How do I harden cold rolled steel?

A. It depends on what type of steel it is. Cold rolled just refers to how it was worked at the mill, not what alloy it is. Some cold rolled steels are hardenable, others are not. If it is hardenable (high enough carbon content) heat it to about 1500 degrees (bright red color ... heat until a magnet won't stick to it and then heat just a tad hotter) and dip it in either oil or water (water results in harder steel but more prone to cracking, oil may be the better choice).

If its a high carbon stainless they usually need to be heated to 2000 (very bright red/orange color)and cooled in fast moving air or oil these are just very rough guidelines since I don't have a clue what type of steel you have. Good luck.

A. If it is a shaft or a pin you're looking for, you could go to a local machine shop and buy it. For farm equipment use I would suggest using a material called C1045. It is a great material for wear and stress loads!

A. If you need a pin of high surface hardness for wear resistance and a softer very tough core try 8620 steel. Machine your pin then take it to a heat treater and have him carburized .030" deep and harden to R/C 60 surface hardness. The core should come up to R/C 35 or so. I have made many replacement parts for punch presses and other machines as well as pins and bushings for heavy equipment.

A. If you want to do it properly you will need to get the parts case hardened. Passing it though a induction coil is how it normally is done. Takes a few seconds but you need the equipment. If you harden it straight though it will crack due to brittleness with any severe use.

A. You are talking about hardening a pivot pin for a backhoe.
1 if you have the right size cold roll you don't really need too.
2 the "farm boy way" we used to do it was heat the pin up evenly cherry red hot then quick cool it in oil (or water) then heat it up again and let it cool very slowly.

 Hi Andy. Janie's question was answered immediately by Jason, and later received 4 more technical replies.

The internet is a giant one room schoolhouse and even if you're "sure he is very aware of the safety issues" (which I'm not, because he's a heating & cooling contractor and he didn't realize that no one can propose a hardening plan without knowing what kind of steel it is), hundreds of other people have now read this dialog and some probably used the technical heat treating advice while others decided that buying OEM replacement pins was a better plan than making their own after reading those safety concerns and considering their own knowledge base which may differ from yours and Janie's. It's all good.

Regards,

 Andy,

I guess some people feel obligated to provide information that will help lower the potential of someone dying.

Criticizing someone's questionable decision making isn't a bad thing... If someone is doing something boneheaded that could lead to someone else's injury then they should be called out on it quickly, and then be shown the right way to do it.

I saw nothing in this thread that appeared to be out of line.