How to control defects in 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 deoxidant 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 deoxidizer powder is generally about 16 mesh.
2) The content of sodium stearate in the deoxidizing agent should be more than 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 tube, which is generally 1.5-2.0g / dm2, and different diameters and lengths of the capillary tube are different in terms of the amount of the oxide removing amount.
3. Mandrel lubrication
Insufficient lubrication of the mandrel or low temperature of the mandrel lubricant 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-wear , The operator should always check the lubrication of the mandrel.
