--- title: "Stainless Steel Flange RFQ Checklist: 10 Details Every Buyer Should Include" date: 2026-06-10T01:04:00Z modified: 2026-06-26T01:07:40Z permalink: "https://www.longanflange.com/blog/stainless-steel-flange-rfq-checklist/" type: post status: publish excerpt: "" wpid: 3701 categories: - Blog featured_image: "https://www.longanflange.com/wp-content/uploads/2026/06/image-21.webp" featured_image_alt: Stainless Steel Flange RFQ Checklist timestamp: 2026-06-26T01:07:40Z tags: - Blog --- A stainless steel flange RFQ should tell the supplier exactly what you need. Include the grade, standard, flange type, facing, size, pressure class, quantity, delivery time, tests, certificates, marking, destination, and packing details. When these details are missing, the quote can take longer. The supplier has to ask more questions, or worse, they may make their own assumptions. One supplier may quote ASME. Another may quote EN 1092-1. Another may leave out testing or export packing. If you are preparing stainless steel flange specifications, use this checklist before sending your inquiry. ![10 Details Every Buyer Should Include ](https://www.longanflange.com/wp-content/uploads/2026/06/image-22-1024x512.webp)## **Why An Incomplete RFQ Costs You More Than You Think** An incomplete RFQ can easily add three to five days of extra emails. The supplier may need to confirm the grade, standard, pressure class, facing, testing, or certificates before giving a high price. It also makes price comparison harder. If three suppliers quote based on different details, you are not comparing the same product. This is common in stainless steel flange orders. A small missing detail can change the cost, especially for large sizes, special testing, or export packing. For DN600 to DN4000 flanges, the risk is even higher. Large flanges may need custom machining, longer production time, and stronger packing. A clear RFQ helps the supplier check material, machine time, inspection needs, and delivery time before quoting. ## **\#1 — Material Grade, Not Just “Stainless Steel”** Do not only write “stainless steel flange.” State the exact grade. Common grades include 304, 304L, 316, 316L, 321, 2205, and 2507. If you know the ASTM grade, add it too. For example, write ASTM A182 F316L instead of only 316L. This helps avoid confusion between Chinese, European, and American material names. If you are not sure which grade to use, describe the working conditions. Tell the supplier the medium, temperature, pressure, and chloride level if you know them. Then ask the supplier to recommend a suitable grade. ## **\#2 — Applicable Standard** The flange standard must be clear in the RFQ. Common standards include ASME B16.5, ASME B16.47, DIN EN 1092-1, and GOST 12821. Different standards can have different sizes, sealing faces, and bolt hole positions. This affects installation. If your project uses more than one standard, list each part clearly. For example, one EPC project may need DIN flanges in one section and GOST flanges in another section. For projects using American standards, confirm [ASME flange](https://www.longanflange.com/wp-content/uploads/wp-mfa-exports/page/asme-flange.md) size and pressure requirements before asking for the final quote. ## **\#3 — Flange Type And Facing** The RFQ should include the flange type and the sealing face. If one is missing, the supplier cannot quote correctly. Common flange types include [weld neck](https://www.longanflange.com/wp-content/uploads/wp-mfa-exports/post/weld-neck-flanges-facts-to-know.md), [slip-on](https://www.longanflange.com/wp-content/uploads/wp-mfa-exports/post/what-is-slip-on-flange.md), blind, threaded, lap joint, and socket weld. Common faces include raised face, flat face, ring type joint, and tongue and groove. Write the full details in one line. For example: “Weld neck flange, [raised face](https://www.longanflange.com/wp-content/uploads/wp-mfa-exports/post/raised-face-vs-flat-face-flange.md).” Or: “Blind flange, flat face.” This small detail helps avoid the wrong gasket, wrong connection, or wrong price. ![Slip-On Flanges](https://www.longanflange.com/wp-content/uploads/2024/07/088b641a27848805159c.jpg) Slip-On Flanges The Slip-On Flange is designed to accommodate lower pressure and temperature applications, featuring a central bore that matches the outside diameter of the pipe. [Inquiry Now](https://www.longanflange.com/products/slip-on-flange/) ## **\#4 — Size And Pressure Class** Write the size and pressure class in the correct system. Do not mix DN and NPS as if they are the same. DN200 and NPS 8 may look close, but they are not the same size. For ASME projects, use Class 150, 300, 600, or the required class. For DIN or EN projects, use PN10, PN16, PN25, PN40, or the required PN rating. Large sizes must be stated clearly. DN600+ flanges are often custom-made, so the size can change the price and delivery time. For DN600 to DN4000 stainless steel flanges, attach drawings if possible. Include tolerances and any special dimensions. ## **\#5 — Quantity And Delivery Schedule** Tell the supplier the total quantity and the delivery schedule. If you need the goods in batches, list each batch. A one-time order and a yearly supply agreement are priced differently. Larger quantities may get a better unit price, but the supplier must confirm capacity first. For large flanges, do not only ask for the price. Ask if the supplier can finish the order within your project schedule. This helps avoid a low quote that later becomes delayed. ## **\#6 — Required Testing And Inspection** List the tests you need before production starts. Basic tests may include dimension checks, hardness testing, and PMI. PMI means checking the material grade with a portable analyzer. Special tests may include UT, RT, PT, and low-temperature impact testing. Also state who will inspect the goods. Will you accept supplier inspection? Or do you need third-party inspection from SGS, BV, or TÜV? Testing affects cost and lead time. If you add it after the quote, the supplier may need to change the price. ## **\#7 — Material Certification Requirements** State the certificate requirements in the RFQ. For many European projects, [EN 10204 3.1](https://www.longanflange.com/wp-content/uploads/wp-mfa-exports/post/en-10204-certificate-types-ped-4-3-valve-flange.md) is required. The MTR should show the chemical composition, mechanical properties, heat number, and heat treatment status if needed. If your project needs [PED](https://www.longanflange.com/wp-content/uploads/wp-mfa-exports/post/ped-4-3-material-certification-flange-valve-manufacturers.md), NACE, or NORSOK documents, say this early. Certificates are not just extra files. They prove that the flange matches the material and inspection needs of the project. ## **\#8 — Surface Treatment And Protection** State whether pickling and passivation are required. This is common for stainless steel, but not every supplier includes it by default. If the flange is for food, pharmaceutical, or sanitary use, include the surface roughness requirement. This may be written as a Ra value. Also, tell the supplier how the flange should be protected during transport. This may include face covers, moisture protection, wooden crates, pallets, or other packing. For long-distance shipping, good packing can prevent damage before installation. ## **\#9 — Marking And Traceability** Tell the supplier what markings are needed on each flange. Common markings include material, standard, heat number, size, pressure rating, and manufacturer name or code. Some projects need piece-by-piece traceability. This is common for marine, chemical, nuclear, and high-spec industrial projects. You should also say how the flange should be marked. Options include laser marking, steel stamping, and paint marking. Traceability helps connect each flange to its MTR, test report, and production batch. ## **\#10 — Destination, Incoterms, and Packaging** Include the final delivery location and Incoterms in the RFQ. Common options include FOB, CIF, and DDP. The destination affects freight cost, delivery time, customs documents, and packing. Some countries may need a certificate of origin, fumigated wooden crates, or special import papers. For extra-wide or extra-heavy flanges, discuss shipping before production is finished. Large flanges may need custom crates, lifting points, protected faces, and special loading plans. Custom Large Diameter Flanges Manufacturer We specialize in manufacturing large diameter stainless steel flanges—custom-made to your specs, forged in-house, and machined with high precision. [Start Your Custom Project with Longan](https://www.longanflange.com/wp-content/uploads/wp-mfa-exports/page/custom-large-diameter-flange-manufacturer-factory.md) ## **Send A Complete RFQ For Technical Review** Before sending an RFQ, match the flange material, size, standard, testing, marking, and packing needs to the real risk of your project. If your order involves [stainless steel flanges](https://www.longanflange.com/wp-content/uploads/wp-mfa-exports/page/stainless-steel-flange.md) from DN600 to DN4000, custom drawings, or multi-standard requirements, Longan Flange can review your specifications and help confirm a suitable production path. [Get a Quote](https://www.longanflange.com/wp-content/uploads/wp-mfa-exports/page/contact.md)