Hardness is a characteristic that applies to a range of materials—metals and nonmetals alike—and is defined as the resistance of the material to deformation, penetration, scratching, or other physical force. Element's experts measure hardness according to the requirements of the material and its applications, with equipment precisely calibrated to the appropriate hardness scales.
The straightforward, timely, and relatively non-destruction nature of hardness testing make it one of the most popular characteristics for engineers interested in materials selection, lot verification testing, the evaluation of material processing, or the comparison of hardness values across multiple material samples. In addition, hardness values can typically be closely correlated with other material properties, such as tensile strength.
Macrohardness and Microhardness Testing
Element’s expertise in static deformation hardness methods include both macrohardness (applied loads of more than 1 kg) and microhardness (applied loads of less than 1 kg) in accordance with a wide range of industry standards, most of which call for the use of an indenter of known geometry and mass which is forced into the material’s surface. The amount of force applied along with the depth of the indentation is recorded and used to calculate the appropriate hardness value for a given point on the sample. Multiple indentations are typically performed to provide a mean hardness value for the entire sample.
On-site Hardness Measurements and Portable Hardness
As part of our On-site Metallographic Analysis, we use portable versions of hardness testing to make on-site hardness measurements on large installations or equipment that are either impossible or impractical to ship to a laboratory. We carry out on-site hardness measurements with the following methods:
- Rockwell C
Element can prepare the surface for each of the above methods and advise you on the most suitable method for your specific project needs. With global access to a team of multidisciplinary engineers and the advanced testing equipment, our hardness measurement services offer the portability, flexibility and high performance for on-site metals verification.
For more information about how we perform hardness testing, or to request a quote, contact us today.
Hardness Testing Standards
American Petroleum Institute
API Spec 5l, API STD 1104
American Society of Mechanical Engineers
ASME Section IX
ASTM A370, ASTM A641, ASTM A1038, ASTM B578, ASTM D785, ASTM D2240, ASTM D2583, ASTM D3363, ASTM E10, ASTM E18, ASTM E92, ASTM E140, ASTM E384, ASTM F606, ASTM F837, ASTM F879, ASTM F912
American Welding Society
AWS B4.0, AWS D1.1, AWS D1.2, AWS D1.5, AWS D3.6M, AWS D8.9M, AWS D14.3
British Standards Institute
BS 903, BS EN ISO 6507, BS EN ISO 6508, EN ISO 6506, EN ISO 6508, BS EN ISO 14271
Deutsches Institut Fur Normung E.V.
EN 1043-1, EN 1043-2, EN 10003-1, EN 10109
Ford Motor Company
GM 500M (Sec. 5.1, 5.2), GM455M (Sec. 5.1)
International Organization for Standardization
ISO 48, ISO 868, ISO 1400, ISO 1818, ISO 3738-1, ISO 4516, ISO 4545, ISO 6506, ISO 7619, ISO 9015, ISO 15156-1, ISO 15614-1, ISO 22826
Japanese Industrial Standard
JIS B1052, JIS B1053
Aerospace Industries Association/National Aerospace Standards Metric Standard
Naval Sea Systems Command
SAE J78, SAE J417, SAE J429, SAE J995, SAE J1199
Brinell Hardness Testing
Element performs Brinell hardness testing on a wide variety of metallic materials, castings, and forgings at forces ranging from 500 to 3000 kgf.
Brinell hardness testing (ASTM E10 and ISO 6506-1) is the oldest hardness method still in common use. The Brinell instrument employs a larger indentor ball (typically 10mm in diameter) and a much higher load (up to 3,000 kgf) than most other hardness test methods.
The larger indenter helps ensure that hardness readings are not adversely affected by small surface flaws. Because of this, Brinell hardness testing is frequently used on rough materials with a large number of surface imperfections, such as castings and forgings.
The most common industry standards for Brinell hardness are ASTM E10 and ISO 6506-1.
Rockwell Hardness Testing
Element provides hardness values on all Rockwell scales, from Superficial Rockwell up to the Rockwell G scale (HRG).
Rockwell hardness testing (ASTM E18 and ISO 6508-1) is generally considered to be the most popular and accurate of all hardness methods. Using a ball or cone shaped indentor, Rockwell hardness is used on metals of all types, except for any material with an irregular structure or surface variations that might influence test results.
The Rockwell method, which is detailed in ASTM E18 and ISO 6508-1, involves the use of a diamond indenter to apply a smaller preload on the material. This preload breaks through the material’s surface to eliminate the effects of any surface treatments. After the preload, the major load is applied to complete the test.
Knoop & Vickers Microhardness Testing
Element's microhardness testing capabilities include a wide range of forces, indenter geometries, and scales, including both Knoop and Vickers.
Knoop and Vickers (ASTM E384) are the two most common scales of microhardness testing. These tests use light loads and small indenters, making them ideal for small samples, very thin materials, surface coatings, or for evaluating the case hardness of a material through a series of indentations that create a hardness profile.
In accordance with ASTM E384, the Vickers hardness method utilizes a pyramid-shaped diamond indenter. In Knoop microhardness, the indenter is rhombic-pyramid-shaped for longer, shallower indentations.
Element’s metallurgical laboratories are equipped with advanced microhardness testing equipment as well as all the tools necessary to provide expert sample preparation services, including sectioning, mounting, polishing, and etching.
Hot Hardness Testing
Element possesses one of very few commercial laboratories with hot hardness testing capabilities, conducted inside a vacuum chamber to elevated temperatures up to 1,600F.
Hot hardness testing is the measurement of material hardness while at elevated temperature. Hot hardness can be valuable for assessing and comparing materials, such as tool steels and wear resistant coatings, which are used in high temperature applications such as valve seats and dies.
Element possesses one of very few commercial laboratories with hot hardness testing capabilities. Element conducts hot hardness testing similarly to normal Vickers hardness testing, except that the test is conducted inside a vacuum chamber which is capable of providing an elevated temperature up to 1,600F.
Shore Hardness Testing
Element provides Shore durometer hardness testing for a wide range of materials, including polymers, elastomers, and rubbers.
Shore hardness testing (ASTM D2240, ISO 7619, and ISO 868) is performed on rubbers and elastomers as well as “soft” plastics like vinyl and fluoropolymers. This test uses a piece of equipment called a Durometer, which consists of a calibrated spring and a cone-shaped or sphere-shaped indenter foot.
Because of the unique properties of plastics and elastomers, Shore hardness values often vary depending upon the amount of time the force is held. It is also not advisable to correlate Shore hardness results with other material properties.
Element’s Shore hardness expertise includes the Shore A, D, M, and OO scales.
Barcol Hardness Testing
Element performs Barcol hardness testing mainly in conjunction with glass transition temperature measurements to indirectly determine the cure of a composite or epoxy material.
Barcol hardness (ASTM D2583) has long been a popular industrial test method thanks to the simplistic and portable nature of the Barcol instrument. This penetration test uses a sharp steel point under a spring load, which is pressed against a flat surface of the material. The hardness of the material is determined based on the depth that the tip penetrates in comparison to a reference material.
The Barcol impressor was developed by Walter Colman to allow the US Army Air Corps to field test the hardness of rivets during World War II, due to concerns that aircrafts might be sabotaged by replacing normal rivets with soft lead or wooden ones.
Today, Element’s experts mainly utilize this method in conjunction with glass transition temperature measurements to indirectly determine the cure of a composite or epoxy material. Other uses include in-lab and field hardness measurements of both reinforced and non-reinforced rigid plastics as well as very soft metals, such as aluminum, brass, copper, and lead.
Vicat Softening Point / Vicat Softening Temperature (VST)
Element performs Vicat Softening Temperature tests on a wide variety of materials including coatings, polymer, composites, cement and plastics.
Vicat Softening Point, also known as Vicat Softening Temperature (VST), determines the softening point for materials that have no definite melting point, such as plastics. It is a measure at which an indenter penetrates into the specimen to a certain depth under a standardized loading using a steady temperature rise.
The high-temperature physical properties of plastics and polymers can be observed using the Vicat Softening tests as Polymers can still withstand loads of temperatures over 200C while others polymers can fail to reach loads at 100C. Our VST tests help you predict the behavior of a material and its ability to retain surface properties at high temperatures.
Element performs Vicat Softening Temperature tests according to international standards and procedures, including ISO 21809, ISO 306, EN 1028 and ASTM D1525. Our VST testing capabilities include materials such as coatings, polymer, composites, cement, and plastics.
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