American Welding Society Forum
I’m looking into welding ASTM A958 Grade SC 8620 Class 80/50 as an “auxiliary attachment”, to ASTM A500 Grade B round HSS. Auxiliary attachments are defined and addressed in the current D1.1 …
D1.1 defines these attachments …
*auxiliary attachments. Members or appurtenances attached to main stress-carrying members by welding. Such mem bers may or may not carry loads.
5.3.1 Engineer's Approval for Auxiliary Attachments. As an alternative to WPS qualification, unlisted materials for auxiliary attachments which fall within the chemical composition range of a steel listed in Table 5.3 may be used in a prequalified WPS when approved by the Engineer. The filler metal of Table 5.4 and minimum preheat shall be in conformance with 5.7, based upon the similar material strength and chemical composition.
These attachments have a published min. tensile property of 80 ksi, and a min. yield property of 50 ksi. The A500 B material has a published min. tensile property of 58 ksi and 42 ksi yield. However, the actual MTR for the A500B material indicates 73 ksi tensile and 56.4 ksi yield, which is much closer to matching the published T & Y of the A958 material (without knowing the actual A958 MTR properties, which will most assuredly exceed the published numbers.
My thoughts are to submit this information, along with a WPS (including preheat of the A958) to the EOR for possible approval of prequalified status on this unlisted A958 material.
Any thoughts are greatly appreciated.
5.3.1 Engineer’s Approval for Auxiliary Attachments. As an alternative to WPS qualification, unlisted materials
for auxiliary attachments which fall within the chemical composition range of a steel listed in Table 5.3 may be used in a
prequalified WPS when approved by the Engineer. The filler metal of Table 5.4 and minimum preheat shall be in
conformance with 5.7, based upon the similar material strength and chemical composition.
Matching tensiles and and yield are not mentioned.
An Engineer can certainly approve. But they would have to have some pretty deep SME or be stupid. One or the other.
Are the attachments fillet welded? That sort of PQR isn't a big time or expense.
How thick are the attachments? If they are 3/16" or less they could be qualifed via D1.3 as sheet to supporting structural member with not too much expense or time impact.
It has been my experience that T & Y properties are the deciding factor when I’ve submitted similar proposals to the EOR.
These are actually CastConneX cast steel connections that will be CJP welded to the ends of HSS round 8.625 x .375 A500 B tubes.
I know there has been some discussion about adding the A958 spec. to the approved base metal groupings, because “the the chemistry of cast steel is similar to typical rolled steel.” (Exploring the Need to Include Cast Carbon Steels in Welding Procedure Specifications,” Welding Journal, October 2015, pp. 56-58).
The parts are too thick for D1.3
I can report to you that the work to bring cast steels into the list of prequalified base metals is continuing. There have been quite a number of joint projects with universities, manufacturers and the AWS, and the results are presented to the TG on Prequalification a couple times a year. I have been there for each presentation and they are persuasive.
To this point there has been no balloting to include any of the cast steels to the prequalified base metal list.
So it will be up to your engineer to put his seal in play and accept your cast base metal as prequalified via chemistry, or to put his seal into play and sign off on a successful PQR. Those appear to be the options.
It seems to me we addressed this subject a short while ago.
Thank you Lawrence.
Al, I posted a related question a few weeks ago, but I wanted to look at the possibility of calling it an auxiliary attachment. I plan on submitting the MTR’s to the engineer and see what he thinks.
If I recollect, these are cast steel fittings welded to the ends of HSS members. Those are usually used as a diagonal brace or main tension or compression member. That hardly fits the definition of an auxiliary attachment.
Happy Memorial Day.
The answer is always no, unless you ask :)
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