Before you use a steel plate in an engineering or construction application, you should determine its strength to ensure it can carry the loads being applied to it. One of the most common strength tests is the ultimate tensile strength test, which determines the maximum stress a material can withstand without breaking. Once you've measured the maximum stress, deriving the ultimate strength value of a steel plate is straightforward.

Measure the length and width of the steel plate. For example, assume a steel plate measures 5 inches by 6 inches.

Multiply the length and width of the steel plate to determine its area. Continuing with the example from Step 1, multiplying five by six equals an area of 30 square inches.

Place the steel plate between the cross heads of the universal testing machine, and align it so that it is perfectly center.

Turn on the machine and the tensile testing software.

Apply tension to the steel plate with the cross heads using the software.

Continue applying tension until the plate fractures. Record the load in pounds that was applied when the plate fractured. As an example, the load was 5,000 lbs.

Divide the load at fracture by the area of the steel plate to determine the ultimate tensile strength. In the example, dividing 5,000 lbs. by 30 square inches equals an ultimate tensile strength of approximately 166.67 lbs. per square inch.