what's the difference in between hot rolled mild steel & high yield steel?

Answer 1

<>Maybe these sites will help:
http://www.ussautomotive.com/auto/tech/Grades/dds.htm
http://www.ucalgary.ca/~design/engg251/First%20Year%20Files/materials.pdf

Answer 2

Materials property wise, mild steel is not the strongest, but cheap. High yield strength steel is a lot stronger due to alloying additions and hardening treatments, but at a higher cost.

I wish people only answer stuff they actually know about rather than plagiarize chunks from internet sites.

Answer 3

hot rolled is straight out of the furnace and formed into a billet.
in cold rolled the two ends of the billet are fixed in b/w a mechanism and twisted to add strength to the rods.

high yield is hot rolled. and has low carbon content

the more the carbon added to the steel, the more harder and less tensile the steel becomes.

Answer 4

just adding to the answer above. your hot rolled is down above the crystalisation temperature. mainly because it requires less force, so if it is already hot really easy to do. cold rolled is below the recrystalisation temperature and benefits from better surface finish but more important work hardening, so this is a really hard steel, better mechanical properties than the hot rolled. galvanised sheets, are dipped in zinc baths. i am not 100% sure on this but this how components are galvanised. sheets or very long beams maybe done differently.

Answer 5

Steels can be classified by a variety of different systems depending on:

The composition, such as carbon, low-alloy or stainless steel.
The manufacturing methods, such as open hearth, basic oxygen process, or electric furnace methods.
The finishing method, such as hot rolling or cold rolling
The product form, such as bar plate, sheet, strip, tubing or structural shape
The deoxidation practice, such as killed, semi-killed, capped or rimmed steel
The microstructure, such as ferritic, pearlitic and martensitic
The required strength level, as specified in ASTM standards
The heat treatment, such as annealing, quenching and tempering, and thermomechanical processing
Quality descriptors, such as forging quality and commercial quality.

Answer 6

Basic commercially available Hot Rolled Steel (ASTM 1010) has a tensil strength of about 21,000 psi
Mild (or cold rolled) steel (ASTM 1018-1020) Has tensil of 25,000 psi,
Chrome alloy steels (chrome molly) (ASTM 4140, 4340) have yeilds from 40,000 to 50,000 psi.