Well, what do I say now? I hate to do it, and say it, but Jiminy you don't know squat. You did not know what normalizing was/is, you don't know how to read a TTT curve, and you don't know the automotive industry, but you try to come across that you do by quoting information that you find on the internet.
You are not as smart as you think you are. That is evident by you continuing to try to argue points that you have no knowledge on. I am not against discussing what you have to say, but I don't want people out there that are trying to learn about heat treating reading your comments and thinking that you are correct when you are wrong.
Plain and simple you are/were wrong about normalizing, about the TTT curves, about the FMVSS requirements, and about statistical reliability.
What you quoted about CPK is correct but you have no idea what it means as with all of the information you have quoted in this and other threads. The God's honest truth is that you don't know what you speak of and my best advice to you is to sit back and learn before you give advice.
No one here wants me to lecture on CP and CPK, but they do want relivant information on how to heat treat steel and that is what I have given. You have given crappy info, here say, and opinions. Back up your information with evidence and emperical knowledge and maybe you can earn some respect.
You had the chance to let it rest when I posted:
I was under the impression that they've been relaxing those standard for years. And once again, I don't believe that tolerances have to be super critical to withstand impact ...In fact I imagine there is a pretty wide margin there ...particularly if they don't test the steel from batch to batch.
What you call 'tight' for a car door part ...I probably dont
But no, you've got to continue to attempt to press your point, even when you are, in fact, proven wrong. And when exposed as being wrong, what do you now resort to? Personal attacks.
0.25mm over 1000mm is pretty tight, especially to hold that to a CPK of 1.33.
Again, we were talking 'strength' tolerances ...and all of a sudden you switch to talking about surface tolerance. Then you try to dazzle us with your 'Cpk' number, which turns out to be total bull$%*^. The fact is that a Cpk of 1.33 is the bare minimum and that the statement ""You must have a Cpk of 1.33 [4 sigma] or higher to satisfy most customers." is, in fact, apparently accurate. I challenge you to prove otherwise.
You post TTT charts without explaining what everyone is looking at, claiming that the metal must follow that curve, without explaining that one can plot many curves that can fall within the boundaries of that graph, and result in different hardnesses for different quenching mediums, which was my point in the first place. And so what if I've never seen a TTT chart before? I'm sure many people here haven't. It's not like it's rocket science, after all ...once it's explained to folks what we're looking at ...and if you would have explained yourself better in the first place than the point would have been moot.
As for the 'normalize' statement ....LOL! I believe the conversation went something like ...Mr Wheeler said something to the effect that there were different meanings to the term 'normalize', and my statement in response was that 'normalize' appears to be a fancy term for anneal. Bad choice of words is all, as I should have better phrased my sentence to convey the point I was trying to make, which was that many times I see the terms used interchangeably, or in a confusing manner. I'm well aware of the difference between 'normalizing' and 'annealing', thanks. It just wasn't worth clarifying the point at the time, as it matters little to me what others may think.
People post stuff ...questions, and I try to respond as best I can. If you don't like my answers, then post your own. But when you're caught red-handed arguing a position that suddenly turns to mush, ala "1.33 Cpk", don't attempt to redeem yourself by starting personal attacks, as that only shows that
you don't know what the hell you're talking about.
about the FMVSS requirements
Refresh my memory, please, as I don't recall what you're referring to.
And yes, I make mistakes, wrong statements, bad wording, misconstrued meanings, etc, as does everyone at one time or another. People are human, they make mistakes ...live with it.
But cripes, argue the point ...don't turn it into a personal attack, as it only makes you look ignorant, and degrades the whole forum experience for everyone.
