How to Operate the Welding Process for Mold Texturing Successfully?
Example: Improper welding causes visible marks after VDI 3400 etching.
Standard Welding Procedure:
A. Pre-heat: Thoroughly pre-heat the mold prior to any welding operation to minimize thermal stress.
B. Material Matching: Always weld the mold using a welding rod made of the same steel as the parent metal (base material).
C. Heat Treatment: Post-weld heat-treat the entire mold to ensure uniform temperature and consistent material hardness.
Textured mold steel requirements steel with a uniform microstructure and free of impurities is best, such as P20, S136, or H13. If the steel contains more impurities, chemical etching is prone to producing material lines and pits, while laser etching is more compatible with different types of steel.
1. Avoid welding as much as possible. If welding is unavoidable, improper welding techniques or mismatched welding rods can result in “weld marks” or “Color difference” after chemical etching or laser texturing. Ensuring the consistency of the steel’s chemical composition is crucial for consistent texture.
2. The tempering temperature and time are very important for the fusion of steel weld joints. The correct sequence is to first temper locally, then place the entire mold in the tempering furnace for further heating and fusion, which is beneficial for chemical etching or laser texturing.