Bessemer Process->Aston Process-> Wrought Iron WHY?

[Tim grows Vegetables]

Hi,

For a couple of days now I've been looking around online regarding ironworking technologies, especially steel making and wrought iron production processes.  I'm a little confused about the Aston Process.

It is my understanding from the sources I've looked through that the Aston Process was developed to take advantage of the very efficient way that Bessemer converters decarburized pig iron which enabled fully decarburized iron to be poured directly from the converter into "cooler liquid slag" to combine and form wrought iron that was then rolled out into muck bars.  

But there's been a recent topic on 1008 low carbon steel etc and how great it is to work with.  If you can make low carbon iron directly in a Besemer converter, why do you need to mix it with slag to make wrought?  Why not just pour the iron and make it into bars without the slag?  That's the part I don't understand.  Why add the slag back in to make wrought when the converter had already separated out the original slag the pig iron might have contained?  There must have been a good reason to create and industrialize the Aston Process, but I don't understand what it was.  

[Frosty]

The Aston process is one type of puddling furnace to mechanize and make more uniform the production of wrought iron from pig.

At that time the world was transitioning from wrought iron to mild steel and there was an entire industry learning to use the new stuff which meant there was a large % of "Traditionalists" who were resistant. So there was still a market for wrought iron and the Aston process was more industrially modern and produced more wrought faster with greater control of the silica content. More consistent better quality wrought iron for less was what the market needed, an honest improvement, not just something to say on a patent application or magazine ad.

Don't go quoting me on that, I just skimmed a couple article headings. If you want more details what I wrote should give you enough leads and search terms.

Why? Pig iron is reasonably pure iron but it has too high a carbon content for forging, rolling, etc. The silica in wrought iron makes it self fluxing and easily forge welded. amongst other things.

Frosty The Lucky.

[S.A. Hill]

The silicious slag in wrought iron acts as a corrosion barrier. There was simply no way for puddling furnaces to compete against the Bessemer converter and steel mills. The Aston process was invented for/by A.M. Byers Co. They produced only welded wrought iron pipe.

The modern-day discussions about using 1008 steel instead of 1018 or A36 stem from the increasing prevalence of A36, and the decreased availability of 1018. A36 is really not intended to be forged, and its manganese content can cause real problems on work that has to go in and out of the fire much more than a few times. 1018 is becoming a special-order material through a lot of distributors, and as such is coming close in price to other mild steels that are much better for decorative forge work. 1006 and 1008 move much easier under the hammer than either 1018 or A36, and time is money. It forge welds more easily, and can go to higher temperatures without burning when doing so.