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  1. Robertmet

    Heat Treating Issues with 4140 (Scaling)

    To me that texture indicates decarb ! Check preheat treat sample for decarb and check you're atmosphere. Temper should be at least 1 hour per inch.
  2. Robertmet

    Self Healing Concrete

    Here's an interesting development for concrete roadways !
  3. Robertmet

    inorganic/organic concrete

    http://www.dailymail.co.uk/news/worldnews/article-1282773/Sweet-rice-secret-Great-Wall-Chinas-strength-longevity.html Here's an interesting find .Like the pumice addition by the ancient Romans the old ways have their benefits !
  4. Robertmet

    Galloping Gertie in Russia

    Tacoma's lessons have been lost on the Russians ! Just open up the sides of the bridge so the wind can go through without problems !
  5. Robertmet

    Heat treating O-1?

    http://www.cashenblades.com/info/steel/o1.html Cashen is a fine blade maker and very knowledgable about metallurgy.As he says O-1 is not just a simple carbon steel. Note soak times ! He and I have been trying to educate knifemakers about metallurgy on forums such as www.bladeforums.com I've...
  6. Robertmet

    Tube failure on new bundle

    Short term failure ? I wish I could remember the exact time but we had a short term failure of copper or copper alloy tubing.After all the tubing was replaced we found by chance that the crew that installed the heat exchanger originally used it as a urinal -too lazy to walk a short distance to...
  7. Robertmet

    Oil Evaporation from Aluminium Surface.

    What's the surface condition of the aluminum ? Oxides can be porous and hold oil.Can it be some reaction between oil and aluminum ?
  8. Robertmet

    Powder coating changing D2 toolsteels property?

    Unclesyd , the old days , I remember them well ! Crucible recently made some CPM-D2 which has better properties by getting away from large carbides.I think this was made primarely for knife makers. I don't know if this will be continued with the sale of Crucible. I agree that H2 should be...
  9. Robertmet

    Automotive Info Source ?

    I thought these techniques were new ! Thanks, exactly what I wanted . Hard to keep up with thinks now that I'm retired.
  10. Robertmet

    Passivation of Stainless Steel 202

    You might like to read the comments in the link as far as non-standard 202. Poor quality 202 may be very different.http://www.worldstainless.org/NR/rdonlyres/16D7CBB1-1E5F-4338-9A5A-F53504A87667/3265/200seriesstainlesssteel.pdf
  11. Robertmet

    Automotive Info Source ?

    I like to try to keep up with metallurgy of cars and trucks. Is there a source for technical details ? Two items in perticular - "Forged powdered metal piston rods" and the liner material for a new aluminum block that uses a spray type coating instead of an iron liner. These are both Ford...
  12. Robertmet

    1966 Materials A7

    Don't confuse this with AISI A7 cold work die steel !!!
  13. Robertmet

    Soldering

    If you went to one of the knife forums such as Bladeforums, I would answer it and other questions as a metallurgy advisor !! Use a 95Sn-5Ag solder and use a flux that states 'for use on stainless steel'. Typical solder techniques are important - heat the blade to melt the solder ,the torch...
  14. Robertmet

    Bodie Creek Bridge at 84 years

    Here's an old railway bridge that has been saved and recently opened to pedestrian traffic. It's very high above the Hudson River and the view is fantastic ! I'm sure it will be a top tourist attraction. www.walkway.org
  15. Robertmet

    Historic Building - Concrete "Class"

    I have "Handbook of Concrete Construction" eigth edition 1943 . I can't find mention of classes and strengths are not here either.They just give mixtures for various applications.
  16. Robertmet

    Hot rolled steel failure analysis.

    The temper doesn't necessarily have to be as high as 1100 F.All you have to do is temper the martensite.The higher temperatures offer stress relief /temper/subcritical anneal !Run some experiments and determine exactly what you need.
  17. Robertmet

    CPM10V HEAT TREAT Problem

    You may get large grains which is bad and migration of carbides to the grain boundaries which is also bad.Microscopic examination will show both. Crucible's Pittsburgh facilities have been bought by Alleghany Industries and the Syracuse facilities bought by a group out of Cleveland that says it...
  18. Robertmet

    Hot rolled steel failure analysis.

    Cutting steel with a laser leaves a thin layer of hardened but UNtempered steel .This is brittle and may be the cause of failure and a simple tempering operation may fix it. I remember in the 60s with the then new EDM we had to spend a lot of time educating people to temper after EDM for the...
  19. Robertmet

    Passivation of AISI 304SS

    ANY process that may contain contaminents can be a problem. A proper SS shop will have dedicated machines and tooling for use only with SS.All too often a non-dedicated step is used without thought .
  20. Robertmet

    Steel revisited in auto industry.

    Porsche Panamera Here's a metallurgist's dream - read the "Body " section.Fascinating what technology can do !http://www.motortrend.com/features/auto_news/2009/112_0906_2010_porsche_panamera_tech_overview/index.html
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