Cold rolled vs. Hot rolled

[archeryantny]

Cold rolled vs. Hot rolled whats the difference?

I'm in the early planning process of building a road boss type grader implement for my L48. I've got a rough idea of what I need in terms of sizes, profiles, and quantity. After doing some topical internet research I noticed that I had a choice of hot or cold rolled steel. Which type is best for implements? Is there a specific type used for ground contact that has higher abrasion resistance?

 

[blueone]

Check this out Guide to Buying Steel Online | Online Metals Guide to Selecting Metals for Your Projectnotice ALLOY that's the key. Its hard to work with you need carbide tooling. I'd go with mild steel and hard-face the cutting edge afterward.

 

[Villengineer]

Assuming that you are talking about low carbon steel, generally cold roll will be slightly stronger, "truer" in size, shape, and straightness and more $. Either would probably be fine for the superstructure, but neither is very good for ground engagement. Steels like A514 (T1) and the AR steels are much better for ground engagement.

 

[djw250]

Yep, either will work for the structure, but you will need a hardened cutting edge and possibly hardened or easily replacable skids. You can check out the one I built recently here.

http://www.tractorbynet.com/forums/build-yourself/158315-finally-built-my-grader.html

 

[archeryantny]

blueone- how would you "hardface" the steel. is that like tempering, or like quenching the steel. thanks

villengineer- I will look into the ARs. I'm gonna need some of that for a shooting backstop i have in the works.

djw250- read through your thread, very nice work. I hope its not patented because I might get into a little trouble. What did you do for a cutting edge, were they salvaged and stripped off another BB or did you buy them new? If so where would one purchase that type of cutting edge new? very nice job! How does it work?

 

[djw250]

blueone- how would you "hardface" the steel. is that like tempering, or like quenching the steel. thanks

villengineer- I will look into the ARs. I'm gonna need some of that for a shooting backstop i have in the works.

djw250- read through your thread, very nice work. I hope its not patented because I might get into a little trouble. What did you do for a cutting edge, were they salvaged and stripped off another BB or did you buy them new? If so where would one purchase that type of cutting edge new? very nice job! How does it work?

No patents here, copy away. In fact, I did quite a bit of copying from a commercial grader that shall remain nameless. The cutting edges and the skids on the bottom of the side pans are from used motor grader cutting edges that a friend of mine got me for free. He knows a guy that works for the Parish (County) road crew, and they change them out pretty regularly and discard the used ones. Plenty of blade left for me, in fact I had to cut them to size with a torch. I have used it both to maintain our 1/4 mile gravel road and to smooth dirt, and it works great for both.

 

[oldnslo]

Hot rolled is usually dirtier and messier to work with but usually warps less when welding. Requires more cleaning for good paint adhesion.

 

[blueone]

Archery,
Hard-face rod is a weld metal w/high carbide chrome and other content it should be available at your local welding supply store, comes in stick or wire form. Next time your by one stop in and ask, most welding suppliers are a good and friendly source of welding knowledge.

Where I work we hard-face mild steel, cold rolled, cast steel, cast iron, manganese[work hardened], and pretty much any other metal we come in contact with.

The key is, if your unsure what base metal you have then you need professional advice to find out, if you want good results from your efforts and expense.

I'm going to add this but BE WARNED it's alot to take-in but here it is http://content.lincolnelectric.com/pdfs/products/literature/c7710.pdf
Check Introduction section 1/Consumable selection then go from there.

Here is Lincoln's site for hard facing consumables http://www.mylincolnelectric.com/Catalog/consumableseries.aspx?browse=104|1847|

I feel as it's the way to go because you only need the special rod, not a whole set of new fabrication tools as you do for alloy steels [carbide bits/end mills]. Unless you are good bit and tool sharpener, I'm not.

I am not a metallurgist it's just what I've found from 15 years of MRO [Maintenance, Repair, and Overhaul] experience that works for us

 

[Groo]

cold rolled is work hardened and has a nice surface.

 

[whistlepig]

Cold rolled has a held size. I.E. a 1" square piece of cold rolled will check 1.001"-1.002". And the size stays consistent from batch to batch. Hot rolled is not a held size. Cold rolled is commonly used for key stock to fit in key ways. Cold rolled is tougher to machine than hot rolled but can be cut with high speed tooling. As far as wear resistant metals you may want to look A-2 (air hardening), W-2 (water hardening), or O-2 (oil hardening). These metals can be worked easily and then heated and quenched in either air, oil, or water. These will give better wear resistance than mild steel.