Application of the hottest nitriding technology

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Application of nitriding treatment technology

nitriding treatment is developed in the production of iron printing can in recent years. It is an inert gas protection device, which makes the weld surface unable to generate oxide film during the welding process. After nitriding treatment, the weld has the characteristics of beautification, fine and uniform weld, increased coating adhesion and so on. Therefore, it has been widely used in recent years

I. jet technology

jet is a high-speed jet of fluid from the nozzle, which is widely used in industrial automation control. Today, we want to introduce the use of the entrainment effect of jet in nitriding treatment in can making

1. Entrainment of jet

the so-called entrainment of jet is a bunch of fluid ejected from the nozzle. Due to the friction between fluid molecules, the originally static medium around it flows forward together

as shown in Figure 1, the velocity of the jet will decrease at this time. This phenomenon is the entrainment of the jet, also known as the pumping effect

2. Wall attachment effect of jet

if we set a pair of baffles on both sides of the nozzle, when the baffle is far away from the nozzle, the situation does not change, which is still the same as that shown in Figure 1. If the two baffles are close to the nozzle and the distance between the two baffles and the nozzle is different, we can find that when the baffle is moved to a certain distance, the jet from the nozzle will change direction in a moment and adhere to the baffle wall near the entrainment to flow. As shown in Figure 2, this phenomenon is called the wall attachment effect of jet. This phenomenon is caused by the pressure difference. Due to the entrainment effect of the jet, in S1

II. The working principle of the nitriding device

for any object with speed, the total budget of our project is 275000 pounds; Half of the funds come from natep to say that it has momentum. Therefore, for the jet, of course, there is momentum. If two jets are emitted from the nozzle from different directions, after the two jets meet, a new jet will be synthesized, and its direction is no longer the same as that of any original jet, but deflected by an angle. According to the law of conservation of momentum m3v3=m1v1+m2v2, as shown in the following figure, the size of the deflection angle depends on the size of the original two jets. If the momentum of the original two jets is equal, the direction of the new jet after synthesis is just in the middle of the original two jets' demand flow for experimental parameters, that is =. If m1v1 m2m2, the direction of the new jet will be between them and closer to the direction of the jet with large momentum. This phenomenon is the momentum exchange of the jet. As shown in Figure 3

nitriding device is a jet element made by using the momentum exchange phenomenon of jet and the wall attachment effect of jet to make nitrogen adhere to the surface of tank body

III. nitriding process

1. Process

liquid nitrogen decompression molding motor synchronization

solenoid valve flow juice jet element wall attached tank body

2. Schematic diagram of jet element (as shown in Figure 4)

IV. nitriding flow control

the key of nitriding treatment is to form a layer of gas protective film in the shape of the tank body to isolate the weld from the air. The formation of the protective film is closely related to the flow rate and flow rate of nitrogen. Due to the blocking of the welding wheel, as shown in Figure 5, a small low-pressure area is generated on both sides of the welding wheel to drive the air flow. When the flow rate is too small, it cannot play the role of nitridation. If the flow rate is too high, a vortex will be formed at the welding point, which will damage the nitriding film. Therefore, it is very important to adjust the pressure and flow of nitrogen. After repeated practice, it is recommended to adopt the pressure below 1kg/m2, and the flow rate of 0.6l/min is better

v. compensation of nitrogen protection

because there is a certain gap between the tank body and the tank body during the welding process, the minimum gap is 1 ~ 2mm, and it often reaches more than 10mm. Therefore, instead, it gives a control signal to the jet, replenishing air to the wall attached jet, so that nitrogen does not cover the tank body. Therefore, in the production process, the head will be partially oxidized and blackened, which is usually called incomplete nitridation

in order to prevent this kind of situation, we suggest that the internal and external nitriding devices should be used together to make the internal nitriding give the external nitriding a compensation air flow, so that the air cannot enter, so as to ensure the quality of nitriding

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