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How to control the defects of seamless steel tubes?

1. Blowing process

1) The injection pressure should be matched with the diameter and length of the capillary tube, to ensure that the blowing is strong and the combustion is sufficient, and that the incompletely combusted deoxidizer cannot be blown away from the capillary tube by the airflow.


2) The purging time should be adjusted according to the direct and length of the capillary, with the standard that no metal oxide suspended in the capillary is blown out again.


3) The nozzle height should be adjusted according to the capillary diameter to ensure good alignment. The nozzles should be cleaned once every shift, and the nozzles should be removed for cleaning after a long stop. In order to ensure that the deoxidizing agent is uniformly blown on the inner wall of the capillary tube, an optional device is used at the spraying deoxidizing agent station, and is equipped with a rotary air pressure.


2. Deoxidizer

Thorium oxide is required to be in a molten state when the core rod is pre-penetrated. Its strength and other strict requirements.


1) The particle size of the oxide removing powder is generally about 16 mesh.


2) The content of sodium stearate in the deoxidizer should be above 12%, so that it can be fully burned in the inner cavity of the capillary tube.


3) The spraying amount of the deoxidizing agent is determined according to the inner surface area of the capillary, which is generally 1.5-2.0g/dm2, and the dosage of the deoxidizing agent is different when the capillary with different diameters and lengths is sprayed.

3. Mandrel lubrication


The mandrel is not well lubricated or the temperature of the mandrel lubricant is too low, which will cause internal scarring. In order to increase the temperature of the mandrel, the cooling water can be used for cooling only once. During the production process, the temperature of the core rod needs to be strictly controlled to ensure that the surface temperature of the core rod is 80-120 ° C before the lubricant is sprayed, and the core rod temperature cannot be higher than 120 ° C for a long time to ensure that the lubricant on the surface is dry and dense before pre-wearing. The operator should always check the lubrication of the mandrel.