Welding

welding

ARC WELDING

ELECTRON BEAM WELDING

RESISTANCE WELDING

ROTATIONAL FRICTION AND FRICTION STIR WELDING

LASER BEAM WELDING

 

ARC WELDING

Arc welding is one of the oldest, most established processes and applicable for a wide variety of applications and metals. Various types of equipment and methods exist going from rather basic (e.g. Shielded Metal Arc Welding – SMAW) to advanced (e.g. highly controlled pulsed Gas Metal Arc Welding - GMAW).

A power/current source is used to create an electric arc between an electrode and the base material in order to melt the metal(s) at the interface. Either direct (DC) or alternating (AC) current can be used and consumable or non-consumable electrodes. The electrode/arc is moved along a certain path in order to fuse the materials; the common weld pool then gradually solidifies and forms the metal joint. While welding the electrodes and metals are usually protected by some type of shielding gas, vapor, or slag. Arc welding processes may be manual, semi-automatic, or fully automated.

Brazing is another assembly method where an electric arc can be used to apply a local heat input (although also other methods exist based on the oxy-fuel process, heating oven, laser beam, …). This process is significantly different from welding because the base metal (parts to join) remains in the solid state. Only the filler metal will attain its fusion temperature and spread over the surfaces that are to be joined.

(image) Wire Arc Additive Manufacturing (WAAM) is also a manufacturing process based on an electric arc. The filler metal (consumable electrode or additional wire) is molten by the arc energy and deposited there where material is required. That way rather complex geometry can be manufactured (deposition/additive method vs. subtractive like machining) without the need for casting or forging tooling.

 

Application field and advantages

  • Well established methods and therefore many suppliers of equipment and materials. The organisation of the welding activities and related QA has been optimized over many years.
  • Very large welding capacities : from thin plates to important  thicknesses (several cm but then multiple passes)
  • Weldability: can be used for most metals as long as there are no metallurgical issues due to fusion and solidification. For example: steels, stainless steel, copper, aluminium, nickel, titanium and most of their alloys. Heterogeneous welds are often possible with the right equipment and choice of filler metals
  • Easy to automatize to various degrees and according to investment and performance requirements
  • Versatile process and generally easy to apply. Used for many applications such as steel and aluminium constructions, shipbuilding, machine building, pipelines, aeronautics etc.

 

CRM facility

Various welding methods and equipment are available:

  • Shielded Metal Arc Welding (SMAW): up to 500A
  • Gas Tungsten Arc Welding (GTAW): from 0A up to 50A (micro welding) and up to 350A (standard)
  • Gas Metal Arc Welding, MIG/MAG welding (GMAW): up to 500A
  • Plasma Arc Welding (PAW): from 0A up to 50A (micro welding)
  • Advanced welding methods: Fronius CMT (advanced GMAW, also used for WAAM), …
  • Mechanization and automation: welding boom, XY positioner, …
  • Additional equipment: clamps and tooling, welding tables,...

    arc welding
 

ELECTRON BEAM WELDING

Electron Beam Welding (EBW) is a high energy density welding process, which generally takes place under vacuum and without filler material. It consists in bombing the parts with high speed electrons; the impact producing a very intense local heating which melts the metal immediately. The relative displacement between the beam and the parts produces a very high quality weld.

Application field and advantages

  • Many possible configurations
  • Very large welding capacities: from very thin to thick thicknesses in 1 single pass.
  • Weldability: all the metal can be fused. For example: steels, stainless steel, copper, aluminum, nickel, cobalt, molybdenum, tantalum, tungsten, titanium and most of their alloys. Heterogeneous welds are possible
  • Reliable, fast and reproducible process
  • Small deformation and thin heat affected zone
  • No protection gas needed (vacuum = best protection)

crm facility

CRM facility

Bodycote Techmeta MEDARD 43

  • Power: 6 kW
  • Chamber size: 500 x 500 x 500 mm³ + cylindrical extension Ø200 mm with a length up to 1250 mm.
  • Welding area X - Y: 200 mm x 200 mm
  • Max velocity of rotation axis: 120 rpm
  • Max velocity of axis X et Y: 3 m/min
  • Chamber vacuum: 10-4 mbar
 

RESISTANCE WELDING

Resistance spot welding (RSW) is a process in which overlapping metal parts are locally joined at the interface between them. The work pieces are clamped together between electrodes (non-consumable but they wear) while a very intense but brief welding current is sent through them. Such a high current density flowing through the limited contact areas (shortest current path from electrode to electrode) will lead to local melting. Subsequent solidification leads to weld formation at the contact surface between overlapping parts (but not between parts and electrodes).

 Application field and advantages

  • Only for overlap welds (between sheets, mesh on sheet, …) and appropriate for (very) thin materials
  • Weldability: can be applied to a variety of metals such as steels, stainless steels, nickel alloys etc., also usable for brass and aluminium but less straightforward
  • Reliable, fast and reproducible process
  • No protection gas and no filler metal needed
  • Typically used when welding particular types of sheet metal, welded wire meshes or wire mesh. It is intensely used in the automotive industry but also metal buckets, electrical connections on batteries, orthodontic components etc.

crm-facility-resistance

CRM facility

 SOUDAX (image)

  • Equipment appropriate for spot  and roll-spot welding
  • Generator frequency: 2000 Hz
  • Voltage (out): 15 kV max
  • Current (out): 10kA max
  • Spot welding duration: from 0 to 1200 ms (increments of 1 ms)

Roll-spot welding cycles: from 1 to 50 pulses/sec

 

ROTATIONAL FRICTION AND FRICTION STIR WELDING

Friction Stir Welding (FSW) and Rotational Friction Welding (RFW) are both solid state welding processes (similar to forging) operating typically at about 80% of the base material melting temperature. After cooling down the parts undergoing the process will be joined by a quality weld.

When FSW a welding tool, consisting of a pin and shoulder, is brought into rotation and pushed into the work piece at the start of the joint. The frictional heat that is generated between the rotating and stationary surfaces softens the material that is in contact with the tool and stirs it locally. Under constant downward pressure the tool is then moved along the welding path while the material is being intensely stirred in various directions.

When RFW the components to be joined are clamped coaxially in the tooling and one of them starts spinning. Upon reaching the required rpm both parts are approached and brought into contact thus generation frictional heat. After a specific time the rotation is suddenly stopped and both parts are pressed into one another (forging stage).

Application field and advantages

  •  Possible weld configurations: for FSW butt welds and overlap welds (others are possible but subject to restrictions), for RFW  mainly butt welds (spinning part requires rotational symmetry)
    • Very large welding capacities : for FSW from rather thin (0.5 mm) up to thick (25 mm) in a single pass, RFW is a fast method for joining bars and tubes in one process cycle
    •  Weldability: typically used for non-ferrous metals specifically when metallurgical issues occur in fusion welding. For example: aluminium, copper, magnesium and most of their alloys. Welding other metals (such as steels, nickel and titatium alloys) or plastics is possible but less obvious.
    • Multi-material welds are possible and often performed between different aluminium alloys (FSW) and very different metals such as aluminium, steels, titanium (RFW)
    • Reliable and reproducible process (automation and controlled welding conditions)
    • Small deformation and no heat affected zone since the process operates below the fusion temperature. Joints typically have high mechanical resistance (compared to arc welding)
    • No protection gas (when welding non-ferrous metals) and no filler metal is needed
    • Typical FSW applications are welding of Al extrusion profiles (shipbuilding, trains), thick aluminium plates (defence, energy), various mechanical components (machine building, aeronautics)…
    • Typical RFW applications are welding of different steel grades (mining), valve heads and compressor turbines (automotive and aeronautics), various mechanical components (machine building, tools)...

      friction crm

      CRM facility


      FSW machines: ESAB 53 UTL and STL  

    • Machines for 1D up to 2.5D welding (no full 3D)
    • Max welding force: 100 kN (process control by force or position)
    • Max spindle speed: 1400 rpm and 3000 rpm
    • Welding area X - Y: 600 mm x 6000 mm
    • Max linear feed speed: 2 m/min
    • Max weldable diam (circumferentially): 2 m
    • Additionally: cooling for FSW tool, various welding tools (retractable pin, bobbin, …), accessories for welding high temp materials (steels, titanium, …)

       

      CRM facility

       FSW machines: ESAB 53 UTL and STL  

    • Machines for 1D up to 2.5D welding (no full 3D)
    • Max welding force: 100 kN (process control by force or position)
    • Max spindle speed: 1400 rpm and 3000 rpm
    • Welding area X - Y: 600 mm x 6000 mm
    • Max linear feed speed: 2 m/min
    • Max weldable diam (circumferentially): 2 m
    • Additionally: cooling for FSW tool, various welding tools (retractable pin, bobbin, …), accessories for welding high temp materials (steels, titanium, …)
       

      Rotational Friction welding machine: SMFI SF20

      friction machine

    •  Power: 20 kW
    • Machine capability: adjustable timing and forces (friction, forging…), process control by force or displacement
    • Max spindle speed: 3000 rpm
    • Max weldable diam: bars diam. 6 mm to 25 mm and tubes up to diam. 50x4 mm
    • Max forging force: 120 kN (300 bar)
 

LASER BEAM WELDING

Laser Beam Welding (LBW) is a high energy density welding process that uses electromagnetic radiation (light) to obtain fine, penetrating HQ weld at elevated speeds. The incident light is concentrated on the part surface leading to very intense local heating which melts the metal immediately. The joint is produced by relative displacement between the beam and the parts. The hybrid laser-GMAW process (HLW) combines laser and arc welding in the same melt pool leading to penetrating welds with increased gap bridging capability.

 

Application field and advantages

  •  Various laser processes are available: pulsed LBW (for better control of the heat input), fiber LBW (for obtaining very fine welds) and a hybrid LBW-arc version
  • Many possible joint configurations
  • Typically without use of filler metal but with some shielding gas (Ar, He, …)
  • Large welding capacities: from very thin to approx. 5mm steel (even more in case of multipass laser-GMAW hybrid welding)
  • Weldability: can be used on most metals. For example: steels, stainless steel, nickel, titanium etc and most of their alloys, copper & aluminium are more difficult. Heterogeneous welds are sometimes possible
  • Reliable, precise, fast and reproducible process
  • Small deformation and thin heat affected zone

 

 

 CRM facility

Trumpf TRULASER CELL 3010

  • Workstation connected to 2 laser sources: pulsed and fiber laser for welding and cutting (max 2 mm thick steel)
  • Laser power (pulsed laser, 1064 nm): 200W continuous, 8 kW peak
  • Laser power (fiber laser, 1070 nm): 400 W

trulaser

Kuka robot with Trumpf optics

  •  KUKA KR30 HA robot equipped for laser and laser-GMAW hybrid welding
  • Laser power: 3 kW
  • Laser specifications: 1064 nm, 600 µm fibre, 25 mm.mrad
  • Laser focal distance: 150 mm and 250 mm
  • GMAW source: Fronius TP4000
  • GMAW source: 3 – 400 A and 14.2 – 34 V
  • Max linear feed speed: > 5 m/min
  • Max linear reach: approx 2 m/min
  • Additionally: positioner with 2 rotational axis,

kuka