Wear study of hot forging punches coated with WC-CoCr and Cr3C2-NiCr through high-velocity oxygen fuel (HVOF) process

Wear is the main factor that causes most of the failures and reduces the lifetime of forming tools. The demand from industrial users for lower costs, higher productivity, and better quality is among the justifications for researching methods to increase the performance of these tools. In this work, the wear that occurs for hot forging tools was investigated. Herein for the first time, a high-velocity oxygen fuel (HVOF) technique was used for punch coatings in a hot forging process. Two punches coated by HVOF were analyzed for wear, one with chromium carbide (Cr3C2-NiCr) and the other with tungsten carbide (WC-CoCr). It was observed that both punches suffered a combination of several types of wear, mainly from thermal fatigue and abrasive wear. It was found that coating properties, such as roughness and hardness, influenced the wear mechanisms. The results showed that WC-CoCr presented a lower roughness and higher hardness, thereby offering a higher resistance against wear compared to Cr3C2-NiCr. The HVOF-coated punches showed a higher resistance against wear, which indicates that HVOF is a promising technique that is capable of increasing the lifetime of forging tools.