BS ISO 18517:2015 pdf free

BS ISO 18517:2015 pdf free.Rubber, vulcanized or thermoplastic一Hardness testing一Introduction and guide
Hardness is a measure of stiffness or modulus which is an important property of rubbers in almost all applications. Its enormous popularity is due to its practical simplicity, versatility in terms of the test piece required, cheapness, and non-destructive nature. Because of this, it is universally used as a quality control test for trouble shooting, as a classification parameter for both compounds and products and as a requirement in material and product specifications. Hardness is widely used as a convenient, non-destructive measure of the state and uniformity of cure of a range of vulcanized products. It can also be used to track ageing, contamination and porosity, and so is suitable for diagnostic purposes.
When a portable, hand-held instrument is needed, for example for testing products, then a spring-loaded durometer or pocket hardness meter is used. The type A durometer is by far the most popular,but the type AO and the IRHD pocket meter have the advantage of a ball indentor which is less prone to damage than a truncated cone. The IRHD pocket hardness meter also has a very low variation in spring force over the hardness range and the results correspond directly to those obtained with dead-load instruments. For very hard rubbers and thin test pieces, types D and AM, respectively, are appropriate. The Shore D scale is usually associated with plastics materials, but is in common use for harder thermoplastic elastomers and ebonite and is sometimes preferred over Shore A and IRHD scales for rubbers over 90 IRHD.
NOTE Durometers have been produced with a built-in device that guarantees the application of the correct foot pressure regardless of the force applied by the operator.
The dead-load methods are intended to be the preferred approach for standard test pieces in the laboratory, the micro dead-load method being used where only thin pieces of material are available. The high and low hardness scales are intended to improve the discrimination at the extremes of the scale,but it has been shown that, for the high scale at least, there is no advantage (for further details, see Reference [1]). The VLRH method is preferred for very soft materials.BS ISO 18517 pdf download.