The gloss of the annealed carbon seamless steel tube determines the quality of the product. There are many other influencing factors. Here are five key elements of seamless steel tube annealing:
1. Annealing temperature.
whether the required temperature is reached. The heat treatment process of steel generally adopts heat treatment and tempering heat treatment process, which is what we usually call "annealing", and the temperature range is 1040~1120 °C (daily standard).
2. Annealing atmosphere.
Generally, pure hydrogen is used in the annealing atmosphere, and the purity of the atmosphere is above 99.99%. If the other part of the atmosphere is a noble gas, the purity can be lower, but not too much CO2 and water vapor.
3. Furnace wall airtightness.
The seamless steel tube furnace should be closed and isolated from the outside gas; if radon gas is used as a protective gas, only one exhaust pipe (for igniting the exhausted radon gas) should be opened. The inspection method can be smeared with soap solution at the joints of the annealing furnace to see if there is gas escaping; the area where the gas can easily escape is the area where the annealing furnace enters the pipeline and the outlet area of the pipeline. In particular, the sealing ring in this place is easy to wear and should be checked and replaced frequently.
4. Protective gas working pressure.
In order to better avoid trace leakage, the protective gas in the furnace should maintain a certain positive pressure. If it is radon protective gas, it is generally specified above 20kBar.
5. Water vapor in the furnace.
On the one hand, check whether the raw material of the furnace wall is dry. When the furnace is installed for the first time, the raw materials of the furnace wall must be air-dried; on the other hand, whether there are too many water traces on the seamless steel tube entering the furnace, especially if there are holes at the top of the pipe, do not let water infiltrate, otherwise it will destroy the atmosphere in the furnace.
The above are the five key elements of seamless steel tube annealing, I hope to help everyone. Tianyang Steel Tube, as a seamless steel tube enterprise, provides seamless steel tubes with high quality, welcome to consult and purchase.