Question

mechanical properties of iron

Answer 1

Pure iron has two main applications, chemical inert vessels and soft magnetic cores. In both cases mechanical properties are something you care less about compared to advantages tied to cost and specific performance. Pure iron is a ductile, relatively soft transition metal. It has a body centered cubic structure with a transition to face centered cubic at 912°C. By then it will have lost almost any yield stress and will be very malleable and deformable.  

The data supplied by producers is limited to the hardness levels in each state. (Page on www.pctmg.nl)

Brinell Hardness (HB) ARMCO Pure Iron (max. typical)
Cold-rolled strip / sheet (105, 90)
Hot-rolled strip / plate (105,90)
Quarto plate (100,90)
Round bar (110,95)

That is for commercial iron. If you push the fella a little and reduce its grain size to the tens of nanometers the hardness will jump to almost a 1000 HV. (Warm compaction of attrition milled nanostructured iron powders