Can forged bar be used to make a forged valve?
Can forged bar be used to make a forged valve?
(OP)
A section of forged bar per ASTM A350 LF2 is used to make a valve body. I was told by a forging supplier that the body could not be claimed to be a forging. OK, but then if the valve body is marked "A350 LF2", would that not imply it was made from a forging, since A350 is by nature a forging specification? Please see thread177-142661 on this subject.





RE: Can forged bar be used to make a forged valve?
RE: Can forged bar be used to make a forged valve?
I'm looking for some assurance that we will not be challenged when we claim the body is forged when it is made from material sliced from a forged bar. This is particularly disturbing, as per ASTM A 788-06 under para 3.2.1.2 "Discussion — Because of differences in manufacture, hot-rolled, or hot-rolled and cold-finished bars (semi-finished or finished), billets, or blooms are not considered to be forgings." Does the specification intend that the material sliced from forged bar be re-forged in order for the body to be made from a "forging" in compliance with A 350?
RE: Can forged bar be used to make a forged valve?
RE: Can forged bar be used to make a forged valve?
The manufacturer's that I've used for these valves are always very clear though to point out that the valves have been manufacturer from Barstock, and I would make sure that you are clear to your client as well.
Barstock is a great way to get valves in exotic alloys fast!
Andy
RE: Can forged bar be used to make a forged valve?
No (unless you forge it afterwards), it is a machined valve. Selling it as a forging is not only unprofessional, it is criminal.
You just happen to be using forged billet as barstock.
RE: Can forged bar be used to make a forged valve?
RE: Can forged bar be used to make a forged valve?
The valve is only legal for sale as a non-forged item. Using "A105 BAR" on it is playing with semantics and unethical.
Cheers,
Ken
RE: Can forged bar be used to make a forged valve?
RE: Can forged bar be used to make a forged valve?
RE: Can forged bar be used to make a forged valve?
As recommended by earlier posts, it is critical to make all material requirements explicit in the valve specification. Which leads leads me to conclude that the answer to my original question is, in a word, no.
RE: Can forged bar be used to make a forged valve?
Machining from bar stocks provides a quick and effective means to produce valves especially in difficult to cast alloys.
RE: Can forged bar be used to make a forged valve?
ASTM A 350 LF2 is listed in ASME B16.34 Table 1 as supplied in two product forms - forging and bar. The key words are "product form" in this Standard. A forging is a product form, and bar is a product form that can be machined into a final product form, but it is NOT a forging product form.
At this point, one has to go back and review the specific material specification, in this case it is ASTM/ASME A/SA 350.
As stated in Scope 1.1, This specification covers forged flanges, ring rolled flanges, forged valves and fittings...
(note the following)....Although this specification covers some piping components machined from rolled bar and seamless tubular products (see 4.3.3), it does not cover raw material produced in these product forms.
Following the reference cited to 4.3.3 in SA 350 it so states,
4.3.3 Except for flanges of all types, hollow cylindrically shaped parts may be machined from rolled bar or seamless tubular products provided that the axial length of the part is approximately parallel to the metal flow lines of the stock. Other parts, excluding flanges, may be machined from hot rolled or forged bar through and including NPS 4.
So, as defined in the Scope of ASME SA 350, forged valves are specifically mentioned or singled out as a product form and, as such, does not imply that product forms can be machined from forged bar and be called forgings.
Thus, forged valves cannot be supplied as forgings from machined, forged bar.
RE: Can forged bar be used to make a forged valve?
Metengr has hit the nail quite precisely on the head. I totally agree with his comments. Applying the rules of the ASME B31 Pressure Piping Codes, a valve body machined from a forged bar (product form) is not a forged valve body. Not withstanding the material at issue, the manufacturing process by which the component is made must comply with a Standard listed in Table 126.1 or 326.1, else it is an unlisted component.
As to the application of such a valve (unlisted component) to a B31 piping system, that would require qualification in accordance with paragraph 104.7.2 or 304.7.2. It might be so qualified, but it cannot be termed a "forged valve body".
Of course, all the above is just my opinion and NOT the opinion of ASME and NOT the opinion of any ASME B31 Pressure Piping Code Committee.
RE: Can forged bar be used to make a forged valve?
What I find interesting is that none of the responders has answered the original question: "if the valve body is marked "A350 LF2", would that not imply it was made from a forging, since A350 is by nature a forging specification?". In my post of 28 Feb 07 18:50, I offered to translate the responses, with "no", which struck some raw nerves. Maybe my phrasing was bad, so let me re-phrase the question so any responder can come back with a one-sentence response to close out this thread:
If A350 LF2 barstock material is used appropriately to make a valve body, how should the body be marked?
RE: Can forged bar be used to make a forged valve?
"if the valve body is marked "A350 LF2", would that not imply it was made from a forging, since A350 is by nature a forging specification?".
The marking would imply that the component was machined from a piece of bar stock that was made to the requirements of ASTM A350 LF2. The marking would not mean that the component was a forged valve body in the Code usage of that term.
"If A350 LF2 barstock material is used appropriately to make a valve body, how should the body be marked?"
I know of no Code, Standard or regulation that would dictate or mandate ANY marking on such a component. Perhaps "Made in XXX" would be appropriate.
Conditions of procurement and sale are generally stipulated by Contracts. Such contracts are liable to the opinions of judges and juries in civil litigation. Clearly, if a contract stipulates that a valve that includes a forged body (as defined by consensus Codes) be provided as a deliverable under the terms of the contract, the valve body that is machined from a piece of forged barstock would not satisfy the terms of that contract.
"I believe we have revealed that interpretation of some requirements can be difficult."
Codes and Standards are mandated by various jurisdictions as part of their "Codes of Regulations" (i.e., laws). This is the only thing that gives Codes and Standards the force of law. Opinions provided in this discussion are the opinions of individuals. I would suggest to you that if you require a interpretation of something addressed by a Code you should submit an official inquiry and get an official interpretation from the full committee (then it would have the force of law). As an example, if you feel that there is something in ASME B31.3 that is vague or ambiguous, you should submit an inquiry to the B31.3 Code Committee using B31.3 Appendix Z as a guide. I can assure you that the ASME Codes Committees make every effort to provide an unambiguously worded document.
Regards, John.