Flame cut 4145
Flame cut 4145
(OP)
We have been requested to flame cut an odd shape from a 4" thick 4145 plate for subsequent machining. What are the preheat and post heat requirements for this kind of operation?
Brad
Brad
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RE: Flame cut 4145
Preheating can help, but the temperature where pearlite forms is way up ~11-1200 F, and if that layer cools fast enough through that temp. range, martensite and/or bainite could form down ~500F.
If the cut surface is to be machined away, there shouldn't be a problem under the hard layer--if it in fact develops.
"You see, wire telegraph is like a very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? Radio operates the same way: You send signals here, they receive them there. The only difference is there is no cat." A. Einstein
RE: Flame cut 4145
RE: Flame cut 4145
RE: Flame cut 4145
I would recommend a preheat of at least 600F, with a slow cool from cutting temperatures (wrap in ceramic blanket, or something similar) followed by a post-heat of at least 1000F; if the flame-cut surfaces are to be subsequently machined, a 1250F post heat would be in order.
rp
RE: Flame cut 4145
"You see, wire telegraph is like a very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? Radio operates the same way: You send signals here, they receive them there. The only difference is there is no cat." A. Einstein
RE: Flame cut 4145
RE: Flame cut 4145
RE: Flame cut 4145
Just because a steel does not possess the same hardenability as 4340 does not mean is is not deep hardening. 4340 has the well-earned reputation of being the deepest hardening of the AISI low-alloy steels, but that does not mean it is the only one.
rp
RE: Flame cut 4145
But some heats of 4145 are of "medium hardenability", but no heats of 4340 are. Keeping in mind that Cr and Mo are expensive, a steel purchaser may get a lean heat of 4145 if he doesn't know how to specify it.
"You see, wire telegraph is like a very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? Radio operates the same way: You send signals here, they receive them there. The only difference is there is no cat." A. Einstein