Hardening gauge plate (O1)

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Hardening gauge plate (O1)

Home Forums Beginners questions Hardening gauge plate (O1)

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  • #565514
    Howard Lewis
    Participant
      @howardlewis46836

      My recollection of heat treatment areas is that the foreman carried a little book in his pocket, as a reference manual, to his many years of experience., Something along the lines of "That should have 30 minutes, but best to give it 35"

      Or the need to quench really suddenly, and in a particular orientation, as Tug says, to prevent distortion.

      Sometimes more black art than precision, to get the job right!

      Howard

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      #565521
      Mike Poole
      Participant
        @mikepoole82104

        At tech college they had a drum of oil for hardening, a friend discovered that a red hot bar about an inch diameter would vaporise a nice cloud of oil vapour before it had lost enough heat to avoid ignition of the cloud when withdrawn from the oil, this was highly entertaining until the instructor appeared, trying not smile he shook his head in disbelief, the entertainment was over with no doubt in our minds that this was not an approved activity.

        Mike

        #565571
        Sam Stones
        Participant
          @samstones42903

          Thanks for an interesting thread Robin. Apologies for any repetition.

          It’s too long ago and I no longer have the endurance to try to reiterate what I learned in ONC and HNC Mech Eng, but for a theoretical insight into what is taking place, take a peek at this –

          **LINK**

          Someone here might like to highlight in simple terms, the basics of the rate-of-change from FCC to BCC and the way it influences properties.

          At a practical level, I’d recommend attention be given to –

          • minimising sharp notches
          • improving surface finish (polishing)
          • thickness transitions
          • times and temperatures
          • immersion technique
          • cleanliness of process
          • tempering
          • finishing
          • etc.

          Incidentally, it may be a surprise to discover that Young’s Modulus of Elasticity hardly changes.

          Have fun, especially with your tests, Robin.

          Cheers,

          Sam

          #565582
          Ramon Wilson
          Participant
            @ramonwilson3

            Well Sam I don't have the honour of being able to say I have an ONC or HNC Mech E to my name (congratulations BTW) but I have placed an awful lot of small pieces of tool steel of differing varieties into a quench in order to heat treat them to specified and very defined limits. Despite my lack of academic prowess, for some fourteen years I had the pleasure of running the machine shop for a company that produced electric terminals on multistage progression press tools.

            In my experience of such it is not essential – to the average home ME – to know what the technical aspects are behind the process but knowing what and what not to do on a practical level is. To me this is far more important to be aware of in obtaining an acceptable result in those conditions. Each to his own though – I guess I'm far more interested in knowing 'how' it works than 'why' but I stress – in the home workshop environment.

            The heat treatment of parts I was responsible for making were mainly punches and anvils/dies in a variety of tool steels for small press tools and parts for the progression press tools. Many of these were quite thin and liable to distort if not handled carefully but they were hung from MS cages – about 10/12 per cage and four cages at a time in the two ovens to be brought to temp. Each cage would be quenched by hand. Sometimes this could be on a daily basis but usually on a weekly one – apart from the silver steel parts previously mentioned I don't recall we ever had a failure

            The punches were usually BO1 and the dies from a different steel. All were then ground to fine limits on thickness and width and the punches then form ground in blocks to create the punch/die profile.

            I have never felt that the technical aspect has ever been a help in producing a well heat treated part in the home workshop – but that's just my approach, others of course may see it through different eyes

            Best – Tug

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