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Re: Cor-ten, was Panel side hoppers

gettheredesigns <rick@...>
 

Hi all,

Cor-ten is only one type of high-strength low-alloy (HSLA) steel, and not all HSLA steels have corrosion-resistant properties. So the use of the term HSLA does not automatically mean Cor-ten or other corrosion-resisting steel was used. "Weathering steel", "Cumoloy", and "copper-bearing steel" are terms used for similar corrosion-resistant steels. Cor-ten is a US Steel trademark. These steels still rust, but the rust adheres tightly, sealing off the underlying metal from the atmosphere.

I can't cite RR-specific references, but the decision to use lighter-gauge HSLA or weathering steel rather than heavier gauge conventional steels is driven by two different factors. One factor is the greater strength of many of these alloys, thus allowing a thinner section to have the same strength as thicker convebtional steel. The second factor is that a "corrosion allowance" is not needed when designing with weathering steels. In designing with conventional steel, the engineer needs to consider retained strength after years of corrosion, and perhaps use heavier sections to compensate. So a new car might be overbuilt in the rust-prone areas, so it will remain in service longer. Weathering steels make this unnecessary, resulting in a lighter car.

The B&LE (a US Steel road) was buying Cor-ten hoppers in 1936--would they have been early-adopters to promote their own product?

Hope somebody finds this interesting...Rick Aylsworth

--- In STMFC@..., "soolinehistory" <destorzek@...> wrote:



--- In STMFC@..., water.kresse@ wrote:



While the panel sizes are not that much different, there appears to be a greater depth of draw and the side-wall angles are more aggressive.  The radii also appear to be smaller.  Do we know if these were cold or warm-formed?  Where any every made out of COR-TEN steel?



Al Kresse
Alas, I really can't answer your questions. My reference materials for the decade of the thirties are seriously lacking. IIRC, the first panel side installations were done in 1931, but they are not in the 1931 Cyc. The earliest reference I can easily lay my hands on is the 1940 Cyc, and at that point the panel side concept was approaching ten years of age, and there is no editorial info, other than SRECo was presenting drawings of two versions. Tony Thompson sounded like he was familiar with a Railway Age article; perhaps he knows more.

The 1940 Cyc. was all abuzz about the new low alloy high strength steels, but no indication how long they had been available. Googling Cor-ten and ASTM A242 didn't fare any better; nine thousand references to rusty sculptures and buildings, but not a single decent history of development with a date.

It's certainly possible, it appears that US Steel was pushing Cor-ten for hopper slope sheets and the like because of its corrosion resistance without suggesting the cross section be reduced... that appears to be where the car-builders were trying to get an edge with "lightweight" car designs that took advantage of the increased tensile strength.

Interesting point about the deep draw of the panels. makes me wonder if the failure mode was rusting through at the bottom corners, since the sheet would have become considerably thinner in those areas.

Dennis
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