Effect of Roughness on the Wear of Cold Forming Tools

The cost of any forged product for the automotive industry is highly influenced by the cost involved during the design and manufacturing of the forging tools. Ideally, these tools shall withstand a significant number of cycles, in order to divide their manufacturing cost in many parts as possible. There are several parameters that affect the wear behavior, and forging companies have different approaches to address the tribological issues. Moreover, a misunderstanding of these parameters may lead to an undesirable premature tool wear.

This work analyses the effect of roughness on the wear of cold forming tools. The adopted tribosystem is the second stage of a horizontal press and consists of a punch of M2 hardened steel in relative movement against a working piece of SAE 10B22 normalized steel. Fifteen punches were manufactured with three roughness levels and their wear was measured after 50.000 and 100.000 forging cycles. A 3D optical profiler and a Scanning Electronic Microscope (SEM) were used to access the surface characteristics of the punches before and after the production batches.