Rockwell hardness testing laboratory
You would like to perform a Rockwell hardness testing on your materials
What is Rockwell hardness ?
Rockwell hardness (RH) is a method of measuring the hardness of materials. It is mainly used for metals and certain types of plastics. This test is used to assess a material’s resistance to permanent deformation (or indentation) when subjected to a load.
Hardness measurement is essential in many fields, such as aerospace, automotive, medical and nuclear, to ensure that the materials used meet specific strength and durability requirements.
What is Rockwell hrc hardness?
Rockwell HRC is a measurement of the hardness of materials, mainly metals, on theRockwell C scale. This method uses a conical diamond indenter (called an ‘indenter’) that is pressed into the material under a heavy load.
The depth of the indentation formed is measured and converted to a value on the HRC (Rockwell C) scale. This scale is particularly used for testing hard materials such as hardened steels, alloys and other metals used in high stress environments. The higher the HRC value, the harder the material.
Why perform a Rockwell hardness testing on your materials ?
Assessing the resistance of materials
Measuring Rockwell hardness enables us to assess a material’s resistance to deformation and wear under stress. This ensures that materials are suitable for demanding applications where high performance is required, such as in environments subject to high mechanical stress.
Quality control
Rockwell hardness measurement provides fast and accurate quality control, checking that materials meet the necessary hardness specifications. This ensures the consistency of finished products and avoids failures due to inadequate materials, by identifying deviations in the production process that could compromise final quality.
Selection of materials
This measurement helps to select the appropriate materials based on the specific needs of an industrial application. As an industrialist, measuring Rockwell hardness ensures that the materials selected offer the durability and performance required for applications such as tools, mechanical components and parts subject to high stress.
Heat treatment efficiency
Finally, it makes it possible to assess the effectiveness of heat treatments on metallic materials and supports research and development by facilitating the improvement or creation of new materials for specific applications.
Rockwell hardness test applications
Rockwell hardness for steel
Rockwell hardness for steel, particularly hardened steels, is generally measured on the HRC (Rockwell C) scale. Heat-treated steels can have values ranging from 40 to 65 HRC, indicating high resistance to deformation and wear. This measurement is essential to ensure that the steel used in tools, gears or structural components can withstand high mechanical stresses without deforming.
Rockwell hardness for aluminium
Aluminium, being a softer material than steel, is often measured on the Rockwell B scale (HRB) or sometimes on other scales adapted to softer metals. Pure aluminium can have values ranging from 15 to 30 HRB, while some harder aluminium alloys can reach up to 60 HRB. This measurement is used to check the strength and suitability of aluminium for lightweight but mechanically demanding applications, such as aerospace and automotive components.
The FILAB laboratory assists manufacturers with Rockwell hardness testing B, C, M and R
Why choose FILAB for Rockwell hardness testing ?
Through our three levels of services: analysis, expertise and R&D support, FILAB assists companies in all sectors with their laboratory Brinell hardness measurement needs.
FILAB provides its customers with the know-how and experience of its team, as well as a state-of-the-art analytical facility.
Les différentes échelles de dureté rockwell
Rockwell hardness analysis is based on the use of different scales depending on the type of material being tested. Each scale is adapted to materials with varying levels of hardness. Here is an explanation of the HRB, HRC, HRM, and HRR scales:
HRB scale (Rockwell B)
- Materials concerned: Soft to moderately hard metals, such as aluminium, brass, copper and certain mild steels.
- Principle: A spherical steel indenter with a diameter of 1/16 inch is used, with a load of 100 kg. This scale measures the depth of penetration into softer materials.
- Applications: The HRB scale is used to assess the hardness of non-ferrous metals and untreated steels, such as aluminium and soft alloys. It is used to determine the resistance of these materials to deformation under low stress.
HRC scale (Rockwell C)
- Materials concerned: Hard metals, mainly hardened steels and hard alloys.
- Principle: A conical diamond indenter, called a ‘Brale’, is used with a load of 150 kg. This scale is designed for very hard materials, measuring penetration resistance under a high load.
- Applications: The HRC scale is used to test the hardness of hardened steels, steel tools and other metals subjected to high mechanical stress. It is the most common industrial scale for hard materials.
HRM scale (Rockwell M)
- Materials involved: Soft to rigid plastics and polymers.
- Principle: A spherical steel indenter with a diameter of 1/4 inch is used, with a lower load (10 kg or 100 kg, depending on the variant). The HRM scale is suitable for thermoplastics and other polymeric materials.
- Applications: This scale is used for plastics such as nylon, polyethylene and polypropylene. It is used to assess the hardness and resistance to deformation of polymers in industrial and manufacturing applications.
HRR scale (Rockwell R)
- Materials concerned: Rigid plastic materials and composites.
- Principle: A spherical steel indenter with a diameter of 1/2 inch is used with a light load (60 kg). This scale is designed for stiffer non-metallic materials.
- Applications: The HRR scale is mainly applied to hard plastics such as polycarbonate or rigid composites. It is useful in the manufacture of electronic components, insulators and other materials where rigidity and hardness are important criteria.
Rockwell hardness table
Here is an indicative table of Rockwell hardness values for various commonly analysed materials :
Material | Rockwell Scale | Rockwell Hardness |
Mild steel | HRB | 55 – 80 HRB |
Hardened steel | HRC | 40 – 65 HRC |
Grey cast iron | HRB | 70 – 100 HRB |
Ductile iron | HRB | 50 – 80 HRB |
Stainless steel | HRC | 50 – 60 HRC |
Brass | HRB | 55 – 80 HRB |
Pure aluminium | HRB | 15 – 30 HRB |
Aluminium alloy | HRB | 30 – 60 HRB |
Copper | HRB | 35 – 55 HRB |
Zinc | HRB | 70 – 95 HRB |
Nylon (thermoplastic) | HRM | 70 – 90 HRM |
Polycarbonate (thermoplastic) | HRR | 70 – 90 HRR |
What are the standards governing Rockwell hardness testing ?
ASTM E18-22
ASTM E18-22 details methods for conducting tests, including prerequisites for testing machines, calibration procedures, and interpretation of results on mechanical materials. ASTM E18-22
ISO 6508-1
ISO 6508-1 specifies the Rockwell hardness test method for metallic materials. It is aligned with ASTM E18 in many respects, ensuring a degree of interoperability between American and international standards.
ASTM D785
ASTM D785 is the standard test method for Rockwell hardness of plastics and electrical insulating materials.
Other hardness measurement methods at FILAB
Brinell hardness testing
Charpy hardness testing
Vickers hardness testing
Shore hardness measurement
Our other mechanical analysis services
Hardness measurement to ISO standards 48-4 and 48-9
FAQ
The Rockwell hardness test is carried out using a Rockwell hardness machine, a piece of equipment specially designed to measure the hardness of materials as a function of the penetration depth of an indenter under a defined load. The machine uses different types of indenter (diamond cone or steel ball) and applies specific loads according to the scale chosen (HRB, HRC, etc.). The machine performs the test by pressing the indenter against the surface of the material, then measures the depth of the indentation. The results are displayed directly on the machine's screen in Rockwell hardness values, providing a quick and accurate assessment of the mechanical properties of the material under test.
Brinell and Rockwell hardness are two commonly used methods for assessing the hardness of materials, but they differ in terms of application and accuracy. The Brinell hardness test uses a steel or carbide ball pressed against the material with a high load, measuring the hardness according to the size of the indentation left. It is often used for softer materials and coarse-grained metals, such as mild steels and non-ferrous alloys. Rockwell hardness, on the other hand, measures the depth of penetration of an indenter (conical or spherical) under a specific load, providing faster results and is suitable for hard materials such as hardened steels. The Rockwell method is more commonly used for series testing, as it does not require manual measurement of the indentation.
Rockwell and Vickers hardness are two methods that differ in the precision of the measurement and the types of materials they test. The Rockwell test is mainly used for relatively hard materials, such as steels and alloys, and is appreciated for its speed and simplicity, particularly in production environments. The Vickers method, on the other hand, uses a diamond pyramid indenter and applies a precise load, making it possible to test very hard materials as well as thin layers or treated surfaces. The Vickers method is more precise and is often used for research tests or applications requiring a fine assessment of hardness on a microscopic scale, unlike Rockwell, which is better suited to rapid tests on mass-production parts.
What are the different Rockwell hardness scales?
- HRB is used for softer, non-ferrous metals.
- HRC is suitable for very hard metals, particularly hardened steels.
- HRM and HRR apply to plastic and composite materials, with differences in the size of the indenter and the loads applied for more or less rigid materials.
These different scales enable materials with varying levels of hardness to be tested effectively, ensuring that each material conforms to its technical specifications for specific applications.
