Hi
Some times I have to build up weld onto a brake press die so that the machinist can mill it into a different shape.
Die's are assumed as being "pre-hardened chrome-carbon brake die steel with a mean 280 Brinnell hardness."(http://www.midwestpressbrake.com/)
Filler rod choices: mild steel, stainless or silicon bronze that is what we have on hand but if there is a better choice please advise.
My problem is that the machinist complains that the weld is to hard and feels that the die can be welded softer.
I have not tried silicon bronze to soft in my opinion and won't hold up to the force of a brake press am I wrong.
Both mild and stainless make the die to hard for him to machine.
I try to minimize heat and give a sec after each pass do you think Annealing the die after its cooled would help.
My opinion is that regardless of filler rod, heat or method the base metal is hard so the end result is that its going to be hard unless you add some thing like aluminum or silicon bronze which won't hold up to a brake press.
Any opinions or suggestions are appreciated.
Thanks
Ron
Jason_alex
- Jason_alex
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How is it being machines?
- Otto Nobedder
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I think your machinist is being a cry-baby. It has to be hard to hold up to the abuse.
Stay with carbon-steel filler. 80- or 90- series rod, if you have the facilites to anneal, then harden and temper. That should shut him up. Stainless will not harden, and silicon-bronze is too soft in it's best condition. You can soften the weld "some" by using more heat, and cooling slowly (bury it in sand as soon as it's done), but you may still have to re-harden it when he's done with it.
Next time, stick-weld it with hardfacing rod, and listen to him cry!
Steve S
Stay with carbon-steel filler. 80- or 90- series rod, if you have the facilites to anneal, then harden and temper. That should shut him up. Stainless will not harden, and silicon-bronze is too soft in it's best condition. You can soften the weld "some" by using more heat, and cooling slowly (bury it in sand as soon as it's done), but you may still have to re-harden it when he's done with it.
Next time, stick-weld it with hardfacing rod, and listen to him cry!
Steve S
I work at a tool and die company so its not just 1 guy that says its to hard to machine.Otto Nobedder wrote:I think your machinist is being a cry-baby. It has to be hard to hold up to the abuse.
Stay with carbon-steel filler. 80- or 90- series rod, if you have the facilites to anneal, then harden and temper. That should shut him up. Stainless will not harden, and silicon-bronze is too soft in it's best condition. You can soften the weld "some" by using more heat, and cooling slowly (bury it in sand as soon as it's done), but you may still have to re-harden it when he's done with it.
Next time, stick-weld it with hardfacing rod, and listen to him cry!
Steve S
My answer is always the same good so I did my job.
They respond can you weld it softer.
All I can say at that point is I will try to find the hardness button and I will turn it to soft.LOL
My welds always come out nice and solid after machining but hard.
I don't know how to fix some thing if I think I'm doing it right.
What I meant by anneal is after its been cooled I would get it red hot with the oxy and then cool it down slowly with a table top burner is that correct if not could you give your method.
Cheers
Ron
- Otto Nobedder
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Ron, that is exactly the process for annealing. Your machinist will love it.
The trick is, when the machining is done, can you re-harden it, then temper it properly? Sure, you can return it to red-hot, and quench it in oil, but there's an arcane art here... To temper it, so it's hard enough, but not brittle, you either have to pull it out of the oil at the right moment, or re-heat it to a known temperature and quench it again.
Of course, I have not asked what's being bent in these dies... If it's 3003 aluminum, that's a different matter from a36 steel or 304 stainless.
Steve S
The trick is, when the machining is done, can you re-harden it, then temper it properly? Sure, you can return it to red-hot, and quench it in oil, but there's an arcane art here... To temper it, so it's hard enough, but not brittle, you either have to pull it out of the oil at the right moment, or re-heat it to a known temperature and quench it again.
Of course, I have not asked what's being bent in these dies... If it's 3003 aluminum, that's a different matter from a36 steel or 304 stainless.
Steve S
Thanks I will experiment on Monday.Otto Nobedder wrote:Ron, that is exactly the process for annealing. Your machinist will love it.
The trick is, when the machining is done, can you re-harden it, then temper it properly? Sure, you can return it to red-hot, and quench it in oil, but there's an arcane art here... To temper it, so it's hard enough, but not brittle, you either have to pull it out of the oil at the right moment, or re-heat it to a known temperature and quench it again.
Of course, I have not asked what's being bent in these dies... If it's 3003 aluminum, that's a different matter from a36 steel or 304 stainless.
Steve S
All different stuff from thin sheet metal to thick 3/8 plates.
We are constantly reusing dies for different purposes.