There is a postcard for sale on eBay of the National Tube Company in Lorain.It is item number 6196149840 and scheduled to end sometime on July 31st. I usually do not like to place information about online auctions on GenForum, however, this directly relates to your inquiry and your email address is hidden.
Once, someone let me know that a postcard of the Christian Hospital in Valpariso, Indiana was listed in an auction.This was rewarding because my grandfather had died there in 1927, and the hospital had since closed.Having the photograph in my collection makes for very interesting conversation, and has been a prize to my father because that and a small newspaper obituary from area newspapers are the only link we have to his passing away at a very early age.
A good source for information about the National Tube Company might be the public library in Elyria. If you visit USGenWeb.net > Ohio > Lorain County, you might find more information about the company there, and if not, there will be links to the library.
Go to a search engine like dogpile.com and put "National Tube Company Lorain Ohio" into the search criteria and you'll find a lot of information.You will find that it was a subsidiary of US Steel.There are some photos at: