doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Iron, Steel & Alloy Staining

Courtesy of Doug Miller
"Wrought iron when browned, leaves a distinctive pattern of longitudinal irregular shiny streaks presumably of iron silicate."

c. 1780 Wrought iron flintlock barrel



TAKE PICTURES KEN!

William Siemens set up the �Sample Steelworks� to develop the Siemens-Martin �Open Hearth� process in 1865, and his steel was in general industrial use by 1875. I've not been able to find any period composition analysis but very much suspect early Seimens steel was low alloy, low carbon; ?1002-1005 and very likely the steel component of Damascus.

P. Webley & Son began using Siemens steel barrels about 1880 and reported excellent results.
John Henry Walsh, The Modern Sportsman's Gun and Rifle: Including Game and Wildfowl Guns, Sporting and Match Rifles, and Revolvers, Volume 1, 1882
�Siemen�s Steel for Gun Barrels�
http://books.google.com/books?id=OLwUAAAAYAAJ&pg=PA445&vq
A 13 bore Siemens barrel did not bulge until 19 1/4 Dram Black Powder with a 1 1/4 oz. ball. Siemens then reported a tensile strength of 55,000 - 60,000. That would be similar to AISI 1010.

By one report pre-WWI Siemens may have been similar to AISI 1021 - 1034 Carbon Steels; The Sampling and Chemical Analysis of Iron and Steel, 1915
Oswald Bauer, Eugen Deiss, William Thomas Hall, p. 88.
http://books.google.com/books?id=03w6AAAAMAAJ&dq

Buturlin cited studies conducted at TOZ (Tula Arms Plant) likely immediately before WWI listing Russian Siemens-Martin tensile strength as 85,300 � 92,400 psi so it is clear that the composition was modified compared to the original process steel.

I am happy to provide test samples. I�ll PM you to share contact information.



I�ve seen the same �sparkle� in the wrought iron of a barrel tube that I etched with FC. It appears that the sparkle is near the center of the wrought strand, with the edges of the strand not showing this effect. Perhaps the edges are changed by being amalgamated with the steel through the forge welding. Below is a micrograph of an etched damascus barrel.



Below is a micrograph image of a broken section of damascus barrel tube. I literally bent the tube over and snapped it in two. The smooth material is the steel, with its much finer grain structure. The very coarse material is the wrought iron. The black stuff in the wrought iron is the silica. The �sparkle� is the iron grain structure. The sparkles in the broken tube, appear very nearly the same as the sparkles in the etched barrel tube. The material below the gaping split is the chemise.



I have some wrought iron anchor chain material, as well as some wagon tire wrought. The anchor chain appears to me, to be of fairly high silica content. I�ve not had a look at the wagon tire to see how it compares.

The silica strands in wrought are very directional. Below are micrographs of the anchor chain iron. The photo of the end of the iron bar displays small dots of silica. The side of the bar shows long strands. It may be best if I do some manipulations of the wrought material to provide multiple angles of the silica strands. I can twist and then flatten it.

It�s interesting to see in the photo of the end of the bar, all of the pieces that were forge welded together during the piling process of making the wrought iron.

It wouldn't be worth an additional micrograph, but I wonder if a section of wrought was heavily drawn like in a classic barrel if the look would start to change. In Doc Drew's barrel pictures that distinguish wrought iron from steel, the strand appearance of wrought seems to changed to a 'string of bb's' appearance. The slag/silica components seem to be reduced in overall percentage of the wrought, and well surrounded and distributed in the iron.

Great pictures Steve. I've always wondered if the extensive drawing and other working of damascus barrels was to minimize the effects of the inclusions and defects that the early smiths knew were in the raw starting materials. I look forward to seeing what Ken thinks of how it takes his finish, and thanks for the materials and forge time that you're sharing.

The silica would definitely be changed, once made into a barrel tube. Coming out of the reverberatory furnace, the silica is in globules within the iron. During piling and drawing out into bar stock, the globules become long strings. Each occurrence of drawing the bar out, lengthens and thins the strings of silica, as well as works some of the silica out of the iron. Piling, welding and drawing out of the wrought iron is continued until the bar stock retains the desired amount of silica content. There were many grades of wrought iron, each containing a certain amount of silica as was desired for the end use of the material.

After the wrought iron is used with steel to make a riband of damascus, the welding, drawing and twisting of the rods will have made innumerable changes to the shape and size of the silica strings. In looking at a micrograph of a damascus barrel sample, there is no way to know at what angle you are viewing the silica string inclusion. Is it from the side, at the end, or at some angle to the directionality of the string? The view from a single plane, doesn�t tell you much about the overall shape of the inclusion.

The extensive amount of drawing out and manipulating the damascus for barrels was much more about creating the desired damascus pattern, than it was to control the silica inclusions. I believe that the use of wrought iron, with its silica content, was to facilitate the forge welding process. As well as it made the damascus steel softer under the hammer and easier to shape into a barrel tube. I�m certain that they had a preferred silica content for the raw wrought iron material, specified to facilitate the welding and shaping work. But the end result of the silica�s condition in the finished product was very much left to chance.

I've mailed the test pieces of 1002 steel and wrought iron to Ken. Looking forward to seeing the results of the testing.

Daryl, I was confused when I first saw that. But now I believe I am simply looking at an editing error that probably occurred in moving from German to English.

Pete

Very good Steve. Remember that most of the forming took place in the rolling mills. By the time the barrel makers got the ribands, everything was set for them.

Pete

As always thank you Steve.

Sorry Daryl, I missed your post on p.1. Here's another image and I believe only two metals are illustrated

Just on observation, it seems to me that the thing in common with later damascus that was elevated to 'art' was two things. First, the material was drawn to much thinner cross sections, and second, twisting was much tighter and in universal use compared to earlier laminated barrels.

The pictures of the wrought iron that Steve showed had the easily visible classic stringy appearance. The historic damascus barrels do not tend to show that stringing in the wrought, possible because of the amount that it was worked and or drawn out. Steve rightfully pointed out that the damascus images are just two dimensional slices of an unknown area. What can generally be discerned is that some of the images slice through a 'star', which might imply that all angles of the 'grain' of the steel/wrought are being shown, from end grain to side view.

Anyway, for some reason or another the classic stringy appearance of the wrought is significant reduced or generally missing. All I suspected is that the makers figured out they could make stronger barrels by minimizing the likelihood that an inclusion or other defect in the starting material would end up compromising a barrel.

No doubt the art of barrel making was important, but there could've been practical implications....maybe. Only thoughts is all, I look forward to anything Ken might share about Steve's test piece.