Tensile Test Specimen

Tensile test specimen is also called tensile test bar, which is used to test the tensile strength, yield strength and elongation for the cast iron and cast steel materials. It is the most important test method to iron and steel castings.

Tensile strength and elongation are the very important and main physical properties for the iron and steel castings. Tensile strength (TS) is also called as ultimate tensile strength (UTS), often shortened as ultimate strength, is the maximum stress that a material can withstand while being stretched or pulled before necking, which is when the specimen's cross-section starts to significantly contract. Tensile strength is opposite of compressive strength and the values can be quite different.

The tensile test specimen dimensions are very important for the accurate test result. There are many different dimensions, such as 10mm, 12mm and 14mm and 20mm, but main principle is the effective length is 5 times of the effective diameter. For example, 10mm diameter with 50mm length, 12mm diameter with 60mm length, 14mm diameter with 70mm length, and so on. Usually, most of metal foundries in China use the 14mm diameter as the standard test specimen.

This principle is suitable for both cast iron and cast steel. Some clients, especially big companies, may issue their own standard to the tensile test specimen dimensions. However, they should obey this principle, otherwise, the test result should not be taken as correct.

As for the sampling point, it is better to get the test specimen from the body of castings, however, it is difficult sometimes, so usually Dandong Foundry will make the test specimen during the production of castings. These test specimen will reflect the tensile strength of the castings made in the same furnace.

As for the tensile test machines, please there are many types. For the old type, we have to calculate the results by the manual, but for the new type of test machine, the computer will calculate the results for you, but all types of test machines are basing on the same theory.

For the photos of tensile test specimen and test machines, please check Dandong Foundry Blog.

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