Adair Posted January 10, 2019 Share Posted January 10, 2019 Hello all, I sent some dies to a heat treat shop. I had 4140 written on the steel. I have a few hundred dollars invested in machining. They were heat treated but do not test above 45 Hrc. I was after 54 Hrc. The representative in the shop thought they behaved like 4130. He can case harden them but these dies are for cold work (sheet metal power hammer). Is there any prudent next step that I might be able to take. I bought the steel new but it was 20 years ago. I must have mislabeled it. -Adair Link to comment Share on other sites More sharing options...
HojPoj Posted January 11, 2019 Share Posted January 11, 2019 Sounds to me like you're stuck with whatcha got. The only other thing that pops into my head would be attempting to hardface the dies, but that'd pretty much eliminate the precision you got with the machining, and I (not having any experience with cold working) don't know if the less-hard substrate would hold up to the abuse and not mushroom. Link to comment Share on other sites More sharing options...
Steve Sells Posted January 11, 2019 Share Posted January 11, 2019 there is not much of a difference between 4140 and 4130, and surely not 9 RHC points worth, in fact the specs over lap a bit Link to comment Share on other sites More sharing options...
Adair Posted January 11, 2019 Author Share Posted January 11, 2019 Thank you both for helping me face the reality. I asked them to just send the dies back. We'll see how long they hold up pounding cold sheetmetal. I'll be curious until the end of time what steel I actually purchased. It was soooo long ago. The first tool steel I ever paid for. -Adair Link to comment Share on other sites More sharing options...
ThomasPowers Posted January 11, 2019 Share Posted January 11, 2019 Don't they have a test gun? Link to comment Share on other sites More sharing options...
Judson Yaggy Posted January 16, 2019 Share Posted January 16, 2019 If they are useless to you in their current hardness try a water quench, then temper immediately. Read up on this forum about water quenching 4140 in larger sections like power hammer dies, the late great Grant Sarver had much to say about it. 4130 should be similar if that's what you actually have. Be sure to round EVERY corner and edge. Link to comment Share on other sites More sharing options...
Frosty Posted January 16, 2019 Share Posted January 16, 2019 I don't know about that Steve, 10 pts. C is the difference between low 30pts. and medium 40pts. carbon steel. No, case hardening won't work for an impact tool it's only really an abrasion resistance technique. Frosty The Lucky. Link to comment Share on other sites More sharing options...
Latticino Posted January 16, 2019 Share Posted January 16, 2019 Guy I just took a class from uses super quench on his power hammer dies, but those are mild steel. Not sure what that would do to medium carbon. Link to comment Share on other sites More sharing options...
Steve Sells Posted January 16, 2019 Share Posted January 16, 2019 According to the specs I looked up: 4140 is stated as requiring between 0.37-.44% carbon, while 4130 is at 0.28 - 0.33% So the variance isnt as broad as I suspected, because I assumed a near overlap in specs, but still 4140 is not going to get much harder than 4130. Fully hardened Brinell hardness of 197 for 1430 to 205 for 4140, The published maximum hardness is just a lab testing, and not a real world spec. I did get one report stating a maximum Rockwell hardness of 54 to 59 HRC for 4140 Link to comment Share on other sites More sharing options...
stevomiller Posted January 21, 2019 Share Posted January 21, 2019 Steve your Brinell numbers are incorrect, way too low, not sure who published that information but it’s in error. Doesntmat h anyofmy book or online references. 205 Brinnel is less than 20RC, which is lower than annealed 4140. 4130 in thin sections and a fast quench can get maybe 50 max, 4140 can reach at least the mid 50s. Prehaerdened 4140, for machining fixtures and tough parts, comes from the vendor at about 30. Judson is correct that Grant used water, but I’d imagine a fast quench speed turbulent oil bath would get get you there safer, if you had it available (ie Parks 50, or some 5-6 second rated oil). Link to comment Share on other sites More sharing options...
Steve Sells Posted January 21, 2019 Share Posted January 21, 2019 then assume the rest of my information is also wrong that came from Alro, except for the HRC reading Link to comment Share on other sites More sharing options...
stevomiller Posted January 22, 2019 Share Posted January 22, 2019 They are a big player, it’s too bad they messed that up, a lot of folks would use their site as reference. Your compositions tho were correct.! Link to comment Share on other sites More sharing options...
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