Precautions for welding materials

Release time: 2023-02-03

1. Stainless steel electrode usually has two types: titanium-calcium type and low-hydrogen type. The welding current shall be DC power supply as far as possible, which is beneficial to overcome the redness and shallow melting depth of the welding rod. The electrode with titanium-calcium coating is not suitable for all-position welding, only for flat welding and flat fillet welding; Low-hydrogen coated electrode can be used for all-position welding.

2. Stainless steel electrodes shall be kept dry during use. In order to prevent cracks, pits, pores and other defects, the titanium-calcium coating shall be dried at 150-250 ℃ for 1h before welding, and the low-hydrogen coating shall be dried at 200-300 ℃ for 1h before welding. It is not allowed to dry repeatedly, or the drug skin will fall off easily.

3. The welded junction shall be cleaned, and the welding rod shall be prevented from being stained with oil and other dirt to avoid increasing the carbon content of the weld and affecting the welding quality.

4. In order to prevent intergranular corrosion caused by heating, the welding current should not be too large. Generally, it should be about 20% lower than the carbon steel electrode. The arc should not be too long. The interlayer cooling should be fast, and narrow pass welding should be preferred.

5. During arc striking, it is not allowed to strike the arc at the non-welding part, and the arc striking plate with the same material as the weldment shall be selected to strike the arc.

6. Short arc welding shall be adopted as far as possible. The arc length is generally 2-3mm, and the long arc is easy to produce thermal cracks.

7. Strip transportation: short arc fast welding shall be adopted, and transverse swing is generally not allowed. Its purpose is to reduce heat and the width of heat affected zone, improve the resistance of weld to intergranular corrosion and reduce the tendency of hot cracks.

8. Welding rod shall be carefully selected for welding of dissimilar steel to prevent hot crack or high temperature heat treatment caused by improper selection of welding rod σ Phase precipitation makes the metal brittle. Select according to the selection standard of stainless steel and dissimilar steel electrode, and adopt appropriate welding process.