Surface-hardened

Surface-hardened describes a material that has undergone a treatment process, typically involving heat and/or chemical alteration, to increase the hardness and wear resistance of its outer layer while preserving the core's original properties. This process creates a durable outer shell able to withstand abrasion, impact, and fatigue, improving the overall lifespan and performance of the component. This is frequently done to improve the lifespan of tools, gears, and other components by making the outer layer much harder while preserving the ductility of the interior.

Surface-hardened meaning with examples

• The gear teeth were surface-hardened through induction hardening, allowing them to withstand the high stresses and friction generated during operation. This treatment greatly extended the gear's lifespan compared to untreated alternatives. The process ensured the core's toughness remained intact, preventing catastrophic failure under extreme loads, making it much more useful in machinery.
• Surface-hardened steel components are crucial in automotive applications, where they are exposed to extreme wear. The crankshaft in that engine has been surface-hardened to improve the contact between it and the bearings. This provides the required hardness and reduced friction necessary for operation. This process is often used to treat pistons as well as the crankshaft.
• The cutting edge of the drill bit was surface-hardened with a nitriding process to enhance its ability to cut through tough materials like hardened steel or other alloys. The hard outer layer of the drill bit resists abrasion, while the core remains flexible enough to prevent breakage under pressure. This results in the ability to perform a large volume of work before needing to resharpen or replace it.
• Surface-hardened bearings are utilized in high-speed machinery to reduce wear and tear. The outer surface is made resistant to damage, extending the life of the bearings and increasing the operational time of equipment. The bearing's enhanced durability also improves the efficiency of the mechanism because the heat produced by friction is reduced.