A comparison study on wear characteristics of Ni-based, Co-based and Fe-based alloys for heated hot stamping tools manufactured by surfacing technology

Abstract

To meet the demanding requirement of ultra-high-strength steel parts with tailored properties, heated hot stamping tools are becoming widely used. However, due to severe working conditions, wear on tool surface is serious. Therefore, the service life of heated hot stamping tools is limited. In this paper, with the purpose of improving the service life of heated hot stamping tools, we aim to find a suitable alloy with better wear-resistant properties to manufacture heated hot stamping tools by surfacing technology. Thus, wear comparison tests between SDCM steel and specimens made of Ni-based, Co-based and Fe-based alloys were conducted under 500 °C and 180 N normal load to determine which kind of alloy has the best wear-resistant properties. Specifically, the mechanical properties, worn volume, worn morphologies and wear mechanisms of test materials were investigated. The results indicate that the Fe-based alloy has the highest compressive yield strength and hardness, but the Co-based alloy has the lowest worn volume, which is 0.49 mm3 at 20 min and 0.70 mm3 at 90 min. And there is no obvious positive relationship between the mechanical properties and the wear-resistant properties of the test materials under the test conditions. The common wear characteristic of the four test materials is that their main wear mechanisms are oxidation wear. The Co-based alloy has the moderate mechanical properties, and its wear mechanisms are oxidation wear and adhesive wear; thus, shear tearing, material transfer and severe abrasive wear are avoided, and the oxide layers adhere to its worn surface instead of spalling. Therefore, the Co-based alloy manifests the best wear-resistant properties and is chosen as the surfacing materials for heated hot stamping tools.