What type of tests are required for samples of built-up sections with plates over 2 inches in thickness?

The requirement for Charpy V-notch testing specifically for built-up sections with plates over 2 inches in thickness stems from the need to assess the toughness of the material, particularly in situations where the structural integrity is critical under dynamic loading conditions. This test is essential in evaluating how well the steel will perform in low-temperature environments or under impact situations.

Charpy V-notch testing measures the energy absorbed by a material as it fractures, effectively providing an indication of how brittle or ductile the material is. The presence of a notch simulates an existing flaw that could be critical under stress, making this test particularly relevant for thicker sections where internal stresses or defects could lead to catastrophic failures if the material is not sufficiently tough.

Other testing methods mentioned may serve different purposes—tensile testing evaluates the maximum load capacity and elongation, hardness testing assesses surface hardness, and impact testing generally refers to similar tests but may not specifically align with the standards set for thicker plate materials. However, the specificity of Charpy V-notch testing to built-up sections aligns best with the focus on toughness necessary for such significant thicknesses in construction.