Nitriding furnace is a equipment with nitriding treatment, which has the characteristics of low processing temperature, short time, small workpiece deformation and high fatigue

Nitriding process

Nitriding treatment refers to a chemical heat treatment process in which nitrogen atoms penetrate into the surface of the workpiece at a temperature medium. The nitrided products have excellent fatigue resistance, corrosion resistance and high temperature resistance.

Pass ammonia gas into the stainless steel vacuum sealed tank in the nitriding furnace, heat to 520℃, maintain the appropriate time,

According to the workpiece material and infiltration layer requirements of 3-90 hours, so that nitriding workpiece surface to obtain a nitrogenous strengthening layer, obtain high hardness, high fatigue.

Operation method:

1. The mold before nitriding is the workpiece that has been normalized or tempered first.

2. Scrub the surface of the workpiece with gasoline and alcohol first, and there shall be no rust, oil and dirt.

3. After loading into the furnace, tighten the furnace cover compression bolt symmetrically.

4. The water inlet of the furnace tank and the furnace cover is passed into the cooling water for circulating water cooling. The lower end of the cooling water in the pipe on the furnace cover is the water inlet, and the upper end is the water outlet. The furnace pot is separately fed into and drained separately. All the water pipes on the furnace cover can be connected in series according to the principle of low inlet and high inlet.

5. Nitrogen exhaust should be sent before heating up, and the flow rate of exhaust should be more than twice that of use.

After 10 minutes of venting, set the temperature controller (as shown below) to 150℃, turn the automatic heating switch on, heat 150℃ while venting to maintain 2h exhaust, and then set the temperature controller to 530℃, reduce the ammonia flow rate, maintain the positive pressure in the furnace, and have a small upward pressure of air flow at the exhaust port. When the furnace temperature rises to 530℃, constant temperature and constant flow nitriding for 3-20h. Then increase the ammonia pressure, so that the exhaust gas to maintain moderate pressure, 4-70h nitriding, and then reduce the ammonia pressure, denitrification 1-2h, cut off the power supply, stop heating, give a small amount of ammonia, so that the furnace to maintain positive pressure, until the furnace temperature drops below 150℃ to stop the ammonia oven

Soft nitriding heat treatment

In order to shorten the nitriding cycle and make the nitriding process not limited by steel grade, two new nitriding processes, soft nitriding and ion nitriding, have been developed on the basis of the original nitriding process in recent years.

In essence, soft nitriding is a low-temperature nitrocarburizing based on nitriding. When the nitrogen atoms of steel infiltrate, there are a small amount of carbon atoms infiltrate. Compared with the general gas nitriding, the treatment result of soft nitriding has lower hardness and less brittleness than that of nitriding.

1, soft nitriding methods are divided into: gas soft nitriding, liquid soft nitriding and solid soft nitriding three categories. At present, gas soft nitriding is widely used in domestic production. Gas soft nitriding is in the atmosphere containing active nitrogen, carbon atoms for low temperature nitrogen, carburizing, commonly used collimating media urea, formamide, ammonia and triethanolamine, they occur thermal decomposition reaction at the soft nitriding temperature to produce active nitrogen and carbon atoms. The active nitrogen and carbon atoms are absorbed by the surface of the workpiece, and penetrate into the surface of the workpiece through diffusion, so as to obtain the nitrogen-dominated nitrocarburizing layer.

The soft nitriding temperature of the gas is commonly used at 560-570 ° C, because the hardness of the nitriding layer is high at this temperature. The nitriding time is usually 2-3 hours, because more than 2.5 hours, with the extension of time, the depth of the nitriding layer increases slowly.

2, nitriding furnace soft nitriding layer structure and soft nitriding characteristics: steel after soft nitriding, the surface of the outer layer can be obtained a few microns to tens of microns of white bright layer, it is composed of ε phase, γ 'phase and nitrogenous cementing Fe3 (C, N), the secondary layer is the diffusion layer, it is mainly composed of γ' phase and ε phase [1].

Soft nitriding characteristics

(1) The processing temperature is low, the time is short, and the workpiece deformation is small.

(2), not subject to steel type restrictions, carbon steel, low alloy steel, tool steel, stainless steel, cast iron and iron-based powder non-metallurgical materials can be soft nitriding treatment. The surface hardness of the workpiece after soft nitriding is related to the nitriding process and materials.

(3) can significantly improve the fatigue strength of the workpiece, corrosion resistance. It also has anti-abrasion and anti-bite properties under dry friction conditions.

(4) Because there is no brittle phase in the soft nitriding layer, the nitriding layer is therefore ductile and not easy to peel off.

Therefore, the current production of soft nitriding has been widely used in mold, measuring tools, tools (such as: high-speed steel tools), crankshaft, gear, cylinder liner, mechanical structure parts and other workpiece processing.

Liquid nitriding furnace editor

Liquid nitriding furnace is suitable for all kinds of nitriding steel air preheating, liquid nitriding, liquid oxidation process. The nitriding furnace has the characteristics of low processing temperature, short time and small deformation of the workpiece