Destructive Material Testing
Tensile test, Charpy impact test, — what the specimens really tell you
AI generated Destructive testing means: the specimen is destroyed in the process, but in return it gives you hard numbers. The tensile test measures strength and elongation, the Charpy impact test measures , and the measures resistance to indentation. These exact values appear in every datasheet — and in every welding procedure specification.
Destructive testing means: you sacrifice a specimen to get hard numbers. These numbers are the language of materials science — they appear in every datasheet, every certificate, and every welding procedure specification. There are three tests you need to be able to read.
The . A standardized specimen (usually taken transverse to the weld) is slowly pulled apart until it breaks. During this, three characteristic values are measured:
• (Re): the stress at which the material starts to deform permanently. The most important strength value.
• (Rm): the stress at which the specimen fractures. Always higher than the .
• (A): how much the specimen stretched before breaking — the measure of formability. Brittle materials barely stretch, tough ones stretch a lot.
In , the tensile test transverse to the weld is the standard proof: the weld must achieve at least the strength of the . If the specimen breaks next to the weld in the , that's good; if it breaks in the weld, the filler was too weak.
The . A notched specimen is struck with a pendulum hammer. The is measured in joules — the energy absorbed during fracture. The more joules, the tougher. Temperature is critical: many steels are tough at room temperature but become brittle in the cold. The transition temperature, where drops sharply, is the key value for low-temperature applications (cryogenic, outdoor in winter).
The . An indenter (diamond or ball) is pressed into the material with a defined force; the size of the indentation gives the . Common methods are Vickers (HV), Rockwell (HRC/HRB), and Brinell (HB). In , is measured as a line across → → . The maximum value in the is a key acceptance criterion — too hard a means and risk of cracking.
All three tests together give the full picture: strength (tensile test), (impact test), and hardening (). If you can read these numbers, you understand any material certificate — and you know whether a weld is really up to the job.