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Up Topic Welding Industry / Technical Discussions / 1930s Semi-steel, what is it?
- - By upsidedown Date 08-09-2007 04:02
Hello,

  Does anyone know what semi-steel is and how to weld it?  I am working on a Federal Dam (built in the 1930s) and the Bureau of Reclamation is requiring us to use E7018; but, since it mixes to the parent metal like oil to water, I suspect there is a better way. I know getting the BOR to change their ways is most likely impossible, but you never know.  Besides, those of us who are doing the welding would just like to know.
   The flood gates have been submerged for decades so I'm sure the metallurgical composition of the gates is only part of the problem.  Though sand blasted, they are still impregnated with who knows what.  Furthermore, it is impossible to weld over the slightest bit of old weld material.  As soon as an arc hits the mostly gouged out old weld, it blows out leaving a thumb sized hole leading to the void caused by poor fit-up.  It's truly a nightmare, the voids are full of rust and contamination so we want to leave some metal there to work with but the old welds are as sound as if they were done with a battery charger and painted coat hangers.  Any ideas?
Parent - - By darren (***) Date 08-09-2007 09:10
6010 5p+ for a couple of down hands and grind it off and then 7018.
ive used this on some very dirty contaminated metal and had success.
it might take more than a couple of times to clean things out. long arc it a little to burn stuff off.
darren
Parent - - By js55 (*****) Date 08-09-2007 13:31
I assume your semi steel is simply semi killed. In other words, incompletely deoxidized.
Parent - - By MDG Custom Weld (***) Date 08-09-2007 15:49
I had a similar problem (not with the base metal type, but the lack of proper molten flow) with members that were sand blasted.  It ended up that the problem was not with the base metal, or the filler.  It was the blasting media used (silica, or other "organic" media) that got entrapped in the porous base metal that inhibited the arc and molten metal transfer.  We sent a few samples of the same parts out and had them re-blasted with steel shot media, and they welded fine.  We have since standardized that any porous material that is to be blasted must be done with steel blast media.  Maybe no help to your specific problem, but it's something to consider.
MDG
Parent - By upsidedown Date 08-10-2007 03:11
  Good point. I'm not sure of the blast media but I will find out.  I have had problems welding when steel shot was used too, but it was on another dam gate made in the 1930s.  Same problem different dam; or, same dam problem for short.
Parent - - By upsidedown Date 08-10-2007 02:46
I do not know. The prints and other paperwork list the material as semi-steel.  Today I found some markings that say Carnigee, I think.
Parent - By ssbn727 (*****) Date 08-10-2007 03:46 Edited 08-10-2007 03:50
That's cast steel made in Carnegie, PA (Car-ne-gie, stretching the first & second syllable, then pronouncing the last one quickly - is the correct way to pronunciate the late Andrew Carnegie last name FYI :)

Just outside of Pittsburgh, PA... Very close to where I live nowadays... Most of those great mills of the thirties are torn down now but, a few like the US Steel (Now called USX) Edgar Thompson & the Mon Valley works are still around and of course, there's still the Union Electric steel mill in Carnegie, PA that's still producing, AK steel, Wheeling/Pitt steel in West Virginia just down the road about forty minutes from here... There are probably more around but off the top of my head I ca'nt remember... I know there's a few pipe mills on the south side making alot of stainless,one of them is an Italian firm that starts with an "M"...

I know there's more but, my memory the way it is lately, I'm lucky that I remember the ones I mentioned :)

Anywho, that's definitely US steel from the old Carnegie works, and more than likely a semi killed cast steel that when compared to the steel making technologies used today - were as Jeff mentioned, incompletely deoxidized but nonetheless, the best steel around in those days except for maybe some German steels.

That's all I can remember so - I'm done! Maybe "Brande" will chime in since he grew up here in these parts and know a heck of alot more than I could ever know about steelmaking history in the greater Pittsburgh region of South Western Pennsylvania. :)

Heck! I'm just a city boy from Manhattan turned semi-redneck "in the burgh" thanks to listening to bands like the "Poverty Neck Hillbillies" and other halfway decent country bands these days!!! That's right!!! This cityslicker has almost turned into a country boy :) :) :) The key word here is "Almost" :)

Let's hear it for my childhood favorite: "The Man in Black" - Johnny Cash!!!

Respectfully,
Henry
Parent - - By Joseph P. Kane (****) Date 08-09-2007 19:57 Edited 08-09-2007 22:28
Upsidedown

In many of the Depression Era dams the welding was done with Oxy-Acetylene gas torches.  I know that Linde #7 rod was used on some oif the penstock tubes.and on penstock tubes to valve bodies.  I have welding instructions similar to what would today would be called WPS's.  (I hope they are worth some money someday)  I suggest you look into welding repairs using OFW.  I saw instructions for 3/8 inch single pass open root welds made at 12 IPM!!!  Try that with your 2007 GMAW machine!!!
Parent - - By ssbn727 (*****) Date 08-09-2007 20:24
HI Joe!
Did you mean 2007 GMAW machine because, I do'nt think that the GMAW process was in existence around 1007 :) :) :)

Respectfully,
Henry
Parent - By Joseph P. Kane (****) Date 08-09-2007 22:29 Edited 08-09-2007 22:35
Henry

Thank you for the editorial comment.  That would have been some welding machine in 1007!!!!
Parent - By darren (***) Date 08-09-2007 20:29
hey js55 would what i suggested work on semi killed steel?

i realize its barbaric but has helped me many times.
darren
Parent - - By dbigkahunna (****) Date 08-09-2007 21:12
Using a 4 headed torch. When the inspector came by, the technique to see if the welder was getting penetration was to push down on the filler rod. If it did not go in, the welder was run off. Since the inspectors had not invented inspection tools, the weld had to be a nickel high and a quarter wide. When you see those OFG welds, take a nickel and a quarter and see how close they are! Them were the days of iron men.
BABRT's
Parent - By upsidedown Date 08-10-2007 03:02
I forgot to mention that these radial arm gates are so old they were rivited togeather when first built (I think they were made in the shadow of the Titanic).  The welding came some time later and as I said in my original post, they look like they were done with a battery charger and bare wire. 
Parent - By reddoggoose (**) Date 08-09-2007 20:27
I think js55 is on the right track. When I looked up welding semi-killed steels it mentioned that "blowouts" may occur during solidification. This sound similar to what you are seeing?
Parent - - By dbigkahunna (****) Date 08-09-2007 21:07
Semi-Steel was a marketing gimmick used up to the mid 1960's. All it is is cast iron. When inspecting tanks this is one thing to look for as they can bust and you will loose a tank of oil. As you have see, they are really hard to weld with stick (impossible). Even brazing them is a fools errand as the issue tends to be cracks on these things. Another thing you see on these, some are one holed instead of two holed. That is another give away when looking at these things. If you see a Darling Valve, look for the swastikas. I have seen a bunch of these made in the 1930's from Germany.
BABRT's
Parent - By js55 (*****) Date 08-09-2007 21:39
Well, we got semi steel explained. Interesting. Mid 60's was a little bit before my adult years. But then again, I knew there weren't no Mig welders in C.E. 1007.
As for semi killed steel, there's nothing unsual about welding semi killed. Most welders weld both on a regular basis without knowing the difference. The semi killed steel undergoes a process of deoxidation that is less thorough than fully killed. Duh. What this means from a welding standpoint is that you will end up with greater Si and Mn in the slag as opposed to contributing to mechncial properties, since they will readily bond to the additional oxygen available in the microstructure of the semi killed steel.  Some mechanicals will suffer.
In some ASTM specs you have to special order fully killed.
This sounds like a good discussion for Giovanni.
Parent - - By DaveBoyer (*****) Date 08-10-2007 01:32
Kahuna is right, semi steel is a form of cast iron, it is stronger than common grey iron. 20% to 70% scrap steel is added to the iron when melting. Carbon is seldom more than 3%.
Parent - - By reddoggoose (**) Date 08-10-2007 17:27
Is that what is referred to as pig iron?
Parent - By js55 (*****) Date 08-10-2007 18:48
Pig iron is a high carbon preliminary rough iron. The early molds for this stuff casued the ingots to somewhat resemble pigs. It is then used as charge for more refining steel making processes.
Parent - - By digger doug Date 08-10-2007 18:38
dbigkahunna,
     Just a little note, the swastika was used by the crane company of chicago
and their old catalog shows fittings with the swastika's on them.
Not in anyway connected to germany.
Parent - By billvanderhoof (****) Date 08-11-2007 04:04
Swastikas, often turning the other way but not always, appear as decorations, perhaps with some religious meaning, on Native American artifacts that can easily be dated to hundreds of years before the Nazis.  If any Native American speakers read this I would be interested to know the correct word and it's meaning.
Bill
Parent - By MBSims (****) Date 08-11-2007 02:35
I agree, "Semi-Steel" is a cast iron.  I ran into this material designation on a turbine runner for one of our ancient hydro plants.  I had discussed it with Dr. Charles Bates at the UAB Casting Research Center in Birmingham and he identified it as a grey cast iron.  We also cut a sample off the runner when it was pulled for metallography and chemical analysis and confirmed it.
Parent - By dbigkahunna (****) Date 08-11-2007 21:54
Another question. Are theses bell and spigot joints? If so, and it appears these welds were run with a electrode, the weld was made with a bare electrode ran DC straight. The electrodes were 5/16, yes that is right, diameter. In 1999 these electrodes were still available from Lincoln. I was on a Wyatt Tank repair project. The original files were still available at the location including the weld procedures. I wish I had copies of the job file as it was fascinating. The tank was basically a riveted tank, without the rivet holes and filet welds. All the pipe joints inside the tank were bell and spigot. Before the perfection of rod coatings, they did not know any better so they welded with bare electrodes. You will be surprised how strong the welds are. When you look through 653 you see information joint efficiency's, etc on lap welded tanks. \BABRt's    
Parent - By dbigkahunna (****) Date 08-13-2007 02:19
semisteel

A grade of cast iron of low carbon content; made by the addition of steel scrap to pig iron while molten.
Found definition
BABRT's.
Up Topic Welding Industry / Technical Discussions / 1930s Semi-steel, what is it?

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