Hardness can be defined as a material's resistance to indentation. Hardness testing is an important step in many industries around the world, including metals, fiberglass, plastics, and rubbers; it is often used to certify quality of materials, test repairs, and can indicate potential coating failure.
DeFelsko offers digital and analog hardness tests in compliance with three different recognized hardness test methods: Shore (A and D), Barcol, and Pencil (Wolff-Wilborn) Hardness.
The digital PosiTector SHD Shore Hardness Durometer is available in either Shore A (for soft rubber, elastomers, neoprene, silicone, etc.) or Shore D (for hard rubbers, epoxies, hard plastics, PVC, acrylic, etc.)
The PosiTector BHI Barcol Hardness Impressor is a digital gage that measures the indentation strength of soft metals and very hard plastics such as aluminum, aluminum alloys, copper, brass, and fiber-reinforced plastics.
The PosiTest PT Pencil Hardness Tester is used to test the scratch resistance and relative hardness of paints and coatings.
The PosiTector SHD measures the indentation hardness of non-metallic materials such as soft rubbers, epoxies, plastics, and thick coatings. Two durometer models are available for different hardness ranges—Shore A and Shore D.
Conforms to ASTM D2240, ISO 48-4/868/7267/7619, and DIN 53505
The PosiTector BHI measures the hardness of soft metals such as aluminum, aluminum alloys, copper, brass, and other materials such as harder plastics and fiber-reinforced plastic.
Conforms to ASTM B648/D2583, DIN EN 59, and AS/NZS 3572.22
The PosiTest PT measures the hardness of coatings and films using the Pencil Hardness (Wolff-Wilborn) method in accordance with ISO 15184 and ASTM D3363.
Conforms to ISO 15184, ASTM D3363, JIS K-5600, BS 3900-E19, MIL C 27 227, ECCA-T4-1, SNV 37113, SIS184187, NEN 5350
Material Hardness is a measure of a material's ability to withstand permanent deformation such as bending, indentation, scratching, abrasion, erosion, or cutting. Measuring hardness is a crucial element of Quality Control.
Hardness can be measured in a variety of ways and means different things to different industries. The exact test method and hardness scale is determined by the material being tested as well as the quality expectations of clients, customers, and quality assurance programs.
Generally, some form of indentor (manufactured to a particular dimension specified by a test standard) is pressed into the material at a certain load and sometimes for a specific amount of time. The depth and/or shape of the indentation is measured and a hardness value is determined. Indentors for a Shore Hardness Durometer (left) as well as a Barcol Hardness Impressor (right) are pictured below:
When performing a Pencil Hardness Test, the pencils have a hardness scale that ranges from 6B (softest) to 6H (hardest) and act as an indentor as they are pushed across the surface by hand or with the assistance of a cart.
Hardness measurement is used as a means of quality control, with specific standards of quality determined by the manufacturer, customers, and other stakeholders. Hardness testing is also a relatively easy and inexpensive way of determining other material characteristics. As an example—for paints, coatings, and linings—hardness may indicate the degree of cure, which will aid in job planning and scheduling—saving valuable time.
The following standards are often used to determine the hardness of materials, including: rubbers (hard and soft), plastics, soft metals (such as aluminum, copper, and bronze), as well as paint, coatings, linings, and films.
Shore Hardness test standards are used to measure the indentation hardness of non-metallic materials such as soft rubber, elastomers, neoprene, silicone, in addition to harder materials such as hard rubber, epoxies, hard plastics, PVC, acrylic, etc.
ASTM D2240 guides the user through twelve types of rubber hardness measurement devices known as durometers: Types A, B, C, D, DO, E, M, O, OO, OOO, OOO-S, and R.*
*Refer to ASTM D2240 for a complete description of the test standard.
ISO 868 specifies a method for the determination of the indentation hardness of plastics and ebonite (vulcanized hard rubber).*
*Refer to ISO 868 for a complete description of the test standard.
ISO 7267 specifies a test method for the determination of rubber hardness of vulcanized- or thermoplastic-rubber roller covers, reported in Shore hardness units (Shore A or D).*
*Refer to ISO 7267 for a complete description of the test standard.
ISO 7619 specifies a test method for determining the indentation (Shore) hardness of vulcanized or thermoplastic rubber using durometers. Reports measurement in Shore A, D, AO, or AM scales.*
*Refer ISO 7619 for a complete description of the test standard.
DIN 53505 offers guidance to measuring rubber hardness using Shore A and Shore D durometers.*
*Refer to DIN 53505 for a complete description of the test standard.
Barcol Hardness test standards are used to determine the indentation hardness of soft metals such as aluminum, bronze, and copper.
ASTM B648 specifies a test method used to determine the Barcol hardness of aluminum alloys using a Barcol Hardness Impressor.*
*Refer to ASTM B648 for a complete description of the test standard.
ASTM D2583 covers the determination of indentation hardness of reinforced and non-reinforced plastics using a Barcol Impressor.*
*Refer to ASTM D2583 for a complete description of the test standard.
DIN EN 59 specifies a test method used to determine the Barcol Hardness of glass reinforced plastics.*
*Refer to DIN EN 59 for a complete description of the test standard.
AS/NZS 3572.22 specifies a test method used to determine the Barcol Hardness of glass (filament) reinforced plastics (GRP).*
*Refer to AS/NZS 3572.22 for a complete description of the test standard.
Paint and Coating hardness standards are generally performed with Pencil Hardness (Wolff-Wilborn) Test.
ISO 15184 specifies a method for determining the film hardness by pushing pencils of known hardness over the film.*
*Refer to ISO 15184 for a complete description of the test standard.
ASTM D3363 describes the test method for determining the hardness of paint and coatings using a set of leads or pencils of decreasing hardness to determine the point at which the pencil will not: 1—gouge the film (pencil hardness) or 2—scratch the film (scratch hardness).*
*Refer to ASTM D3363 for a complete description of the test standard.
JIS K 5600-5-4 specifies a test method for determining film hardness by pushing pencils of a known hardness over the film.*
*Refer to JIS K 5600-5-4 for a complete description of the test standard.