CEMENTATION STEELS Cementation steels are low-carbon, non-alloyed or alloyed steels that are hard and wear-resistant on the surface and softer and tougher in the core, used in the manufacture of parts resistant to variable and impact stresses. Gaining these properties to the part is achieved by impregnating the steel surface with carbon. Cementation steels are used in the manufacture of parts such as gears, shafts, piston pins, chain links, sprockets and rollers, discs, guide bearings, rolling bearings, rollers, some measurement and control instruments, medium-forced parts, cutting tools. In order to harden the cementation steels, the cementation process is performed. During this process, high temperature carbon is impregnated on the surface of the material. Since the cementation process is applied after the part takes its final shape partially or completely, it is very easy to process the part. If there are areas on the surface of the part that will be processed later and which do not want to harden, these areas are covered with a special paste or electrolytic copper. Since the carbon cannot penetrate these areas, the part can be easily machined afterwards. After hardening with cementation, the core area of ​​the material will retain its softness, making it highly 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. The good results of the cementation process are closely related to the internal structure cleaning of the steel used. Internal structure cleaning is also the process of purifying the gases (hydrogen, oxygen, nitrogen) dissolved in the liquid and cleaning it from oxide and sulfur inclusions. In general, at the end of the cementation process, the depth of the cementation layer can be between 0.2 and 1.5 mm. Fatigue life increases as the depth of the cementation layer increases in the surface hardening process. It is the amount of carbon element that affects the fatigue life the most. The amount of carbon dissolved in the austenite phase is the most important factor affecting the surface hardness. The amount of carbon on the surface should be controlled to be between 0.80% and 1.0%. The larger the cross section of the material used, the higher alloy steels should be used. The characteristic usage area of ​​these steels is gear manufacturing, and they can also be called GEAR STEELS due to the place of use. The important thing in gears is the high wear and fatigue resistance. USAGE AREAS OF CEMENTATION STEELSII; • Medium-time, construction and machine parts, • Lever arm, bushing, pulley, gear wheel, measuring instruments, • Vibrating and low-forced, structural and machine parts, • Gear wheel, cardan socket, pin, shaft, bushing and similar parts, • All kinds of drivetrain and steering parts, • Roller bearing, pulley, gauge, piston pin, differential part, ball screw • Camshafts, sprocket, standard tension universal joints • There are many areas of use in machinery and automobiles, such as small-sized, over-stressed parts such as gear wheels, sprockets, shafts, axles, bushings, dial slots, pins and similar parts, and switch bearing parts. SEMENTASYON STELL MKE NORMU DIN NORMU C Si Mn Cr Mo Ni Ç 1020 C 15 0.18-0.24 0.15-0.30 0.30-0.50 - - - Ç 3115 - 0.12-0.18 0.15-0.35 0.40-0.60 0.55-0.75 - 1.10-1.40 Ç 3315 14 NiCr14 0.14-0.17 0.15-0.30 0.40-0.60 0.60-0.80 - 3.25-3.75 Ç 3415 14 NiCr18 0.11-0.18 0.15-0.35 0.30-0.60 0.90-1.30 - 4.25-4.75 Ç 4120 20 CrMo5 0.15-0.24 0.15-0.35 0.60-0.90 0.90-1.30 0.20-0.30 - Ç 8620 - 0.16-0.24 0.15-0.35 0.60-0.90 0.40-0.60 0.15-0.25 0.40-0.70