1215 Hot Rolled vs Cold Rolled

[b_unruhly]

Hello,

Beginner question here--first time poster, long time listener.

We are working on a project that specifies Cold Rolled 1215 steel, unfortunatly we only have hot rolled avaiable in our market in the required diameter (60mm)

Is there a heat treatment protocol we can prescribe to our hot rolled 1215 to match mechaianical properties of 1215 cold roll?

Are there availble resources that can estimate mechanical properties of steel according to various heat treat protocols?

Thanks,
Ben

 

[EdStainless]

Do you have specification?
Are there required properties?
It might just be for surface finish and dimensional control.
The amount of material removal in machining to get full cleanup will be different.

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[mfgenggear]

OP
Answer Ed Stainless, also is there any heat treat requirements. Compare the data sheet or specifications of the cold roll, and hotroll. Run the stress numbers. Is it acceptable. We have no clue what it is and what end product is.
This not a simple question. And the required stress loads is required
Secondly is there a safety issue. Or not.

 

[b_unruhly]

Hello, sorry for the missing information--yes we have spec requirements as follows:

Bar Diameter: 60mm

Ts 65,000-110,000 PSI
Yield 55,000-100,000 PSI
Elongation in 2": 10-22%
Reduction in Area: 25-55%
Shrearing Strength PSI ApproxL 55000
Brinell: 143-256
Rockwell Hardness 90-102

It's a round part that has a bore in the center and a slot, A fastener is used to clamp this around a shaft. We made a sample using HR 1215 and it is now showing deformation at the clamping area.

We are not able to find CR in this larger diameter--so we are wondering if we can utilize HR instead.

 

[mfgenggear]

Op
I shall jump in. I am sure Ed will respond with a better answer.
I would investigate by running a test sample thru heat treat. Using a specification AMS 2759/2 or similar. Have a heat treaters normalize, harden and temper to the required hardness.
Pull tensile and charpy test. And validate the actual requirements.
Now according to von misses. Calculate the required hardness required, and diameter.
The required minimum yield tensile.
You can substitute alternate material but cold roll is worked harden. To achieve the yield , and ultimate tensile. And hardness. Cold roll is work hardened. While hot roll will require heat teat to achieve the same properties.

 

[weldstan]

The minimum tensile and yield strength values will be tough to meet without heat treatment. Typical minimum values that I used to see were approximately 45 ksi and 55 to 60 ksi for hot rolled product without controlling of hot rolling perameters but that was a long time ago.

 

[EdStainless]

OP, what are the spec properties of the hot rolled material?
It might make it, or it might not.
1215 will hardly respond to HT at all, not enough carbon.
Some high Mn steels (15xx) will HT even with low C.

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[mfgenggear]

Op
Unfortunately as others have stated, there is no secondary heat treat specified on the data sheet.
Yield is 33.4KSI which is way under the requirements.

https://www.matweb.com/search/datasheet.aspx?matguid=23ec6e54ecc2462c90c862d2b59830cd&ckck=1

 

[b_unruhly]

Thank you all for your feedback.

Is there somewhere I can find a specific heat treatment protocol to give to the supplier that might give us the properties we are looking for?

Over here in this part of the world, playing guess and check can take weeks or months. That's if you find a supplier even willing to do the work. Generally they don't want to do anything besides heat to a given hardness, maybe a case depth if you are lucky.

 

[mfgenggear]

Op
It is appears cold working the material will improve physical properties.

 

[EdStainless]

If you want to try to Q&T;
Autenitize at 1550F followed with water quench.
Then temper at 600F.

You really need to move to a higher C alloy for these sizes that you can't get cold finished.
Something like 1126 or 1132 in a normalized condition might get what you need.
If not then move to 1140, I don't have data sheets handy to check the min properties.

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[weldstan]

Due to the variations in carbon and manganese content and assuming that they will be at the lower side of the requirements, your ability to meet te requirements with heat treatment are essentially nil. But give it a try with the heat treatment proposed by Ed above.

 

[MFAMET]

1215 is not thermally hardenable due to the low carbon. The HR mechanical properties are basically determined by rolling temperature and cooling rate. So, why you have to concern any heat treatment? The only thing you need to ask is the HR tensile strength. Cold rolling could bring up some strength depending on the reduction.

 

[MintJulep]

deformation at the clamping area.

This probably has more to do with the fit between your part and the shaft than it does with material properties.

 

[mrfailure]

Is the diameter too large to cold roll? Is this product form for this diameter available anywhere in the world? If not, it is clear the material specified is really Unobtainium and you should look for an alternate material as hot rolled 1215 will not cut it.

 

[MagBen]

Like genetic austenitic stainless, this alloy is considered "not heat treatable", Q&T is unlikely to get you martensite. However, some sorts of heat treatment may get you a smaller grain size, which can bring you a higher yield strength per the Hall-Petch relationship. otherwise you will need some degree of hardening work to boost strength, either hot roll at lower temp (warm roll) or cold roll. normally max diameter to cold roll is 3'', could extend to 4'' depending on roll equipment.

 

[b_unruhly]

Thank you all very much.

This was super informative.

I won't be able to try your sugguestions, as our supplier was able to find cold rolled 1215 they could import.

But, this has come up countless other times and will keep comming up. Lots of US Spec materials are not available in our market

The sugguestion to start with higher carbon steel if heat treating makes a lot of sense.

Is there some kind of online resource/calculator to predict mechanical properties of materials after heat treatment?

 

[Wrenchbender]

OP, on your last question: "Hardenability curves" exist for many steel alloys. Some are available online; many are published in the ASM Handbooks. Standard ASTM A255 covers the lab test set up. Results give hardness vs depth below the exterior surface that is in contact with the quenchant. Outside the lab, life is different and can depend on part geometry, agitation, quench rate, etc.

 

[EdStainless]

There is a publication from Timken 'Practical Data for Metallurgists' that contains a lot of HT information.
The DL is free.

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[mfgenggear]

Yes Ed that was one my goto heat treat data and depth