What is the reason why the workpiece of the vacuum furnace is blue after it comes out of the oven?

It is estimated that it is oxidized, maybe there are some problems with your operation, I don't know what you do with a vacuum furnace, but according to my experience, it should be first vacuumed to 10 to the -2 power pascal, and then the temperature is raised to about 300 degrees Celsius, and then the vacuum is evacuated to 10 to the -3 power pascal, and then the temperature is raised to carry out the operation you need, whether you are diffusion welding or vacuum sintering, heat treatment, etc., you should follow this, and then the surface temperature of the workpiece measured by the thermocouple should be lower than 200 degrees Celsius when the furnace is opened, In this way, it is estimated that 1cr13 will not have blue color.

The main purpose is to avoid oxidation, high-temperature volatilization of excess materials on the surface of the workpiece such as oil stains, water stains, etc.

If you need to study it specifically, you can contact me.

According to the description. I suspect that the air humidity has been high recently, and there is water on the surface of the workpiece before it enters the furnace.

At high temperatures, the surface of the workpiece reacts with water to form a dense ferric oxide oxide film, which completes a process similar to the blue baking process.

40cr vacuum quenching tempering 400 degrees tempering in the hot chamber、Drop to 260 degrees in the cold chamber 70 degrees baking color blue fish color what is the reason thank you.

Some workpieces require the processing temperature to be below 900, and there is no problem with the surface color of the workpiece, mainly because the color of the tray is a little yellow, but the surface color of the tray is also good after the processing temperature exceeds 900. The heating element is graphite rod, and the inner cavity is graphite hard felt. It is inferred that the tray is oxidized during the heating process, and after more than 900 years, the oxide film of the tray is reduced due to the reduction of graphite.

Is your workpiece made of stainless steel and the tooling made of ordinary steel?

It stands to reason that there should be no bluing at 900 degrees. Our company often does this kind of temperature.

The analysis is that your workpiece has good oxidation resistance.

How long your device has been in use. Was this the issue before. Have you communicated with the manufacturer? Or there may be a description in the manufacturer's instruction manual.

Heat-treated nickel-chromium workpieces...

What I understand is that the general high-pressure gas quenching furnace is about 1300. The heat-generating material is molybdenum or graphite.

Is the temperature requirement for your device to be 900?

After quenching, the hardness of the workpiece was tested. Is it that you are filled with impure gas. Nitrogen bar.

However, you can weld first and then carburize and quench, is it wear-resistant or there is a problem with the welding between the floor and the shaft! Of course, it is best to stress before carburizing and quenching. I don't know what you mean by flooring, I think it's less lifespan, or how stressed it is; And what do you mean by not having a long life?

Is there a requirement for core hardness or strength of the workpiece? If there is, photonitriding after normalizing should not meet the requirements.

After vacuum heat treatment, if it is gas quenched, the surface is metallic; Oil quenching should be cleaned and tempered in a vacuum. Generally speaking, after vacuum tempering, the surface of the workpiece will change color, and it will be more light gray. The reason for this is that the nitrogen purity during tempering is not enough, and the water content is high.

If 10% pure nitrogen is used, the color of the surface will be greatly improved.

I don't know why the reason for the discoloration may be that the vacuum of the furnace is not enough, or it may be that the shielding gas is not pure, or it may be that the furnace temperature is too high, and I don't know what the landlord said is the color of the blued or the color of the flange If it is the color after the blue, it means that the oxidation is a little big In addition, I have not used a special vacuum tempering furnace, only in the vacuum quenching furnace to do tempering (furnace with convection), and the color is basically the same as the color after the quenching of real air.

1. The temperature of the furnace door is too high.

2. When quenching, the charging shielding gas is not pure, and 5 9 argon gas is used.

3. It is also possible that your kind of metal will change color at high temperature (after being charged with protective gas).

Reply 8 Our inconsistencies, the color changes a lot, mainly the color is gray, quenched out of the metallic color, very beautiful, after tempering it will not work.

May I ask the landlord, is it only used for vacuum tempering? If there is follow-up processing, it doesn't matter, mainly let the furnace ensure its furnace temperature uniformity If there is no follow-up processing, you can take the floor method or use a vacuum tempering furnace with a diffusion pump in high vacuum.

Ask what the parts will look like if the furnace leaks? I haven't come across this yet.

There are many factors, such as whether the surface of the parts is clean, whether the hot chamber is polluted, whether the cold chamber is fully degassed, whether the furnace body is leaking, etc

It could be that the stove is leaking, or it is leaking a little, causing this color. Leak detection, and then press the heat exchanger.

It shows that the vacuum degree in the vacuum furnace is insufficient, which leads to the oxidation of the sintered products.

Is it vacuum furnace annealing? There are several reasons for this: 1. Insufficient protective atmosphere 2. Insufficient vacuum 3. Early baking 4. Water and gas entering the furnace 5. Reaction with oxides in the furnace.

On the line of hair color treatment, there is equipment and technology for strip hair color treatment.

What happens when the bright strip turns yellow during annealing.

Insufficient vacuum causes surface oxidation, and the color is generally yellow or blue. Check the tightness of the furnace body, because it is a plastic ring, which is easy to age.

When the vacuum degree is not enough, it is generally blue or reddish-brown; Green color is relatively rare, sometimes there is glow in the furnace cavity during vacuum brazing, and it will have a slight greenish color when things are deposited on the surface of the workpiece.

If it is confirmed to be oxidation, it is estimated that there is a problem with your welding parameters, such as the vacuum degree at 300 degrees and the vacuum degree at 500 degrees during the brazing process. Is there a rapid cooling of inert gases?

Oxidized. The vacuum is not enough.