|CALCULATION OF WEAR RATE|
A common used equation to compute the wear rate is (Archard,1953).
Vi =ki F s
where F is the normal load, s the sliding distance, Vi the wear volume and ki the specific wear rate coefficient. Index i identifies the surface considered.
The k-value is given in m3/Nm or m2/N, sometimes in mm3/Nm. From design view the wear displacement h is more convenient than V. With hi =Vi /A, the contact pressure p=F/A where A is the area subjected to wear then:
hi =ki p s
The sliding distance s can be replaced by s=v.t where v is the mean value for the slide rate and t the running time.
Because the k-value depends just like the friction coefficient on
a lot of parameters this factor is to be find experimentally.
|k [10-15 m3/Nm]||class||Examples|
class 2/3: with teflon re-enforced bronze - tempered steel, dry.
class 3: hardwearing plastics - tempered steel, moderate load, dry.
class 4: bronze (Pb) - tempered steel, after running in, boundary lubricated fatty oil.
class 7: grinding.