Casehardened steel can be provide with tough core and abrasion-resistant surface, wherein high surface hardness will be beneficial for polishing treatment. Carbon content in the casehardened steel is less than 0.25%. during heat treatment, carbon element can strengthen the intensity of core. To get higher surface hardness, carbon content on the surface must be increased, whereby can be achieved through adding carbon accelerant during the course of heat treatment. The ideal carbonization temperature depth is 0.6—1mm. after quenching and tempering, the surface hardness can reach 58—62HRC. Since the carbonization temperature is rather high, the dimension change is bound to occur, which requires extra follow-up treatment.
Case hardening is a technique in which a metal surface is reinforced by the adding of a thin layer of another metal alloy that is more durable, increasing the object’s life. This is particularly significant for the manufacture of:
Machine parts / Carbon steel forgings / Carbon steel pinions
Case hardening is suitable both for carbon and alloy steels, and typically mild steels are used. Case hardened steel is formed by diffusing carbon (carburization), nitrogen (nitriding) and/or boron (boriding) into the outer layer of the steel at high temperature, and then heat treating the surface layer to the desired hardness.
Parts that are subject to high pressures and sharp impacts are commonly case hardened. For theft prevention, lock shackles and chains are often case hardened to resist cutting, while remaining less brittle inside to resist impact.
Case hardening is also known as surface hardening.
Corrosionpedia Explains Case Hardening
Case hardening is a simple method of hardening steel involving the use of metal that has low carbon content, and combining it with a metal that has a higher carbon content. The combination of metals produces a product that is much harder. The addition of the low-carbon metal creates a material that can be molded easily into desired shapes.
The surface improvement not only increases the product strength, but also assists in avoiding weakening of the iron. One advantage of this method of hardening steel is that the inner core is left untouched, and therefore still processes properties such as flexibility and relative softness.
Case hardening is usually performed after the formation of the component into its final form. Components that are subjected to severe impacts and high pressures are generally case hardened. Case hardening steels are particularly suitable for:
Screws / Fasteners / Firing pins / Rifle bolts / Engine camshafts
Because hardened metal is usually more brittle than softer metal, it is not always a suitable choice for applications where the metal part is subject to certain kinds of stress. In such applications, case hardening can provide a part that does not fracture, but also provides adequate wear resistance on the surface.
Typical applications of the Case-hardening steel include:
Transportation: Case-hardened components are needed in any engine-driven vehicle, whether it’s a small car, a racecar, a truck or an ocean vessel.
Energy generation: Gear wheels and large components have to withstand cyclic stress and wear in hydroelectric power stations, wind-turbine generators, propeller drives of drilling rigs and steam-turbine gears of power stations.
General mechanical engineering: General mechanical engineering: Applications in this area include forging presses, metal rolling equipment, machine tools; drivelines of mining equipment and heavy-duty transmissions; earthmoving equipment and heavy-duty construction cranes. Wear resistance and good fatigue strength are always key characteristics of the case-hardened steels used for these applications.
According to the need of cost and function of mold, the classification of mould steel is more and more abundant.
in mold manufacturing, casehardened steel is often used in many mold
Wow, this article you posted is good, my brother is learning such things, your blog is very helpful for him, thanks! happy new year
thanks! happy new year!
I am a steel distributor and I like reading such articles， thanks for sharing