Fasteners that meet ASME SA-574 specifications

[exquadrum]

My company is building a pressure vessel and I need to find a source for socket head cap screws that meet SA-574 specs, or ASTM B637 GR2 specs.

Suggestions for sources would be greatly appreciated.

Thanks!

Rick Howard
Exquadrum, Inc

 

[arto]

Why, Unbrako's of course:

http://www.spstech.com/unbrako/htm/unbrako.html

 

[exquadrum]

Thanks!

I actually found Unbrako, and have their engineering guide.

The only reference to material spec in the guide is "A574" which is an ASTM specification.

It is my understanding (my boss speaking) that A574 is not "good enough." It must be SA-574 to meet the ASME spec for a pressure vessel.

Pardon my ignorance on this subject. I am perfectly willing to be "enlightened!"

Rick

 

[deanc]

See the Forward in any Code Book. Also see UG-10.

Look up this spec in SecII Part A. The ASTM spec for bolts should be OK.

 

[metengr]

According to the 2004 Edition of the ASME B&PV Code, Section II, Introduction, ASTM A-574 is identical to SA-574 for editions 1982-1997a with the following clarifications;

1.Except that Table 1 on chemical requirements has been deleted and Supplementary requirement S1 is now mandatory.

2. Paragraphs 6.1 and 6.2 have been revised to refer to Table S.1 and 6.3 has been deleted. The yield strength value in 7.3 has been editorially corrected.

 

[unclesyd]

exquadrun,
You have a point that is becoming quite common and is a point of contention that the lawyers are going to love.
This is one of the problems I been associated with in my working with a fastener company. At one time you could merely convert an ASTM 574 to SA 574 and use their physicals if the material was an acceptable material by the ASME Code. It is extremely hard for a fastener supplier to supply a fastener to an ASME Specification. The primary reason is that materials for fasteners are supplied, tested, and certified under ASTM specifications and made into fasteners which are duly certified to ASTM specifications. You would be hard pressed to find a fastener manufacturer or distributer that has the ASME Section II.

metengr; deanc
How would one go about certifying a fastener to ASME when all you can purchase is ASTM certified material. Would you use a stamp of some sort or partial data report. Again I don't think that there are many fastener distributers that have the personnel that can read and completely understand an MTR and much less cross match it to another specification. Why is the cutoff date 1997, what’s is the difference. I just call two of the largest distributers/importer of fasteners in the US and none were aware of a cut off. One importer has over a million pounds of fasteners en route and all are to ASTM specification The outfit that I’m associated with has 3 containers (120,000) lbs of ASTM A193 B7 and B16 stud stock along with ASTM A194 nuts sitting in the warehouse. I have not found any supplier with an ASTM Section II.

You haven’t even thought about the comingling of fasteners as you have now with everyone trying to be top dog in the specification business. Even though the supply train is shortening it’s still 9-12 months on some ASTM items.

 

[metengr]

unclesyd;
I reviewed the ASME SA-574 Specification for Alloy Steel Socket-Head Cap Screws. Under ordering information in the Specification, the following is stated;

4.1.1 ASTM Designation and Year of issue
4.1.2 Quantities
4.1.3 Size and length

Optional requirements for Orders include inspection at point of manufacture, certified test reports, additional testing, packaging, supplementary requirements and special requirements.

My understanding is that a supplier that can manufacture the alloy steel socket head cap screws under ASTM A-574 can issue a certificate of conformance indicating compliance with ASME SA-574, and any supplementary requirements listed on the purchasers PO.

The ASTM and ASME Specifications are nearly identical other than what was stated above.

Why does Section II limit the approved ASTM edition to 1997a? Most likely, Section II has not yet caught up with the later editions of this Specification.

 

[deanc]

Not really that big a problem. See page xxvi,second column in the Forward of SecVIII. Then see UG-93(a)(2).

The Stamp Holder can do a "work around" and still meet all the requirements. This is not a short cut,only use of all the Code rules.

 

[exquadrum]

Thanks to all that have replied!

I have orderd myself a copy of ASME Section VIII Pressure Vessels so that I can read all of this for myself.

Again, thanks to all. I have the information that I was looking for!

Rick
Exquadrum, Inc

 

[unclesyd]

I think I’ll go back to the purchasing end of the fastener business.

I realize that there maybe ways and means to overcome some of the difficulties in getting a particular fastener if you are the consumer but a seller doesn’t have that option if they are going to supply a certifiable quality fastener. As a distributer we cannot and will not restamp anything other the what the traveler states. It’s hard enough just keeping everything straight with just one set of standards and if you add another one you have chaos.

Our problem as a supplier comes when the manufacturer can't certify that the materials meet the ASME specification, usually for the simple reason that they don't have a $500 copy of ASME Section II on hand. And if you stamp the certificate as meeting a standard/specification without a copy of the standard on hand and having someone familiar with same you are asking for trouble. What is happening is that some mid level suppliers are evidently just stamping an MTR as complying to the ASME specification with the ASTM fastener.

I know this is probably the case as we got an RFQ for (160) 2.5" x 18.5 first to first with 1/8" chamfer ASME B16 material. We couldn’t supply the studs as requested (ASME) and so replied. That same day a competitor call and asked did we have 2.5" ASTM B16 stock, yes, and was immediately faxed an order from them for the 160 studs that we had received the RFQ. I reckon everyone was happy.

ASTM is bad enough as I posted the question about ASTM A193 no longer being in the current Fastener Handbook. This was the result of an audit conducted by a large power company and their contractor. They callout ASTM A193 B7 and B16 on the majority of their purchase orders and for this reason asked to see our current copy of the Standard. We didn’t have it in the 2005 Handbook and could only refer to the 1995. In reality what would we do with it if we had a current copy other than display it. The only routine testing we do is hardness test for certain customers to meet the purchase order conditions.

I'm off the box now.

 

[deanc]

unclesyd:

Don't be sad---understand the frustration and by the way you have some great posts. Yes indeed things could be better. However,I do not believe there is any intent of the Code to prevent construction with unworkable rules.

Over the years I have learned more about bolts then I ever wanted to and things continue to change.

I would advise:
1.Read the entire section/paragraph of the Code rule.
2.Remeber the construction Code overules the support Code.
3.Talk to your AIA.
4.If it was easy,everyone would do it.

Have fun.