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I am specifying a product made in Australia, which is made of "Grade 520 Steel." The manufacturer of the product lists a minimum yield stress of 520 N/mm² (75,400 psi) and a minimum ultimate stress of 650 N/mm² (94,300 psi) with a minimum elongation of 20% and Young's modulus of 205 kN/mm² (29,700 ksi.) They describe the steel as "A fine grain micro alloyed carbon steel which is fully weldable." The raw steel form should be solid round bar.

My problem is that the plan checker wants a reference to a normative documents (ISO, EN, ASTM spec, etc.) for the material grade. I cannot find who (if anyone) defines this grade of steel. What is the standard organization and standard number that would govern this material?

I have, of course contacted the manufacturer, but what's above is all that they've been able to tell me so far. The only material specification '520' I've been able to find is a withdrawn ASTM tube spec. This component is significantly over-designed, so I'm not concerned with the actual properties, just finding the appropriate document. There are other products available made with ASTM materials, but for visual reasons we'd prefer the Australian product.

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    $\begingroup$ It seems like the manufacturer is lazy. How do they know that they are getting the correct material? or is it a special material just for them? $\endgroup$ – hazzey Feb 28 '15 at 20:52
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    $\begingroup$ I hope my answer is useful for you to do some further research. The material sounds impressive as the properties are quite high for both strength and elongation. I'm interested to find out the ultimate answer myself now. Hopefully the vendor knows. $\endgroup$ – wwarriner Feb 28 '15 at 21:02
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    $\begingroup$ Finding a standard which specifies a 520 grade steel doesn't mean that the manufacturer's product will conform to it. Even if you can find a standard, it'll mean nothing unless the manufacturer can provide certification from an approved testing house which shows they meet it. So I'm afraid your only course is to keep on at the manufacturer until they either give you full details or admit that they have no certification (in which case you find a new manufacturer!). $\endgroup$ – AndyT Mar 2 '15 at 13:02
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    $\begingroup$ @AndyT Understood. When (if) we purchase the product, we'll get a certificate of conformance or MTR as we do with all steel components. I was just hoping that while I wait on the vendor, I could make a high-confidence guess to show for the building department. Of course, if that was not what the manufacturer actually provided, we would correct it in our next submittal. I'm giving the vendor a couple more days to figure it out, and if they can't we'll probably have to switch to the american product. $\endgroup$ – Ethan48 Mar 2 '15 at 13:39
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    $\begingroup$ I finally got clarification on the material. It's a European grade according to EN 10267. I haven't purchased the spec myself yet, but it looks like it's specifically for microalloyed cold worked steel, not just an umbrella standard. $\endgroup$ – Ethan48 Mar 3 '15 at 16:46
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I saw some material for tension rods that match the material properties that you gave, but these places do not list the steel used. It might be proprietary:

A third manufacturer Macalloy, has a similar component that also doesn't list a material specification, but it does have an independent certification of its material properties. This leads me to believe that this is a custom steel that is only guaranteed by its given properties and the agreements between the company and the foundry.

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  • $\begingroup$ I hadn't considered that it could be a custom steel. If that's the case, their engineering department should have their own testing data. I'll try asking the question this way. $\endgroup$ – Ethan48 Mar 1 '15 at 20:59
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ASTM A615 appears to standardize rebar using that grading designation: i.e. Grade 520 [MPa] (or Grade 75 [ksi]), but only provides testing to ensure that a particular material is at least some strength. The test does not specify composition, only that the material is plain carbon-steel.

BSEN10149 is a British standard grading for steel alloys evidently, and some grades together with mechanical properties are noted on a commercial site, though none of the grades meet the properties you are looking for.

The American Society for Metals has a useful article on HSLA steel grades and associated ASTM standards, but none appear to be for bar material with the required yield strength, though they may be relevant if you intend to do your own testing and verification.

The Society of Automotive Engineers has an article on a grade 980X which according to [Wikipedia] has the required strength but not elongation at failure, and is not in bar form. There is also no associated testing standard that I can see. There may be one in the article but I do not have access.

It is possible this alloy has no current standard, in which case it is highly recommended you verify the properties of the alloy for yourself. Vendor data is often fudged optimistically. Materials of a given category, such as microalloyed steels, always trade off strength for ductility, and the alloy you describe is above the tradeoff curve for all of the microalloyed steels I've seen in my brief search for this answer. That doesn't mean such an alloy doesn't exist, but it would make me cautious. Either the alloy is a new development that is specially made by this vendor, or they are erring optimistically in their marketing. In either case you should consider verifying the properties, prior to putting the materials in service, using the closest applicable testing standard available.

Edit: this answer is attempting to give the OP starting points. Unfortunately I don't have a single answer. Perhaps if the OP obtains their own answer from the vendor at some later time, they could post and accept it.

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  • $\begingroup$ Thanks! Yeah, there are certainly lots of standards for similar steels, but I'm hoping to find the one that directly covers this material. I don't know if we have any users who work in Australia though. I think you're totally right that the next best option would be to do our own testing if the vendor doesn't come through. If I get a definitive answer, I'll definitely let everyone know. $\endgroup$ – Ethan48 Mar 1 '15 at 0:29

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