Product review (1 stars): Samsung Should Recall The Original Drum
So, I have the same model of Samsung dryer drum, and of course it has a crack and missing piece out of the drum.  The thing that tipped me off to this break was the loud thump, thump, thump.
  I bought this dryer during a thanksgiving sale in 2011.  Lowe's was out of stock so they said as soon as they get them in they would deliver it.  So at the end of January 2012, almost over 8 weeks wait, we got the dryer in.  Within the first two weeks of using it, there was a clickity clacking noise from the front of the dryer sounded like a roller.  Waiting so long to just get to use this dryer, I didn't want a technician saying we'd have to get another one, so we just let it be.  To this day it still makes a racket when drying, but it started sounding horrible with the thumping sound.
  Seeing as the drum broke and thinking Samsung would stand by their products, I called them around May or June the first time.  Before I called them, I thought I had read somewhere in the owner's manual that the drum had a lifetime warranty.  Of course this was not the case as they promptly said the dryer was out of warranty, but they referred me to an authorized repairman.  As I see it, since there's no warranty (Samsung repeatedly made sure I knew this), I don't need an authorized repairman, as I can replace a drum.
  After finding the replacement drum for this dryer, the cost just for the part is over half of what I paid for the dryer.  I realized at this point the problem is with the design and quality control at Samsung.  This is the first and last stainless steel drum dryer I will ever buy.  The reason is that this is the first drum I've ever seen break.  I've never seen or heard of a steel drum breaking, and I've had 6 dryers in my lifetime, not including this one.  So I called Samsung again today and asked if there was a powder coated direct replacement drum so this won't happen again.  I told them how this is ridiculous that the drum is broken.  The two people I talked to just apologized, but couldn't help with the part.  They once again referred me to a parts store, and I couldn't get anywhere with them either.  So I threw my hands up and said since I have all Samsung appliances and this dryer is the only thing that I'm having problems with, I'll just not buy anything Samsung anymore.  Of course they said,"ok that's fine with them".  What has the term customer service come to mean.
  So just like you reading this, I did find the direct replacement drum and on just the Sears repair site it says there's been over 1400 repairs done just to replace this drum.  Now I'm not sure but if 1400+ steering wheels fell off of one make of car,  I'm sure a recall for that part would happen.
Hey Samsung, make this right and fix this problem, or stop selling.

Update:  I have found a direct replacement for this stainless drum.  It's part number:  dc97-07520k
This is a white powder coated drum.
I found mine at Parts Dr. Com, but you can just do a search on Amazon or Google.
I have been using it in my dryer since early December 2015 with no problems.  I hope this helps.