JIS K 6251 is a Japanese Industrial Standard titled "Rubber, vulcanized or thermoplastic – Determination of tensile stress-strain properties." It specifies the methods for measuring the tensile stress-strain behavior of rubber materials, including:
| Feature | JIS K 6251 | ISO 37 | ASTM D412 | |---------|------------|--------|-----------| | | Japan | International | USA | | Test piece shapes | Dumbbell (Types 1-4), Ring | Dumbbell (Types 1, 2, 3), Ring | Dumbbell (C & D), Ring | | Test speed (Dumbbell) | 500 ± 50 mm/min | 500 ± 50 mm/min | 500 ± 50 mm/min (Die C) | | Thickness measurement | At three points | At three points | At three points | | Temperature | 23 ± 2°C | 23 ± 2°C | 23 ± 2°C | | Correlation | Highly similar to ISO 37 | Largely interchangeable with JIS | Slightly different die geometry | Jis K 6251 Pdf
Consequently, JIS K 6251 was introduced to specifically focus on tensile properties. This shift meant that manufacturers exporting goods from Japan or importing raw materials into Japan had to update their testing protocols to match the new, more globally aligned standard. The current version of JIS K 6251 is technically equivalent or modified from ISO 37, the international standard for rubber tensile testing. JIS K 6251 is a Japanese Industrial Standard
: Summaries of properties and testing methods using this standard can be found in technical datasheets from manufacturers like test parameters : Summaries of properties and testing methods using
: The percentage increase in length at the moment of rupture.
The standard applies to vulcanized rubber and thermoplastic rubber across a wide range of hardness levels, from soft and flexible to relatively hard compositions.