K-TIG Vs TIG

how does K-TIG compare to TIG welding?

Conventional TIG/GTAW is a melt-in process. Surface tension causes the molten metal to circulate, moving the heat first to the sides and then flowing to the bottom of the weld pool, before returning to top centre of the pool. This results in a broad, shallow and typically turbulent weld pool. Conventional TIG tends to be restricted to currents below 250 amps because higher amperage causes distortion and depression of the weld pool surface. Generally this is unstable.

K-TIG, on the other hand, maximises the arc pressure to create enough force to penetrate the materials being welded. K-TIG uses higher than conventional welding currents, usually between 320 and 600 amps and even higher if a thicker material needs to be welded.

After the material has been penetrated, the K-TIG process creates and maintains an incredibly stable ‘keyhole’. The cavity can convert to a self-stabilising structure by using the sides of the pool as an elastic membrane, attached to the top and bottom opening in the material.

The self-stabilising nature of the keyhole makes the entire process highly efficient by only melting the amount of material required to achieve full penetration. In comparison to conventional TIG-GTAW this energy is wasted.

Arc on time is typically reduced by 50x to 100x as compared to traditional TIG welds.

Both TIG/GTAW and K-TIG only use one gas throughout the welding process, typically argon although mixes can be used to optimise particular applications. Gas is delivered in K-TIG in the same manner as conventional TIG, flowing down the electrode and the gas cup.

The Benefits of Switching

How does K-TIG overcome the issues of TIG Welding?

 K-TIG overcomes the most common issues associated with TIG:

  • Penetration: The practical upper limit for single pass conventional TIG welding is generally considered to be 2mm. K-TIG can comfortable perform single pass welds in 16mm thick titanium, 14mm zirconium, 13mm austenitic stainless steels, Hastelloys, Inconels and a wide range of nickel and cobalt alloys, and 9mm in conductive materials such as ferritic steels and some carbon steels.
  • Speed: Operators will be able to perform welds at significantly faster rates if using a K-TIG system. TIG welding can only go at 300mm/min, while K-TIG can reach speeds of 1000mm/min.
  • Weld Quality: A major benefit of keyhole welding is the absence of porosity in the solidifying weld. The keyhole allows vaporised impurities to pass out the through the back of the keyhole meaning they don’t get trapped as evolved gases. The simple square butt joint design also removes the chances of "bridging" during fill passes and resultant lack of fusion. TIG welding offers precise welds but the finished product will be highly-dependent on the skill of the operator. TIG’s parameters are fairly sensitive for mechanised welds, especially arc voltage and because melting through the joint thickness is the only way to achieve penetration porosity can often become trapped in the solidifying weld.
  • Joint Preparation: Joint preparation for TIG welds is both costly and time-consuming. V- or J- groove preparation is required and mechanised groove preparation is preferred to ensure process consistency. The removed joint metal needs to be replaced with filler, which adds to the cost. With K-TIG, there is no groove to fill (unless over 14-16mm thick) and a simple square butt joint design is all that is required for a quality weld.
  • Welding Cycle Times: The low energy density of TIG means penetration is limited. Root and fill passes are performed at a slow travel speed meaning lengthy welding times. K-TIG’s high energy density keyhole allows for single pass penetration of thick joints at a very high travel speed, which shortens weld times and lessens the amount if weld passes that are required.
  • Keyhole Stability: K-TIG keyholes are extremely stable because of the surface tension in the weld pool and high travel speeds. The keyhole is also self-correcting and able to dynamically respond to fluctuations in the arc forces. TIG welding is reliant on a ‘melt through’ approach and a V-groove root pass, followed by filler passes, for materials beyond 2mm all of which adds to the time of the weld, cost of labour and consumables and the possibility of welding defects.
  • Circumferential Weld Overlap Tie-In: The K-TIG keyhole is produced from a high energy density arc and patented torch design, without any plasma gas or complex constricted arc required.  As a result, at the overlap and slope out of a circumferential weld, the process is extremely simple to slope down to close out the keyhole and end the weld. Due to the limited penetration capability of TIG welding, the overlap can be difficult to "tie in" or fuse properly, as the weld metal from the original start of the weld can be a barrier to full penetration at the overlap point.
  • Weld Appearance: With proper gas shielding of the face and root sides of the weld, the K-TIG process inherently produces a very smooth and uniform weld appearance that requires no further grinding or dressing.
  • Distortion: Due to the low energy density of the process, the slow travel speeds that are typical with multiple weld passes result in substantial weld shrinkage and distortion when using TIG. The high energy density of K-TIG and the high travel speeds that can be achieved with single pass penetration result in remarkably low weld shrinkage and distortion.
  • Process Consistency: The high energy density arc from K-TIG produces a smooth and consistent keyhole through the joint, with very little variation for the duration of the weld.  The process is simple enough, and the electrode is large enough, that erosion (and process drift) are negligible. The TIG process can be "dialled in" to achieve sound welds in a mechanised mode, with a root pass typically followed by multiple fill passes.  However, the tungsten tip erodes throughout the weld and the process is quite sensitive to arc voltage and other parameter variations which can lead to process drift.
  • Consumables Cost: The electrodes in K-TIG systems are reasonable priced and have a long lifespan. Nothing else on the system is subject to erosion or wear and it has a 100% duty cycle power supply. TIG electrodes erode fairly quickly and need re-dressing or replacement on a regular basis.  The gas lens can become also become contaminated and require replacement.
  • Skill of Operator: K-TIG requires minimal training due to the simplicity of the process and the sophistication of the K-TIG controller. Operator training can be completed in 3 hours and comprehensive supervisor training in 1 to 2 days. TIG requires welder training of 1-2 weeks.
  • Duty Cycle: The 1000 amp power supply that K-TIG uses is considerably more than is required for any keyhole process, giving it 100% duty cycle rating. TIG welding systems are typically provided with power supplies in the range of 300-500 amps and are typically only rated for 60% duty cycle. 

We’re getting significantly cleaner welds with K-TIG

Jeff Thomas, Vice President, Operations, TITAN Metal Fabrication

I’m currently using TIG, can I switch to K-TIG

Absolutely! If you have some simple automation equipment or are willing to invest in it, weld with materials thicker than 3mm and larger than 3inch diameter (if circumferential); you’re well on your way. Check out this 6 questions quiz to see if K-TIG would work for you.

How Do I Change to K-TIG?

It really couldn’t be easier.

If you’re currently using TIG, the upgrade process is simple. Your existing welding automation system can still be used.

Literally all you have to do is setup the K-TIG system, and integrate the controller into your existing automation system (if you wish).

Be a hero in your organisation.

Book a live demonstration to see what K-TIG could do for your company.