Summary for crca steel strips stiffness Discussion
CRCA steel strips stiffness is the main issue here: Mallikarjun Patil asked why his 0.8 mm office-furniture pedestals felt flimsier than imported 0.5 mm parts made from the same CRCA steel, and whether a mechanical process could stiffen or toughen the strips. James Watts suggested the likely cause was not the material but the fit and dimensions of the assembled parts, advising tighter tolerances and closer mating fits. In a follow-up, another responder noted that sheet-metal stiffness rises with the cube of thickness, so a 0.8 mm sheet should normally be much stiffer than a 0.5 mm sheet if the designs are truly the same. That responder added that the imported parts may be formed into a more rigid shape, such as corrugation, and said hardening the steel or changing to a hardenable grade is possible but probably not the first explanation without drawing review.
Q. Hello Everybody,
Our Company is into manufacturing of office furniture. We use CRCA
(Cold rolled close Annealed) Steel for pedestals & storages of
0.8 mm thick strips.
The problem is our pedestals feel flimsy, not stiff when compared with the imported one produced by same CRCA steel of 0.5 mm thick, & it was much stiffer than ours.
please suggest me any mechanical process of stiffening, toughening the CRCA strips.
Your thoughts will be much obliged
Mallikarjun Patil
buyer – Daman, India
A. If they are the exact same design, I will bet a cup of tea that the competitor is using a lot closer fit on the mating parts. Tighten up your tolerances and dimensions and see what happens.
James Watts
– Navarre, Florida
July 30, 2009
A. Hi, Mallikarjun. The stiffness of a plain sheet metal bracket is proportional to the 3rd power of its thickness. Therefore, your bracket of thickness 0.8 mm, all other things equal, should be more than 3x as stiff as your competitors bracket of 0.5 mm thickness.
So, either James’ theory is right or perhaps you are not recognizing that your competitor’s pieces are deformed (like corrugated roofing) into a more productive shape than your plain brackets?
Yes, it’s probably possible to harden your steel to stiffen it, or to switch to a more hardenable steel, but the numbers don’t seem to point towards that being the probable need. All of this is, of course, guesswork since James and I have not analyzed drawings of what you are talking about. Best of luck.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
Need quick confidential answers? $25
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July 2010