What is the function of a hardness tester in metalworking?

The function of a hardness tester in metalworking is to assess the metal's resistance to deformation, which is correctly identified in the chosen answer. Hardness testing provides a measure of how resistant a material is to localized plastic deformation, such as indentations or scratches. This characteristic is crucial for determining how materials will perform under stress and wear conditions, making it invaluable in applications where materials are subjected to impacts or excessive loads.

This assessment can help engineers and manufacturers select appropriate materials for specific applications, ensuring that they choose metals that can withstand the operational environment without failing prematurely. For example, a high hardness value may indicate that the metal is suitable for components subjected to abrasion or impact.

Other options, such as measuring the weight of metals, evaluating thermal conductivity, or determining the elasticity of metals, do not pertain to the primary purpose of a hardness tester. While these factors are important in metalworking and materials science, they are measured using different methods and instruments tailored to those specific properties. This highlights the specialized role of hardness testing in the broader context of material evaluation.