In general, work hardening is the strengthening of a material or polymer by plastic deformation. This strengthening happens because of dislocation movements and dislocation generation inside the crystal structure of the material.
When it comes to work hardening steel, which is also known as strain hardening steel or cold worked steel, this refers to a type of steel that becomes stronger and tougher through mechanical deformation rather than heat treatment.
The Process of Work Hardening Steel
This process involves subjecting the steel to plastic deformation such as bending, rolling, or hammering, which causes its crystal structure to change in a way that increases its hardness and strength. The more the steel is “hit” or “impacted,” the harder it becomes. Some work hardening steels are heat treated to a specific hardness before they are put into service.
- Initial State: Work hardening steel starts in a relatively soft and ductile state. Its crystal structure is made up of tiny grains that can slide past each other, allowing for easy plastic deformation without significantly increasing its strength.
- Plastic Deformation: When the steel is subjected to mechanical forces, its grains are forced to move and slide against one another. This movement causes dislocations, which are essentially defects in the crystal lattice structure. These dislocations hinder the sliding of grains and require energy to move.
- Resistance to Movement: As more deformation is applied, the dislocations become tangled and piled up. This makes it harder for the grains to slide past each other, increasing the steel’s resistance to further deformation.
- Increased Strength and Hardness: The piled up dislocations effectively prevent the steel’s grains from easily sliding, resulting in increased hardness and strength. The steel becomes more resistant to bending, denting, gouging, and other forms of plastic deformation.
- Strain Hardening: As the process continues, the steel becomes more and more work hardened. This phenomenon is often referred to as strain hardening. The steel’s properties change without altering its chemical composition, which sets it apart from heat treated steels.
How is Work Hardened Steel Used?
Work hardened steel is commonly used in various applications, including mining chutes, conveyors, grizzlies, screens, bucket lips, and components requiring both strength and ductility. Moreover, this type of steel is also used for the heading of bolts and cap screws, and for the finishing of cold rolled steel.
ENDURA Steel and the TRIP Effect
ENDURA Steel from Titus Steel is a unique work hardening steel that can handle wear eight times more than mild steel. ENDURA starts off as a relatively low hardness steel but can work harden to a very high hardness steel.
Due to the process of heat treatment and quenching in oil rather than water, the microstructure of this steel is very homogeneous and limited when it comes to tearing, shearing, and gouging. It’s helpful to think of ENDURA’s microstructure as a row of pick-up sticks neatly laying next to one another, rather than mixed up in a pile.
INDUSTEEL, a steel producer distributed by Titus Steel in Canada, has developed a revolutionary metallurgical phenomenon known as the TRIP (Transformation Induced Plasticity) Effect, which is achieved by the spontaneous rearrangement of metallic atoms under stress.
Think of catching a baseball. If you make your hand stiff to catch the ball, the impact of the ball can cause damage. But if you loosen your hand to catch the ball, the impact of the catch isn’t as severe.
This is how the TRIP Effect of ENDURA Steel works when rocks, gravel, and other abrasive materials crash into the metal, and why it outlasts all the other wear steels.
Contact Titus Steel today to learn more about ENDURA Steel – a unique, easy-to-process work hardening steel with a homogeneous microstructure, the TRIP Effect, and the ability to work harden into an extremely strong and tough material.