Kettle testing and use – recent developments

GAA Conference 2011

Critical asset

• The Kettle is a critical asset in your galvanizing plant.• Some examples of kettle value:– Between 5-10 days of sales– Between 10 – 25% of the zinc it holds

• Another aspect is the full replacement cost including:– New kettle– Zinc losses from pump out/remelt (5-10%)– Lost production– Associated services

Kettle strategies

• Regular pump out testing• Regular in service testing• Fixed replacement timeframe• Hope for the best

Testing

• Three types of thickness testing:– External wall zinc cooled– Internal wall – pump out– Internal wall – submersible probe

• Kettle testing using submersible probes is now well established and in use by many galvanizing companies in Europe and USA with some tests completed in Australia/NZ during 2010/11

KID testing

Testing (Continued)

• Significant downsides of the current equipment include:– Size (difficult to transport)– Use of cooling gas

• Development of non cooled probes is progressing.

• A probe owned by a galvanizing plant is now conceivable

Outcome of more testing

• The more testing is done (particularly if by an organisation who is able to aggregate the data) then it becomes clearer to see the need for greater understanding heat transfer into the kettle

• Kettles that are replaced often contain substantial surface areas above 40mm!

• This is a clear indication that there is opportunity to improve CC performance

Wear maps

Combustion chambers

• Most kettles exhibit a similar pattern of wear• For each square metre of wall thickness at or

below 30mm there will be at least 5 sqm of wall at 40mm or above

• An even distribution of heat could extend kettle life significantly – but at what cost

Kettle designs

• Relatively few changes to kettles have been made over the last 20 years.

• The flared kettle or champagne glass design has been around for some time now. Whilst there has been some uptake this design is in limited use in Australia.

• Only 1 built by Furphy Engineering.• Chinese appear to be more adventurous.

Pump outs

• Pump out services involving molten transfer are now common in Europe and North America.

• Molten transfer vessels are electrically heated and have a capacity of 80 tonne.

• Significant reduction in downtime – even with only half of the zinc transferred molten.

Pumping out

Pumping zinc

Molten transfer vessel

Pumping into moulds

Cooling

Pumping zinc back into kettle

Outsourced shut-downs

• In addition to pump outs there are also fully outsourced shut downs occurring – as in other industries.

• Recent project involving kettle replacement was as short as 4 days from last dip to molten metal in the new bath!

• With the shortening of time offline made possible by the molten transfer – these shutdowns can occur outside normal shut periods such as Christmas/Easter etc.

Use of jacking cranes

Kettle removed

Changeover works

Furnace re-lining

Stainless Steel

• Increased aluminum content requires different bath materials

• The use of Stainless steel 316 in kettles has been a recent development for Furphy Engineering.

Thank you!