Forming Control and Wear Behavior of M2 High-Speed Steel Produced by Direct Energy Deposition on Curved Surface

Area of Science:

• Materials Science
• Manufacturing Engineering
• Surface Engineering

Background:

• Direct Energy Deposition (DED) is a promising additive manufacturing technique.
• Optimization of DED process parameters is crucial for high-performance applications like roller die cutters.
• Understanding the effects of scanning strategy and overlap ratio on material properties is essential.

Purpose of the Study:

• To investigate the influence of scanning strategy and overlap ratio on the microstructure, microhardness, compressive properties, and wear resistance of M2 high-speed steel (HSS) deposited via DED.
• To identify optimal DED parameters for producing die-cut knives with enhanced performance.
• To provide valuable references for the DED of die-cut knives.

Main Methods:

• DED of M2 HSS onto a 316 L cylindrical surface.
• Systematic variation of scanning strategies (e.g., cross-scanning) and overlap ratios.
• Microstructural analysis, microhardness testing, compressive property evaluation, and wear resistance testing.

Main Results:

• Grain size decreased along the deposition direction, increasing hardness from 187 HV to 708 HV.
• Cross-scanning strategy reduced porosity defects, enhancing compressive strength.
• Optimal compressive strength (3904 MPa) and wear resistance (8 × 10^-6 mm³·N^-1·m^-1) were achieved with cross-scanning and a 50% overlap ratio (M-3 sample).
• Wear rate initially decreased then increased with rising overlap ratio.

Conclusions:

• Scanning strategy and overlap ratio significantly impact the microstructure and mechanical properties of DED-processed M2 HSS.
• Cross-scanning with a 50% overlap ratio provides a uniform, dense microstructure, leading to superior compressive strength and wear resistance.
• The findings offer critical insights for optimizing DED parameters in the manufacturing of high-performance die-cut knives.