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Recent content by Gerry45

  1. Gerry45

    Induction hardening of C45 and 42CrMo4

    Thanks all for your useful comments. Gerry
  2. Gerry45

    Induction hardening of C45 and 42CrMo4

    Cory, Thank you for that guidance. Re the hardenability of the two materials, would this be best compared by CEQ or by say a Jominy test (or other ?!) ?
  3. Gerry45

    Induction hardening of C45 and 42CrMo4

    Some induction hardening trials have been carried out for me using specimins made in C45 steel. In production however, the material I will use will be 42CrMo4. Unfortunately the C45 tests have produced hardening depths that are just a little under specification. So, what do you think... will...
  4. Gerry45

    Hertzian Contact Stress and Material Hardness

    Yes, I think you have it about right ....but Im not quite so sure a pair of hardened and pair of soft component will show exactly the same deflection characteristics with only the level of recovery being different. I think that once the soft components are taken into their plastic region they...
  5. Gerry45

    Hertzian Contact Stress and Material Hardness

    The elastic modulus of steel is pretty independent of the type of steel or its heat treated condition. However, what is important in a hertzian contact situation is the stress level at which the material deforms plastically. So a piece of mild steel raceway will have the same INITIAL behavior as...
  6. Gerry45

    Method for load sharing in multiple drive-unit assembly

    I have a large and heavy piece of industrial equipment that is rotated into different angular positions via a 2m dia gear ring. The gear-ring is driven by the output pinions of six electric motor powered gear units positioned around it. The system works well under power because the six...
  7. Gerry45

    Crane Slew Bering Inspection

    Try Lloyds Register in Fenchurch, London. The offer a grease analysis service as a condition monitoring service for approval purposes. Gerry
  8. Gerry45

    Distance measurement to a moving component

    Hi, I dont know whether I'm in the right forum here, but if not perhaps someone can redirect me to a more appropropriate place....but in the meantime... I would like some advice on how to measure without contact, to an accuracy of about 0.050mm, the distance of a machined spot near the...
  9. Gerry45

    roller burnishing

    The ancient clock makers process of 'roller burnishing' appears to be making a bit of a come-back as a low cost way of creating a good surface finish together with some superficial work-hardening of the work piece. Does anyone know if the process is as effective as it claims to be and how one...
  10. Gerry45

    normal sliding pattern in a ball bearing

    I've always known such markings as 'Heathcote slip bands'. Unfortunately I've no idea who Heathcote was but I have seen them them many times. They tend to show up best when lubrication has been marginal (i.e. allowing some ball~raceway surface interaction) and loading heavyish (i.e. wide...
  11. Gerry45

    hardness values

    So at a diameter of 32mm, you would get perhaps 100% martensite at the core ? So at with 64mm and spherical, we would be closer to 100% than 50% martensite ? I guess the remaining material is mainly austenite and the difference in structure gives rise to potential residual stresses ?
  12. Gerry45

    hardness values

    Thanks both for your good info. Carburise, what do you mean by 'ideal diameter'. Previously someone said the the maximum thickness for full through-hardening in 100Cr6 was 32mm. This seems along way from the dimensions you give of 85 and 230mm so these things may not be connected. Perhaps you...
  13. Gerry45

    hardness values

    Can anyone advise me on the ideal and expected surface and core hardnesses for bearing quality balls of 64mm diameter made from 100Cr6 and 100CrMn6 ? Am I right in believing that the 100CrMn6 would give a more uniform hardness and therefore less internal residual stress ?
  14. Gerry45

    3 ball versus 2 ball crushload tests.

    Does any one here have experience of crush testing of large bearing balls ? 1) Im setting up a specification for the purchase of large (say 50~70mm) carbon chrome steel balls and want to include a strength test. I see some ball manufacturers qualify the strength of their products using a 2...
  15. Gerry45

    bearing balls and rollers in 100Cr6

    Many thanks for your comments. Goahead - you say "a tough core might be prefered for some applications" ...I think this is the line that some suppliers take too. But does a tough core not also create a 'notch sensitive' surface layer due to residual tensile stresses ? If so, perhaps in my...

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