Radius Grinding Stainless Steel Vessel Fillet Welds

TA10 radius stainless tig welds on pharma vessels

Introducing the new Cibo RebelOne TA10 unitised disc.  With TA10 discs the radius grinding and polishing of large vessel, stainless steel fillet welds is a whole lot easier.  Fabricating larger tanks and vessels requires stronger welds whilst the standard of finish required can be higher still; particularly for pharmaceutical applications.

Traditional unitised discs do not have the aggression and durability to radius some of the larger stainless steel fillet welds which need to be laid on mixing vessels and tanks.  So the only alternatives have been:

  1. An abrasive belt file.  Involving lots of belt changes.  Belt files can easily cause additional damage which often needs to be re-welded and the whole polishing process repeated, or…
  2. Using grinding discs or abrasive flap discs to remove the weld.  Not only is it difficult to access the weld in this way but it is also difficult to radius the weld consistently.  Additionally, more damage can easily be caused when using such an aggressive disc in an uncontrolled manner.  Flap discs often necessitate an excessive number of intermediate stages to finish the vessel to the required customer specification.

RebelOne TA10 fillet weld grinding discs remove all these problems.

What is Different about the new TA10 Fillet Weld Grinding Discs?

Cibo TA10 unitised fillet weld grinding disc

TA10 discs use a high performance engineered abrasive to ensure a fast cutting action.  With the new production processes Cibo have squeezed even more cutting action into a thinner & higher density disc without losing the flexibility which is such an advantage when radiusing fillet welds on stainless steel vessels.  The previous minimum disc width was 4.2mm, our new TA/10/T30 disc is now 3mm wide which is ideal for thinner welds, the new wider disc minimum on the TA/10/T31 disc has reduced from 6.8mm to 6mm wide giving even more cutting power, higher aggression & a longer life.

  • TA/10/T30 4.2mm squeezed to 3mm discs with no reduction in material
  • TA/10/T31 6.8mm squeezed to 6mm discs with no reduction in material

The Process – Grinding Fillet Welds to Leave a Mirror Polish Finish

Step 1:  Grind & Radius Stainless Fillet Welds

Grind out the top of the tig weld and radius along the weld seam with the TA10 operating at a speed between 4,500 to 5,500 rpm.  Use the flexibility of the TA10 disc to blend the fillet with the parent metal as soon as the radius has been formed.  This will create an invisible weld with zero risk of entrapment.

Note:  The video was completed using the 3mm wide TA/10/T30 discs

Top Tip:  TA10 will leave a burr free and entrapment free surface finish which will be safe for use in a food environment. 

Step 2:  Blend the Grind Lines, Remove the Weld Colour

If a bright but not mirror polished finish is needed to meet the customer specification then this can be achieved with one additional process step using the GA Combi unitised discs.  GA combi discs combine a more aggressive centre with a soft finishing outer edge.  The GA6 is ideal for blending the grind marks from the TA10.

We used the new Cibo FinitAll narrow head grinder for our video work.  Mount the GA10 disc on the FinitAll then run along the weld seam at a 45 degree angle to the weld.  The heart of the GA6 disc will blend the sanding marks to a finer finish.  This will only take a few seconds.  Once the surface finish has visibly improved flex the disc to the side to blend and polish the weld surface with the stainless.  This will create a bright and consistent finish.  Ensure when you are using the softer outer face to come far enough away from the fillet weld to remove any remaining weld discolouration or blueing.

Top Tip:  GA6 discs have an aggressive centre and a bright finishing outer face.  Ensure you polish with the outer face in contact with the stainless surface for a fine, bright finish.

Step 3:  Mirror Polish Radiused Stainless Fillet Welds

One of the benefits of removing and radiusing fillet welds with the unitised discs is that it is easy to control the weld repair zone.  Sanding marks will be controlled to within a couple of mm of the welded area.  The only sanding that comes further away from the weld is with the side of the GA6 combi disc to remove any weld discolouration.  This makes the mirror polishing process child’s play.

Remove the GA6 combi disc and replace it with a 6mm wide felt polishing disc (SKU:  MHV/5600/T31).  Spin the disc on the machine and dress the disc with the green PV/101 polishing soap.  Once there is enough polish on the disc run directly over the fillet weld in the same way as the GA6 discs.  This will leave a clean, bright polished surface which blends in beautifully to meet pharmaceutical vessel specifications.

Cibo FinitAll Narrow Head Grinder

All the above videos were completed using the new Cibo FinitAll narrow head variable speed grinder.

The FinitAll machine uses a planetary gear construction to reduce the head depth and is ideal for stainless vessel grinding.  Use the FinitAll to create perfect radiused stainless steel vessel fillet welds.

Cibo FinitAll Machine Specification

Voltage:  Available in 230 volt

Motor Power:  1,000 watt

Max rpm:  7,600 rpm

Min rpm:  2,000 rpm

Thread mounting:  M14mm, thread length 19mm

Machine weight:  2.3Kg (excl. power cable)

Max disc diameter:  150mm

Min disc width:  3mm

Max disc width:  13mm

Can I see a Full Video of the Fillet Weld Grinding Process?

If you would like to see the full grinding process for creating an invisible weld radius on stainless steel tig welds then follow the link to our AFS Youtube Channel where you can see this video and many more besides

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