What are the causes and countermeasures for cracking of high-performance Q235NH weathering steel?

1. Poor weldability, resulting in inability to weld; set proper welding conditions.

2. Repair bad weldments, leading to poor welding; matters needing attention in the cutting process.

3. Pollution of the welding part (oil, water, dust removal) Set the welding speed after the welding pollution is appropriate, otherwise it will lead to rapid welding.

4. Pay attention to the lack of protection and combustion-supporting gas caused by the oxidation of the welding part, and carefully manage the shielding gas.

5. Pay attention to whether the processing limit ratio is abnormal in the number of welded parts, the processing limit pipe expansion processing, and the adjustment speed of the expansion pipe expansion rate.

6. Materials with poor cleanliness; improve the cleanliness of materials.

7. When the elongation rate of Q235NH weathering steel is insufficient, normal annealing treatment is required.