Welding material precautions

1. Stainless steel electrodes usually have two types: titanium calcium type and low hydrogen type. The welding current is as DC source as possible, which is good for overcoming the redness and shallowness of the welding rod. The electrode of titanium-calcium type coating is not suitable for all-position welding, only suitable for flat welding and flat angle welding; the electrode of low-hydrogen type coating can be used for all-position welding.

2. Stainless steel electrodes should be kept dry during use. In order to prevent cracks, pits, pores and other defects, the titanium-calcium type coating is dried at 150-250 °C for 1 h before welding, and dried at 200-300 °C for 1 h before the low-hydrogen type coating. Do not repeat the drying many times, otherwise the peel will fall off easily.

3, the welding mouth is cleaned, and at the same time prevent the welding rod from oil and other dirt, so as not to increase the carbon content of the weld and affect the welding quality.

4, in order to prevent heating and intergranular corrosion, the welding current should not be too large, generally should be about 20% lower than the carbon steel electrode, the arc should not be too long, the layer is fast cold, narrow tunnel welding is appropriate.

5. When guiding the arc, be careful not to induce arcing at the non-welding part. It is best to use the arc-leading plate with the same material as the weldment to induce arcing.

6, should try to use short arc welding, arc length is generally 2-3mm, the arc is too long to produce hot cracks.

7. Transport bar: Short arc fast welding should be used. Generally, lateral swing is not allowed. The purpose is to reduce the heat and heat affected zone width, improve the resistance of the weld to intergranular corrosion and reduce the hot crack.

8. Welding of dissimilar steels should be carefully selected to prevent the welding rod from improperly appearing hot cracks or high temperature heat treatment to cause σ phase precipitation and embrittlement of the metal. Refer to the selection criteria for stainless steel and dissimilar steel welding rods and adopt appropriate welding procedures.

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