Hardness 2

[JHWC]

Hi All,

For the hardness unit, can I say HB = HBW?

Thanks,
Jeffrey

 

[mp87]

Hi JeffreyHo,

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.

 

[JHWC]

Thanks.

So back to the question, how do we differentiate HB and HBW?

I am assuming the same unit.

Thanks,
Jeffrey

 

[Dalinus]

Brinell hardness number
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

 

[dbooker630]

ASTM E10-14 (Standard Test Method for Brinell Hardness of Metallic Materials) shows all testing to be done with a tungsten carbide ball (sect. 5.2.3), hence the W is added to all values. The HBW is used for all hardness ranges from 1 to 650 HBW.

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.

 

[CoryPad]

mp87,

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.

 

[mp87]

Hi CoryPad,

Thanks for the advice, I wasn't aware of this change.

 

[JHWC]

Thanks CoryPad! =)