With the amount of scrap metal floating around there and numerouse civil engineering disasters that we are seeing can we blame impure scrap steel? Is there a market for virgin steel made from 100 pure Missabbi Iron Ore and 100 % Pennsyvania Hard Coal?
That may be a stretch. I don’t think they just melt down old pintos and make I-beams out of them.
The mines on the Mesabi Range are producing Iron Ore as fast as they can go, but Hard Anthracite Coal is useless for steel-making. You need good quality bituminous coal to make coke, which you then use to make steel. You can make bad steel from good ingredients if you don’t manage the process well.
I do not recall hearing about any epidemic of structural failures. Even if there is such an epidemic there are two question that must be answered. How many of those failures are caused by defective steel? How many of that those components are made from recycled steel?
This is rubbish, as you surmise. There’s no epidemic. Defective steel is not cited as a factor in any collapse in the last 30 years that I can recall. Low grades of scrap steel is a factor in obtaining high-quality surface finish for cold-rolled sheet steel such as is used for automobile bodies and appliance shells, which is why those steels are mostly made from iron ore with a smaller proportion of scrap – but even in those steels, scrap is used.
(Norris – actually we USED to make I-beams out of Pintos, but not any more, as I think there are no Pintos left to melt! [:-,] Except for the ones that self-melted.)
RWM
If anything recycled steel is higher quality than new steel. There are far more impurities that need to be removed from iorn ore than would be in remelted steel. Therefore the chemistry can be controlled much better. Besides, no matter what the source a grade of steel has a range for every impurity or alloying agent not a fixed amount. it would be virtually impossible to produce anything if it were otherwise. All materials are tested to be sure they are in spec. before construction of anything. Deffered maintenance is another issue and a major cause of most disasters not materials.
You’re talking about two different processes. Scrap steel is usually melted in electric-arc furnaces. Iron ore (taconite) is used in blast furnaces using coke and oxygen to remove the carbon from the iron to make steel.
…Would those several crane failures in NYC qualify as failures being discussed…and the massive crane failure on here in one of the posts yesterday.
I don’t know if the cause has been determined on the above failures yet but certainly steel is one of the major ingredients.
99.9% of crane failures are caused by operator error – either operating the crane beyond its load rating, operating it during excessive wind, failure to ensure the ground it sits on is capable of accepting the load, or failure to observe obstructions. One of the tower crane accidents in New York is tentatively focused in an inappropriate welding repair. The other is tentatively focused on the crane-raising procedure and a worn nylon sling.
While lack of understanding or overestimate of materials performance is with some frequency a contributing factor in structural failures, what you’re referring to is not a lack of understanding, it’s a lack of quality control of the material, i.e., the structural engineer did his job but the steel mill didn’t. This is an exceedingly rare occurance in structural steel because the steel is manufactured and inspected under long-established and well-understood and effective methods.
RWM
I think we may have been “Trolled” on this one as there is no knowledge of either steel making or metalurgical coal in the initial post. What is reffered to as “Pennsylvania hard coal” is probably a reference to anthracite which is not used in steel making and never was.
The problem with todays STEEL is alot of it is foreign. Most countrys don’t have the same standards that we have and the steel is a lower quality, it might be high quality to them but not for us, the only reason we use it is because it cheaper then domestic. Just wait, we’ll start getting cheat chiness steel rail and watch the disaster and wreck double. Its going to happen.
BTW what is Canadian “metallurgical coal” used for? I understand CP hauls a lot of it, and that it goes to Europe, but exactly how or what purpose it serves I don’t know.
It probably has less to do with poor quality steel than it does poor designs and poor maintenance. In the case of the I-35W bridge collapse, it appears now that the designers built the bridge too lightly, too great a span with not enough reinforcement. Plus steel rusts, you need to keep it painted and in good shape or it can go bad over time.
Ironically the GN stone arch bridge a few hundred yards from the 35W collapse will probably be there 2000 years from now, like the old Roman viaducts still in place in Italy, since stone weathers the elements better.
Metallurgical coal is used to make coke. Today most coke is used in blast furnaces for iron making. Proportionally small quantities are used in foundry and other industrial applications.
Most coals have poor or no coking qualities. Met coal thus commands a very high price relative to steam coal. Prices for some grades have soared to more than $150/ton.
The preponderance of met coal mined in Canada goes to Japan, Korea, Taiwan, and China, where it competes with Australian and South African coking coal. U.S. coking coal resources are not exhausted, but most of the coking coal that is easy to get to has already been mined, leaving remaining resources under heavy cover, in areas of unfavorable geology, or at great distances from markets. Virtually all of the good, easy-to-mine met coal in the U.S. has come from Appalachia. Met coal with marginally acceptable coking qualities is found in the West at a few locations (Sunnyside, Utah; Somerset, Colo.) but by Appalachian standards this would not be coking coal.
RWM
Most countries actually do have the same standards we do for steel, particularly because the steel industry is global with shared technology, management, and ownership between countries. The quantity of imported steel to the U.S. is shrinking as fast as the value of the dollar. No one in the U.S. is going to use rail that does not meet AREMA standards.
RWM
I think you are right. The same poster put up some odd initial posts in other forums simultaneously. Consider us trolled.[D)]
RWM
Ding! Ding! Ding! Trainfinder alert! One of the posts was about Amtrak and Cleveland. Who has the traveling trophy?[:P]
My Grandmother, rest her soul, was ninety two years old when she died. And I’m positive, that she could have designed a better bridge than the I35W bridge that collapsed into the Mississippi. We Salt the roads in this state seven months out of the year, so they designed a bridge with a steel understructure!? Which taxpayer paid genius said OK to that?
How did they make such a big error in the gusset plate design? It seems like that gusset plate and girder design had been around for a long time prior to the 35W bridge. If I understand it right, the same error was committed on other bridges of that era. I also understand that the UofM performed a structural analysis of the design fairly recently and gave it their approval. When I see photos of those gusset plates, they look too thin, just going on judgement alone.
The fall 1976 tower crane failure at SDG&E’s Encina plant was due to resuing bolts that Leibherr said were one time use only (still human error).
There’s an interesting new book on the Titanic that claims that the sinking was due to poor quality control and lack of inspection of the wrought iron used in the rivets of the first fifth and last fifth of the ship. The authors noted that the steel plates and steel rivets had to be inspected and tested.
The Hyatt Regency walkway collapse in 1980 was due to the contractor making a seemingly minor change in the supports holding up the walkways.