Definitition of full hard, half hard and 40% cold reduced 1

[bogiedreamer]

Full hard - strip is rolled to half of the original thickness
Half hard - ?
40% cold reduced - ?
How do you calculate the original thickness for half hard and 40% cold reduced? I thought I could find any definition online but I am not able to.

 

[bogiedreamer]

I came up with this equation
Final Thickness * (1+ 𝐶𝑜𝑙𝑑 𝑅𝑒𝑑𝑢𝑐𝑡𝑖𝑜𝑛 %/100) = 𝑂𝑟𝑖𝑔𝑖𝑛𝑎𝑙 𝑇ℎ𝑖𝑐𝑘𝑛𝑒𝑠𝑠

For example, final thickness .005" with 40% cold reduction

.005" * (1+ .4) = .007"

Is this correct?

 

[kumkumvijay]

I share my opinion as below:
Generally 95% reduction done to achieve the full hard. So I feel it’s not direct calculation to calculate the original thickness for H12, H14, H16 by applying the % cold reduction. Also if the metal is annealed after the orginal thickness then it can be again cold work. So it may not be possible to predict the initial thickness based on temper cycle always.

But for the 40% reduction, its direct calculation.
After 40% reduction, if the thickness is A then then for 100% consider as Bmm then the formula is B=2.5A.
Thickness after 40% reduction = A
Thickness with 0% reduction= B
Then Original thickness B = 2.5*A.

 

[EdStainless]

Look in A666, the definition is based on tensile strength, not reduction.
The same terms are used for strip, wire, and tube. But the actual strengths and reduction ratios are different for different product forms. In fact there is no definition for these in the tubing world.

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Plymouth Tube