steel a36 or 43a

Discussion in 'Materials' started by alanrockwood, Mar 29, 2010.

  1. alanrockwood
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    alanrockwood Senior Member

    What's the difference between a36 steel and 43a steel, and can they be used interchangeably?

    Thanks.

    Alan
     
  2. Angélique
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    Angélique aka Angel (only by name)

    A36 steel is a standard steel alloy without advanced alloying which is a common structural steel used in the USA.

    http://en.wikipedia.org/wiki/A36_steel


    43A steel (UK-BS4360) = ~ A570Gr40 (USA-ASTM) = ~ 1018 (USA-SAE) = ~ 14-13-12E (Sweeden-SIS) = ~ S275 (Europe-EN10025)

    http://www.steelstrip.co.uk/international_equivalents.htm

    http://www.islandsteeluk.com/3Chart.html

    http://www.gunduzlermetal.com/norm_euro.html

    Don't know the exact specs of A36, so can't say.


    Good luck!

    Angel


    PS

    A36 Mild (low-carbon) Steel (USA-ASTM)

    http://www.onlinemetals.com/alloycat.cfm?alloy=A36

    Strength only in psi here so it has to be converted before it can compared, but chemistry is different from 43A.
     
  3. alanrockwood
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    alanrockwood Senior Member

    Thanks for the interesting reply and for the link.

    One of the links (http://www.islandsteeluk.com/3Chart.html) gave a minimum yield strength of 245 for type 43a steel, which I think would be Newtons per square mm. That works out to be 35,500 pounds per square inch, almost exactly the same specification as for a36.

    I found some other charts for 43a that listed the minimum yield strength to be anywhere from 230 to 275 Newtons per square mm, so it's kind of hard to pin that number down exactly. In any case, it sounds like 43a is roughly comparable to a36, at least as far as minimum yield strength is concerned.
     
  4. Angélique
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    Angélique aka Angel (only by name)

    If roughly comparable is good enough depends on your application.

    The differences in chemistry can make them react differently in extreme conditions like for example in extreme cold or extreme hot circumstances.

    Here for example the requirements to S275 in a fire (S275 = ~ 43A).

    ‘‘ Behaviour of BS EN 10025 grade S275 steel

    A modern grade S275 hot rolled structural steel section, subjected to fire conditions which raises its temperature above 600 ºC, may suffer some deterioration in residual properties on cooling. In no situation however, whatever the fire temperature, will the room temperature yield stress or the tensile strength will fall further than 10% below their original values. Thus, where it can be safely concluded that the steel members will be utilised to less than 90% of their maximum load bearing capacity or that any loss in strength will not bring the properties below the guaranteed minimum, replacement should not be considered necessary providing the member satisfies all other engineering requirements (eg straightness).’’

    Don't know about the requirements to A36 in these conditions so can't say it's comparable, or even roughly comparable, to 43A in that kind of circumstances.

    What do you want to build with it and why do you want to interchange A36 and 43A?

    Good luck!

    Angel
     
  5. alanrockwood
    Joined: Jun 2009
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    alanrockwood Senior Member

    I would be interested in building with steel. Type 36a is the most common type of structural steel in the USA and is available anywhere in the USA.

    I believe type 43a steel is used in the UK for many of the same applications as type 36a in the USA. However, in the USA I am pretty sure it would be a special order item and there therefore more expensive. Consequently, it would be good to know if a36 steel could be substituted for 43a steel if a boat plan called for 43a.
     

  6. Angélique
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    Angélique aka Angel (only by name)

    Seems to be no problem to me for your application, but I don't know all the specs and I'm no expert.

    Maybe one will show up here who can give you security on this. And you can always ask a supplier where you can buy both.

    Good luck!
    Angel

    PS

    From post #2: - ‘‘ 43A steel (UK-BS4360) = ~ A570Gr40 (USA-ASTM) = ~ 1018 (USA-SAE) ’’

    A570Gr40 (ASTM) and 1018 (SAE), how about the USA availability and price of these two USA substitutes for UK's 43A (BS4360) ?
     
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