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Hot roll work hardening like SS

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  • Hot roll work hardening like SS

    Drilling some holes in A36 angle. Dwell for a second and the drill refused to go further. Had to take out the die grinder to remove the affected area. Reminded me of SS, had to keep a constant feed.

  • #2
    Originally posted by RB211 View Post
    Drilling some holes in A36 angle. Dwell for a second and the drill refused to go further. Had to take out the die grinder to remove the affected area. Reminded me of SS, had to keep a constant feed.
    Why would you program a dwell when drilling mild steel?
    Last edited by Bented; 04-14-2022, 06:14 AM.

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    • #3
      The A36 isn’t A36 ?
      Mark

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      • #4
        Originally posted by Bented View Post

        Why would you program a dwell when drilling mild steel?
        Using Bridgeport, manual. I guess I dicked up.

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        • #5
          Don't let it get so hot.

          JL..............

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          • #6
            A36 has a pretty wide specification when it gets made. It often contains a lot of recycled steel with could be anything from remelt to ball bearings. So melts can and will vary from run to run, sometimes by quite a bit.

            I went through this years ago with a customer that was breaking punches, (and even the Ironworker) try to punch holes in some A36 angle. After much testing and a whole lot more digging, I discovered that Canadian made A36 is harder than US made A36 as a rule. And since the customer was working his Ironworker up to capacity, he was having all the breakage of punches and his machine. A switch to US made A36 and the issues went away.
            If you think you understand what is going on, you haven't been paying attention.

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            • #7
              Originally posted by JoeLee View Post
              Don't let it get so hot.

              JL..............
              It was getting hot, coolant would of been useful

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              • #8
                Originally posted by RB211 View Post

                It was getting hot, coolant would of been useful
                Well, if it was getting hot then that's what caused it. Yes coolant or slowing down the speed and feed wold help.

                If your chips are coming out blue you know it's getting too hot. Last time I ran into anything like that I was using a hand drill and spinning way too fast, but that was 30 + years ago.

                JL.................

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                • #9
                  Sounds like bedframe rails. Watch out for that stuff. Some machines and welds decent, some is difficult to machine and/or welds like to crack.

                  Super tempting. Looks like good project material and it is, just be advised.

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                  • #10
                    Originally posted by strokersix View Post
                    Sounds like bedframe rails. Watch out for that stuff. Some machines and welds decent, some is difficult to machine and/or welds like to crack.

                    Super tempting. Looks like good project material and it is, just be advised.
                    Yup, you can be welding and everything is going fine and then you hit a crap spot in the steel end end up with this. All kinds of impurities burning up and you get gas pockets.

                    Click image for larger version

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                    JL....................

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                    • #11
                      Not bedframe rails, actual angle iron stock bought from the local metal supplier.
                      Click image for larger version

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                      • #12
                        good rule of thumb I use with steel is run it slow and feed it hard. Plus cutting oil. Drills last way longer even though it feels like you're working them harder.

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                        • #13
                          Originally posted by mattthemuppet View Post
                          good rule of thumb I use with steel is run it slow and feed it hard. Plus cutting oil. Drills last way longer even though it feels like you're working them harder.
                          I had the most luck with this strategy. I'm used to working with cold roll or higher quality steels, first time I had "surprises"

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                          • #14
                            Originally posted by mattthemuppet View Post
                            good rule of thumb I use with steel is run it slow and feed it hard. Plus cutting oil. Drills last way longer even though it feels like you're working them harder.
                            I started working on steel with lower RPM after watching a bunch of the early Keith Fenner videos. And yep, drills and end mills both last longer turning at lower than the tables suggest. Of course the tables are listing the maximum speeds so commercial shops can blend process time against tool life to get the best bang for the buck. But as a hobbyist the best bang for the buck for me is more of a focus on the tool life or time between sharpenings. So the slower within reason the better for tool life.

                            RB211, so you were running slower than the typical maximum for this situation? I'd guess a hard inclusion as mentioned. I'm not sure what they are doing to re-form the scrap into new stock but I'm guessing that whatever the process they don't take much time or effort to mix things around or let things diffuse and even it up.
                            Chilliwack BC, Canada

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                            • #15
                              If I get to a point where I have work hardened material and I need to get on with the job I sharpen a carbide tipped masonry bit and punch through with it. Or use a carbide center cutting endmill and get rid of the hard spot.
                              Location: The Black Forest in Germany

                              How to become a millionaire: Start out with 10 million and take up machining as a hobby!

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