What Should an RFQ for OEM Stainless Steel Ball Valves Contain?
Key Takeaway
A quote is a price for a set of assumptions, and every field an RFQ leaves blank is filled in by the factory with its own. Two quotes for the same request can then price two different valves. Write each requirement as a standard designation instead of a trade word: the ASTM grade for each part, the thread by its ISO or ASME name, the rating system, the test standard with edition and acceptance rate, the EN 10204 type, and an Incoterms rule with a named place. Then line the replies up in one sheet and ask about every row a factory left empty.
What is a factory actually pricing when it quotes a ball valve?
A route, not a product name. For a cast stainless body the route runs through casting, heat treatment, machining, assembly and test, in that order, and several of those steps change with a choice the RFQ did not make. A choice the RFQ leaves open still has to be made before a price can exist, so the factory makes it.
This article starts after the model decision. Whether you hold a drawing, a service requirement or a catalogue number is covered in OEM, ODM or Private Label, which also has a short table of what each model sends. What follows is the longer list, field by field, and what the factory does with each.
Which words in a ball valve RFQ can mean more than one valve?
Six of them, at least: 316, BSP, a bare pressure figure, “tested”, “certificate” and the delivery term. Each looks complete on the page and leaves a choice open underneath.
| Word in the RFQ | What it can stand for | Write this instead |
|---|---|---|
| “316” | A body cast to ASTM A351 CF8M, or a part turned from wrought 316 bar. The two are ordered against different standards with different limits. A351 puts chromium at 18.0 to 21.0 %, against 16.0 to 18.0 % for ASTM A240 Type 316. | A grade and a standard for each part: body, ball, stem, seat and seals. See CF8M against 316. |
| “BSP” | A taper thread that seals on the thread (ISO 7-1: male R, female Rp or Rc), or a parallel thread (ISO 228-1: G) that is not meant to seal on the thread and needs a gasket or O-ring. | R, Rp or G, with the size and the standard. NPT is a separate family with a 60° flank angle against 55° for the ISO threads. See thread identification. |
| “1000 psi” | 1000 WOG is a non-shock rating at ambient temperature. A steam rating (WSP) is a separate mark with a much lower figure. A Class is a class, not a psi figure. | The rating system, and the service temperature it has to hold at. See reading valve markings. |
| “Tested” | API 598 acceptance, or ISO 5208 at a stated leakage rate. Both may be run on every valve or on a sample. | Standard, edition, rate, medium, and whether every valve is tested. See API 598 or ISO 5208. |
| “Certificate” | EN 10204 type 2.2, 3.1 or 3.2. They differ in whose inspection they report and whether it covers the heat or lot supplied. | The type for each item. See sample approval. |
The fifth row hides a second question. Marking standard MSS SP-25 lists the melt designation as a conditional element, required only as the specification requires. A heat number appears on the body when the RFQ asks for it, and the certificate can be tied to a particular valve only if it does.
What does the drawing have to say about a cast body?
Which surfaces are cast, which are machined, and the tolerance that applies to each. A cast surface is toleranced under a casting standard and a machined surface under its own drawing tolerance, so one general note across the drawing leaves the factory to decide which one it meant.
ISO 8062-3 supplies general dimensional tolerance grades for castings, with geometrical grades and machining allowance grades alongside, for all cast metals. The 2023 edition is the second and replaces the 2007 edition, which is withdrawn, so the drawing should name the edition it relies on. The standard covers tolerances on indicated linear dimensions. It does not apply to a 3D model that has no indicated dimensions, so the standard’s general tolerances do not reach a model sent without a dimensioned drawing.
The machined features need tolerances of their own wherever they decide fit:
- The bore and the seat pockets, where the seat meets the ball.
- The end connection, whether thread, socket or flange, with its standard.
- The face-to-face length, and the standard if the order cites one such as ASME B16.10.
- On an actuated valve, the mounting pad and the stem end, which ISO 5211 sets out.
Put the drawing revision on the RFQ and carry it onto the order. A reply that quotes revision B against an order written at revision C is a reply to a different request.
What do quantity and schedule change in a quote?
They decide which of three minimums the factory is quoting. A minimum order quantity is the melt, the tooling and the machining setup reported as one number, as the MOQ article breaks down. A line that says only “1,000 pieces” hides which of the three applies.
Give three figures instead. The first order, the annual volume, and whether the year is one run or a series of call-offs. Then ask which floor is binding on your part. If the answer is the tooling, ask in the same message how the tool is paid for and who owns it afterwards, since payment does not transfer ownership by itself.
Ask what the lead time is counted from. Drawing approval, deposit and tooling completion are three different dates, and a lead time without one is a number with no start.
Which delivery term belongs in the RFQ, and why does it need a place?
An Incoterms 2020 rule, with the agreed port or place beside it. The International Chamber of Commerce publishes the rules, eleven in the 2020 edition. The table shows four of them, and they split the work differently.
| Rule | Export declaration | Main carriage | Insurance | Modes |
|---|---|---|---|---|
| EXW | Buyer | Buyer | Not required; the buyer would be wise to insure | Any |
| FCA | Seller | Buyer, after handover to the buyer’s carrier | Optional | Any |
| FOB | Seller | Buyer; the seller is not responsible for the water transport | Optional | Sea and inland waterway only |
| CIF | Seller | Seller, up to the agreed port of destination | Seller must insure, to Institute Cargo Clauses (C) | Sea and inland waterway only |
Two consequences follow. An EXW unit price leaves out the export clearance that an FOB price includes, so the two cannot be set side by side until one is converted. And a container shipment does not suit FOB or CIF: the Dutch Chamber of Commerce guidance says FCA is more suitable for containers, and that CFR and CIF cannot be used for container transport.
Packaging belongs in the same paragraph. Carton and pallet specification, the marking on the carton and the language of the documents cost the factory time, and a reply cannot price what was not stated.
How do you compare the quotes that come back?
Put them in one sheet with the same rows, and treat an empty cell as a question. A factory that left a row blank priced its own assumption for it. Ask what the assumption was.
| Row | Line up |
|---|---|
| Price basis | Incoterms rule and named place; whether packing is inside the price |
| Material route | Grade and standard for each part, and whether the body is cast or machined from bar |
| Test | Standard, edition, acceptance rate, medium, and whether every valve is tested |
| Documents | EN 10204 type for each certificate, and whether the heat number is marked on the body |
| Quantity floor | Which of melt, tooling and setup is binding; the tooling charge shown separately; who owns the tool |
| Lead time | The event it is counted from |
| Deviations | Anything the factory changed from the RFQ, listed by the factory |
The last row is worth asking for in the RFQ itself. A changed material, thread, test or document type is a different valve. Compare its price with the others only after the deviation is put back.
How do you build the RFQ, step by step?
- Decide the model first. Settle whether you hold a controlled drawing, a service requirement or a catalogue part number, because each sends the factory different information.
- Freeze the drawing. Fix the revision. Say which surfaces are cast and which are machined, name the casting tolerance grade with the edition of ISO 8062-3, and give explicit tolerances for the machined features that matter.
- Write materials by part. Give the body, ball, stem, seat and seals each a grade with the standard it comes from, instead of one word for the whole valve.
- Write connections and rating by standard name. Thread family and size by standard designation, the rating system with its temperature basis, and the face-to-face standard if one applies.
- Write the test, the documents and the marking. Test standard, edition, acceptance rate, medium and whether every valve is tested. EN 10204 type for each certificate. Marking content, including the heat number if the certificate has to be traceable.
- State the quantity honestly. First order, annual volume and whether the year is one run or call-offs. Ask which of the melt, tooling and machining floors is setting the minimum, and how tooling is charged and owned.
- Name the delivery term and ask for deviations. An Incoterms 2020 rule with its named place, the packaging specification, and a request that every reply list its deviations. Send the same file to every factory.
Send one file to every factory. If each gets a slightly different version, the sheet above stops lining up for a reason that has nothing to do with the factories.
What can an RFQ not settle?
Whether the factory can build what it priced. A complete RFQ makes the quote comparable, and the quote is a statement on paper. A factory audit tests whether the system behind it works, a sample approval tests one unit against the drawing, and a lot inspection tests the shipment. Whether the certificates the factory shows cover the site that will ship your order is the question in What Does a Valve Manufacturer’s Certification Actually Prove?
Frequently Asked Questions
Can I send only a competitor's part number as the RFQ?
You can, but the factory then has to work backwards to the service conditions, and the quote comes back resting on assumptions. Send the media, pressure, temperature, cycling frequency, end connections, required certifications and target market with it.
Does 1000 WOG mean the valve is good for 1000 psi?
Only for cold, non-shock service. WOG stands for water, oil, gas, and the figure is a non-shock rating at ambient temperature. Steam has its own mark, WSP, with a much lower figure, so the RFQ should state the rating system and the service temperature.
Does BSP mean a tapered thread?
Not necessarily. BSP is used for two families. The taper family seals on the thread and is written R for the male and Rp or Rc for the female under ISO 7-1. The parallel family is written G under ISO 228-1, is not designed to seal on the thread, and needs a gasket or O-ring. NPT is a third family with a 60 degree flank angle.
Which Incoterm suits a container shipment?
The Dutch Chamber of Commerce guidance recommends FCA rather than FOB for container shipments, and says that CFR and CIF cannot be used for container transport. It names CIP as the rule where the seller arranges carriage and insurance.
Do heat numbers have to be marked on the valve body?
Only if the specification asks. MSS SP-25 lists the melt designation as a conditional element. If the certificate has to be traceable to a particular valve, the RFQ should say that the heat number is to be marked on the body.
What should I do if a factory quotes something other than what I asked for?
Ask each factory to list its deviations from the RFQ as a separate section of the reply. A changed material, thread, test or document type is a different valve, and the price should be compared against the other quotes only after it is put back to the RFQ.
Related Articles
- OEM, ODM or Private Label: What Each Model Means for a Ball Valve Order
- Why Does an OEM Ball Valve Carry a Minimum Order Quantity?
- Who Owns the Tooling on a Private Label Valve?
- How Do You Approve a Stainless Steel Ball Valve Sample From a New Supplier?
- What Should You Check When You Audit a Ball Valve Factory?
- What Do the Markings on a Ball Valve Body Mean?
- API 598 or ISO 5208: What Does a Ball Valve Leakage Test Report Prove?
- Stainless Steel Ball Valve OEM Manufacturer in Taiwan
Referenced standards and sources: Incoterms 2020, described through the Dutch Chamber of Commerce (KVK) guide and the ICC Incoterms 2020 page; ISO 8062-3:2023, through its SNV catalogue entry; ISO 7-1 and ISO 228-1 pipe threads, through Engineering ToolBox; NPT and BSPT flank angles, through Project Materials; ASTM A351 and A240 chromium limits, MSS SP-25 elements, WOG and WSP marks, EN 10204 types and the minimum order quantity floors, from the linked articles on this site.
None of the standards above was read in full. The Incoterms, ISO 8062-3 and thread descriptions come from the publishers’ and secondary pages named here, so check the wording in the edition your contract cites. No price, tolerance value, lead time or minimum quantity is given, because each belongs to the part and the factory. The cover image is a generated illustration, not a photograph of a particular workshop or product.