Hello Pals,
Many times we come across hardness values written as HB & HBW. Now if you wonder why there is this W and what difference it makes in hardness value then lets explain it as below.
HB - Steel Ball
Difference in indenter used for hardness testing >>Difference in material used for ball in indenter.
So only difference in HB & HBW is material of ball used in Indenter. W in HBW indicates Tungsten material for ball.
HBW hardness values are more correct than HB values.
Many times we come across hardness values written as HB & HBW. Now if you wonder why there is this W and what difference it makes in hardness value then lets explain it as below.
Difference between HB & HBW:
Simplest explanation for difference
HB - Steel Ball
HBW- Tungsten Ball
Difference in indenter used for hardness testing >>Difference in material used for ball in indenter.Why Difference in material?
Why Not Steel Ball:
Indenter used in brinell hardness testing is ball indenter. In many indenter material of ball used is steel. But while testing some material which have higher hardness this steel ball used to get deform to some extent. This deformed ball indenter if used again give incorrect hardness values. Hardness values with steel ball indenter is expressed as HB.Why Tungsten Ball:
Now to over come this problem , Tungsten (W) material is used for ball in indenter. By using Tungsten, problem of deformation of ball in indenter while testing material of high hardness is totally eliminated. Higher hardness of Tungsten resist deformation. To express this hardness values with tungsten ball HBW is used instead of just HB.So only difference in HB & HBW is material of ball used in Indenter. W in HBW indicates Tungsten material for ball.
HBW hardness values are more correct than HB values.