Hardness
Hardness
(OP)
Hi All,
For the hardness unit, can I say HB = HBW?
Thanks,
Jeffrey
For the hardness unit, can I say HB = HBW?
Thanks,
Jeffrey
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RE: Hardness
HBW means that the Brinell hardness measure has been carried out with a hard metal ball. This applies to hard materials, such as quench hardened and tempered steels.
For softer materials, such as cast irons and annealed steels, a steel ball shall be used.
The threshold between one indenter and the other is set to 350 HB according to EN 10003-1.
RE: Hardness
So back to the question, how do we differentiate HB and HBW?
I am assuming the same unit.
Thanks,
Jeffrey
RE: Hardness
up to ASTM A370-07a HB (D = diameter of the steel ball, mm)
I don't have 08, but in ASTM A370-09a there is HBW (D = diameter of the tungsten carbide ball, mm)
So if you go according to standards, then HB is not HBW.
But I personally would use HB for HBW for general designation now.
Older designation:
HBS - for tungsten carbide ball
HBW - for steel ball
BHN - sometimes on drawings
Dalin
RE: Hardness
If you are not using the standard 10mm ball and 3000 kg load, and 10-15 second dwell time (10/3000/15), then you must also list the ball diameter, load, and dwell time following the 'HBW' when expressing a result. It would be a good idea for you to purchase a copy of this ASTM standard for your reference.
RE: Hardness
Both ASTM E10 and ISO 6506 require hardmetal/tungsten carbide balls, steel balls shall NOT be used.
Dalinus,
HBS is an old designation for steel ball. HBW is for hardmetal/tungsten carbide ball.
JeffreyHo,
You should use HBW for everything now, except any legacy parts/documents that used older testing with steel balls.
RE: Hardness
Thanks for the advice, I wasn't aware of this change.
RE: Hardness