Application of the Sinter-HIP Method to Manufacture Cr-Mo-W-V-Co High-Speed Steel via Powder Metallurgy

Area of Science:

• Materials Science
• Metallurgical Engineering

Background:

• 1.2C-4Cr-4Mo-10W-3.5V-10Co-Fe high-speed steel (JIS SKH57; ISO HS10-4-3-10) is typically made by casting and forging.
• Powder metallurgy offers a route to enhance the properties of this steel.

Purpose of the Study:

• To evaluate the impact of sintering conditions on precipitate formation and porosity in high-speed steel.
• To assess the mechanical strength and toughness with and without hot isostatic pressing (HIP).

Main Methods:

• Powder metallurgy techniques were employed.
• Sintering conditions were varied, including the application of hot isostatic pressing (HIP) at 1463 K.
• Static bending and impact tests were conducted to evaluate mechanical properties.

Main Results:

• Hot isostatic pressing (HIP) at 1463 K effectively eliminated pores.
• HIP prevented the coarsening of precipitates during sintering.
• Both toughness and strength were improved by 50% when HIP was applied.

Conclusions:

• Sintering via hot isostatic pressing (HIP) at 1463 K is crucial for optimizing the microstructure of 1.2C-4Cr-4Mo-10W-3.5V-10Co-Fe high-speed steel.
• HIP significantly enhances the mechanical properties, specifically toughness and strength, of powder metallurgy processed high-speed steel.