Cementation steels are low carbon, unalloyed or alloy steels used in the manufacture of parts that are hard and wear-resistant on the surface and softer and toughness properties are desired in the core, and are resistant to variable and impact forces. These features are given to the part by impregnating carbon on the steel surface. Cementation steels are used in the manufacture of parts such as gears, shafts, piston pins, chain links, sprockets and pulleys, discs, guide bearings, roller bearings, rollers, some measuring and control tools, medium forced parts, cutting tools. Cementation process is applied to harden case hardening steels. During this process, carbon is absorbed on the surface of the material at high temperature. The machining process is very easy, as the cementation process is applied after the part has been completely or partially finished. If there are areas on the surface of the part that will be processed later and do not have to harden, these areas are covered by covering with special paste or electrolytic copper. Since carbon cannot penetrate these areas, the part can be easily processed later. Since the core area of the material will maintain its softness after hardening with cementation, it becomes quite resistant to impacts.
Cementation steels are much cheaper than high carbon steels, which can give the same hardness on the surface and are in the tool steel class. However, the selection of the cementation steel and the correct cementation process should bring a lot of attention and experience. Good results of the cementation process is closely related to the internal structure cleaning of the steel used. Internal structure cleaning is also the process of purifying from gases (hydrogen, oxygen, nitrogen) dissolved in liquid, and cleaning from oxides and sulfur inclusions. In general, the depth of the cementation layer can be between 0.2 and 1.5 mm at the end of the cementation process. In the surface hardening process, fatigue life increases as the depth of the cementation layer increases. Fatigue is the amount of carbon element most affected by its life. The amount of carbon dissolved in the austenite phase is the most important factor affecting surface hardness. The amount of carbon on the surface should be controlled to be between 0.80% and 1.0%.
As the cross-section of the material used grows, higher alloy steels should be used. The characteristic usage area of these steels is gear manufacturing, and can be called GEAR STEELS by their usage. The important thing in gears is high wear fatigue resistance.
USAGE AREAS OF CEMENTATION STEELS ;
• Medium time, construction and machine parts,
• Lever arm, bush, reel, gear wheel, measuring tools,
• Vibrating and low-force building and machine parts,
• Gear wheel, cardan housing, pin, shaft, bushing and similar parts,
• All kinds of powertrain and steering parts,
• Spool bearing, spool, gauge, piston pin, differential part, ball screw
• Camshafts, gear wheels, standard tension universal joints
• There are many uses in machinery and automobiles such as gear wheel, sprocket, spindle with small size, axle, bushing, dial seat, pin and similar parts and switch bearing parts.