Case hardening a part question

[Chris Edmondson]

I have a couple custom screws I've turned 30° points on for a project, they've also been threaded 1/4-28. The material is 1/4" diameter 12L14 steel rod.

I'd like to case harden the tips but, I've never done this before. Reading the Brownell's Surface Hardening Compound directions, it sounds simple enough; heat to cherry red, dip in the compound, heat to cherry red, quench in water. Repeat the heat-dip cycle if desired before quenching. I have both propane and MAP torches.

Whenever anything sounds easy, there's often some hidden leghold trap waiting for an unsuspecting operator.

Is it really this easy? All pearls of wisdom welcomed.

Thanks.

 

[hogpatrol]

According to this article, not optimum steel for that process.

12L14 Steel - What is it? & what is it used for? - Ryerson

Discover 12L14 steel, the fastest machining carbon steel grade, perfect for high-volume production of screws and fasteners. Learn its properties and applications here.

www.ryerson.com

 

[Chris Edmondson]

According to this article, not optimum steel for that process.

12L14 Steel - What is it? & what is it used for? - Ryerson

Discover 12L14 steel, the fastest machining carbon steel grade, perfect for high-volume production of screws and fasteners. Learn its properties and applications here.

www.ryerson.com

12L14 is unsuitable for hardening because it's a low carbon steel, case hardening is another matter. The purpose of the Brownell's compound (and others) is to bond carbon to the surface so that the surface may be hardened, also known as Case Hardening. At least that's my understanding.

 

[whatsupdoc]

Carburizing - Wikipedia

en.m.wikipedia.org

Dimensional changes Edit ​

It is virtually impossible to have a workpiece undergo carburization without having some dimensional changes. The amount of these changes varies based on the type of material that is used, the carburizing process that the material undergoes and the original size and shape of the work piece. However changes are small compared to heat-treating operations.


Starting with the correct material is more better for you.

 

[Chris Edmondson]

Carburizing - Wikipedia

en.m.wikipedia.org

Dimensional changes Edit​

It is virtually impossible to have a workpiece undergo carburization without having some dimensional changes. The amount of these changes varies based on the type of material that is used, the carburizing process that the material undergoes and the original size and shape of the work piece. However changes are small compared to heat-treating operations.


Starting with the correct material is more better for you.

What would you suggest?

 

[hogpatrol]

What would you suggest?

A2/Drill rod.

 

[Chris Edmondson]

A2/Drill rod.

I thought about that but, I'd be trading off machinability for the ability to harden the steel al the way through. The points on these screws may see rubber mats or wood as a contact point, I just don't want them to be blunted right away. The "nut" in this case is 1/2" thick 6061 aluminum, the 12L14 threads won't see any action there.

That said, the local hardware store has drill rod, I'll give it a try .

 

[Walt Krafft]

Another thread where the op argues with every comment. The lead in suspension in 12L14 will hinder the hardening. Will it get harder? Probably. But there are much better steels to begin with. The low carbon the hardware stores sells would be better. A2 tool steel and you could skip the carborizing. If you have problems machining A2, work on your machining skills.

 

[DRK]

A2 will work or find some 01. Heat treat & oil quench.

 

[jackieschmidt]

12L14 is a low carbon free machining steel that will not respond to Heat Treating to enhance properties.

However, just like any other Ferrous based metal, you can induce carbon into the surface at a high temperature to increase the surface hardness. The generic name most call this is case hardenning. The case is generally rather thin, in the neighborhood of .030 inch or less.

This is how the vast majority of commercial loading dies are made. If you have ever done any modifying to a die, you know test once you break through the case hardenned surface, it machines like butter.

So in short, yes your 12L14 will case harden. Is it the best? No.

An easy solution would be to go to jThe Home Depot and get a couple of grade 8 bolts large enough to make your pieces. Then, you would have strong parts that would respond quite well to the tip hardenning.

 

[Chris Edmondson]

This is how the vast majority of commercial loading dies are made. If you have ever done any modifying to a die, you know test once you break through the case hardenned surface, it machines like butter.

So in short, yes your 12L14 will case harden. Is it the best? No.

Thanks, if these screws are half as durable as any of my loading dies, I'll be happy

 

[Jonnyofalltrades]

I've used Casenit many times on similar steel. It will work great for you.
Why use a more expensive grade of steel when you don't have to?

 

[Jonnyofalltrades]

The Brownell's stuff is just Casenit rebranded.

 

[Jonnyofalltrades]

Sorry, should have spelled it with a K.
Kasenit.

 

[AccelR8]

I thought about that but, I'd be trading off machinability for the ability to harden the steel al the way through. The points on these screws may see rubber mats or wood as a contact point, I just don't want them to be blunted right away. The "nut" in this case is 1/2" thick 6061 aluminum, the 12L14 threads won't see any action there.

That said, the local hardware store has drill rod, I'll give it a try .

We don't know the application but if there's no vibration or real heavy loads, the steel you have as it is my be hard enough already so as not to wear in contact with wood or rubber. It will play well I think with 6061.

I find O1 machines very well and gives a good finish. I use an anti-scale compound from Brownells when heat treating it. The suggestion to use grade 8 bolts may be the best way to go.

 

[whatsupdoc]

At this point just try case hardening the screws and see.

 

[Will Henry]

I have carburized and case hardened a ton of stuff made with low carbon steel. I have done this with Kasenit, I have done it by heating with a flame rich in carbon, I have done it by packing it in a crucible with various carbonaceous materials (bone meal, powdered milk, coal, etc.). Low carbon steel is perfect for this task and any dimensional changes won't be significant, unless you screw up. Since you are primarily concerned with hardening only the pointed tip, I think this will be perfect. With the steel, less sulphur is better for heat treatment, so is less lead. Both elements are there to improve machinability though, so it's a trade.
When you use the compound, the use of a slightly carbon rich flame will help prevent any scaling.
I used Kasenit to harden the inside of a sizing die I made from low carbon steel. I filled the inside with Kasenit, heated it in the furnace, then quenched it. I polished it out and it worked like a hot damn.
I called the company once to ask about using an oil quench to reduce warpage and he thought it should work fine. I chose to quench in water soluble oil coolant which worked out OK. WH