Free Brinell to Rockwell Calculator

How Our Brinell to Rockwell Calculator Works

This free Brinell to Rockwell calculator helps engineers and manufacturers convert hardness values instantly using ASTM E140 standard conversion tables. When selecting materials for injection mold tooling, accurate hardness conversion between Brinell and Rockwell scales isn't just useful—it's essential for your tooling decisions.

The Brinell hardness test uses a hardened steel or carbide ball pressed into the material under a specific load, typically 3000 kgf for steels. The resulting indentation diameter determines the hardness value. This method excels at measuring softer materials and provides excellent repeatability for large-grained or non-homogeneous materials.

The Rockwell hardness test, conversely, measures indentation depth rather than diameter. The Rockwell C scale (HRC) uses a diamond cone indenter and is the standard for hardened tool steels above 20 HRC. The Rockwell B scale (HRB) uses a 1/16" steel ball for softer materials. Our Brinell to Rockwell calculator handles both HRC and HRB conversions seamlessly.

Brinell to Rockwell Conversion for Injection Molding

In injection mold manufacturing, material hardness directly correlates with tooling longevity, surface finish quality, and overall production economics. Here's what the numbers mean for your operation:

Rockwell C to Brinell Calculator: Technical Details

Converting between Rockwell C and Brinell scales requires understanding that no mathematical formula provides perfect correlation. The ASTM E140 standard establishes empirical conversion tables based on extensive testing of carbon and alloy steels.

Our Brinell to Rockwell calculator uses linear interpolation between ASTM E140 data points, providing accuracy within ±2% for typical tool steels. For critical specifications in your tooling projects, we always recommend direct hardness testing using the scale specified in your material datasheet.

Beyond the Brinell to Rockwell Calculator: Other Scales

Beyond the standard HRC and HRB scales covered by our Brinell to Rockwell calculator, the Rockwell E scale serves a specialized niche—measuring softer materials like bearing metals, plastics, and some aluminum alloys. Using a 1/8" ball indenter with a 100 kgf load, HRE fills the gap between HRB and the superficial Rockwell scales.

For injection molding applications, you'll primarily encounter HRC (tool steels), HRB (pre-hardened steels and aluminum), and occasionally Shore hardness for elastomeric components. Understanding these relationships ensures accurate material specification across your supply chain. Need help with material selection? Check out our plastic part design services or use our clamp force calculator for your next project.