Improving the Performance Properties of Eutectoid Steel Products by a Complex Effect

Area of Science:

• Materials Science
• Metallurgy
• Mechanical Engineering

Background:

• Hypereutectoid steels are vital for tool production, particularly forming rolls.
• Carbide mesh structure influences tool performance and durability.
• Controlling cementite mesh is key to preventing brittle fracture and enhancing wear resistance.

Purpose of the Study:

• To assess hypereutectoid steel carbide mesh crushing methods for tool production.
• To investigate the effect of silicon and various modifiers (Ti, V, N) on cementite mesh structure.
• To evaluate the impact of cyclic heat treatments and cooling rates on material properties.

Main Methods:

• Studied hypereutectoid steel (1.79-1.83% C, 0.35-1.15% Si) with Ti, V, N modifiers.
• Applied multi-stage normalizing and annealing with controlled cooling rates (25–150 °C/h).
• Conducted microstructure analysis using metallography, micro-X-ray spectral analysis, and image segmentation.

Main Results:

• As-cast modifying additives alone are insufficient for effective carbide mesh crushing.
• Multi-stage normalizing with accelerated cooling (up to 150 °C/h) successfully crushed the cementite mesh.
• Optimized heat treatment enabled carbide mesh crushing for products up to 600 mm in diameter.

Conclusions:

• Effective carbide mesh crushing in hypereutectoid steel requires specific heat treatment protocols.
• Multi-stage normalizing combined with accelerated cooling is crucial for optimizing tool steel performance.
• Controlled cooling above 450 °C is essential for achieving the desired microstructure and properties.