Percentage Measuring

Home > Uncategorized > Percentage Measuring

May 21st, 2011 admin

Percentage Measuring

Your last search for Percentage Measuring has brought you to our Commercial Kitchen Equipment site simplechurchtribe.com - Our software is designed for product search, from thousands of vendors based on your search criteria.
Below you will find the products that our software has returned for you. If you cannot find the items that you are searching for, please use our search box at the top right of our site.
Thank you for stopping by our site.

Percentage Measuring

In steelmaking, what does the 'amount' of cold working refer to?

For example, in the statement

''Hardness generally increases most rapidly in the first 10 percent reduction (cold work), whereas the tensile strength increases more or less linearly"

what exactly is this percentage measuring? If something has been cold-worked by 10%, what has been done to it?

Also is 'reduction ratio' the same as 'degree of cold working'? If not, how are they different?

Thank you!

Cold working means it has either been forged by a drop hammer or a hydraulic press while the metal is cold. It compresses the grain structure and makes it more dense, without making it brittle. If it has been cold worked 10% it means the original piece of steel has had it's cross sectional area reduced by 10% in the forging process.

It is not exactly a 10% compression but it is a changing of a shape that reduces the cross sectional area by the 10%. For example if the piece started out as a 2" square bar and you pounded it into a 1" rectangle, with a 10% reduction it would not be a rectangle of 4" wide by 1" thick, but it would be reduced by 10% , which is a bar 3.6"x 1". But some of that 10% of the metal will be " squeezed" out like an extrusion.

So what happens is in reducing cross sectional area by 10% you increase the length of the piece by a little less than 10%. They don't really compress the steel by 10%, they just basically pound it from a square block into a long rectangle. And the more they deform it from the square block to a longer and thinner rectangle, the higher percentage of reduction that has been made. Reductions of 20:1 aren't uncommon

Reduction ratio refers to the original cross section area of the poured ingot to the final maximum cross sectional area of the forging

Degree of cold working means that cold rolled metal is given a rating based on the degree it was cold worked. "Skin-rolled" metal undergoes the least rolling, being compressed only 0.5-1% to harden the surface of the metal and make it more easily workable for later processes. Higher ratings are "quarter hard," "half hard" and "full hard"; in the last of these, the thickness of the metal is reduced by 50%.

There is some good excerpts at this link about forging:

http://books.google.com/books?id=N1dYgnS4JPEC&pg=PA27&lpg=PA27&dq=reduction+ratio+in+steel+forging&source=bl&ots=AeAsl0gUX6&sig=0blmKOipuJPF77ZzRK7Z8hi1JRU&hl=en&ei=Xc_ESpfyDMPBlAeMiJmSAw&sa=X&oi=book_result&ct=result&resnum=2#v=onepage&q=reduction%20ratio%20in%20steel%20forging&f=false

Hobart F 101 Fat Percentage Measuring Kit Animal Beef Testing
	$225.00 Time Remaining: 18d 5h 40m Buy It Now for only: $225.00 Buy It Now \| Add to watch list

HOBART F101 Portable Fat Percentage Measuring System
	$149.99 Time Remaining: 17d 22h 54m Buy It Now for only: $149.99 Buy It Now \| Add to watch list