What does "Proof Load" refer to in testing?

In the context of testing materials, "Proof Load" specifically refers to a predetermined load applied to verify that a material or component can perform its intended function without being deformed or failing. It is not the maximum load the specimen can withstand or the point at which the material begins to fail. Instead, it serves as a benchmark to ensure quality and performance standards are met.

The proof load is set below the material's yield strength to confirm that the material is capable of handling the loads it will encounter during normal use without experiencing permanent deformation. This load effectively tests the integrity of the component without putting it at risk of failure under typical operational conditions. The term "value on the corresponding load" captures the essence of what proof load signifies in testing, as it denotes a specific measurement that ensures reliability and safety.