Rockwell Hardness Conversion Calculator

Calculate and convert Rockwell hardness across different scales and materials

Hardness Analysis Configuration

Scale B (HRB): Steel ball indenter, 100 kgf load

Indenter: 1/16" steel ball | Load: 100 kgf | Range: 20-100 HRB

Calculate Rockwell Hardness

Formula
HRB = 130 - 500 × d
N = 130, h = 500

Hardness Calculation Results

Rockwell Hardness
80.0
HRB
Indentation Depth
0.100
mm

Calculation Details

Formula: HRB = 130 - 500 × d

Scale: Scale B (HRB)

Indenter: 1/16" steel ball

Applied Load: 100 kgf

Example: Rockwell B Hardness

Given Values

Indentation Depth (d): 0.1 mm

Scale: B (HRB)

Formula: HRB = 130 - 500 × d

Calculation Steps

HRB = 130 - 500 × 0.1

HRB = 130 - 50

HRB = 80

Result

The Rockwell B hardness number is 80 HRB, indicating a moderately hard material suitable for many engineering applications.

Rockwell Scales

Scale B (HRB)
Steel ball, soft materials
Range: 20-100
Scale C (HRC)
Diamond cone, hard materials
Range: 20-70
Scale A (HRA)
Diamond cone, very hard
Range: 20-88

Typical Hardness Ranges

Brass55-93 HRB
Aluminum15-95 HRB
Mild Steel80-100 HRB
Tool Steel55-66 HRC
Cast Iron20-40 HRC

Hardness Standards

ISO 6508:Metallic materials testing
ISO E140:Hardness conversion tables
ASTM E18:Standard test methods
All conversions based on international standards

Testing Tips

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Use Scale B for softer materials (copper, aluminum)

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Use Scale C for harder materials (steel, cast iron)

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Ensure proper specimen preparation

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Maintain consistent testing conditions

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Consider material-specific conversion factors

Understanding Rockwell Hardness Testing

What is Rockwell Hardness?

Rockwell hardness testing measures a material's resistance to plastic deformation by measuring the depth of penetration of an indenter under specific loading conditions. Unlike other hardness scales, Rockwell hardness is dimensionless and provides quick, reliable results for quality control.

Test Procedure

1. Apply minor preload (10 kgf)

2. Apply major load (varies by scale)

3. Remove major load, maintain preload

4. Measure permanent indentation depth

5. Calculate hardness: HR = N - h × d

Scale Selection Guide

Scale B (HRB)

Steel ball indenter, 100 kgf load

Best for: Copper alloys, soft steels, aluminum

Scale C (HRC)

Diamond cone, 150 kgf load

Best for: Hard steels, cast iron, tool steels

Scale A (HRA)

Diamond cone, 60 kgf load

Best for: Cemented carbides, thin materials

Hardness Conversion

Brinell Hardness (HBS)

Steel ball indenter, measures impression area

Vickers Hardness (HV)

Diamond pyramid, universal scale

ISO E140 Standard

International conversion tables

Engineering Applications

Quality Control

Production line testing and material verification

Material Selection

Design optimization and specification

Heat Treatment

Process control and validation