Weldability test for early to mid-1920's steel 1

[PEinc]

thread725-167138

unclesyd,

In the referenced thread, you stated, "A quick test to see if it is readily weldable is to make a one side fillet weld,7018 electrode, a 1/4" 2"x2" tab in an inconspicuous place and try to forcibly remove it.
Try first in the hard direction, hitting one time on the weld side. Then hit it from the easy side. It shouldn't break out the hard way. The weld should fail hitting from the easy side."

This sounds like the same test recommended by AISC. However, AISC does not give a very good explanation of the test. Can you please provide a little more detail for this test. Such as, how hard is hard enough for hitting the plate? Is it better to use E70 or E60 electrode? Hard direction is downward? Easy direction is upward? Please explain why a good weld should easily break when hit from the easy side. Is there anything special to look for when the weld has failed when hit on the hard side?

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[gtaw]

The test described is very subjective.

Another test that can be used is to obtain a small sample of the steel to be welded and have it analyzed to determine the chemistry of the steel. The following elements should be included in the report and considered before welding is contemplated:
Carbon: <0.3%
Sulfur: <0.04%
Phosphorous: <0.04%

Once you have determined your actual chemistry does not exceed the limitations noted, you can plug the actual chemistry into a carbon equivalency formula to determine the carbon equivalency. There are several equations that can be used. Each equation has its own guidelines and recommendations. I suggest using the method described in AWS D1.1-2006 (or later) in Annex I.


Best regards - Al

 

[PEinc]

Thank you, but I don't think they will let me cut a sample from the existing 5 story column of this historic building.

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[metengr]

Why not remove a 1/2" round plug sample from the original column at the location where a new column will be joined by welding? A hole saw is ideal and would allow for a full chemical analysis.

 

[unclesyd]

I not against any of the above suggestions but I you can't lay a bead on the base metal the tests above are mute.
I used the welded tab many times and it hasn't let met down yet. The test is not anymore suggestive than the chemical test proposed. If you actually weld on the subject steel you take out more variables, one in particular is Silicon Stringers.
As stated make the weld on one side and allow to cool. It should bend toward the weld without the bead tearing out from the base metal. If you night want to weld the second tab and try to bend it the hard way, One other test if there is any doubt is the Navy test which is accomplished by welding a 1 1/2" circle spiraling inward, leaving a 1/2" hole in the middle.

Do you see any welding on the column?

 

[PEinc]

No welding is seen. The column is made of 2 flange plates, one web plate and 4 angles, all riveted together around 1924. Eventually, the bottom of the column gets cut off and a new base plate is welded to the column. I am involved with picking up the column so that the contractor can remove the footing and build a deep foundation wall under the column. I asked the CM to ask the project structural engineer if anyone had determined the weldability of the steel. I got no response. YET! So far, it seems that the project engineer has just assumed that the steel is weldable.

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[Duwe6]

PEinc, please do not ASSume that that steel is actually weldable. It may not be, especially if it has a high sulfer content -- thus the need for a chemical analysis. A high carbon content can be worked around by using a high 250-350°F continous preheat and 100% E-7018 rods.

The 'gold standard' weldability test is to remoive a paperback-sized section. Split the section longways, using a saw -- 'cold-cutting' of the split only. Weld the pieces back togather, using no [ambient] preheat and a less-than 120°F interpass temp. Perform Face and Root Bends per AWS D1.1 or ASME Sect IX -- both are the same. If the bends pass, you have very weldable steel.

If not, use a higher preheat on the next test, and pray a lot.

 

[Guest102023]

You need to determine the carbon equivalent using the IIW formula. Two options for testing:

(1) Portable spark tester - expensive but almost zero damage.
(2) Remove and collect scrapings using a clean carbide burr. This is standard practice on buried pipelines. It can be done leaving not more than 0.020" removal.

You might be surprised at the quality of the steel. I once had to repair a 1913 vintage steel on a hydro turbine and it was low carbon and quite weldable.

 

[Guest102023]

p.s., on a heavy section of that vintage there may be a significant decarburized layer, so any method would need to allow for that.

 

[PEinc]

Duwe6, it appears to me that the only one "assuming" the steel is weldable is the project's SE. I will not be allowed to remove a paperback-sized piece of the column for analysis, but thank you for the response. I'll do some research on your suggestions. The project SE indicated (and then "un-indicated") that this column is supporting 425,000 pounds. My load estimate is less than 350,000 pounds. I'm using the larger load. I can't afford to drop the city's art museum.

brimstoner, I'm not a welding expert so I'll have to look into your two options also. Thank you.

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[unclesyd]

If all you are going to weld is a base plate and with you specified loading I would that there is no shear loading. I would get to the end where the base plate is going to be attached and try welding small tabs on the ends of the column components. If it is not weldable there should be no problem clearing the affected area.

Be real careful when clean the column. I would bet that it has a red lead primer. When you try to weld get the area as clean as possible before attempting to weld.

 

[PEinc]

unclesyd, the base plate is the least of my worries. I am picking up the old column so that the contractor can remove its foundation completely, cut off the bottom of the column, excavate 25' deep in rock, build a new tunnel, and then reset the old column on a new base plate that the project SE designed and wants welded to the bottom of the column. I need to support 425 kips with micropiles and, hopefully, a welded connection. The micropiles, steel cap beams, and jacking beams need to be located far enough away from the column to clear the existing pyramid-shaped footing and the new tunnel wall.

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[unclesyd]

Again I may be missing something.

Will all the welding required be on the base plate to column connection?

 

[PEinc]

I do not know how much other welding is required for the existing steel on this project. I am involved only with temporarily supporting this one column. The base plate is not in my scope of work. There is much more work involved in converting this basement area into useable museum space.

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[PEinc]

FYI, here's the latest:

My client hired a company to come in and analyze the composition of the steel in the 1923-ish riveted column. The company did a Positive Material Identification (PMI) Test. According to the testing company, "The material has suitable alloying and iron elements to be categorized as a weldable material..."

The analysis-by-weight showed:
ZN - 0.01% MN - 0.37%
FE - 98.48% ZR - 0.01%
PD - 0.03% CU - 0.32%
NI - 0.18% CR - 0.05%
TI - 0.49% AG - 0.04%

Their recommendation is to use E6010 rod for pitted and dirty areas where the base material cannot be completely prepped/cleaned and E7018 rod where surface preparation can bring the base material to an "as new" condition. The company will be on site to inspect the welding when the work is being performed.

Thank you for all of your comments.

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[metengr]

The problem with the PMI analysis results above is it only types the material. There is no carbon content, phosphorus or sulfur contents reported, which would have a direct impact on weldability of the steel. Oh well....

 

[Duwe6]

And it takes very little sulfur to make it unweldable. I strongly recommend that you use the 'Spark/Plasma Test' PMI method, or send in some metal shavings for Mass Spec analysis. I agree with Metengr that it appears that your PMI was done using XRF -- x-ray fluorescence, thus did not test for C, P, Su, or any other light element.

In short, I would not stand anywhere near that column when it was cut without ANYTHING definitive for weldability. XRF is good for sorting 304 and 316 stainlesses, Hasteloy, etc. and determining the chrome content of carbon steel. It tells you nothing about the weldability of carbon steel.

 

[Guest102023]

metengr,

I have given up trying to disabuse owners and inspection techs (and a few inspection engineers!) of the notion that PMI provides a chemical composition. People see two decimal places on a sophisticated looking display, believe them and then report them.

'Oh well' is right ...

 

[PEinc]

Thank you both. I will pursue this farther.

http://www.PeirceEngineering.com

 

[PEinc]

FYI, I just got the results back from testing a steel sample using 86-SCA-0, Rev. 11, Direct Reading Atom Emissions Spectroscopy.

Al = 0.011% B = 0.0004% C = 0.20% Cr = 0.008% Cu = 0.016%
Mn = 0.42% Mo = 0.012% Ni = 0.031% P = 0.006% S = 0.021%
Si = 0.007% V = 0.001%

CE = 0.2785 = C + (Mn+Si)/6 + (Cr+Mo+V)/5 + (Cu+Ni)/15

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