Introduction

Density and hardness are two core physical indicators for solid carbide round bars. These parameters reflect sintering quality and material composition, directly affecting grinding behaviour, wear resistance and the final performance of finished cutting tools and wear components. Rleey tests density and hardness batch by batch for all carbide round bar products to guarantee stable material quality.

What Is Carbide Density & How It Is Measured

Cemented carbide density is measured in g/cm³. Density value is mainly controlled by WC grain and cobalt binder ratio. For example, YG8 grade carbide has typical density of ~14.8 g/cm³. Unqualified sintering will create internal pores and reduce density, which leads to reduced strength and premature part failure. Density testing uses the Archimedes water immersion method for each production batch.

Carbide Hardness: HRA Scale for Cemented Carbide

Hardness of tungsten carbide is measured by HRA Rockwell A scale, not HRC. Higher HRA means better abrasive wear resistance. Increasing cobalt binder reduces HRA hardness but improves toughness. Hardness testing is performed on the cross-section of sintered carbide round bars to verify consistent material across the whole rod.

Density & Hardness Reference Table

How Density & Hardness Affect Machining

• Higher hardness carbide rods are harder to grind, require suitable diamond grinding wheels
• Stable, full density carbide gives predictable grinding removal rate, no unexpected chipping
• High hardness blanks hold cutting edges longer for finished drills and end mills
• Consistent density ensures uniform material response during heat and coating processes

Low Density Risks: Porosity & Sintering Defects

Low density caused by insufficient sintering creates microscopic pores inside carbide round bars. Porosity reduces transverse rupture strength. When grinding or cutting, hidden pores can trigger cracks or tool breakage. Every batch of Rleey carbide round bars is inspected to avoid porous material.

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