How to use the non-coating weathering steel

Non-coating weathering steel has certain corrosion resistance (oxidizing acid, organic acid, cavitation), heat resistance and wear resistance. Usually used for power station, chemical industry, petroleum and other equipment materials. The weldability of the weathering steel without coating is poor, and the welding process and heat treatment conditions should be paid attention to.
 
The non-coating weathering steel has greater hardening after welding and is prone to cracks. If the same type of flux-cored wire is used for welding, preheating above 360℃ and slow cooling around 750°C must be performed.
 
In order to improve the corrosion resistance and weldability, the appropriate amount of stability elements Ti, Nb, Mo, etc. are added appropriately. When using the same type of flux-cored welding wire, preheating above 200℃ and tempering treatment at about 800℃ after welding should be carried out.
 
The non-coating weathering steel has good corrosion resistance and oxidation resistance, and is widely used in the manufacture of chemicals, fertilizers, petroleum, and medical machinery. When welding the non-coating weathering steel, the carbide is precipitated by repeated heating, which reduces the corrosion resistance and mechanical properties.
 
The non-coating weathering steel should be kept dry when used. The titanium-calcium type should be dried at 150℃ for 2 hours, and the low-hydrogen type should be dried at 200-250 ℃ for 1 hour to prevent the coating of the welding wire surface from oil and other dirt to avoid Welding seam increases carbon content and affects weldment quality.
 
In order to prevent the corrosion between the eyes due to heating, the welding current should not be too large, about 24% less than the flux-cored wire, the arc should not be too long, the interlayer cooling is fast, and the narrow weld bead is suitable.
 
The non-coating weathering steel has titanium calcium type and low hydrogen type. Titanium calcium type can be used for AC and DC, but the penetration depth is relatively shallow during AC welding, and it is prone to redness at the same time, so DC power is used as much as possible. Diameter 3.0 and below can be used for all-position welding, and 4.0 and above for flat welding and flat fillet welding.