What is the difference between hot and cold rolled steel?

[Tom H]

CRS generally has a specific carbon composition, usually 1018/1020 as noted above.

HRS is generally supplied as A36, a 'low carbon', steel, which is spec'd by performance, not chemical composition.  The carbon content is less controlled and it can vary somewhat.

Both of these terms used alone, signify the above.

Many steels can be supplied in various forms , as hot rolled, or cold finished, or whatever, but they will also have the grade designation.

For example, razor blades are made of high carbon alloy, which may be supplied "cold rolled", but it is definitely not CRS with the low carbon.

The usual concept of 'hardening' requires a steel with more carbon then simple CRS or HRS, old wives tales and backyard recipes not withstanding.

 

[george m.]

Dear Tom,

"Backyard" or not google or otherwise look up "super quench."  It was formulated at Sandia National Laboratory which, IMO, is a pretty respectable pedigree.  I have seen a chisel forged from a bar of mild steel, hardened in supper quench, and then used to cut a piece off of the bar from which the chisel was forged.  The edge of the chisel was still sharp.

I have been able to make RR spike knives reasonably hard with super quench.

Is high carbon steel better? Yes. Can you do fairly well with mild steel and super quench? Also, yes.

Hardeningly,

George M.

[gote]

Wikiedia has the requirement that the contributors give references. Also that "original research" which would include "opinioins" are not allowed. Corrections and rewrites are also recorded and possible for all to read.

Also I think that we should stick to blacksmithing and avoid calling contributions "dribble" and making depreciating remarks about contributors' personality.

Have anice weekend

Göte

 

[b4utoo]

I will consider my sources in the future...After a day cooling off. FROSTY. I AM SORRY FOR MY COMMENTS EARLIER.

[turbo7]

For my part, I shall refrain from using simillar terms in future. Good on ya b4utoo.

[Steve Sells]

I have a few examples of where wiki was wrong,  but to be more traceable/proovable, I would like to point out there was a time when Dr. Jim Hrisoulas, and myself  both had our respective web sites listed in wikipedia as references for pattern welded steel.  Someone had them both removed and replaced with a link to another smiths site, siting our sites as having no content,   funny how politics qualified as reason to removes us.. our web sites got removed because we do not pay dues to their private guild. For the record the site that replaced ours is a nice web site, that was not the real problem, and since that group got non members information removed and replaced with their own, that leads me to believe other areas can also be effected for personal gain.

Edited April 19, 2015 by Steve Sells

[SmoothBore]

since that group got non members information removed and replaced with their own, that leads me to believe other areas can also be effected for personal gain.

​Exactly.

If you can't trust the data to be impartial and unrestricted, ... then you simply can't trust the data.

 

Same goes for GOOGLE, YAHOO, Ask.com., etc.

Their mercenary manner of doing business, ... taints the results found on those sites.

 

.

[Tom H]

Dear Tom,

 I have seen a chisel forged from a bar of mild steel, hardened in supper quench, and then used to cut a piece off of the bar from which the chisel was forged.  The edge of the chisel was still sharp.

    Hardeningly,

George M.

​George,  Try it with CRS.

And, you might notice that I said "usual concept of hardening".  Case hardening is a different animal.

[ThomasPowers]

That wasn't case hardening.  I saw Robb Gunter do the same demo at Quad-State back when it was still at the Studebaker's place and I asked for and received the chisel.  It was A36 though.