Dumb Question - Hot rolled vs. Cold rolled??

[mete]

Steve, last time I researched that it depended on what type of carbide !! The more you research the more complex it gets !!

 

[Steve Hayden]

From what I have found on carbide chemistry, the transition metal carbides tend to be the most molecular with the Fe2C version sharin the two outer shell electrons with the metallic binds, while some of the others less, depending on charge balance. The remaining structure seems to be a strange hybrid bond.

We talk of weight percent Carbon, but chemically it is quite a bit higher-1wt% C is around 4 1/2 Mol% in formula units. I haven't done the math to figure it exactly-I'm lazy in my old age.

If you combine the 4 1/2% in Fe2C, then you are up to about 13 1/2% of the steel. Some complex alloys have much higher % carbides.

 

[mlovett]

OK, I give up. Which is more machinable. HR, or CR. How about in 416 s/s, that we usr for guards? Mike

 

[Alarion]

I've had a look at Admiral Steel site.
The links seem to malfunction. Anyway, you can see that both cold and hot rolled steels are sold in various states.
You need the ANNEALED steels if you want them soft, as both cold and hot rolling can partially harden steel, apparently (I believe work hardening in one case, and hardening due to an abrupt drop in temperature in the case of hot rolling, but I'm just supposing that, I have no hard fact.)

When mild steel (iron) is concerned, HOT rolled is SOFT, COLD rolled is HARD (work hardening)

 

[mete]

Machinable ? It's not whether it's HR or CR but whether it's annealed or not .416 is a free machining grade of 410 and it can be heat treated ,it should be annealed for better machinability.