MillCarb^™ three times tougher than any other vertical roller mill (VRM) solution

Progress report on Welding Alloys’ hardfacing repair of vertical roller mill (VRM) rolls for a Malaysian power plant.

Our last article about this Welding Alloys Far East Integra^™ service team VRM repair project was in 2021 – and now in 2023 we can provide an exciting update.

The in situ inspection of the MillCarb^™ vertical rolls installed in the coal-fired plant in 2019 concluded that the rollers continue to be in excellent condition. This is after a total throughput of 1.1 million tonnes.

Pieter du Plessis, Group Product Engineer, Integra^™, confirmed that while the hardfacing of the MillCarb^™ rolls did show some signs of wear (5-8mm), the surfaces remained smooth and did not exhibit high-wear areas typically seen on standard vertical roller mill rollers.

“The first inspection took place in December 2020 and the results were so impressive the customer postponed maintenance of the vertical roller mill rolls, and continued with the MillCarb^™ rolls for the next year,” said Integra^™ & Maintenance Manager at Welding Alloys (Far East) Sdn. Bhd, Gianni Morselli.

“This inspection we are reporting on here was conducted in May 2022 and the results were everything we expected and then some,” added Gianni Morselli. “On top of the decrease in wear rate, the even wear pattern exhibited on the MillCarb^™ rolls has helped to maintain stable mill output for longer time periods.”

“This resulted in prolonged constant power consumption per tonne of coal ground,” said Integra’s Pieter du Plessis. “These factors combined contribute to a significant decrease in total cost of ownership.”

Fast Facts:

• The MillCarb^™ hardfaced rolls have completed around 20,000 hours and will continue until the next major inspection in 2023
• The vertical roller mill solution will provide continuous operation capability for at least three years without the need for re-welding.

Dr Venugopal Thota, Managing Director of Welding Alloys (Far East) Sdn. Bhd, said: “In this case calculations indicate where standard vertical roller mill solutions have a wear rate of 1mm for every 63 000 tonnes of coal ground, MillCarb^™ only wears at a rate of 1mm for every 170 000 tonnes of coal ground, indicating MillCarb^™ has the ability to handle at least three times the throughput for the same amount of wear.”

What is MillCarb^™?

MillCarb^™ is a fully-repairable, welded ceramic composite metal matrix alloy providing an optimised engineered wear protection solution for grinding components, such as vertical roller mill rolls. MillCarb^™ has been developed together with industry-leading mill OEMs and experts in material science to ensure optimum performance when needed most and is setting new standards for the cement and coal milling industries.

The tight controls and unique welding process of MillCarb^™ result in a final product of up to 20mm thick, embedded with uniformly-distributed ceramic-carbide particles throughout the entire thickness of the welded overlay. The size, shape, make-up, and deposition techniques of these particles were determined through a scientific approach, combined with real-time testing ensuring that particle segregation is virtually eliminated.

One of the advantages of MillCarb^™ is the uniform wear rate throughout the deposit thickness. Dilution from the base material has little effect on the wear rate and the solution does not necessarily rely on the choice of welding consumable, chemistry, and cooling rates for its success.

To find out more about how you can benefit from prolonged service life and reduced total cost of ownership of grinding components, including vertical roller mill solutions, simply contact your local Welding Alloys team.

Read our 2021 report on this Welding Alloys Far East Integra^™ service team vertical roller mill repair project.