Tensile Test Method for Roller Chains

Tensile test is one of important measurements to review the chain quality. Through the test, we can inspect whether the finished chains have any defects after production and assembly; the possible defects might include poor or inappropriate materials, heat treatment, components, and assembly. 

Tensile testing standard for chains are specified by multiple international standards except for the stainless steel chain.

Tensile strength test method

ISO 606 standardization (Short-pitch transmission precision roller and bush chains, attachments and associated chain sprockets) is one of the most commonly adopted testing standards for the tensile testing. Below are some key points when carrying out the test.

1. The chain to be tested for tensile strength should be at least five pitches in length.
2. When testing, the connecting between the specimen and the testing machine, apply a tensile force slowly to the ends of chain by using fixtures which permit free movement on both sides of the chain centerline, in the normal plane of articulation.
3. During the testing, the tensile force should be increased slowly. The extending speed should not exceed 50.8mm/min. As the tensile force increases, the chain will be elongated at the same time, until the highest tensile force to break the chain. The ultimate tensile strength is the maximum stress that the chain can withstand while being stretched before breaking. This can also be reviewed from force/extension diagram; the highest point on stress curve is the tensile strength of the chain.
4. If the fracture or breaking occurs on the position where the chain and grip is connected, the test should be considered invalid.
5. Tensile test is a destructive test, which means that the test is accomplished by forcing the chain to fail under stress factors. Even though there is no visibly crack on the surface, the chain should not be used after testing.