High-Temperature Deformation and Cracking of Extrusion Die Cores Case

During continuous hot extrusion of copper, most manufacturers face technical challenges, such as high-temperature deformation and die core cracking. After heating copper billets to forming temperatures exceeding 650℃, the extrusion dies undergo plastic deformation through the die core under high extrusion press pressure. The die core not only endures sustained high mechanical pressure but also generates significant thermal stress from intense friction with the high-temperature copper. So it makes it highly susceptible to high-temperature softening, deformation, and localized cracking. These issues drastically shorten the service life, require more frequent changes, and cause fluctuations in copper product dimensional accuracy and unstable output quality. Consequently, they directly impact the continuous operational efficiency and overall production costs of the production line.

SYTOP has dedicated years to researching and producing cobalt alloy products, specializing in custom-made components that are wear, corrosion, and high-temperature resistant. The performance of cobalt alloys has long been validated by the market. Previously, multiple continuous extrusion equipment manufacturers recognized the core advantages of cobalt alloys and sought collaboration with us to apply this material in die core production. However, during the initial application, cracking issues still arose in the die cores. This was not due to substandard material performance. After repeated disassembly, testing, and analysis, our technical team identified the core issue: the difference in thermal expansion coefficients between the cobalt alloy and the mold substrate. The original interference fit design of the die cores could not accommodate the high-temperature conditions of copper hot extrusion. The disparity in thermal expansion and contraction under temperature changes induced internal stresses, ultimately leading to cracking. After pinpointing the root cause, the technical team immediately launched specialized R&D focused on addressing the thermal expansion coefficient discrepancy. They redesigned the core's interference fit parameters and optimized the adaptation solution through multiple rounds of process debugging.

Following extensive real-machine testing and parameter calibration, the redesigned cobalt alloy extrusion die inserts successfully resolved high-temperature deformation and cracking issues. Partner equipment manufacturers achieved stable installation and operation of the inserts, while the continuous copper hot extrusion production line attained more consistent output quality and extended die service life. The technological breakthrough not only enabled our company to successfully enter the copper extrusion die insert market but also earned global recognition through superior product performance and customized technical solutions. Currently, multiple domestic and international copper processing and extrusion equipment manufacturers consistently select our cobalt alloy extrusion die cores, with the product's stability and reliability extensively validated across the copper extrusion industry.