doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Forging lines on old actions?

I edited DAM16SXS pictures:

Thanks Mike - much easier now to see the curvature of the billet imperfection lines.

Very interesting...they show well!

I found a glossary of forgings at https://www.forging.org/glossary-forging-terms

Flow lines � Patterns in a forging resulting from the elongation of nonhomogeneous constituents and the grain structure of the material in the direction of working during forging; usually revealed by macroetching. See also Grain Flow.

I think today "nonhomogenous" means "dirty" metal. Modern chromoly alloys and specialty steels are often vacuum-arc-electro melt and often vacuum-arc-electro re-melt (more than one melt, often with a trimming of the ends of the ingots to remove impurities prior to remelt), which efficiently homogenizes any intended constituents and removes unintended constituents/impurites.

Some reference info.
http://en.wikipedia.org/wiki/Electric_arc_furnace

http://en.wikipedia.org/wiki/Vacuum_arc_remelting

Chuck, I agree with youabout today's metals. I think the definitions you gave would equally apply to a situation of unequal carbon content of plain carbon steel made as described above. The case on the rods would be of higher carbon content than the core. Unless literally melted, this difference in carbon content would be retained during the forging process. So, what we are seeing is sort of a steel-steel damascus of very simple pattern. Had the rods been twisted and rolled out per pattern welded barrels we would see a much more complex pattern of these lines.

DDA

If I'm not mistaken, these actions were made of wrought iron. A thin layer of carbon may have been added by case hardening, but I don't believe wrought iron had any carbon in it to make it a steel. I believe wrought has a stringy pattern just on its own.

I think the finer the lines that show, chances are the more the wrought was forged out to reduce the effect those lines may have on the integrity of the final part. I suspect the difference in appearance is from components other than carbon. Chances are, forging different carbon content steels together ends up evening the carbon content between the two.

I just had a look at the bottom of the action of a Holloway SLE Pigeon (not a best work gun, but no slouch either) of 1890ish vintage. I has these "stripes" clearly visible and easily mistaken for scratches. The look I took included a 2X to 12X folding pocket glass made it clear that they are not scratches of cracks. A 30X pocket microscope was ver interesting. Along the "stripes I found several areas of both black and white inclusion; very narrow/thin bands of inclusion, but definitely inclusion of something not steel, things that would qualify for Chuck's dirty steel.

I'll look at a few more guns and see if I get similar findings. Photos --- mmmm, I dunnno, we will see. Most interesting!!

DDA

craigd
Following the patenting of the Bessemer process in the U.K. in 1856 which resulted in low cost conversion of pig iron into steel.Bessemer steel rapidly became the prime source for steel as used in gun barrels, locomotive rail, gun body actions etc.
The Bessemer process was licenced into the U.S.A.by the early 1860,s.
The steel used in both American and British gun body actions during this era would have been forged from billets of steel made by the Bessemer process. Prior to improvements to the Bessemer process the refining of the steel was not always perfect.This is the reason we some times see the forging lines in the action of both British and American guns made in the 1860-1900 time frame.

Craig,
Wrought iron is not a material that is typically compatible with forging as it can have a tendency to crack when hot forged. It was as close to pure iron as was available at the time (.10-.25%). I think what we're looking at with these actions is early Bessemer steel with contaminants or constituents that weren't homogenized.

Sometimes I take for granted the knowledge and scholarship that the members of this board can bring to bear on a technical topic. Thanks to all of you who contribute to such discussions as this one.