Microstructural evolution during DPRM process of semisolid ledeburitic D2 tool steel

Area of Science:

• Materials Science
• Metallurgy
• Manufacturing Engineering

Background:

• Semisolid metal processing offers unique advantages over liquid or solid-state methods.
• Achieving high-quality, cost-effective metal forming requires understanding microstructural evolution in the semisolid state.

Purpose of the Study:

• To investigate the microstructural evolution of ledeburitic AISI D2 tool steel in the semisolid state.
• To determine the potential of the direct partial remelting (DPRM) process for producing AISI D2 with a uniform globular microstructure.

Main Methods:

• Experimental study of AISI D2 tool steel.
• Differential scanning calorimetry (DSC) for liquid fraction determination.
• Optical microscopy, scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), and X-ray phase analysis for microstructural and phase characterization.
• Hardness measurements for mechanical characterization.

Main Results:

• The direct partial remelting (DPRM) process was found to produce a uniform globular microstructure in AISI D2 tool steel.
• The microstructure consists of metastable austenite within globular grains (approx. 50 μm) and eutectic carbides at grain boundaries.
• Phase analysis identified specific carbide types and austenite evolution.

Conclusions:

• DPRM is a viable method for producing AISI D2 tool steel with a desirable globular microstructure.
• This semisolid processing approach offers a minimum process chain for cost-effective, high-quality metal forming.
• The characterized microstructure provides a basis for further optimization of tool steel manufacturing.