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Chromova 18 steel, again...

Discussion in 'The Kitchen Knife' started by Gator, Jun 11, 2019.

  1. Gator

    Gator Silver Contributor

    Hi All,

    Sorry, this is kindda long I guess :)

    In essence, in my quest to maintain knife steel database I try to keep data as accurate as possible, even when on occasion it becomes rather difficult.
    I suppose you all know, Cromova 18 steel is an alloy used by Global in their kitchen knives. At some point, I got multiple confirmations that it was most likely AUS6M steel, or more high end AUS-118 steel. Later I did doubt, but mentioned in the Cromova18 notes. I have not encountered any other mentions since then.

    Last week, site visitor contacted me with the Cromova 18 composition results. He was kind enough to to make multiple measurements at my request, using xray spectrometer.
    Unfortunately, those spectrometers can't detect Carbon...
    Out of the 4 measurements, I compiled both, average and median(1st/2nd numbers in the list below) values as following:
    • Cr - 17.315 / 17.305
    • Mo - 1.1225 / 1.115
    • V - 0.1335 / 0.136
    • Mn - 0.38525 / 0.3975
    • Ni - 0.1775 / 0.176
    • Si - 0.4745 / 0.4785
    • Cu - 0.0245 / 0.0235
    Next, I entered the data in the knife steel database advanced search engine. Click on the link if you are curious, and click on the advanced button to see the exact search criteria used.
    Search returns 12 alloys, but in reality those fall into 2 groups, 440B series and Takefu Cobalt Special(CoS) series.
    I dismissed CoS, because the spectrometer wouldn't miss 2%-3% Cobalt, and I doubt Yoshikin/Global wouldn't tell us about the presence of rather expensive alloying material like Cobalt in their product.
    That leaves SUS440B stainless steel, Japanese JIS standard equivalent of good, old AISI 440B steel.
    SUS440B steel allows Nickel and up to 2% Mo, and trace amounts of Cu, none of which are present in AIS 440B. Basically it's is an excellent match for SUS440B standard spec, all values are within that spec, except for the Carbon for which I have no data due to spectrometer limitations.

    I am curious, what do you guys think, and for one, does anyone have precise info by any chance to exclude guess work?
    What do you guys think, are the results conclusive enough to consider CroMoVa18 to be SUS440B equivalent?
     
  2. Gator

    Gator Silver Contributor

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