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  1. #1
    Join Date
    Oct 2010
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    Victoria, Australia
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    Default Can wrought iron be arc welded?

    Hi,
    I've googled for info on this but can't get a definitive answer.

    My house was built in the 1930's and it has a pair of original (art deco style) solid wrought iron gates in the driveway. One of the gates is broken and I am wondering if a suitable repair can be done by arc welding the broken pieces together. It is made of heavy 1/2" square solid wrought iron bar and I think it would be genuine wrought iron, not the stuff they pass off as wrought iron in these modern times. The gates are rectangular in shape and on one of them the wrought iron has a broken cleanly in the top corner, just above the hinge, on the side nearest to the gate post.

    I am a competent arc welder but have not done any work on cast iron or wrought iron and therefore don't know what type of rods and what welding technique would be required to make a strong enough repair of the gate.

    Can any experienced welders on this forum offer me any advice on this matter, please?

    Thanks,
    redx.

  2. #2
    Join Date
    Jan 2004
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    Mackay North Qld
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    6,446

    Default

    Quote Originally Posted by redx View Post
    Hi,
    I've googled for info on this but can't get a definitive answer.

    My house was built in the 1930's .
    Can any experienced welders on this forum offer me any advice on this matter, please?
    .
    Hi RedX
    True wrought iron should have a carbon content in a range of 0.03 to 0.05 % making it around the same carbon content of what you know as mild steel or low carbon steel.

    That makes it weldable but like most things, it is not so straightforward.

    Welding procedure
    Bear in mind that due to the manufacturing methods and the absence of national Standards (at the time of manufacture ) the mechanical properties of wrought iron may vary widely even in two similar samples.

    Hence a degree of variation may be encountered if a weld repair is attempted and satisfactory results from one sample may not carry over to a second.

    The procedure for welding wrought iron is, in very similar, but not the same to that used for welding structural steel.
    * Avoid excessive penetration into the parent plate. This may cause slag inclusions in the weld metal.
    * When stick welding, use small-diameter electrodes, which need low current. These should be rutile based only. Higher tensile electrodes will cause cracking problems.Anybody offering advice to use L/Hyd electrodes simply do not understand the problems they can cause.
    *Techniques to minimise shrinkage due to welding should also be adopted.
    These may include the use of stringer beads, buttering of the wrought iron prior to completing the structural weld, and keeping the weld preparation to a minimum.
    * Minimise heat build-up back-stepping and cooling-out between runs.

    Lastly be really careful when welding these old gates.The era they were made in means it is likely that lead-based paints were employed. Sandblast them if you can.

    If there is any great weight or stress on these gates, forget it.They will hold their own weight but would not recommend beyond that.

    Good luck

    Grahame

  3. #3
    Join Date
    Oct 2010
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    Victoria, Australia
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    Default

    Hi Grahame,

    I appreciate you giving me that information and good advice. Thanks very much.

    Merry xmas,
    redx

  4. #4
    Join Date
    Dec 2013
    Location
    San Antonio, Texas, USA
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    Default

    You may need a high-nickel filler metal (rod or wire) as well. These are expensive, ask your welding supplier. If the structure being repaired is complex you should also preheat to minimize cracking due to thermal stress.
    The stone age didn't end because the cavemen ran out of stones...

  5. #5
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    Jan 2004
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    Mackay North Qld
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    Default

    Rob,
    I am not seeking to offend but I believe you have confused wrought iron for cast iron.

    Nickel-based electrodes are suitable when the carbon content is around 2 to 3% which is typical for cast iron. Wrought iron at 100 times LESS carbon % and should not be confused with cast iron.
    Preheat is for cast iron to overcome the cooling differential which welding creates. In the wrought iron there is so little carbon it does not matter. We are attempting to AVOID shrinkage, so heat input needs to be minimised.

    The following was found at the TWI-Uk welding institute and is a cut & paste

    < This is possible using manual metal arc or shielded metal arc (MMA or SMAW)) welding with rutile-coated electrodes complying with BS EN 499 E38 X R XX or AWS E6013, or by MAG (GMAW) welding with a filler wire complying with BS EN440: G2Si or G3Si, or AWS ER 70S-2.

    Because of the high oxygen content of wrought iron, the MAG (GMAW) welding filler wires recommended contain aluminum as well as silicon and manganese as de-oxidizers, and there is some evidence that this gives sounder welds than other filler wires. However, results also depend on the quality of the wrought iron being welded, and weld tests using samples of the actual iron to be welded are recommended.

    Rutile electrodes are chosen for MMA (SMAW) welding because of their low penetration and their ease of use for positional welding, and the lower tensile properties reduce the stress on the heat affected zone (HAZ).>

    You have to remember that during welding the wrought iron is greasy ( not the right word here, but indicates what I am trying to get at ).The slag melts way below the temperature that the base metal (the wrought iron) - does.

    TWI does testing/development on behalf of companies who undertake to weld wrought iron in the UK. One can rely on their findings.

    Grahame

  6. #6
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    Oct 2010
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    Victoria, Australia
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    Default

    Quote Originally Posted by Grahame Collins View Post
    Rob,
    I am not seeking to offend but I believe you have confused wrought iron for cast iron.....
    Well Grahame, you are probably right.

    Here in Australia gates like mine have always been known as "wrought iron gates". There is also balustrading and fences made of the same stuff and always known as "wrought iron fences" or "wrought iron balustrades". Whether they are actually wrought iron or cast iron I don't know, but always just naturally assumed them to be wrought iron. I read somewhere last night that true wrought iron, when it breaks, peels apart like the pages of a book. If this is the case then what I have is cast iron ( as you suggest) because the break has snapped cleanly in two.

    Thanks for setting me straight.

  7. #7
    Join Date
    Oct 2008
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    Cairns, Q
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    Default

    Hi redx,

    Could I suggest that, if your gates were built in the 1930s the chances are that, while they could possibly be wrought iron, they are more likely to be mild steel. The ready availability of true wrought iron fell off very quickly after the 1890s. You mention a clean break in one of the gates. Typically this does not happen with wrought iron; a break in wrought iron usually has a fibrous appearance and looks more like this:
    https://www.realwroughtiron.com/abou...-wrought-iron/

    I haven't tried this, but a spark test has been suggested as a fairly reliable way to differentiate wrought iron from mild steel. The comparison is shown here:
    https://www.youtube.com/watch?v=Yq2FwCn3qFA


    I have machined bits of wrought iron in the past, and the layers of slag inclusions in the metal were quite visible on the freshly machined surface. The above article also suggests a test which will show this feature.

    Frank.








  8. #8
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    Jan 2004
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    Mackay North Qld
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    Default

    redx

    Just to be clear,
    I was referring to this post by Rob Steeper

    Quote Originally Posted by rob streeper View Post
    You may need a high-nickel filler metal (rod or wire) as well. These are expensive, ask your welding supplier. If the structure being repaired is complex you should also preheat to minimize cracking due to thermal stress.
    Sorry rob ,I jumped in a bit quick there.

    Franco is entirely correct in saying that its easy enough to ID the material the gates are made from. The term wrought iron in the nineteen sixties generally referred to the application.

    In real terms the handrails and fence panels brought in for repair, the type, as referred to by the general public as wrought iron could be:
    Wrought iron proper
    Cast iron
    Fabricated steel

    Under the ubiquitous coat of dark green paint which they all seemed to be painted with, the wrought iron and the cast iron required an ID. The shop I worked as an apprentice, specialised in Cast iron welding. A touch with the 7" angle grinder ID'd them quickly.

    Sorry guys, it's just me being pedantic again ( bloody school teachers) Say wrought iron and I am off on that track and not considering other possibilities.

    Hopefully redx,s gate is of steel and an easy repair is possible.

    Grahame

  9. #9
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    Oct 2010
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    Victoria, Australia
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    Default

    Thanks Rob, Frank and Grahame,

    I did Frank's Youtube 4" grinder test on my gates and the sparks they produce are definitely less active and less in number compared to the sparks from some mild steel that I have. The colour is a lighter shade of orange as well.

    A couple of the uprights on both gates have been bent at some point in their life, where someone has backed their car into them probably. If they were cast iron I would expect them to snap instead of bending as they have, so going by this and going by the spark test I'm inclined to think the gates are wrought iron after all. I'll have a shot at welding them on the weekend to see what happens.

    Thanks very much for your replies. I appreciate the help and information you all have given me.

    redx

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