Hard rubber flexural strength test

Hard rubber is a hard material made by adding sulfur and other additives to rubber and vulcanizing it. Due to the action of a large amount of vulcanizing agent, it has a high hardness. Bending strength refers to the maximum bending stress endured by the specimen during the process of bending to failure.
Bending stress refers to the stress generated when the specimen is bent, and its value is the ratio of the maximum bending moment value produced by the applied force to the bending resistance moment. The hard rubber flexural strength test can apply static force at the center between two hard rubber seats to bend the sample, and measure the flexural strength of the sample.
Zhongke Testing Reliability Experiment Center has the capability to test the reliability performance of various hard rubbers and provides professional bending strength testing services for hard rubbers.

Hard rubber is mostly used to make hoses, glue sticks, rubber plates, partitions and battery cases. In addition, it is also widely used as protective equipment, insulating gloves, insulating rubber boots, etc.

1. Measure the width and thickness of the stressed part in the middle of the sample. Measure three points respectively and take the median, accurate to 0.02 mm.
2. Install the testing device for the bending strength test on the testing machine, adjust the zero point of the testing machine pointer, and the cutting edge of the indenter in front of the sample should be 15 mm to 20 mm higher than the plane of the two points.
3. Place the wide side of the sample on the two stands so that the lengths of the protruding parts at both ends are approximately equal.
4. Start the testing machine and adjust the speed of the testing machine so that the sample is damaged or reaches the maximum value within 30 s ± 15 s.
5. When the indenter contacts the sample, the timing starts. At the end of the specimen, record the force value indicated by the testing machine.
6. Observe the cross section of the sample to determine whether there are pores, impurities and other internal defects inside the sample. If there are defects, the sample data will be invalid and the sample should be resampled for measurement.

HG/T 3844-2008 Hard rubber - Determination of flexural strength
GB/T 2941 General procedures for preparation and conditioning of rubber physical tests