For_(Als < 0.01%) straight seam welded pipe, the impact of two deoxidizers on total oxygen in VD treated steel is small, and can be controlled below 20 *10-6. The total oxygen content can be reduced after Si-Al-Ba deoxidization process, and the effect of deoxidization process is stronger than that of Si-Ca deoxidization process.


When Si-Ca and Si-Al-Ba deoxidizers are used in high frequency longitudinal welded pipes, the number and size of inclusions in the melting process are completely different. The number of inclusions in Si-Al-Ba is less than that in Si-Ca after deoxidation, and the size of inclusions is smaller.


When Si-Ca and Si-Al-Ba are used in high frequency straight seam welded pipes, the secondary oxidation of molten steel occurs during casting, but the secondary oxidation of Si-Al-Ba deoxidized molten steel is more serious.


Inclusions in forging materials differ greatly from those in aluminium inclusions. When Si-Al-Ba is used to deoxidize, the inclusions in forging materials are mainly blocky and chain alumina. High frequency straight seam welded pipes are deoxidized by Si-Ca. The content of Al inclusions in Si-Ca alloy is less than that of Si-Al-Ba alloy.


According to the length of the factory or double length, the length of the pipeline is usually 4 to 10 meters. The surface quality of steel pipe should be smooth, and defects such as folding, cracking, delamination and welding should not be allowed. Minimal defects such as scratches, scratches, misalignment of welding, burns and scars on the surface of pipes are allowed, which do not exceed the thickness of the negative wall. Allow weld thickness at the wall and the presence of internal welds