SKD11 (ASTM D2) tool steel is a versatile high-carbon, high-chromium, air-hardening tool steel that is characterized by a relatively high attainable hardness and numerous, large, chromium rich alloy carbide in the microstructure. SKD11 tool steel provides an effective combination of wear resistance and toughness, tool performance, price, and a wide variety of product forms. Adding of CNTs increased the performance of mechanical properties more. 1, 3 vol% CNTs was dispersed in SKD11 matrix by mechanical alloying. SKD11 carbon nanocomposite powder was sintered by spark plasma sintering process. FE-SEM, HR-TEM and Raman analysis were carried out for the SKD11 carbon nanocomposites.

The development of machining technology has coincided with the recent development of a diverse amount of materials and tools. The developed materials largely consist of hardened steel for vehicle and the mechanical industry. The machining of the hardened steel is performed in a lathe and many kind of machining centers, but it is difficult to machine because its hardness is the most difficult-to-cut materials. Hard-turning is a kind of machining process which omits the final grinding process and replaces it with a single accurate cutting process. In this paper, the turning of SKD 11(HRC 58) was performed using the CBN tool in order to recognize the optimum process conditions. The cutting force, tool life and wear, surface roughness were measured. Examining the machining characteristics when cutting of high hardened steel, low cutting speed and high conveying speed were identified to be effective in cutting conditions of SKD 11. Tool life was most effective in the conditions with 65m/min of cutting speed and 0.193mm/rev of feedrate and approximately 0.5um of very good surface profile was acquired at 0.079mm/rev of feedrate. Therefore, when cutting with Low CBN tool, it could be considered to be sufficient in reducing the steps of precision machining or replacing the polishing

SKD11 (ASTM D2) tool steel is a versatile high-carbon, high-chromium, air-hardening tool steel that is charac- terized by a relatively high attainable hardness and numerous, large, chromium rich alloy carbide in the microstructure. SKD11 tool steel provides an effective combination of wear resistance and toughness, tool performance, price, and a wide variety of product forms. The CNTs was good additives to improve the mechanical properties of metal. In this study, 1, 3 vol% CNTs was dispersed in SKD11 matrix by mechanical alloying. The SKD11+ CNT hybrid nanocomposites were investigated by FE-SEM, particle size distribution, hardness and wear resistance. The CNT was well dispersed in the SKD11 matrix and the mechanical properties of the composite were improved by CNTs addition. It shows good fea- sibility as cold work die tool.