How do you do a rubber hardness test?
With the development of industrial industry, rubber fittings industry is also in high-speed development, the production of accessories materials also presents a diverse range of characteristics. Rubber fittings in the car is very wide range of uses, in addition to tires, the average family car will use 200-300 kinds of rubber fittings, trucks and industrial vehicles will be used to 400-600 rubber fittings, how to control the quality of rubber fittings rubber fittings manufacturers are generally concerned about the problem. This rubber hardness is one of the objectives of rubber parts quality control.
Hardness is one of the most basic physical properties of vulcanized rubber, and the hardness of the compound is closely related to physical properties such as constant tensile stress, tear strength, elasticity, compression permanent deformation and Young's modulus.
Hardness testing is widely used in quality control situations due to its simplicity of operation, low cost and non-destructive nature. Hardness can also be used to conveniently identify the vulcanization effect and uniformity of a range of vulcanized rubber products.
What is rubber hardness
Rubber hardness is defined as the depth of indentation formed by pressing a defined shape of pressure needle into the measured material under specified conditions, and then converting the depth of indentation into a hardness value.
Test Methods
Currently the mainstream rubber hardness test methods are Shore Hardness and International Hardness.
1、Shore hardness
Shore hardness is the use of a certain shape of the steel pressure needle, under the action of the test force vertical pressure into the surface of the test specimen, when the surface of the pressure foot surface and the surface of the test specimen completely affixed to the surface of the pressure foot, the pressure needle tip end face relative to the plane of the pressure foot has a certain outstretched length (i.e., the depth of the pressure needle into the measured object), the size of the length value to express the magnitude of the Shore hardness.
The indentation needle is connected to a linear measuring device and the measured indentation depth value is then converted to a Shore hardness value by a mechanical or electronic system. The deeper the indentation, the softer the material.
Shore hardness tester measured the value of the readings, its unit is "degrees", the description of the method is divided into two kinds of A, D, respectively, representing a different hardness range, 90 degrees below the Shore A hardness tester test, and data, 90 degrees and above the Shore D hardness tester test and data.
2. IRHD (International Rubber Hardness)
The resistance of an elastic material or rubber to indentation by a ball indenter is measured by the depth of the ball indenter pressed into the material under test. An initial contact force is applied to a 1, 2.5, or 5 mm ball indenter and the depth of indentation is set to zero. The force is then increased to a specified total load, at which point the depth of material indentation is measured.The IRHD value is related to the depth of indentation by the indenter. This measurement is often used to test smaller parts and O-rings.