Stainless Steel 304 Flanges Manufacturer & Supplier - USA Piping Solution

For critical piping systems demanding reliable connections, look to USA Piping Solution. We operate as a dedicated US-based manufacturer and supplier, focusing squarely on high-performance Stainless Steel 304 Flanges. Our philosophy centers on providing components engineered not just to meet specs, but to deliver lasting service in tough industrial environments. Whether your project requires readily available ASTM A182 F304 Flanges or needs a more customized approach, our team ensures every part conforms to demanding international standards. Quality commitment, deep inventory, and accessible technical expertise are why businesses across the country rely on USA Piping Solution. Let's explore how our SS 304 offerings can benefit your next project.

What are Stainless Steel 304 Flanges?

Fundamentally, SS 304 Flange components act as the crucial linking points within piping infrastructure. They create secure junctions – joining pipes to other pipes, valves, pumps, or essential equipment – often designed so they can be taken apart later for maintenance or modification. The near-universal use of Grade 304 stainless steel for these parts isn't by chance; it stems from a remarkably effective combination of real-world advantages:

• Corrosion Resistance: It provides dependable protection against common atmospheric elements and holds its own against a broad spectrum of chemicals encountered in industrial processes.
• Ease of Fabrication: This grade is known for being straightforward to form and weld, which simplifies manufacturing and installation.
• Reliable Strength: For a great many pressure-containing applications, Grade 304 offers entirely suitable mechanical strength.
• Hygienic Surface: Its naturally smooth, non-porous finish makes it easy to keep clean, a vital characteristic in sectors like food, beverage, and pharmaceuticals.
• Sound Economics: It hits a practical sweet spot, balancing robust performance with a cost profile that makes sense for numerous applications when compared to higher-priced alloys.

You'll often see Grade 304L (UNS S30403) listed in specifications. That "L" points to its lower carbon content. This modification is particularly helpful during welding procedures because it greatly reduces the likelihood of chromium carbide precipitation forming along grain boundaries. Why does that matter? Because that precipitation can negatively impact corrosion resistance right next to the weld, a concern especially with thicker materials. Material carrying dual 304/304L certification is very common and offers versatility – it meets the low carbon advantage of 304L while still delivering the minimum strength associated with standard 304. USA Piping Solution ensures you have access to both standard 304 and these flexible dual-certified options.

Types of Stainless Steel 304 Flanges

Choosing the correct flange type is a key decision impacting system integrity, cost, and ease of maintenance. USA Piping Solution provides a full spectrum of Stainless Steel 304 Flanges, each tailored for distinct connection methods, pressure handling capabilities, and installation contexts:

Slip-On Flange

A popular choice known for its straightforward positioning and slightly lower initial cost, the 304 Stainless Steel Slip-On Flange (SORF) literally slides onto the pipe end. Two fillet welds, one inside and one outside, are typically required to secure it properly.

• Where They Shine: Often found in lower-pressure systems and general service piping where the extreme stress management of a weld neck isn't necessary. Alignment during fitting is generally easier.
• Good to Know: Its ability to withstand fatigue stresses is typically less than that of a comparable weld neck flange.

Weld Neck Flange

Easily spotted by its characteristic long, tapered hub, the 304 Weld Neck Flange (WNRF) is engineered for superior structural reinforcement. A critical design feature is that its internal bore perfectly matches the pipe's inside diameter, promoting smooth, unimpeded flow.

• Where They Shine: This design is the preferred solution for demanding conditions – think high pressures, very high or very low temperatures, or significant cyclic loading. It's the standard in critical services within Oil & Gas, Chemical, and Power Generation. The connection uses a single, robust butt weld, valued for its strength and ease of inspection.
• Good to Know: This type offers the highest level of joint integrity and manages operational stresses exceptionally well.

Blind Flange

Picture a solid disc, drilled only with bolt holes to match a mating flange – that's a 304 Blind Flange (BLRF). Its function is simple: to seal an opening securely.

• Where They Shine: Essential for terminating a pipeline, closing off equipment nozzles during shutdowns or testing, or capping connections intended for future system tie-ins. It bolts directly against another flange, relying on a gasket compressed between them to create the seal.
• Good to Know: Its job is purely containment. Therefore, it must be strong enough to handle the full internal pressure of the system plus the considerable forces applied during bolt-up.

Socket Weld & Threaded Flanges

• Socket Weld (SW): In this configuration, the pipe end inserts into a machined recess (the socket) within the flange. A fillet weld around the pipe's outer diameter secures the joint. SW flanges are typical choices for smaller diameter piping (often NPS 2 and below) operating at higher pressures.
• Threaded (Screwed): These possess internal pipe threads (NPT is the US standard) designed to engage with externally threaded pipe ends. They provide a purely mechanical joint, useful in situations where welding isn't desirable or allowed. Generally restricted to lower pressure and moderate temperature services, they can potentially be more prone to leakage paths than welded joints, especially under conditions involving vibration or temperature swings.

Beyond these primary styles, USA Piping Solution connects you with other essential flange types. This includes Lap Joint flanges (which require separate "stub end" fittings), Orifice flanges (built to accommodate flow measurement elements), Spectacle Blinds (providing positive isolation capabilities), and Reducing flanges (allowing direct connection between different pipe sizes). Furthermore, we can facilitate the procurement of custom-designed flanges based on your specific engineering drawings.

Stainless Steel 304 Flange Specifications

Predictable performance and safety in any engineered system hinge on strict adherence to established standards. You can specify Stainless Steel 304 Flanges from USA Piping Solution with confidence, knowing they are manufactured and rigorously tested according to these vital industry benchmarks:

ASTM A182 / ASME SA182

Consider this the foundational material specification governing forged or rolled alloy and stainless steel flanges, fittings, and valve parts designed specifically for elevated temperature service.

• Defining the Grade: Within this comprehensive standard, the designations ASTM A182 F304 and F304L precisely define the required ranges for chemical elements and the minimum acceptable levels for key mechanical properties for this stainless steel.
• What it Controls: The specification mandates exact percentages for alloying elements, minimums for strength (tensile and yield) and ductility (elongation), hardness limits, necessary heat treatments (solution annealing is standard for 304/304L), and the specific testing protocols required to confirm compliance.

ANSI, DIN, BS, EN Standards

While material standards dictate the "what," dimensional standards dictate the "how" – ensuring flanges physically fit together correctly:

• ANSI/ASME B16.5: In the United States, this standard reigns supreme for pipe flanges and flanged fittings in sizes NPS ½ through 24. It meticulously details dimensions for all standard pressure classes (150# up to 2500#). Specifying an ANSI B16.5 304 Flange ensures direct interchangeability within systems built to this common framework.
• ASME B16.47 Series A & B: When projects involve larger pipe diameters, typically NPS 26 through 60, these standards provide the necessary dimensional guidelines.
• Global Project Needs: We understand that many projects operate internationally. USA Piping Solution is equipped to supply flanges manufactured to meet DIN (German), BS (British), EN 1092-1 (European), JIS (Japanese), and other global dimensional standards as your specific project demands.

Chemical Composition and Mechanical Properties

The reliable real-world behavior you expect from Stainless Steel 304 Flanges – their ability to resist corrosion and handle stress – originates directly from their carefully controlled chemistry and the resulting physical characteristics.

Chemical Composition (Typical %)

Element	Grade 304 (S30400)	Grade 304L (S30403)
C	0.08 max	0.03 max
Cr	18.0 – 20.0	18.0 – 20.0
Ni	8.0 – 10.5	8.0 – 12.0
Mn	2.00 max	2.00 max
Si	0.75 max	0.75 max
P	0.045 max	0.045 max
S	0.030 max	0.030 max

Mechanical Properties (Typical Minimums)

Property	Grade 304	Grade 304L
Tensile Strength	75 ksi (515 MPa)	70 ksi (485 MPa)
Yield Strength	30 ksi (205 MPa)	25 ksi (170 MPa)
Elongation	40%	40%
Hardness (HBW)	201 max	201 max

How This Translates: These numbers reflect a material offering a solid foundation of strength coupled with excellent ductility (the ability to bend or stretch without breaking). Flanges are typically delivered after a solution annealing heat treatment, which optimizes their resistance to corrosion. Importantly, these types of stainless steel gain hardness through mechanical work (like forming), not through thermal hardening processes. Grade 304 also performs well resisting oxidation at elevated temperatures and is recognized for its excellent weldability using standard industry procedures.

Applications and Industries Served

Its adaptable nature makes the SS 304 Flange a truly essential component across an incredibly wide range of industrial activities:

• Oil & Gas operations, from extraction to refining and distribution
• Chemical and Petrochemical production facilities
• Power Generation plants, including critical cooling water circuits
• Municipal Water Treatment systems and clean water distribution
• Food and Beverage processing, where cleanliness is non-negotiable
• Pharmaceutical and Biotechnology manufacturing, ensuring product purity
• Pulp and Paper production mills
• Architectural designs and structural engineering projects
• Marine environments, particularly for handling freshwater
• HVAC (Heating, Ventilation, Air Conditioning) and commercial Refrigeration systems

Stainless Steel 304 Flanges Size Chart

USA Piping Solution provides access to the full range of standard flange sizes, covering small-bore NPS ½” all the way up to large-diameter 48” (and often larger capabilities exist), all produced according to the relevant ANSI/ASME dimensional specifications. The table below gives a representative look at Class 150 Weld Neck Flange dimensions per ASME B16.5:

NPS	OD (in)	Thick (in)	Hub Dia (in)	LTH (in)	Bolts	Hole Dia (in)	Bolt Circle (in)
1/2"	3.50	0.44	0.88	1.75	4	0.62	2.38
1"	4.25	0.56	1.38	2.00	4	0.62	3.12
2"	6.00	0.75	2.56	2.50	4	0.75	4.75
4"	9.00	0.94	4.81	3.00	8	0.75	7.50
6"	11.00	1.00	7.00	3.50	8	0.88	9.50
12"	19.00	1.25	13.38	5.00	12	1.00	17.00
24"	32.00	2.00	25.50	7.00	20	1.25	29.50

Quick Reminder: This data is for illustration. Always consult the official standards or our technical team for precise dimensional information corresponding to your specific flange type, size, and pressure class.

Surface Finish and Pressure Ratings

• Flange Face Finish: Creating a dependable, leak-free seal hinges significantly on the preparation of the flange face where the gasket makes contact. Common options include:
• Raised Face (RF): The industry default for many steel flange applications. It typically features a precisely machined surface texture (often spiral or concentric serrations, 125-250 µin AARH) that helps the gasket material seat correctly and maintain the seal.
• Flat Face (FF): Generally specified when mating flanges to equipment that also has a flat face (like certain pumps or cast iron valves) or when using specific types of full-face gaskets, typically in lower-pressure duties.
• Ring Type Joint (RTJ): This specialized design incorporates a machined groove engineered to hold a solid metal ring gasket. This creates a robust metal-to-metal seal, providing maximum reliability for high-pressure and/or high-temperature services where leaks cannot be tolerated.
• Pressure Ratings: Flanges are categorized by pressure classes (like Class 150, 300, 600, etc., following ANSI/ASME guidelines). These classes directly relate to the flange's ability to safely contain pressure at various operating temperatures. As the pressure class number rises, the flange itself becomes physically more substantial – thicker body, larger overall diameter, and requiring more (or larger diameter) bolts to handle the increased forces. Selecting the appropriate pressure class based on the system's design parameters is a fundamental aspect of safe engineering practice.

Certifications and Quality Assurance

At USA Piping Solution, delivering quality products isn't just a goal, it's a procedural commitment. We ensure the integrity and full compliance of every SS 304 Flange that leaves our facility through a rigorous quality assurance framework:

• Sourcing from Vetted Partners: We procure raw materials and forgings exclusively from manufacturers demonstrating robust and verifiable quality management systems.
• Providing Complete Material Traceability: Every flange shipment is backed by a Mill Test Certificate (MTC) conforming to EN 10204 3.1. This crucial document verifies that the material's chemical analysis and tested mechanical properties meet all requirements of the specified standard.
• Executing Dimensional Verification: Our quality team performs careful checks of all critical dimensions using calibrated instruments, ensuring adherence to the relevant standards (ASME B16.5, B16.47, etc.).
• Conducting Careful Visual Inspections: Each flange is visually examined to assess surface quality, confirm proper identification markings are present and legible, and evaluate overall manufacturing workmanship.
• Utilizing Positive Material Identification (PMI): As an added layer of verification, we employ techniques like X-Ray Fluorescence (XRF) analysis to confirm that the material grade is exactly as ordered (304 or 304L), preventing potential material mix-ups.
• Supporting Third-Party Oversight: We readily accommodate and cooperate with inspections conducted by independent third-party agencies whenever mandated by customer contracts or specific project quality plans.

This diligent, multi-step quality process provides assurance that the flanges you receive are not only fully compliant with all relevant standards but are also built for reliable performance and long service life.

Why Choose USA Piping Solution for SS 304 Flanges?

Making USA Piping Solution your supplier for Stainless Steel 304 Flanges delivers practical advantages for your procurement process and overall project success:

• Ready-to-Ship Inventory: Our substantial investment in stocking ASTM A182 F304 Flanges across a wide array of types, sizes, and pressure classes often means faster fulfillment and reduced project delays.
• Unwavering Quality Commitment: Our established quality assurance protocols ensure you receive flanges that consistently meet or exceed industry specifications, contributing directly to system safety and reliability.
• Competitive Market Positioning: Through efficient operations and strong supplier relationships, we aim to provide top-tier quality flanges at fair, competitive price points.
• Accessible Expertise: Our experienced personnel understand the technical nuances and are available to provide guidance, helping you select the most suitable components for your specific application challenges.
• Focus on Reliable Service: We know that responsiveness matters. We prioritize clear communication and efficient logistics to ensure your orders arrive correctly and on schedule, anywhere in the US.
• The Benefit of a Domestic Supplier: Enjoy straightforward communication, accessible support, and the confidence that comes from working with a US-based company invested in your success.

Related Products

To better serve as your single source for piping requirements, USA Piping Solution also maintains inventory and supplies a broad range of related materials:

Final Call to Action

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