GB/T 6031-2017

This standard specifies four methods for determining the hardness of vulcanized rubber or thermoplastic rubber with a smooth surface (standard hardness methods) and four methods for determining the apparent hardness of bent surface samples (apparent hardness methods). The hardness values are expressed in International Rubber Hardness (IRHD). The hardness range applicable to these methods is from 10 IRHD to 100 IRHD. The main differences between these methods lie in the diameter of the spherical indenter and the magnitude of the applied force. The appropriate method should be selected based on the specific application. The application scope of each method is shown in Figure 1. This standard does not specify the method of determining hardness using portable hardness testers, which is described in ISO 76192. Note: X--hardness (IRHD); a--methods L and CL; b--methods N, M and methods CN, CM; c--methods H and methods CH.