ENGINEERED
WEAR SERVICES
EXTENDED PART
LIFETIME
INCREASE MILL
EFFICIENCY
During the height of the COVID-19 pandemic, Welding Alloys undertook a project to repair a vertical roller mill (VRM) at Hanson Cement’s site in Purfleet, Essex. The work involved the repair of a Loesche 46 2+2S VRM grinding table and rollers, which suffered extensive wear during the processing of 3 500 tonnes of granulated blast furnace slag.
Welding Alloys has a long-standing relationship with Hanson Cement and wear services to the Purfleet plant commenced at the commissioning of its VRM, back in 2001.
Both companies acknowledged the complexity and challenges to complete the project within the limited shutdown period while complying with the COVID-19 measures. As part of the overall planning, a new innovative shift pattern was designed, which would reduce the hours required to complete the hardfacing operation. Additionally, demarcated areas of movement were marked out to simplify social distancing adherence and an unused canteen area was made available to Welding Alloys, limiting the need for shared spaces.
The VRM table and rollers refurbishment was urgent, because once the rolls and table gap go outside of optimum tolerances, productivity reduces considerably resulting in poor performance and outputs.
Following the initial wear audit assessment by Welding Alloys’ technical team, they determined that the grinding components should be taken back to the profile template, using the Integra™ mill wire products. These products are specifically designed for hardfacing and re-profiling of grinding components used in vertical grinding mills. Data from previous projects at Purfleet where these products were applied on rollers and tables, showed very successful results.
Throughout the project, all aspects of welding were monitored by trained Welding Alloys Integra™ team members who held the relevant safety training passports and underwent first aid training. The risk assessments were adjusted to include the COVID-19 measures and to deal with the confined spaces associated with mills. This included taking body temperature readings at the start of each shift; providing hand sanitising stations; travelling to and from sites in separate vehicles; and maintaining social distancing. Welding Alloys completed the work on site ahead of schedule in only three days, including the installation of the equipment in the VRM and the removal of equipment at the end of the refurbishment.
Challenge
Repair Loesche 2+2S VRM grinding table and rollers during COVID-19
Solution
Rebuild grinding components to profile template using Welding Alloys specifically designed wires
Result
Increased service life of components
The improvements achieved included increased service life of components, better grinding efficiency, and lower energy consumption.
Wear reduction is a key part of any mills’ maintenance strategy, and Welding Alloys is at the foreground of wear management technologies and innovation, globally. Through ongoing improvements in formulas and processes, hardfacing has remained the preferred solution to increase wear life for traditional grinding components in the cement industry. For the work on the vertical roller mill (VRM) at Hanson Cement’s site in Purfleet, the hardfacing was applied using the automated WA mill kits, the ideal choice for in situ mill repairs.
To reduce the project duration and time, Welding Alloys used a separate mill kit for each mill component. Each kit was programmed to run 24/7 and both the rolls were repaired simultaneously. The results achieved on this project set a new benchmark for the repair of vertical roller mills (VRM) and is an example of the continuous improvement culture adopted by Welding Alloys.
Welding Alloys group can supply new hardfaced cement mill rollers and tables, adding extra wear lifetime to the components before going into service. This will increase production output and limit the plant downtime substantially. Welding Alloys supplies standard rollers and table castings and by using the group’s proven Mill and MillCarb Cored Wire products, the lifetime of service parts can be extended by 100% or more.
These changes are now implemented in their workshops across the world and form part of the standard business offer to customers, providing even greater flexibility and service.
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