I don’t quite get the US steel pennies from the WWII era. Wouldn’t steel have been in even more demand than copper? Why wasn’t there a steel shortage?
Steel is much more abundant than copper, and the pennies were zinc plating over steel. Remember, copper, which was needed for shell casings, is a semi-precious metal, and steel isn’t.
ETA: FWIW, pennies before 1943 were bronze, not pure copper. Fully copper (or, copper enough to be considered “copper”) cents hadn’t been used since, IIRC, 1856. Since about 1979, cents have been a zinc core with a brass coating (or bronze, but IIRC, it’s brass).
Steel is much more common and much less expensive than copper. Think of ‘tin’ cans- they were made of steel, ubiquitous, and treated as trash after their contents were eaten. The U.S. had the biggest steel-producing industry in the world then. It may still, come to think of it.
Then - absolutely. Now? Nope - and it’s not even close: China makes almost half of the world’s steel while the U.S. makes only about 5.5%. (2013 data)
Wow. Didn’t realize it was that low. We’re still fourth, and 87 million metric tons is a lot more than the 1200+ metric tons of copper produced here in 2004. http://upload.wikimedia.org/wikipedia/commons/f/f0/US_Primary_Copper_Production_v2.svg
Googling yields the following:
1793 to 1837: 100% copper
1837 to 1857: 95% copper (with tin and zinc, which makes bronze)
1857 to 1864: 88% copper (with 12% nickel)
1864 to 1942: 95% copper (bronze, again)
1943: steel with zinc coating
1944 to 1962: 95% copper (bronze, again)
1962 to 1982: 95% copper (with 5% zinc, no tin)
1982 to present: 2.5% copper (97.5% zinc)
My asshole neighbor’s brother stole all mine.
Your chart is wrong, the US copper production numbers are about 1.2 million metric tons per year (6.6% of world production). Consumption is 1.8 million tons (10% of world consumption, a thirdish is imported), or about 11 pounds per person per year.
A customer of my wife’s restaurant often leaves tips with a few 1943 steel pennies thrown in. This guy has a bunch apparently. Curiously, someone went to the trouble to have them newly zinc coated. We have a few of them.
There’s an anecdote about copper shortage in WW II that most of you have heard a dozen times, but I’ll repeat it for any young 'uns.
While steel was an easy substitute in pennies, a much better conductor was needed for the electromagnets used to refine U-235 for the device eventually dropped on Hiroshima. With copper desperately needed for other military purposes the Manhattan Project decided to substitute …
… Silver! … Taken on loan from the U.S. Treasury.
In total almost 15,000 tons of silver were used by the Project. (99.99997% of this was eventually returned to the Treasury.)
The usual punchline is: After ordering thousands of tons of silver, the scientists were asked to convert their request to troy ounces!
Ninja’d!
It’s worth mentioning that silver is actually better than copper for this job (price apart) because it is the most electrically conductive metal- 5% better than copper.
Today, high-end hifi victims sometimes use silver wire, on the principle that if it costs more it must be better, right? Not so. Its use is pointless.
It’s likely you didn’t lose much. Even in mint condition they’re only worth a few bucks.
Unless they were dated 1944.
Also Jefferson five cent pieces saw silver used to replace their nickel content during 1942-1945.
Here’s a link to that story, by the way https://www.y12.doe.gov/sites/default/files/history/pdf/articles/07-10-11.pdf
"The first meeting to discuss the loan of the silver that I have found was described by Col. Nichols in his book “The Road to Trinity” as happening on Aug. 3, 1942. He states, “As a result, on Aug. 3, I visited Assistant Secretary of the Treasury Daniel Bell. He explained the procedure for transferring the silver and asked, ‘How much do you need?’ I replied, ‘Six thousand tons.’ ‘How many troy ounces is that?’ he asked. In fact I did not know how to convert tons to troy ounces, and neither did he. A little impatient, I responded, “I don’t know how many troy ounces we need but I know I need six thousand tons - that is a definite quantity. What difference does it make how we express the quantity?’ He replied rather indignantly, 'Young man, you may think of silver in tons, but the Treasury will always think of silver in troy ounces”
6 tons is exactly 175,000 troy ounces, btw, in case anyone ws wondering. You can scale up from there. Too bad they didn’t have google in 1942… 
OK – no one asked but – there are a few authenticated as well as some 1943 “copper” cents. The thought at one time was that mint workers had run some through basically as a joke or lark to create some “one of a kinds” for themselves. The actual story is much more dull. The totes used to move the planchets to the die-striking machine had a slight lip on the inside. Most folks now feel that some planchets were stuck under the lips and not knocked free until after the change of metal. So a few off-metal errors (in a manner of speaking) got through and into circulation.
If so, they’re likely counterfeit. There are only about 30 known to exist.
So my memory isn’t perfect. 1857 was when the design of the penny changed to the flying eagle, and they went from being about the size of a half dollar to the current size (it was also the last year for the half-cent, a bronze coin about the size of a quarter), and I knew the composition changed then. Also, it may be that the plating on zinc of current cents is pure copper, but FTR, today’s pennies aren’t alloys like the previous copper-zinc-tin cents. The copper is plating over zinc. Get a couple of pliers and break one apart. It’s kind of interesting.