# Work Hardening percentage calculation

1. Jun 2, 2015

### Ben James

Plate previous cold-worked 20% is 50 mm thick. It is then cold-worked further to 33 mm. What is the total percent cold work?

I know %CW= (Ao − Ad/ Ao) x 100

I know the answer should be 47.2%, but I don't get that. What are the first steps I need to take?

2. Jun 2, 2015

### RUber

Start with what you know. I assume Ao is initial thickness and Ad is thickness after work. If not, please provide more detail on what these variables are.
.20 = (Ao -Ad1/Ao) --- Are you sure this shouldn't be (Ao-Ad)/Ao?
Solve that to find Ao.
Then plug in to find your percentage::

3. Jun 2, 2015

### RUber

I worked it out, and yes... it is clear that using the assumptions I made above, you need to use $.20 = \frac{Ao -50}{Ao}$ to find Ao. And then apply the same formula to find $x = \frac{Ao -33}{Ao}\times100\%$.