimize and keep the amount of distortion at a technically acceptable level and are therefore critical to this application. The use of this design assumes accessibility to both surfaces for machining and inspection purposes. Whenever possible, hollow areas should be vented to the outer surface of the part. The larger the ratio between the focal length and collimation length, the larger the depth of focus becomes for a given fiber. The seam tracking data is then fed back to the optic controller, which translates the information to reposition the galvo motors in the head to direct the laser beam to the required location. CVE electron beam welding machine with a medium-sized chamber. Tier Joint — Figure 17. The FABRICATOR has served the industry since your free subscription. Virtually all metals can be welded with an electron beam. Only use non-magnetic materials, or materials that can be properly demagnetised. Further advantages are; minimal distortion, a very narrow HAZ (heat affected zone) and as the welding normally takes place within a vacuum environment the risk of hydrogen contamination of the weld is minimised. The final products are made from many components, and these components need to be joined in some way.

Electron beam welding applications
Electron beam welding joint design http
Electron beam welding joint design and engineering

Electron Beam Welding Applications

Inspection Techniques. The molten metal flows around the keyhole and solidifies in its trail. Quality Procedures and Manuals, detailed operation sheets, Approved EB weld schedules with configuration controls. Adaptation of technologies such as real-time seam tracking, gap bridging, beam oscillation, and integrated clamping to laser-related processes allows for them to be used in a more mainstream approach. This joint design may be used for materials as thin as 0. These electrons are accelerated using a high voltage, typically in the range of 30kV to 150kV and with the aid of a focus (convergence) coil and a deflection coil, the electrons can be formed into a narrow convergent beam and accurately positioned on the work piece. This type of configuration can also lend itself to finish machined details though the additional material used to locate the joint is sometimes removed after welding. The process laboratory occupies about 4, 000 square feet within the service facility. A conventional electron beam welding machine, as shown in Figure 1, consists essentially of a device for producing a focussed beam of electrons (an electron beam column) mounted on, or in, an evacuated chamber that contains devices for holding and moving a workpiece.

EBW fusion welding process run on a single pass creates joints with minimal distortion and possesses the ability to join different metals. The weld strength is determined by the amount of weld along the seam, so the amount of penetration determines the amount of weld strength. This process was sufficiently large to be machined to parent metal diameter and give a smooth bore. An alternative welding process using EBW has been adopted by a number of leading turbocharger manufacturers. A penetration weld is the commonly used trial weld technique to determine the welding parameters for a specific part thickness. Laser welding energy sources utilize either a continuous wave (CW) or pulsed output of photons. 4 Machines for electron beam welding and other processes. As the electron beam is moved forward, material melts at the front of the beam.

Similarly, what joint configuration is best? EB welders have matured to meet the demands of modern industries such as the low volume, high quality aircraft industry, as well as mass production-orientated automotive industry. However, if under-fill or unfavourable shape of the bead is produced it can be rectified by a subsequent cosmetic pass provided the workpiece is not to be machined after welding. Recently, there has been some work done to develop lasers that can approach the penetration of an electron beam. The surface focus of the beam at low beam current levels is usually checked by machine operators prior to carrying out welding. These characteristics make EBW an extremely valuable technology. For structural components, it is often necessary to join relatively dissimilar materials such as boron steels to either electrolytically galvanized or hot-dipped material. Process Characteristics of Electron Beam Welding (EBW): The welds produced by EBW are typical in shape as they are formed fry nailhead penetration which differentiates it from finger penetration of high current gas metal arc welding (GMAW) process, as shown in Fig.

A narrow heat-affected zone allows for welding delicate assemblies. A welcome side effect of preheating in mass production is that welding speeds can be safely increased, making the process more economical. A complementary solution exists that includes some of the features noted above regarding optical seam tracking and beam oscillation. This eliminates the need to do a lot of postweld machining and cleanup. As regards increasing the welding process efficiency, ensuring the best quality of welded joints and facilitating operators' work, electron beam welding equipment manufacturers offer many additional systems, including the following [44]: automatic beam alignment system, electron-optical monitoring system, automatic seam tracking, control of the process, fast deflection generator, wire as well as powder feeder. However, these advantages are gained at the expense of low weld depth to width ratios, reduced weld penetration and small gun-to-work distances. Although Inconel may be prone to weld cracking, performing the electron beam process at a relatively slow speed ensures good mixing in the fusion zone and produces a crack-free joint. This combination of dynamic movement and fast solidification may result in vapor pockets created by a too rapid solidification of the molten material behind the beam. Optical tools allow for adaptability in welding. Cleaning and Painting Facilities. Filler wire feeding equipment is usually similar to the one employed for gas tungsten arc welding though specific needs may necessitate the use of specially designed units for use in vacuum chambers.

Electron Beam Welding Joint Design Http

If you are not sure which system is right for your application, please get in touch! In the case that a lap fillet is the functional joint that needs to be processed, similar issues are seen here as well regarding joint location and required overlap. Electron beam welding's excellence at joining dissimilar materials comes into play at this point. Using this approach, it is necessary to maintain close to zero gap to ensure proper welding of the joint. For this reason, the weld depth ranges from only a few tenths of a millimeter to 1 mm. NDI—Leak checking, Die Penetrant inspection, Laboratory Testing and Demonstration Capabilities. Axial and circumferential welds can be performed with a rotary tilt device that is mounted on top of the x-/y-table.

Manufacturers of these units had conventionally used inertia friction welding techniques to join the investment cast, Inconel wheel to the carbon steel shaft. As in steel, the welds will again be very narrow, with a small heat affected zone. Conventional Electron Beam Welding. If welding through the top sheet (3 in Figure 2), the laser beam must penetrate through the top sheet and into the bottom sheet, and all that energy spent penetrating the top sheet doesn't add any weld strength.

This welding technology is achieved by having only the electron beam gun inside a vacuum box while the workpiece itself remains outside of the vacuum chamber. LBW - Simpler Tooling, Shorter Cycle Times. The addition of nickel shim may also be useful to achieve the desired ratio of austenite to ferrite for corrosion protection. This is critical to get the same power density to ensure repeatable results. This provides the ability to weld difficult or "impossible to weld" alloys. Because it is a noncontact process, welding in holes and in tight spaces is possible if the beam width as it comes into focus is considered. Larger spot sizes accommodate larger variations but require much more energy input to achieve the same weld penetration depth.

There are two variants or modes of the main process viz., medium vacuum EBW and non-vacuum EBW. This system has the ability to provide various inclination angles to accommodate alterations in joint position for two- and three-layer welds as flange heights change relative to one another. Lap welding has many different considerations. It is beyond the scope of this paper to detail the weldability of various metals; therefore, the following examples will focus on certain production applications. Medium volume production is typically performed in chamber machines with specialized tooling.

Electron Beam Welding Joint Design And Engineering

For those manufacturers and many others not specifically mentioned here, welding processes have to meet increasingly stringent standards that have become more prevalent over the years. The work chamber may be filled with helium as it offers less obstruction to the EB and gives better penetration shape than obtained with argon or air as atmosphere. Applying a large load evenly across the part surface, such fixturing can be ideal for stamped parts with large variations in surface flatness. Weglowski,... A. Phillips, in Welding and Joining of Aerospace Materials (Second Edition), 2012. The ability to process in this manner is provided via a combination of features, including optical seam tracking, integrated clamping, and beam oscillation capabilities, in one tool—the Scansonic FSO (Flange Welding Optic). Duplex and Super Duplex Stainless Steels.

This method tends to create voids within the material lattice of the part. Butt welding requires accuracy and process repeatability but can achieve strong welds with minimal heat input. Typical welding spot sizes are from 50 to 900 µm in diameter. As with any rule, there are exceptions. Further improvements to weld quality can be achieved by using different weld patterns to eliminate undercuts and irregular penetrations.

Square butt edge preparation demands the use of fixtures to keep the work components in the required alignment; however when fixtures are to be avoided the joint may be modified to rabbet type as shown in Fig. The exit end of the nozzle is an assembly of Inconel 625 and Hastelloy, and the support stem is type 347 stainless steel. Dissimilar metal combinations that are metallurgically compatible can also be welded. Although filler metal is not normally added to the weld pool, it can be added via bare wire. Although this joining method produced a joint of adequate strength, the post-weld machining, grinding and heat treatment operations were expensive and time consuming.

See list in section 2. 00013 mBar) with the electron gun at a higher pressure of around 1E-6 torr (0. 010" will require larger than desired beam diameters and can risk "missed joint" type lack of fusion defects. After you've selected the right material for your welding project, the next important consideration is joint design. However, these lasers require exceptionally high power (close to 100 kW), which makes them both exceptionally expensive and exceptionally dangerous to work with. Because of EB welding's precision and automated repeatability, the aerospace industry developed quality standards to make sure the human elements of the welding process were tightly controlled. Widely accepted across many industries, EBW permits the welding of refractory and dissimilar metals that are typically unsuited for other methods. Other fields of applications for Titanium materials are, for example, medical implants for which pure titanium is preferred over its alloys. Heat conduction laser welding is used for corner welds on the visible surfaces of device housings as well as other applications in electronics. Geometry limited applications.

This type of welder typically employs a 2-station dial index with one part in each of the stations.