--- title: 6 Trusted Custom Stainless Steel Flanges Manufacturers  date: 2025-07-31T12:34:04Z modified: 2025-08-04T02:02:08Z permalink: "https://www.longanflange.com/blog/trusted-custom-ss-flange-manufacturers/" type: post status: publish excerpt: "" wpid: 3042 categories: - Blog featured_image: "https://www.longanflange.com/wp-content/uploads/2025/04/2117136485.jpg" timestamp: 2025-08-04T02:02:08Z tags: - Blog --- If you’re looking for reliable custom flanges—especially custom large diameter flanges—you need factories that manufacture from start to finish. As a professional stainless steel flange manufacturer, Long’an Flange knows what precision, speed, and certified quality look like. Here are six trusted factories that meet the mark: 1. [**Long’an Flange**](https://www.longanflange.com/wp-content/uploads/wp-mfa-exports/page/stainless-steel-flange.md) ![](https://lh7-rt.googleusercontent.com/docsz/AD_4nXe3Kj36q49wGQMuJO5jxC_PWKlHGLKTeIU0QudXUpJGuWaF0wn6Q2iu-IFE5Qqg2_ix-fCirM8kBJx9Jv6OTDJ-dZPu_eiDY8vmo_fTIGqLDZHtj0WDn2suq7fBTl5CvyjJkad3XQ?key=UKvMaCLcbbG1XbpXSQ9Wgw) Source: Longan Flange **Long’an Flange** delivers stainless steel flanges ranging from standard sizes to oversized tools—up to 6,000 mm in diameter. We work with stainless steel grades (304, 316) and advanced alloys (duplex, super-duplex, 254 Mo). Inside our factory, every flange is forged, CNC-machined to precise dimensions, and finished with clean sealing faces. Our quality team runs PMI, ultrasonic, and hardness tests, alongside spectrometer checks and full documentation. Certified to ISO 9001/14001/45001 and compliant with ASME, DIN, EN, and GOST standards, our production suits critical pipelines, marine, and power sectors needing both accuracy and international compliance. 2. **Texas Flange** ![](https://lh7-rt.googleusercontent.com/docsz/AD_4nXe2zg6x_H-Weqmel_NBc9FMKRmFbaWeITWeDvL3Szw8A9YHD1BcOIE-uDLFSmB8k0rTkXjYhiKnApEGXpwolS3x19v6tjSfrKs8wwA0G1CEvn__EqzNx5hdRzMXE6b-oQDTRnvr0g?key=UKvMaCLcbbG1XbpXSQ9Wgw) Source: Texas Flange Since 1986, **Texas Flange** has specialized in high-spec stainless steel flanges up to 5 meters in diameter and rated for extremely high pressure (20,000 psi). Their in-house capabilities include CNC machining, custom drilling patterns, precision beveling, and heat treatment. Texas Flange supports fast, engineer-backed quotes and caters to both domestic and export markets. They ship polished, pressure-tested custom flanges that comply with ANSI B16.5/B16.47/AWWA/API standards. Their ability to combine speed, engineering flexibility, and code adherence makes them a solid choice for construction, energy, and industrial pipeline projects where turnaround time and specification matter. 3. **R&M Forge and Fittings** ![](https://lh7-rt.googleusercontent.com/docsz/AD_4nXcdcMzx9an_seE8iSX5LRpBuQZ_tUFcRg08bzC_Kr0pVXMc2RKr_GzeTtJ-CmEX4K-pvGGrBjjYocIOJjV6Xiu81h0Ky8nTH7_JPoVgj5bxto9MADtmypl1iwM6NsMR-2l5_1fm?key=UKvMaCLcbbG1XbpXSQ9Wgw) Source: R&M Forge and Fittings **R&M Forge and Fittings** focuses on rugged, heavy-duty flanges—up to 6.3 meters in size—crafted from stainless and exotic alloy steels like C276 and Alloy 625. Their facility performs forging, precision machining, heat treatment, and hydrostatic batch testing onsite. R&M is a go-to option for oil refineries, offshore platforms, and power plants needing flanges that withstand harsh chemical environments and high mechanical stress. Buyers choose R&M for its consistency with ASME B16.47 Series A/B specs, reliable batch traceability, and the ability to blend performance with alloy excellence—without sacrificing turnaround or compliance. 4. **TruStop Inc.** ![](https://lh7-rt.googleusercontent.com/docsz/AD_4nXdDUL4xIww54JixXeI5M917v8_knxXpa94BZZ_5eqepiru7Re9k9NEINDSBLDNpLpoNVRueARg34g7TzgU0ep26NFIt6E-Z5y7VTHflBK2FaMbAMMxr4LL9MR4-nWuv6NN96mTJxA?key=UKvMaCLcbbG1XbpXSQ9Wgw) Source: TruStop Inc. **TruStop** delivers manufacturing precision for stainless steel flanges up to 72″—offering super-tight machining tolerances (±0.0005″) and polished finishes. Their specialties include helium leak testing, coordinate-measuring inspections, and full hydrostatic pressure certs. Common materials are 304L, 316L, and Alloy 20, polished to 16Ra or better. They serve industries like pharmaceuticals, aerospace, and clean-room manufacturing, where leaks or dimensional variances are unacceptable. If your application demands hermetic sealing, traceable documentation, and quality assurance under controlled conditions, TruStop provides the engineering and process consistency to meet those needs. 5. **Appleton Stainless Incorporated** ![](https://lh7-rt.googleusercontent.com/docsz/AD_4nXcOdIoks8KslmblwVdR11XPWPDHkcnrBWYbKwyKvA9xV_e3WEfgeuGALFSBD-SMITAjl6rCoq0TnQ9NNL0Il0bIWRGq6mb4qZ75uME_f-e0yuDZYmF0AIjitXCFTFD_zz1zLhVGcA?key=UKvMaCLcbbG1XbpXSQ9Wgw) Source: Appleton Stainless Incorporated **Appleton** produces hygienic stainless steel flanges and fittings—typically 304L, 316L, and 317L—aimed at food, biotech, and semiconductor markets. Their Seattle-area workshop delivers CNC machining, orbital welds, centerline or electropolishing (20–25 Ra), and BPE-certified processes. Most custom orders ship within 5–15 working days, making them ideal for projects with tight deadlines or sanitary standards. Appleton stands out for balancing fast turnaround, polished surfaces, and industry-specific certifications—especially where cleanliness and precision matter more than diameter or pressure. 6. [**Taiyuan Iron and Steel Group, Co. Ltd. (TISCO)**](http://www.tisco.com.cn/) ![](https://lh7-rt.googleusercontent.com/docsz/AD_4nXcDjVZ_qCKAfy4TM2zp_79I5m7SQAD1TIx4sTAzU_8NYks0987N6XfMIm5XQyGy4Xkfn9jMlsHFZvNLBp3L283LopUfGYBVVwGiv7U-PgmQ2CqJ5B8fguIJd5cMA-yLWrRXOq4I1g?key=UKvMaCLcbbG1XbpXSQ9Wgw) Source: TISCO **TISCO** isn’t just a steel mill—it’s a polished stainless steel flange producer handling everything from smelting to finished part. They specialize in 304, 316L, and duplex grades with in-line polishing achieving mirror finishes. TISCO supplies high-volume polished flanges used in architectural façades, industrial piping, and OEM applications. Their in-house certification (ASME, ASTM) and third-party quality audits back large-scale international orders. They offer polished durability at competitive pricing—and with production control built into the raw material stage, they reduce lead times and piece-level variability. ## **Quick Comparison Table** If you’re weighing options, here’s a quick side-by-side look at what each manufacturer offers in terms of size range, materials, lead times, and specialties. | **Manufacturer** | **Max Size** | **Standout Feature** | **Typical Buyers** | | --- | --- | --- | --- | | Long’an Flange | 6000 mm (6 m) | Global-certified, full traceability | Pipeline, petrochemical, marine | | Texas Flange | 203″ (5 m) | Rapid quoting, custom specs, fast delivery | Utility, infrastructure, export markets | | R&M Forge | 250″ (6.3 m) | Heavy-alloy, rugged large flanges | Refineries, offshore | | TruStop Inc. | 72″ (1.8 m) | Tight tolerances, leak-proof performance | Pharma, aerospace, precision equipment | | Appleton Stainless | 20″ | Polished hygienic flanges, clean finish | Food, biotech, semiconductor | | TISCO | Bulk sizes | Smelt‑to‑finish polishing, high volume | Industrial, architectural, OEMs | ## **What Makes These Factories Stand Out** Not every flange factory can deliver on custom specs, size range, and industry standards. Here’s what sets these manufacturers apart when it comes to stainless steel flange production: - **Coverage from Small to Large:** All six manufacturers tackle custom large diameter flanges, ranging from standard sizes to specialized batches several meters wide. - **Material Range:** They offer standard stainless grades (304/316L), duplex alloys, and specialty materials—all traceable and tested. - **Quality Control:** Every factory features in-house testing—PMI for identifying the alloy, pressure tests, leak checks, and dimensional inspection—to ensure components work flawlessly in the field. ## **Custom Flanges: Conclusion** At [**Long’an Flange**](https://www.longanflange.com/wp-content/uploads/wp-mfa-exports/page/about.md), we match these competencies: large-diameter CNC machining, certified materials, strict in-house testing, and worldwide compliance. Let’s talk about your next flange requirement—whether it’s size, sealing, finishing, or spec-driven performance.[Reach out now](https://www.longanflange.com/wp-content/uploads/wp-mfa-exports/page/contact.md) to get a quote, request samples, or connect with our engineers.