From the beginning, Charles Warman worked tirelessly to maintain the position of Warman pumps as a market disruptor, researching and developing new materials to continuously take it to the next level.
Materials innovation takes us to the very start of the Warman pump story in 1938 in Kalgoorlie, when Charles Warman introduced replaceable rubber liners for slurry pumps. This invention was groundbreaking; by utilising rubber as the primary wear material of the liner, Warman was able to provide unmatchable value through a part that was easy to remove and offered customers superior wear performance.
However, there are a number of applications where rubber simply isn’t suitable. Metal alloys remain the material of choice for dealing with larger, coarser particles, high temperatures and hydrocarbons. It is important to understand different properties of various alloys, as using the wrong one could have serious consequences for your operation.
Over years, Warman pumps manufacturer, Weir Minerals, developed two leading ranges of alloys delivering excellent wear resistance and lower total cost of ownership: strongest iron-chrome alloys in the Hyperchrome range and high-chromium white irons in the Ultrachrome range.
The Ultrachrome alloys are a series of high chromium white irons that deliver excellent wear resistance in moderate to highly corrosive environments. These alloys contain varying amounts of chromium carbide, an incredibly hard material measuring 1600 Vickers hardness units which provides excellent wear resistance.
Weir’s most popular alloy is Ultrachrome A05, which contains approximately 27 per cent chromium by weight, resulting in a chromium carbide content of about 25 per cent by volume.
With this moderate chromium carbide content, A05 is what’s known as a “near eutectic” alloy, providing a great balance of hardness and toughness. Suitable at pH4 and above, A05 provides modest corrosion resistance to a number of components, such as the impellers, casings, volute liners and throatbushes in the legendary Warman pump range.
The Ultrachrome range also has several hypoeutectic alloys – these have a lower proportion of wear-resistant chromium carbides, but a higher proportion of free chromium in the iron matrix which dramatically improves corrosion resistance.
Weir Minerals’ Hyperchrome range consists of a number of hypereutectic iron-chrome alloys, featuring high proportions of chromium carbide to produce incredibly strong metals.
With a higher chromium carbide content than hypoeutectic options, the hypereutectic alloys have historically been avoided, as they typically contain very large chromium carbides (up to 100µm in size or larger), resulting in a very brittle casting. However, Weir Minerals utilises a specific process to refine the carbides and ensure they do not exceed 50µm, in order to provide quality wear resistance and retain useful mechanical strength.
As an example, Hyperchrome A61, containing 50 per cent chromium carbide, achieves outstanding erosion resistance that makes it ideal for conditions with a broad particle size distribution, such as mill discharge slurries.
The latest innovation from Weir Minerals, Hyperchrome A68, benefits from new metallurgical advances that combine the robust wear resistance of A61 with the anti-corrosive properties of Ultrachrome A05, making it ideal for moderately corrosive environments that require a harder alloy. Having the two together in one material provides a synergistic bonus to overall wear life, which can be found in throatbushes, impellers and volute liners handling mill discharge slurries and tailings.
Using the wrong material can significantly degrade a component’s wear life and put a plant at risk of an unplanned shutdown. Contact Weir Minerals to discuss the best material for your critical components and ensure you deploy a cost-effective material which will go the distance.