The welding hot crack of high-strength weathering steel is mainly the crystallization crack of the weld. The existing welding practice has proved that the hot cracking tendency of high-strength weathering steel weld is smaller than that of ordinary weathering steel, which is estimated to be related to the lower sulfur and phosphorus content and higher manganese content of high-strength weathering steel and the alkaline electrode used in hand arc welding.

In order to avoid welding hot cracks of high-strength weathering steel, the main measures taken are:

(1) Selection of alkaline electrode and flux.

(2) Arrange the welding order reasonably and minimize the welding stress.

(3) Control the shape of the weld. In the case of concave and flush fillet welds and narrow and deep butt welds, the material with a low melting point is easy to accumulate in the center surface of the weld when the weld crystallizes, and the crystallization crack is easy to occur under the action of welding tensile stress. For wide and shallow butt welds, when the columnar crystals grow upward, most of the impurities are pushed to the surface and dispersed, the phenomenon of tensile stress concentration is greatly weakened, and the thermal cracking resistance of the weld is high. Therefore, the shape factor (width-to-thickness ratio) of the butt weld is generally controlled at 1.3-2, and there is a weld residual height of 12 mm (only for the car body weld). The shape of the butt weld and fillet weld shall be slightly convex, the end of the weld shall adopt the back-welding finishing method, and the arc pit of the hand arc welding and semi-automatic gas welding shall be fully welded. Automatic submerged arc welding should be equipped with a starting plate and a drawing plate.

(4) Adopt reasonable welding specifications. The greater the welding current, the greater the welding penetration and the greater the fusion ratio. Appropriately reduce welding current and increase arc voltage.