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  1. karlmet

    Good Place to Start for Examining Microstructures?

    I believe Buehler & Struers both do materials preparation & basic microscopy courses but I wouldn't have thought they will manage to even touch on the basics of micorstructures in a course lasting just a few days!
  2. karlmet

    Ferritic Nitrocarburising

    Just our own procedure metalhead 10-20micron surface layer plus 100 micron diffusion zone
  3. karlmet

    Ferritic Nitrocarburising

    Just for a wear resistant surface layer I presume? It's for a range of materials. The trials are due to change of H/T company and it is my first experience with such a grade being used. Karl
  4. karlmet

    Ferritic Nitrocarburising

    Vickers indentation across (what should be) the diffusion zone Av397Hv in the etched ferrite and as low as 320Hv in the pearlite suggesting its not a uniform diffusion. Core is around 300Hv I have also etched in 5% nital and can see further etching of the carbon saturated areas close to...
  5. karlmet

    Ferritic Nitrocarburising

    I will try etching them in 5% nital and see if I achieve any further etching in the ferrite you suggest may be the diffusion zone, although could it be possible it has only diffused in areas with ferrite close to the surface and have a lot less/no diffusion in the pearlite? If this is the case...
  6. karlmet

    Ferritic Nitrocarburising

    Metalhead, 700/3 grade I'm lead to believe, I can clearly see the visible layer but I was expecting to see somewhat of a diffusion zone below that. Without the facility to do EDS analysis I can't be sure but would I not expect to see a darker etching layer of around 50-100microns? PS sample is...
  7. karlmet

    Ferritic Nitrocarburising

    Attached is a micrograph of a tufftrided sample from a new H/T supplier. I can see there is a good white layer of 10 microns although no nitrogen diffusion zone. Is this because the test piece used is a predominantly pearlitic microstucture and the pearlite is acting as a barrier to the...
  8. karlmet

    Ellingham Diagram

    Hi could anyone provide an example of chloride corrosion on austenitic stainless steel shown on the ellingham diagram please?
  9. karlmet

    Dimethylformamide & Triethylamine

    Thanks Stonecold, It basically looks like it has originated from the welding in the rebolier (possibly due to chloride in the water) and also in the bottom tray (waste) due to formic acid from the dimethyformamide? I will upload pictures soon.
  10. karlmet

    Dimethylformamide & Triethylamine

    Basically this is the problem, A separation column has failed in service It is constructed with 316l the plates are 10mm thick, the welding process was stick, the vessel is used to seperate dimethly formamide (DMF) and tri-ethylamine (TEA). I cant give you any info on the welding procedure or...
  11. karlmet

    dimethyl formamide and tryethylamine separation failure

    Hi all, I have been given a project to work on and wondering if any of you will be able to help with the chemical side, a breif description below: It is constructed with 316l the plates are 10mm thick, the welding process was stick, the vessel is used to seperate dimethly formamide (DMF) and...
  12. karlmet

    RA in Ovako 146s

    Thanks TVP,I'm awaiting response on these claimed results.
  13. karlmet

    RA in Ovako 146s

    Thanks, some interesting info.Klemm's tint etch could be worth trying as an alternative. Any idea on the claimed >800Hv? As no carbide network is visible and the material has been tempered I would have thought this would be near impossible to achieve?
  14. karlmet

    RA in Ovako 146s

    http://imageshack.us/g/252/52862252.jpg/ The above link is of the samples from the HT comapany and from an independent lab (supposedly from the same sacrificial test piece). Microstructures look very different and a difference in hardness of approx 200Hv.
  15. karlmet

    RA in Ovako 146s

    Hi All, I have attached a micrograph of Ovako 146s case hardened steel, I am estimating around 10% RA in the case (independent lab from H/T company state "No RA") I am also achieving hardness results to support the level of RA agains independent lab results of >800Hv! Is there a more accurate...

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