These processes are thermochemical processes carried out with low temperature and low waste, which improve the surface properties of finished or semi-finished products. Material surface, material composition, surface cleanness, equipment and process parameters are extremely important parameters in the formation of final properties which gas nitriding and gas nitrocarburizing processes will provide to the product.
Gas Nitrocarburizing
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Gas Nitrocarburizing process times range from 30 minutes to 7 hours. In the gas nitriding process, besides ammonia gas, carbon dioxide is also given to the environment. With the effect of nitrogen and carbon temperature obtained as a result of fragmentation during the process, it forms a thin layer of iron nitrocarbide by diffusion through the surface of the piece. The process is divided into two as ferritic nitrocarburizing at 560-580 degrees, or austenitic nitrocarburizing at 590-720 degrees. Since the temperature applied in austenitic nitrocarburizing process is higher, the risk of waste is higher.
The white layer formed after the gas nitrocarburizing process significantly increases the corrosion resistance of the material. Furthermore, the corrosion resistance of the material can be further increased by forming a layer of iron oxide (1-3 microns) on the material surface by the post oxidation process applied after the nitrocarburizing process.
Gas Nitriding
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Gas nitriding is a process that can last up to 100 hours at temperatures between 490 and 560 ° C.In the gas nitriding process, ammonia gas in the process environment is decomposed to form the atomic nitrogen gas, and the nitrogen is diffused to the surface of the material by the temperature's effect. The amount (depth) of nitrogen, which is controlled by the duration and temperature parameters and is diffused, interacts with nitriding alloy elements present in the chemical structure of the material, and forms nitride inclusions. As a result of the nitriding process, a layer of iron nitride (also called white layer) is formed on the surface of the material (about 5-30 microns). This layer increases the corrosion and wear resistance of the material. The area between white layer and nucleus is called diffusion layer, and it contains intense amounts of nitride inclusions. The diffusion layer particularly enhances fatigue resistance of the material, and also improves its wear resistance.
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The mechanical properties, which gas nitriding and gas nitrocarburizing processes add to the material, are quite similar. The most important difference in terms of process selection is that gas nitriding is a very long process (cost) but it is carried out at low temperatures (very low waste); and when examining gas nitrocarburizing, the process time is short (low cost) but it is done at a relatively high temperature (more waste).
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Process in Onerler
Gas nitriding furnaces are used for nitriding processes in our company.
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In our company, all of gas nitriding, gas nitrocarburizing, and post oxidation processes are carried out.
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All of our 3 nitriding furnaces have charging capacities of 600 kg and 2000 kg, and of German origin with their brand is IPSEN.
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With the NitroProf program in our furnaces, temperature, time, and gas flows that are vital for the process are automatically controlled and recorded.
In our company with extremely important know-how in gas nitriding and gas nitrocarburizing processes that we have been carrying out since 2007, we provide the best quality to our customers with our expert staff and state-of-the-art equipment.
Benefits of The Processes
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High Wear Resistance
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High Surface Hardness
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Low Friction Coefficient
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High Corrosion Resistance
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High Fatigue Resistance
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Minimum Dimentional Change After Process
Suitable Steels
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Crankshafts (fatigue – wear resistance)
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Gas springs (high wear resistance, corrosion resistance and aesthetic appearance after post-oxidation treatment after nitriding)
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Hot forging dies and form molds
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Washers (Low friction coefficient)
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Springs ( High fatigue resistance
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Aluminum injection molds
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Plastic injection molds (Wear resistance, adhesion inhibition and high fatigue resistance)
Potential Problems After Processes
Since the nitriding process is performed at lower temperatures than other processes, the problem of waste is much lesser. Despite this, very small dimension changes can observed in finished and nitrided materials.
Since nitriding is a surface treatment process, it is very important that the material is clean. Cutting fluid, boron oil and similar impurities from processes such as machining and grinding adversely affect the process visually and metallurgically. Since the mechanical properties to be obtained from the nitriding process are directly related to the alloying elements of the steel, a wrong choice of steel does not provide the expected performance values from the material.
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Heat Treatment
BOSB Turuncu Cad. No: 12, 16120
Nilüfer/Bursa, TURKEY
+90 (0224) 242 43 10
+90 (0224) 242 43 11 (fax)
Steel Supply
BeÅŸevler Sanayi Sitesi 26.Blok No: 6-15
Nilüfer/Bursa, TURKEY
+90 (0224) 441 97 13
+90 (0224) 441 46 15 (fax)