Doubt about steel 5

[Galvano]

Good Morning,
I have a piece of a machine, which is a sheet of steel 0.3 mm thick.

On this sheet are mounted some rollers that press a notebook that passes through a conveyor belt. The function of the sheet is to act as a spring. (After bending, he returns to his initial position)

I have seen that there is a type of steel according to German standards, I think it is CK75. Would it be suitable for manufacturing that sheet? What other types of steel are there that are valid to manufacture this 0.3 mm thick sheet? Is there any other equivalent designation other than the German one?

Greetings

 

[TugboatEng]

I guess it depends on your region. Here in the USA, AISI 1075 would be the equivalent. Heat treatment is going to be the most important factor to consider.

 

[Galvano]

Thanks, Spain. I don't know if there is a similar steel.

 

[RolMec]

Ck75 means it is a cold rolled spring steel.
Could you verify your part being made of that material? Else, imo you need to contact a good supplier to make an assessment of your application / the material used.

Roland Heilmann

 

[Galvano]

The function of this 0.3 mm thick sheet in the machine is that some rollers mounted on it put pressure on a notebook and once it passes, it recovers its shape.

I see that it is a more suitable type of steel for this and that it is supplied in sheets. I assume there is another but I don't know.

 

[MintJulep]

RolMec's posted picture identifies a 9 equivalents.

If that is not enough, there are more here

https://equivalentmaterials.com/materials/aisi-1075

One of them is an EN identifier. C75S.

You're in Spain. Spain is in the EU.

These are spring steels. You are describing something with a spring's function.

Might work. Might not. You haven't given enough details to let anyone tell you more.

 

[Galvano]

What details are necessary? Dimensions? Forces?

 

[MintJulep]

What details are necessary? Dimensions? Forces?

Yes, those would be a good start.

 

[EdStainless]

And maybe a hardness?
At least that you give you an approximation of what properties to look for.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[Galvano]

Dimensions

Width 30mm length 86mm thickness 0.3mm

Surface hardness is not important, the important thing is that it acts like a spring.

The bending force at its longitudinal ends is minimal, it has to be deformed allowing the passage of a notebook transported by a conveyor belt.

 

[MintJulep]

For your case I suggest gravity, together with a hinge.

 

[Galvano]

No, this part is necessary

 

[EdStainless]

If the piece is fixed at one end and flexes, then strength is super important.
The strength has nothing to do with the force that it takes to flex, but it does determine how far it can flex before it becomes bent.
So to preserve the shape and springiness you need this to be heat treated correctly so that it is strong enough.
And in most steels the hardness correlates fairly well with strength.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[Galvano]

I've seen 40-50 HRC in some pages.also say that the original strap seems stainless (same surface appearance)

 

[MintJulep]

From what I see here so far I think that you will not be able to properly quantify your requirements, select the right material and successfully design a spring-based device to press down on notebooks passing by on a conveyor.

I am assuming that gravity is in a useful direction for you.

So, instead of a rollers on a spring use rollers on a hinged flap. Have a simple way to add weight to the flap.

This way the users can tune the machine as needed by simply adding or removing weight.

 

[IRstuff]

It seems to me that you've jumped automatically to a conclusion that ANY springy steel would be adequate, but you seemingly ignored the forces involved/required; a spring is modeled by F=-k*x, so what k do you need and how will that relate to the material selection?

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

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[Galvano]

I don't know the strap constant. Being a sheet I don't know how it would be calculated.

What I know is that I have seen coiled leaf springs that have this steel. But I doubt if the C75S is supplied hardened or if it needs to be tempered to serve as a strip.

 

[IRstuff]

Well, you ostensibly know, or can calculate, what force is applied, and you know, or can calculate, how much deflection occurs. But, that might be getting too far into the weeds, and might just be easier to get the plate assayed, which would allow you to figure which alloy(s) is might be and have someone fabricate another copy with the putative alloy

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

faq731-376 forum1529 Entire Forum list

http://www.eng-tips.com/forumlist.cfm

 

[TugboatEng]

We're talking s few dollars worth of material here. Maybe just grab a piece of hardened 1075 and give it a shot. Even give 1095 a run. It's more wear resistant and may perform better.

 

[Galvano]

Exactly. It is a simple sheet with 6 holes. My question is whether I should put hardened C75S or simply C75S in the manufacturing drawing (I don't know if the C75S is supplied already hardened or should I say so)

I would also like to know if this steel is stainless or should it be coated. The original that is in the machine has the appearance of stainless.