Conversion Help - daj/cm^2 to ftlbs/in^2

Hello Guest

You're not mucking up. I haven't been through your calcs in detail, but converted using Mathcad and get 533 foot pounds/ in^2 as near as makes no difference.

But I'm not familiar with the test, so can't comment whether this is a realistic figure for steel.

Cheers.........Codey

Thanks, Now I have to look at the assumptions- are the units right- ie, is Charpy impact ft pounds only or foot pounds per unit area. back to the books... Thanks.

yank

Your conversion appears correct.

I still get a kick out of using the Google calculator, which has the advantage of taking units pretty literally, so if you do an "incorrect" conversion, the units will come back looking very strange... or it won't do the calculation at all. I don't use it routinely, but it remains fun.

You type this into the search window:

11.2 decajoules per square centimeter in foot pounds per square inch

and you get back this:

(11.2 decajoules) per (square centimeter) = 532.947068 foot pounds per (square inch)

Thanks,

I still think theres a problem, as I dont think that this is an accurate depiction of the impact properties. maybe if I make the per square inch go away i can get to morerealistic value. now what would the size of an charpy specimen be??? hmm

Yank

Hi Milo,

hope you are fine?

I list below the sample sizes used with the Charpy Test, for you to view.

As you know any figures derived, are only 'estimates', because a person is judging the percentages of brittle and ductile simply by the shape of the break.

Whether a fracture was brittle (breaks on a flat plane) and ductile (breaks with jagged edges and shear lips). Or an 'estimate' of somewhere between the two? This is bound to be subjective and could easily vary depending on the persons experience and knowledge of such tests?

The paragraph directly above I wrote for anyone who may not be familiar with this test, (not you of course Milo).

Sample sizes

According to ASTM A370,^[9] standard specimen for Charpy impact test is 10mm×10mm×55mm. Sub-size specimen are: 10mm×7.5mm×55mm, 10mm×6.7mm×55mm, 10mm×5mm×55mm, 10mm×3.3mm×55mm, 10mm×2.5mm×55mm. Details of specimen as per ASTM A370 (Standard Test Method and Definitions for Mechanical Testing of Steel Products).

According to EN 10045-1,^[7] standard specimen sizes are 10mmx10mmx55mm. Sub-size specimens are: 10mmx7.5mmx55mm and 10mmx5mmx55mm.

^{Good luck}

Milo,

You are correct in taking into account the sample size. The fracture face is 10mm x 10mm so when you convert that into square inches you get 0.155. When you then multiply that with your 532 ft-lbs/square in, you get the original 82.6, which is the correct number you or your friend are looking for.

Hi Guest,

You may have sent this erroneously. I am not Milo. !!!

Good luck

Maybe something lost in translation? Could the data have been deci instead of deca joules?

Just a thought.

Mike

Hi Guest, come and join us. There is a useful utility called Convert.exe, it's free, just google for it.

Tony

Try downloading "Engnet conversion" - very hand little tool.

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