To reduce the hydrogen, oxygen, and nitrogen impurity gas content in the rectangular steel pipe, the following eight measures can be considered to take in production:

1. Pay attention to the point that 80% of the hydrogen in molten steel comes from raw materials, refractories and moisture in the atmosphere.

2. In the control to reduce the [N] content in the rectangular tube, in addition to the vacuum treatment of molten steel and reducing the contact of molten steel with the atmosphere, the focus is on the control of alloy content.

3. Reasonable order of joining. The order of adding deoxidizer is as follows: before tapping, add a small amount of Fe-Mn in the ladle, add Fe-Si after tapping, and feed Al with a wire feeder when refining outside the refining station.

4. Control the slag composition, temperature, and slag amount to improve the ability of inclusions to dissolve in the slag phase.

5. Lowering PH2 can reduce the solubility of hydrogen in the rectangular tube, so vacuum degassing can be used to reduce the [H] content in steel.

6. The use of appropriate stirring emphasizes that the inclusions in the rectangular tube can be removed, and the steel slag will not be involved in the molten steel. In addition, soft argon blowing can be used before the refining is completed.

7. The direct contact between the molten steel and the atmosphere should be reduced. The molten steel after vacuum treatment should avoid re-transmission and heating, and the argon pressure should be controlled to prevent the molten steel from being exposed, and protection should be done during pouring.

8. When blowing oxygen in the electric furnace, try to improve the end point control accuracy and reduce overblowing. At the same time, the technology of slag flowing before tapping, eccentric bottom tapping and sufficient rectangular tube molten steel reserved in the furnace are used to prevent slagging.