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Stress relieving 1018

Kann1987

Plastic
Joined
Apr 2, 2019
We had a 3" bar of 1018 sit in our heat treat oven for 7-1/2 hours at 950 degrees (F) per a stress relieving spec from a customer. It was only supposed to be in for four hours. Can someone inform me if this will negatively affect the properties if the material?
 
Did the costumer specify 7.5 hours? If so, what the book says is not your problem.

I don't think over annealing 1018 should cause too many problems, granted if you are building aircraft parts I wouldn't deviate from the requirements. If you are making ag parts it probably will not be much of an issue.
 
I was going to say that it could lose a little strength which is basically what TDegenhart said. Bigger grains = lower strength (as well as increased susceptibility to corrosion). This is assuming the material was not hardened prior to the stress relief treatment. If it was, I would hardness check to make sure it is still in spec.
 
So are you asking us if it is okay to ship parts that are not conforming to the customers requirements?
Would you ask if the hardness was out of spec? Or if a critical dimension was out. Would you ship and hope the customer does not notice?

Call the customer and ask if they can use the material after your mistake. Be prepared to eat the material and do the right thing.
 
granted if you are building aircraft parts I wouldn't deviate from the requirements.

Is there even anything anywhere on a plane that is made from 1018? I'm just asking.

Of all the parts and prints I've seen over the years, very rarely even see 4140 or other variations
of 4xx0.


As for the original question. They did say 4 hours. And I honestly don't know if
the extra time would adversely effect the properties of 1018. Those properties being
basically, "Just a lump of Steel". To me 1018 is the material I use when it really
just doesn't matter.
 
Is there even anything anywhere on a plane that is made from 1018? I'm just asking.

Of all the parts and prints I've seen over the years, very rarely even see 4140 or other variations
of 4xx0.


As for the original question. They did say 4 hours. And I honestly don't know if
the extra time would adversely effect the properties of 1018. Those properties being
basically, "Just a lump of Steel". To me 1018 is the material I use when it really
just doesn't matter.

Have to agree with Bob. 1018 is the 'bottom of the barrel' material so if it meant something you would be using 4140 or 1144 or tool steel, etc....
 
Thanks all. Ultimately I do agree with Erich, it is up to the customer to accept or reject. I don't know much at all about heat treating, or what the standards are for stress relieving.
 
just put it in the freezer for 3-1/2 hours. Then maybe your rolling average works out about right.

I thinks the 4 hr is a minimum soak time. Keyword being minimum.
 
:-) Can 1018 ever be so hard to have stresses in it ? :-)
...lewie...

1018 is actually notorious for internal stresses and post machining movement (at least in my neck of the woods). I make some 12" dia cylindrical parts from 1018 and our process is to rough the part to about .1" over/under size and let the parts rest for a few days before finishing to allow them to settle. This is after choosing annealed and stress relieved material.
 
Is there even anything anywhere on a plane that is made from 1018? I'm just asking.

Of all the parts and prints I've seen over the years, very rarely even see 4140 or other variations
of 4xx0.
It's not an aero part, it would have required a HT cert for the process and they wouldn't have missed the timer.

But you're right, there is no 1018 on (at least) commercial airplanes. They always use something with some alloy to reduce weight. 4130 tubing is sommon on small planes and helos. 4330 V-mod is pretty common on hardpoints and structural mounts on commercial jets, also used for high strength fasteners.
 
We had a 3" bar of 1018 sit in our heat treat oven for 7-1/2 hours at 950 degrees (F) per a stress relieving spec from a customer. It was only supposed to be in for four hours. Can someone inform me if this will negatively affect the properties if the material?

ask a expert but I believe usually you have in over 1 hour per inch thickness cause it takes time to warm up thicker parts (some call it soaking time) so 3" thick thats 3 hours minimum to get 3" part up to temp, 4 hours is a extra 1 hour, might ask others but if part in furnace and power shut off it can take many many hours to cool off if door left closed. not everybody takes part out immediately, often its left to cool off by itself slowly and maybe take parts out the next day.
.
big hot furnace full of hot heavy parts not many going to want to unload it when hot. just saying I never heard of immediately unloading hot parts, maybe some leave furnace door open to cool quicker. like I said ask others that do heat treat as their job
 
Is there even anything anywhere on a plane that is made from 1018? I'm just asking.

Of all the parts and prints I've seen over the years, very rarely even see 4140 or other variations
of 4xx0.


As for the original question. They did say 4 hours. And I honestly don't know if
the extra time would adversely effect the properties of 1018. Those properties being
basically, "Just a lump of Steel". To me 1018 is the material I use when it really
just doesn't matter.

The only 1018 aircraft parts I can remember making were just balance weights where only the shape and density mattered.

We see 4140/4340 used in landing gear components.
 
So are you asking us if it is okay to ship parts that are not conforming to the customers requirements?
Would you ask if the hardness was out of spec? Or if a critical dimension was out. Would you ship and hope the customer does not notice?

Call the customer and ask if they can use the material after your mistake. Be prepared to eat the material and do the right thing.

Save face, scrap the bar, buy new and do it right, never tell the cust you are a twit and you cant do the job right....Phil

LOL it's 1018, the customer isn't going to care.
 
You're fine - use the bar. Worst you made some extra scale.

So at one point of my live I was the metallurgical engineer for a commercial wire mill - we annealed 3000 to 5000 tons of steel per month so I have experience with annealing cycles. As others have said - 4 hours would be a minimum for a 3" bar. The practice is normally 1 hour and 45 minutes per inch -> 4 hours if you round up. Nothing happens very fast at 950 F. At that temperature the bar is not even red. You can't even see any difference in the microstructure at that temperature - even for cold worked material. A few extra hours in the furnace at 950 F only hurts the bottom line of the heat treater, not the bar microstructure
 
You are missing the point, the cust. spec was a 4hr time, you on your own used a 8hr cook time, It don't mater if it was harmless, you didn't do what the cust asked for...Now you can tell him and lose face or replace the stock and redo it to the cust specs. As 1018 is cheap and easy to obtain I would just replace and do it the way the cust wanted.Once you lose the trust of the cust you are done. Lets say you just reuse the 8 hr shafting and there is ANY fault is your problem when the lawyers find out. It will not mater what you think, you didnt follow the specs from the cust...Phil
 








 
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