BHN, HV, HRB, and HRC Hardness Conversion Chart

BHN, HV, HRB, and HRC Hardness Conversion Chart

Hardness measures a material’s resistance to deformation. Professionals across industries can make informed decisions about materials and their applications by understanding the BHN, HV, HRB, and HRC hardness conversion chart.

This knowledge aids in selecting the right material for specific purposes, ensuring longevity and efficiency. As technology advances and demands precision, a clear grasp of hardness conversion becomes indispensable.

This article will guide you through these units, their relevance, and how to interpret conversion charts effectively. Dive in to elevate your technical expertise.

What Is Hardness?

Hardness defines a material’s resistance to deformation. A hard material doesn’t easily dent or scratch when applied to an external force. Technically speaking, hardness examines how substances stand against localized plastic deformation. This is often gauged through indentation.

Different testing methods ascertain hardness. Each offers insights into material properties, particularly in manufacturing. Hardness ensures that parts perform efficiently and last long in their applications.

It’s not just about resistance. Hardness provides clues about a material’s brittleness, elasticity, and yield strength.

Consider metals in machinery. Their hardness determines wear resistance and durability. Similarly, in construction, the hardness of materials affects building longevity. Thus, understanding hardness is foundational in many technical fields.

Hardness Units

Each hardness unit serves distinct purposes and materials. Their correct application ensures accurate readings and appropriate material selection, underpinning successful engineering and manufacturing endeavors.

Rockwell [HRC/HRB/HRA]

Rockwell hardness represents a standard in industry measurements. The test uses preliminary and major loads and measures the indentation depth. The difference in scales, HRC, HRB, and HRA, depends on the indenter type and test forces.

With a diamond cone indenter, HRC is common for harder materials like hardened steel. HRB, utilizing a ball indenter, assesses softer metals.

HRA, meanwhile, evaluates harder alloys and thin materials. Rockwell’s quickness and simplicity make it a popular choice among engineers.


BHN stands for Brinell Hardness Number. It signifies the hardness of a material by measuring the diameter of an indentation made by a standard-sized ball, typically made of tungsten carbide, under a known force. The greater the indentation, the softer the material.

It provides an average measure over a wider area than other methods, making it suitable for heterogeneous or coarse-grained materials.

When materials exhibit varied compositions, BHN becomes crucial. The method, though accurate, might be slower than others like Rockwell.

Brinell [HB]

The Brinell test, represented as HB, involves pressing a hard ball into the material surface under a specific load. The diameter of the resulting impression calculates the hardness.

The formula relates the force applied and the surface area of the indentation. Materials with larger impressions indicate softer constitutions.

Since it encompasses a larger test area, the Brinell method is preferred for materials with varied microstructures, like castings or forgings. It gives a comprehensive view of material hardness, balancing between surface and bulk properties.

Vickers [HV]

Vickers hardness, or HV, uses a diamond pyramid as an indenter. The test applies a precise force for a defined period, producing a square indentation. The diagonals of this impression determine the hardness value.

The Vickers test boasts versatility. Its scalability allows testing from micro to macro levels. Consequently, it’s chosen for diverse materials, from thin films to bulky samples.

Its precision makes it a go-to for researchers and industries requiring detailed analysis.

Hardness in Machining

Hardness in Machining

In machining, understanding the intrinsic hardness of materials, whether raw or tooling, remains paramount. This knowledge informs decisions, optimizes processes, and ultimately guarantees quality in the end product.

Raw Materials

Machining transforms raw materials into finished parts. Hardness dictates this transformation. The harder a material, the more challenging it becomes to the machine.

Yet, hardness ensures wear resistance in the final product. Machinists balance these factors for efficiency and quality.

For instance, softer metals like aluminum might be easy to machine but lack wear resistance. Conversely, tougher steels resist wear but demand more effort to machine. In essence, selecting the right raw material directly influences machining success.

Tungsten Carbide

Tungsten Carbide

Tungsten carbide stands out in the machining world. This compound, made of tungsten and carbon, possesses exceptional hardness.

Often used in tooling, tungsten carbide endures where other materials falter. Its hardness translates to durability, allowing tools to maintain sharpness longer and withstand high-stress operations.

In fact, for tasks involving abrasive materials, tungsten carbide tools are a preferred choice. While this hardness proves advantageous, machining tungsten carbide requires specialized equipment and expertise.

Read More: Machined Parts: Comprehensive Guide on Types, Advantages & Design Secrets

Conversion Chart

A hardness conversion chart serves as a vital tool. It equates different hardness measurements, bridging gaps between scales. With materials tested under various scales, such charts facilitate comparisons.

Tensile Strength (N/mm2)Vickers Hardness (HV)Brinell Hardness (BHN)Rockwell Hardness (HRC)Rockwell Hardness (HRB)
32010095 56.2
350110105 62.3
385120114 66.7
415130124 71.2
450140133 75.0
480150143 78.7
510160152 81.7
545170162 85.0
575180171 87.1
610190181 89.5
640200190 91.5
675210199 93.5
705220209 95.0
740230219 96.7
770240228 98.1
800250238 99.5
Table 1. Hardness Conversion Chart

Learn More: Metal Strength Chart: Which Metal Has the Highest Strength?

Understanding the Conversion Chart

Understanding the Conversion Chart

Navigating a hardness conversion chart might seem daunting initially, but it transforms into an invaluable asset with comprehension.

Structure and Layout:

Most charts are presented in a tabular format. Rows or columns often represent different hardness scales – Rockwell, Vickers, Brinell, etc. By locating a value in one scale, you can trace across or down to find its equivalent in another.

Utilizing the Chart:

Start by identifying your known hardness value. Locate this scale on the chart. Next, follow the corresponding row or column to find the desired conversion. For instance, with a Rockwell value, tracing horizontally might lead to its Vickers counterpart.


At times, your exact value might not be listed. Here, interpolation is key. You can approximate the conversion by assessing values slightly above and below yours. While not pinpoint accurate, interpolated values often suffice for many applications.



No chart is universal. Some are tailored for specific material types or ranges. Ensure the chart in use suits your material.

Furthermore, recognize that conversions are approximations. Different hardness tests probe material properties differently. Therefore, while conversion charts bridge scales, they’re not flawless.


For repeated tasks or projects, always resort to the same chart. Variations might exist between charts due to differing methodologies or updates. Sticking to one ensures consistent and comparable results.

Beneficial Applications:

Beyond straightforward conversions, these charts have wider applications. They assist in material selection, quality assurance, and research.

For instance, researchers might compare materials across several projects that employed different hardness scales. Here, the chart becomes an indispensable unifier.

Check Out: GD&T 101: An Introduction to Geometric Dimensioning and Tolerancing


In the realm of materials and engineering, hardness stands pivotal. We grasp their significance through the nuanced exploration of scales like Rockwell, Brinell, and Vickers.

Conversion charts, while technical, bridge knowledge gaps, fostering consistency across diverse measurements.

In essence, understanding hardness and its conversions isn’t mere trivia. It’s essential to guiding decisions in manufacturing, research, and more. Harnessing this knowledge propels industries forward, ensuring precision and quality.

Kemal Manufacturing stands as a beacon in this domain. With our emphasis on quality and precision, we adhere to these principles and promotes widespread application, ensuring that products meet the highest standards of durability and efficiency.

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