1. Regarding the curling phenomenon of the coating: ① The coating is curled because there are more second-class gloss agents. ② The coating is involuted due to the excessive amount of a type of gloss agent.

2. Regarding the fragility of the coating: ① The second-category gloss agent is too high. ② Out of proportion.

3. Regarding the coating becoming black, and the edges being burnt: DK is too large.

4. Regarding the coating turning blue, and the bonding force in the recessed hole being poor: DK is too small.

"DK" means "Dry Kiln."

Answers

• 
  Why are seamless steel pipes stronger? 31/10/2025 14:08:30
• 
  Is stainless steel wire better at preventing rust than galvanized steel wire? 31/10/2025 07:36:00
• 
  How to distinguish between hot-dip galvanizing and cold-dip galvanizing? 28/10/2025 14:16:19
• 
  What are the production processes and differences between welded steel pipes and spiral steel pipes? 27/10/2025 16:41:23
• 
  What are the characteristics of double-sided submerged arc spiral steel pipe? 27/10/2025 08:16:52