The hardness of rubberelastic polymers and elastomers according to shore is determined using the test procedure standardised to iso 76191 or astm d2240. The hardness testing of plastics is most commonly measured by the shore durometer test. The brinell and vickers methods have been used historically in the uk, the brinell method for softened steel and vickers method for either softened or hardened steel. Astm d2240 and iso868 are the two most common specifications that we see. The shore durometer is a device for measuring the hardness of a material, typically of polymers, elastomers, and rubbers. Standard test method for rubber propertydurometer hardness. Astm d1415 18 standard test method for rubber property. Because of the popularity of the shore hardness method, a durometer is often referred to as a shore durometer. Some conditions and procedures that have to be met.
A standardised test used industrywide, the shore d hardness technique measures the depth of penetration of an indenter, generally using astm d2240 and iso 868 test methods. Shore hardness is a measure of the resistance of a material to penetration of a spring loaded needlelike indenter. The measuring instrument is actually a durometer, but shore hardness is named after its inventor albert shore. No simple relationship exists between indentation hardness determined by this test method and any fundamental property of the material tested. This shows the limitation in simply modifying bushes for a higher load case by increasing the shore hardness of the rubber compound. Shore a vs shore d hardness 165 wambold road, harleysville, pa 19438 18005236688 2157236051 fax 2157992518 shore hardness astm d2240 shore hardness is a relative measure of exactly what the term implies hardness. The bareiss test stand is determined for series of measurements and serves for picking up the manual hardness testers acc. Hardness test methods a scale b scale c scale hr15t hr30t. Shore durometer hardness testing of rubber and plastics matweb.
The term is also used to describe a materials rating on the. The dimensionless reading of the shore a and d readings range between 0 and 100. This document specifies a method for determining the indentation hardness shore hardness of vulcanized or thermoplastic rubber using durometers with the following scales. The rockwell method was first introduced in the us. Rubber elastomers are measured using the shore type a scale. Pencil hardness testing is performed according to the procedure described in astm d3363, standard test method for film hardness by pencil test. Lower numbers indicate less resistance and softer materials. The method is used widely in quality control and belongs to the macroscopic group of methods. It is possible to pile several specimens to achieve the 6. Hrc known as rockwell c, a 150 kgf load is applied via a diamond in this method. Another test standard, the vickers hardness value hv, is commonly used in microhardness or microindentation hardness testing, as is the knoop hardness test hk. The hardness of plastics is most commonly measured by the shore durometer test or rockwell hardness test.
The shore test hardness value consists of three main components. The ease with which the hardness test can be made has made it the most common method of inspection for metals and alloys. Plastics and ebonite determination of indentation hardness by means of a durometer shore hardness iso 868 type a and d if you are interested in a method that is not listed here, please contact us about custom testing. Any testing carried out as well as their results are dependent. The type of material and expected hardness will determine test method. Shore d hardness test durometer scale hardness of plastic. Durometer hardness testing explained engineeringclicks. Shore durometer hardness testing of rubber and plastics.
Shore d hardness is a standardized test consisting in measuring the depth of penetration of a specific indenter. This test method is applicable to waters that are clear in appearance and free of chemicals that will complex calcium or magnesium. Use of the instrument in combination with a test stand is recommended for laboratory tests. The initial hardness has normally a higher value in comparison with the hardness after a set test time and the result is obtained automatically during the standard execution of the hardness test. The test measures the penetration of a specified indentor into the material under specified conditions of force and time. Both methods measure the resistance of plastics toward indentation and provide an empirical hardness value that doesnt necessarily correlate well to other properties or fundamental characteristics. Materials such as cast irons and powder metals will need a much larger indenter such as used with brinell. The shore a scale is used for softer rubbers while the shore d scale is used for harder rubbers. In which hardness testing method does an experienced operator test the material by scratching the surface. Hardness comparison of polymer specimens produced with. Easy measurements on plastic, rubber and synthetic fibers, in compliance with astm and iso standards. In this test method, the indentation depth of a springloaded indenter into the material is determined. This testing can assist customers with determining the durometer across a surface and to ensure that.
The designation of the shore method that defines the indenter and the associated parameters. Accounting for more than 90% of the current domestic rubber hardness testers. For specification purposes, it is recommended that test method d785 be used for materials other than those described in 1. Standard test method for rubber propertyinternational hardness. The scale provide an empirical hardness value that doesnt relate directly to the mechanical properties of the material being tested. The shore hardness cannot replace the correct establishment of the static and dynamic stiffness of the component. Shore hardness tester stand with shore durometer, digital. The test method designation is astm d2240 while related methods include the like of iso 7619. The shore hardness test method is the oldest, most widely used and most convenient rubber hardness measurement method. Equipped with a drag indicator, which holds the highest measured result. The shore scleroscope, ass mentioned before, measures the rebound hardness of a material, and depends on the resilience of the hammer for consistent results. Shore d hardness is a standardized test consisting in measuring the depth of. Standard test method for rubber propertydurometer hardness1.
The higher the shore value is, the higher the dynamic restiffening tends to be. The shore scleroscope is not only small and mobile, it also leaves no impressions on the tested surface. Shore a and shore d hardness scales are common, with the a scale being used for softer and the d scale being used for harder materials. Shore irhd hardness testing machine for rubber and plastic. The shore hardness tester is easy to carry, simple in results. Principally, the importance of hardness testing has to do with the relationship between hardness and other properties of material. Any specification may be referred to as either a shore or type for example, shore a 70 durometer or type a 70 durometer. The test methods employed vary greatly from a field applied test to a very controlled laboratory test. The testing process involves pressing a carbide ball indenter into the. It measures hardness values in pointsthat range from 0 to 100. The calculation returns the maximum shore reading at the beginning of the test time.
It is measured by the depth of indentation that is created on the material with a specified force. Both specifications are used for materials ranging from 20 to 90 durometer. Hardness testers for plastic and rubber automatic testers, portables or bench top, for shore and irhd hardness methods. Durometer shore hardness test ld0550, ld0551 application a reliable instrument for measuring the impression hardness of soft materials such as coatings, plastics and rubber. The results vary between a minimum shore hardness of 0 to a maximum shore hardness of 100 which relates to zero penetration. Most of the rubber hardness testers used in china are type a shore hardness testers. Shore hardness is measured with a durometer test instrument to determine how a given material resists permanent indentation. So, the astm stipulates that the test method focuses on the penetration of a certain type of indentor when it is pushed into the chosen material under certain conditions.
If the dwell time deviates from the standard, a time is indicated as a suffixed fourth component. Apr 19, 20 shore a vs shore d hardness 165 wambold road, harleysville, pa 19438 18005236688 2157236051 fax 2157992518 shore hardness astm d2240 shore hardness is a relative measure of exactly what the term implies hardness. F1957 test method for composite foam hardnessdurometer hardness 2. Introduction to hardness testing asm international. The astm test method designation is astm d2240 00 and is generally used in north america. The indentor for the instrument is then pressed into the specimen making sure that it is parallel. Shore hardness is nothing but a measure of the hardness of a given material or how resistant it will be to permanent indentation. Pencils containing lead centers with various hardnesses shown in figure 4 are prepared then used to attempt to scratch or gouge the coating. A chart is then used to convert the averaged diameter measurement to a brinell hardness number. Durometer, like many other hardness tests, measures the depth. Durometer type a for materials such as e lastomers. The hardness figure is followed by a code indicating the test method. For example, both the hardness test and the tensile test measure the. This test method is an empirical test intended primarily for control purposes.
The hardness is obtained by the difference in penetration depth of a specified dimension ball under two conditions of contact with the rubber. For the love of physics walter lewin may 16, 2011 duration. This test measures the resistance of the plastic toward indentation. A brinell hardness result measures the permanent width of indentation produced by a carbide indenter applied to a test specimen at a given load, for a given length of time. Automatic hardness testers customizable hardness testers for rockwell, brinell, vickers and jominy hardness test methods. With readings taken between 0 and 100, shore hardness measures are dimensionless. The lower detection limit of this test method is approximately 2 to 5 mgl as caco3. Rubber elastomers are measured using the shore typea scale. Variants on the rockwell hardness test procedure are used depending on the material and strength of a part. The hardness value is determined by the penetration of the durometer indenter foot into the sample. Determination of shore hardness to iso 76191, iso 868 and astm d2240 is a test method that can be easily performed with a portable hardness tester.
The shore a scale is a measure of the shore a hardness of elastic materials such as rubber or soft plastics, and the shore d scale is a measure of the shore d hardness of hard plastics and rubbers. This microhardness test is used on very small metal parts, brittle materials or thin sheets with material features that are unable to be tested by the other methods. The test method designation is astm d2240 and is generally used in north america. In the united states, the two most commonly used tests are the brinell and rockwell tests. Durometer shore hardness test manual ld0550, ld0551. The specimen is first placed on a hard flat surface. Used to measure the hardness of rubber and plastics according astm d2240, din 53505, iso 868 and iso 7619. Nov 17, 2014 several standard test methods exist for the measurement of rubber hardness. Shore hardness, using either the shore a or shore d scale, is the preferred method for rubberselastomers and is also commonly used for softer plastics such as polyolefins, fluoropolymers, and vinyls. Oct 14, 2011 for the love of physics walter lewin may 16, 2011 duration. With readings taken between 0 and 100, shore hardness measures are. Durometer hardness is used to determine the relative hardness of soft materials, usually plastic or rubber. Test methods used to measure shore d hardness are astm d2240 and iso 868.
The hardness shore d method comes into its own when a material is too soft to be measured by the rockwell test. The brinell hardness test was the first standardised test to be widely used, especially on metals. Type shore a durometer shore a durometer is appropriate for measuring the hardness of specimens that are flat, parallel, and of a certain minimum thickness. Shore a scale is applicable for rubber and soft plastics whereas shore d is for hard. Feb 15, 2012 used to measure the hardness of rubber and plastics according astm d2240, din 53505, iso 868 and iso 7619. Ardl regularly provides durometer and irhd testing according to specified methods or customer requirements using hand held and stationary equipment to penetrate a material with a special indentor. The rockwell hardness test method, is the most commonly used hardness test method. Hardness test methods a scale b scale c scale hr15t. The most widely used hardness measuring instrument is called the durometer. The pickup device of the test stand allows a quick and easy clamping of the hardness tester. Shore test the hardness of rubberelastic polymers and elastomers according to shore is determined using the test procedure standardised to iso 76191 or astm d2240. Jul 28, 2017 variants on the rockwell hardness test procedure are used depending on the material and strength of a part. Shore a scale is used for testing soft elastomers rubbers and other soft polymers. According to astm d224015 standard test method for rubber property durometer hardness, the test specimen must be at least 6.
461 231 933 76 231 771 493 289 1132 1215 943 247 1401 247 4 1548 1415 534 150 121 869 22 1325 208 739 427 729 879 1038 652 1187 374 286 141 1059 785 739 1325 57 619 1224 365 507 443 376 829 229