If you were given the task to develop the world’s best wear steel, how would you develop it?
High wear resistance steel does not just depend on hardness but on other factors such as crack resistance, work hardening, ductility, and softening resistance. Most wear steels rely on chemistry to achieve hardness. However, the “in service” performance of the steel is strongly influenced by the microstructure obtained after heat treatment.
3 Main Processes to Develop High Wear Resistant Steel
Superior wear resistance is mainly due to the following:
This is critical in developing the optimum wear steel. The initial structure should not be fully martensitic but a mix of martensitic, bainite and retained austenite. This will allow the steel to work harden when submitted to impact “in service”.
This is known as plastic deformation, whereby the surface of the steel hardens while the material underneath remains ductile. As the surface of the steel is worn away, the next layer continues to work harden yet the steel remains ductile in the middle. This ductility dramatically improves life by delaying tearing and shearing of metal particles on the surface. To simplify, the steel is a trampoline which gives a little when impacted.
Fine Dispersion of Micro Carbides
Ideally, you would want a fine homogeneous dispersion of micro carbides, which will improve the sliding wear resistance.
This can be achieved by the chemical composition and a controlled cooling rate in oil rather than water. This homogenous microstructure differs from other 500 HB wear steels, which are water quenched, making them fully martensitic. Think of “pick-up sticks” falling down in a random pattern versus carefully laying each stick down in a homogenous pattern.
Ideally, you do not want your wear steel to soften at a high temperature.
To accomplish this, one would use a combination of chromium, molybdenum and titanium. This combination allows the wear steel to be effective up to 450°C (840°F). It also allows for processing at a high temperature (550°C), followed by slow air cooling, without any effect to the hardness of the wear steel.
· ENDURA and ENDURA Dual Are the Optimum Wear Steels
ENDURA and ENDURA Dual are the only wear steels that have a fine homogeneous micro structure. They work harden due to the TRIP Effect from 430 BHN to 560-580 BHN. They are easy to process. They also do not lose their Hardness at a high temperature. So you don’t have to develop the optimum wear steel, it’s already been done for you.
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