Why was steel of decades ago so much better quality than today?

[Fawken]

The steel on my tractor is some of the best I've seen. Can't break it. It's only a 33 year old tractor and the steel matches the quality of my 1975 Hico bush hog. But yes the steel on everything is either weaker or they use a thinner section to save weight for better economy.

 

[KennyG]

The technology of steel today, like almost all technology, is very advanced compared to the past. The flip side is that the increased control over the attributes lets designers cut out all the margin. As an example auto body steel is probably half the thickness it used to be but will go 4 times as long before it corrodes. However, I agree that farm implements is a bad place to cut margins because they are expected to have a life of many decades.

 

[TnAndy]

The technology of steel today, like almost all technology, is very advanced compared to the past. The flip side is that the increased control over the attributes lets designers cut out all the margin. As an example auto body steel is probably half the thickness it used to be but will go 4 times as long before it corrodes. .

Hmm....so does that explain why the differential cover on my 2003 Chevy truck rusted thru (you wouldn't even think that possible, huh ? ) in 2013 ? Steel was complete CRAP....you could flake big hunks off the outside with a knife or screwdriver.

Naturally the way I found out was when the bearings locked up from lack of oil.

And when it happens to yours, GM makes a "kit".....cover, bolts, gasket....which tells you mine isn't the first one.

 

[Oaktree]

Hmm....so does that explain why the differential cover on my 2003 Chevy truck rusted thru (you wouldn't even think that possible, huh ? ) in 2013 ? Steel was complete CRAP....you could flake big hunks off the outside with a knife or screwdriver.

Naturally the way I found out was when the bearings locked up from lack of oil.

And when it happens to yours, GM makes a "kit".....cover, bolts, gasket....which tells you mine isn't the first one.

Nothing new either. I had a late-60s vintage International pickup (well, it had been a pickup once...bed was long gone before I got it) in the 70s and had the same thing happen to me as did with you (same results too ).

 

[ultrarunner]

Quality alloys of steel is what made the Model T and Model A Fords stand the test of time.

Ford used quality material at an affordable price... he was a stickler for the strength of the spokes on his wheels and the axles on his cars... plus he pioneered the use of stainless on low price automobiles... I can take a headlight or radiator shell from a 1930 Ford that has been sitting out in the woods 50 years and buff it to look like new!

When the circus came to town... I noticed all the tent stakes were Model A Ford axles... the last Model A was 1931... how's that for quality...

Also... much of the old stuff is forged vs cast... forged is umtenth times better except it costs more... the grain of the metals flows when forged making forged parts extremely tuff...

I know an old farm mechanic that only uses Caterpillar bolts when he needs one... I guess the expensive CAT bolts are just made better.

 

[williaty]

Hmm....so does that explain why the differential cover on my 2003 Chevy truck rusted thru (you wouldn't even think that possible, huh ? ) in 2013 ?

I don't work on Chevys, so I can't speak to your specific problem, but there is a VERY common problem from MANY manufacturers right in that production timeframe. I'd have to go find paper notes to get the exact compounds based off the conversations I've had with design engineers, but the short version is that the DOTs screwed over the automakers. A few years earlier, some company came up with a new anti-corrosion treatment that was much cheaper, caused fewer regulatory headaches, and was more effective against the de-icing agents used in the US at the time. The major OEMs did their extended lifecycle testing to confirm that the new coating was actually better and then switched to coating all their stuff with it. About the time those cars hit the streets to actual owners, a new de-icing agent suddenly became popular from the Rust Belt all the way to the Canuckian border. The problem was that the new de-icing agent ate the new coating for breakfast. The OEMs were livid as they suddenly had gigantic warranty exposures on parts and there were even several recalls for control arms rusting through. In states just a little farther south where they only used sand, beet juice, or basic sodium chloride as a de-icing agent, the rust problems were non-existent.

 

[Egon]

If you want real steel figure out what that old steel pillar in India was made from.

 

[sixdogs]

Quality alloys of steel is what made the Model T and Model A Fords stand the test of time.
...

Also... much of the old stuff is forged vs cast... forged is umtenth times better except it costs more... the grain of the metals flows when forged making forged parts extremely tuff...

I know an old farm mechanic that only uses Caterpillar bolts when he needs one... I guess the expensive CAT bolts are just made better.

I bought some Caterpillar bolts a couple years back for something serious and I was astounded at the price. The quality of the bolts, however was like beyond comparison. You could polish one up and put it in an art show.

 

[Gary Fowler]

I think the old iron used in farm implements must have been a type of weathering steel like we see used in some items today. They certainly don't rust up as bad as the new stuff. 75-100 years of exposure has little rusting developing and what covered with rust is just surface and can be buffed out easily. Leave a piece of modern iron unpainted and exposed to the elements and I doubt you would find a piece of it left after 50 years.
Perhaps it was lack of metallurgy knowledge that led them to increase the alloying elements more than was needed for strength that are now missing or at least much smaller % of them so the metal might be stronger, but is sure isn't weathering like the old stuff.

 

[Gary Fowler]

If I was still working and had my $100K nuclear analyzer for metals, I could readily determine what elements were in old iron and the %. Perhaps some TBN member has access to an analyzer and can do this test to determine exactly what makes the old iron so rust resistant. The bolts were also rust resistant.