Well type furnace manufacturer introduces the characteristics of gas nitriding furnace and its equipment

(1) The gas nitriding furnace has low processing temperature, short processing time and small workpiece deformation.

(2) The gas nitriding furnace is not limited by the steel type. Carbon steel, low alloy steel, tool and die steel, stainless steel, cast iron and iron based powder unmetallic materials can be subject to soft nitriding treatment. The surface hardness of gas nitriding furnace workpiece after soft nitriding is related to nitriding process and 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 the properties of scratch resistance and bite resistance under dry friction conditions.

(4) As there is no brittle phase in the soft nitriding layer of the gas nitriding furnace, the nitriding layer has certain toughness and is not easy to peel off.

Therefore, at present, soft nitriding in the production of 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 structures.

Regulations of well type nitriding furnace process specification:

1、 Nitriding temperature

1. Commonly used at 500-530 ℃, it can ensure that nitrides have large dispersion and high hardness

2. With the increase of nitriding temperature, the depth of nitriding layer increases, but the hardness decreases significantly. The nitriding temperature is higher than 550 ℃, and the high hardness of most steel grades is lower than 1000HV

3. With two-stage nitriding, the temperature of the second stage is usually lower than 560 ℃

2、 Nitriding time

1. The nitriding layer thickens with the extension of time. The growth rate is large at the initial stage, and gradually slows down later. Generally, the penetration rate is about 0.01 mm/h

2. With the prolongation of holding time, the nitrides aggregate and grow up, and the hardness decreases. The higher the temperature, the longer the time, the more severe the growth

3、 Ammonia decomposition rate

1. When the decomposition rate is 20-40%, there are many active nitrogen atoms, and the part surface can absorb a large amount of nitrogen

2. If the decomposition rate exceeds 60%, the hydrogen content in the atmosphere will reach more than 52%, which will produce denitrification. At this time, not only the number of active nitrogen atoms decreases, but also a large number of hydrogen molecules and nitrogen molecules stop near the part surface, making nitrogen atoms difficult to be absorbed by the surface, thus reducing the nitrogen content on the part surface and reducing the depth of the nitriding layer. Before nitriding, the pipe joints of the heating furnace, nitriding tank and the whole nitriding system shall be checked for air tightness to ensure no ammonia leakage and unimpeded flow in the pipeline.