ROCHO gas nitriding furnaces are designed to meet customers' stringent process requirements
Date: Aug 12th, 2022
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ROCHO gas nitriding furnaces are designed to meet customers' stringent process requirements, treatment temperature and process time, and ammonia decomposition rate. At present, gas nitriding furnace has been widely used in the treatment of wear-resistant workpieces such as molds, measuring tools, tools (such as high-speed steel tools), crankshafts, gears, cylinder liners, and mechanical structural parts.
The gas nitriding furnace can meet the following strict process requirements:
1, The processing temperature of the gas nitriding furnace is low, the time is short, and the deformation of the workpiece is small.
2, The gas nitriding furnace is not limited by the steel type, the nitriding process is widely used in the carbon steel, low alloy steel, tool and die steel, stainless steel, cast iron and iron-based powder unmetallurgical materials.
3, The gas nitriding furnace can significantly improve the fatigue strength, wear resistance and corrosion resistance of the workpiece. The gas nitriding furnace also has properties such as anti-galling and anti-seizing under dry friction conditions.
4, The gas nitriding furnace has no brittle phase in the nitrocarburized layer, so the nitrided layer has a certain toughness and is not easy to peel off.
The requirements of the process specification of the gas nitriding furnace:
Nitriding temperature
1, Commonly used at 500-530 °C, it can ensure that the nitride has a large dispersion and high hardness
2, As the nitriding temperature increases, the depth of the nitriding layer increases, while the hardness decreases significantly. When nitriding is greater than 550 °C, the high hardness of most steel grades is lower than 1000HV.
3, Using two-stage nitriding method, the temperature of the second stage is often lower than 560℃.
The nitriding time
1, The nitriding layer thickens with time, the initial growth rate is large, and then gradually slows down. Generally, the permeation rate is about 0.01mm/h.
2, As the holding time prolongs, the nitrides aggregate and grow, and the hardness decreases. The higher the temperature, the longer the time, the nitrides grow stronger.
Ammonia decomposition rate
1, When the decomposition rate is 20-40%, there are many active nitrogen atoms, and the surface of the parts can absorb a large amount of nitrogen
2, When the decomposition rate exceeds 60%, the hydrogen content in the atmosphere is as high as 52% or more, which will cause denitrification. At this time, not only the number of active nitrogen atoms is reduced, but also a large number of hydrogen molecules and nitrogen molecules are stagnant near the surface of the parts, making nitrogen atoms It is not easy to be absorbed by the surface, so that the nitrogen content on the surface of the part is reduced, and the depth of the nitrided layer is also reduced. Before nitriding, the air tightness inspection should be carried out at the pipe joints of the heating furnace, the nitriding tank and the entire nitriding system to ensure that the ammonia gas does not leak and the pipeline is unobstructed.
All of heat treatment furnaces, such as gas nitriding furnace , gas carburizing furnace, vacuum annealing furnace, are designed and manufactured by our company, our engineers team have extensive experience and strict technical specifications to meet the strict technical requirements of customers, contact us to get a professional technical consultation and solutions.
