Testing
What we measure, and what it tells you
Nine properties, each verified either in-house on every batch or certified per heat. Here is what each one is actually for.
Two kinds of testing
Per heat, and per batch
Chemistry and mechanical properties belong to the heat — one melt of steel, cast and rolled together. Every bar from that heat shares them, so they are certified once per heat and reported on the certificate that travels with the material.
Dimensions, straightness, surface and hardness belong to what we did to the bar. Those are verified in-house on every batch we draw, because they are the properties our process controls and the ones that vary if a die wears or a setup drifts.
That split matters when you read a certificate. A chemistry result tells you what steel it is. A dimensional check tells you what we made from it.
The tests
Nine properties, and why each one matters
Chemical composition
Certified per heat and reported on the certificate
Percentage of C, Si, Mn, P, S and alloying elements such as Cr and Pb
Confirms the material is the grade ordered. For carburising grades, Mn and Cr drive hardenability; for free cutting grades, S drives machinability; for anything welded, C is the deciding number.
Tensile strength
Certified per heat
Maximum stress the material carries before fracture, in MPa
The headline strength figure a designer works from. Note it is measured in a stated condition — cold drawn, annealed or hardened and tempered give different numbers for the same steel.
Yield strength
Certified per heat
Stress at which permanent deformation begins
Usually the number that actually governs the design, because most parts must not deform permanently in service.
Elongation
Certified per heat
Percentage extension at fracture over a gauge length
A measure of ductility. Low elongation warns that a material will crack rather than bend — relevant for cold formed and shock loaded parts.
Hardness
Verified in-house per batch and reported
Brinell (HB) or Rockwell (HRB / HRC) as applicable
A quick, non-destructive indicator of condition. On case hardening grades the supply hardness matters directly — the bar must be soft enough to machine before carburising.
Hardenability (Jominy)
Certified per heat on H grades
Hardness plotted against distance from a water-quenched end face
The defining property of an H grade such as 16MnCr5H. It predicts how deep the hardened structure forms, which is what determines case depth on a fixed carburising cycle.
Dimensional accuracy
Verified in-house on every batch with micrometers
Diameter or across-flats measured against the ordered ISO 286 h-band
Determines whether the bar feeds through a collet and how much stock has to be removed. The most frequent practical cause of a rejection.
Straightness
Verified in-house after straightening
Deviation from a straight line over the bar length
Governs bar feed reliability on automatics, runout on finished shafts, and the machining allowance needed to clean up a long component.
Surface finish
Verified in-house during and after drawing
Visual and tactile inspection along the drawn length
Fatigue cracks start at surface defects, and seal life on a hydraulic rod depends directly on surface quality. Also the first sign of a worn or scored die.
What a test certificate does not do
If a result looks wrong, tell us
Tell us what you need
Every dispatch ships with the certificate. Tell us the grade, size and quantity and we will confirm availability.