Top 10 Carbon Steel Flange Suppliers | 2025 Guide

In critical industrial sectors like oil & gas, petrochemicals, and waterworks, the integrity of a piping system is paramount. While pipes and valves often get the spotlight, the humble flange is the unsung hero ensuring secure, leak-free connections. Selecting the right carbon steel flange supplier is not just a procurement task; it is a crucial decision that impacts project safety, timelines, and budget. An unreliable supplier can lead to costly delays, material failures, and significant operational risks.

This guide is designed for engineers, procurement managers, and project leaders who understand that quality components are the foundation of a successful operation. We will explore the essential criteria for choosing a supplier that aligns with your technical and logistical needs. More importantly, we provide a curated list of the top 10 global suppliers for 2025, moving beyond the obvious names to include specialists and innovators who deliver exceptional value. This comprehensive overview will equip you to make an informed decision and secure a partner dedicated to your project's success.

How to Choose the Right Carbon Steel Flange Supplier

Choosing a supplier involves more than comparing price lists. It requires a thorough evaluation of technical compliance, manufacturing capabilities, and logistical reliability. A misstep in this process can compromise your entire system, making a strategic approach essential.

Material Grades and Standards

Carbon steel is favored for its strength, durability, and cost-effectiveness, making it a staple in many industries. However, not all carbon steel is created equal. The most common and trusted material specification for carbon steel flanges is ASTM A105, which covers forged carbon steel piping components for ambient and high-temperature service. When evaluating a supplier, confirm they provide flanges made to this standard.

A reputable carbon steel flange supplier will offer complete material traceability. This means they can provide a Material Test Report (MTR) for every flange, detailing its chemical composition and mechanical properties. This documentation is your assurance that the product you receive is exactly what you ordered and is safe for its intended application.

Certifications are Non-Negotiable

Certifications are the bedrock of quality assurance in the industrial supply chain. They are independent verifications that a supplier's products meet rigorous safety, design, and performance criteria. For carbon steel flanges, two sets of standards are particularly critical.

• ASME (American Society of Mechanical Engineers): ASME B16.5 is the standard for pipe flanges and flanged fittings up to 24 inches in nominal pipe size. For larger diameters, ASME B16.47 is the relevant standard. Compliance ensures flanges meet specific requirements for dimensions, tolerances, materials, and testing.
• ASTM (American Society for Testing and Materials): As mentioned, ASTM A105 is the key material standard. Suppliers should also adhere to other relevant ASTM standards governing manufacturing and testing processes.

Always ask a potential supplier for proof of their certifications. A lack of proper certification is a major red flag and should disqualify a supplier from consideration for any critical application.

Understanding Pressure and Temperature Ratings

Flanges are rated in "classes," which indicate their maximum pressure-holding capacity at increasing temperatures. Common ratings include Class 150, Class 300, Class 600, and so on, up to Class 2500. It is a common misconception that a Class 150 flange is rated for 150 PSI under all conditions.

The pressure rating of a carbon steel flange decreases as the operating temperature increases. For example, a Class 150 A105 carbon steel flange can handle approximately 285 PSI at ambient temperatures but is only rated for around 150 PSI at 500°F (260°C). A professional supplier will have engineers or technical staff who can help you select the correct flange class based on your system's specific pressure and temperature requirements, ensuring a safe and reliable seal.

Evaluating Supplier Capabilities

Beyond the product itself, the supplier's operational excellence is key. Consider their inventory levels and lead times. A supplier with a large in-stock inventory, like those mentioned in the research, can prevent project delays.

Furthermore, distinguish between a manufacturer and a distributor. Manufacturers like Coastal Flange create the product and can often accommodate custom orders. Distributors like Mattsco Supply Company offer a wide range of products from various brands and may provide superior logistical support. Your choice depends on whether you need a standard part quickly or a custom-engineered solution.

Top 10 Carbon Steel Flange Suppliers for 2025

Our list of top suppliers for 2025 was compiled based on market reputation, specialization, product quality, and ability to serve diverse industrial needs. We have included a mix of large-scale manufacturers, agile distributors, and niche specialists to provide a balanced view of the market. This ranking prioritizes suppliers who offer proven reliability and exceptional value.

Texas Flange

Company Overview:
Based in Houston, Texas, Texas Flange has established itself as a premier US-based supplier of carbon steel, stainless steel, and alloy flanges. With a strong focus on the American market, they have built a formidable reputation for quality products and responsive customer service. Their deep inventory and industry expertise make them a go-to source for projects requiring quick turnarounds.

Strengths:
Texas Flange is renowned for its extensive stock of ANSI, API, and AWWA standard flanges. This allows them to fulfill orders rapidly, which is a significant advantage for time-sensitive MRO (Maintenance, Repair, and Operations) work and fast-track projects. Their user-friendly online resources and knowledgeable sales team simplify the often-complex process of flange selection and procurement.

Specializations:
While they offer a comprehensive range of standard flanges, including Weld Neck, Slip-On, and Blind types, Texas Flange excels in providing high-quality domestic products. They serve a broad array of industries, with a particular stronghold in the oil & gas and petrochemical sectors concentrated around the Gulf Coast. Their commitment to adhering to stringent industry standards makes them a trusted partner for critical applications.

Metal Zenith - Premium Steel Manufacturing Solutions

Company Overview:
Metal Zenith is a leading steel manufacturing and distribution company from China with over two decades of experience. Acting as a strategic partner of the renowned Ansteel (Anshan Iron and Steel Group), they provide premium steel solutions to a global clientele. Their business model combines the robust production capacity of a major steel mill with the agile service of an expert distributor, offering a unique value proposition.

Strengths:
Metal Zenith's core strength lies in its unwavering commitment to quality and precision. They implement a rigorous 10-point quality inspection process, ensuring materials like their high-strength steel coils meet and exceed international standards such as ASTM A1008 and JIS G3141. With a technical team possessing over 15 years of engineering experience, they provide comprehensive support from material selection to final application analysis, helping clients optimize for both cost and performance.

Specializations:
The company specializes in providing fully customized steel solutions, including carbon steel flanges manufactured to precise specifications. Their product offerings include various grades like HRB400 and SS400, available with multiple surface finishes. Leveraging both BOF and EAF steelmaking technologies through their partnership, they can cater to a wide spectrum of industrial needs, from large-scale construction and infrastructure projects to demanding automotive and manufacturing applications. Their proven ability to deliver over 5 million tons worldwide with a 95% client retention rate speaks to their reliability and customer-centric approach.

Coastal Flange, Inc.

Company Overview:
Operating since 1986, Coastal Flange is a US-based manufacturer with a distinct specialization in large-diameter carbon steel flanges. Headquartered in Houston, Texas, they have perfected their manufacturing processes to deliver high-quality, often custom-engineered, products. While their primary market is North America, they are steadily growing their global footprint.

Strengths:
The key differentiator for Coastal Flange is their expertise in manufacturing large-diameter flanges, stocking domestic options from 26" through 96". This is a niche that many suppliers cannot fill from inventory. They leverage cutting-edge technology to ensure rapid lead times without compromising on quality, a crucial factor for large-scale infrastructure projects in the waterworks, petrochemical, and oil & gas industries.

Specializations:
Coastal Flange is the ideal partner for projects requiring non-standard or custom-engineered flanges. They can manufacture to customer-provided dimensions or to published specifications such as ASME, ANSI, and AWWA. Their product catalog prominently features Slip-On, Weld-Neck, and Blind flanges, with a clear focus on custom solutions for heavy industrial applications.

Ulma Forja, S. Coop.

Company Overview:
Part of the Mondragon Corporation, Ulma Forja is a world-leading flange manufacturer based in Spain. With a global presence and a history of engineering excellence, Ulma is synonymous with high-quality, high-specification forged steel components. They serve the most demanding industries where performance and reliability under extreme conditions are non-negotiable.

Strengths:
Ulma's strength is its advanced manufacturing and forging capabilities. They produce a wide range of flanges in carbon steel, stainless steel, and exotic alloys designed for high-pressure, high-temperature, and corrosive environments. Their commitment to R&D and stringent quality control has made them a preferred supplier for major EPC (Engineering, Procurement, and Construction) contractors worldwide.

Specializations:
Ulma specializes in flanges for critical service applications, particularly in the offshore oil & gas, subsea, and nuclear power sectors. They are experts in producing large-diameter flanges, compact flanges, and custom-designed swivel-ring and anchor flanges. Their ability to meet complex project specifications and provide extensive documentation makes them a leader in the high-end market.

Mattsco Supply Company

Company Overview:
With nearly 50 years of experience, Mattsco Supply Company is a trusted US-based distributor of pipes, fittings, and flanges. Based in Tulsa, Oklahoma, they have built their business on a foundation of reliability, timely delivery, and customer-focused service. They position themselves as a dependable partner for projects where supply chain efficiency is critical.

Strengths:
Mattsco's primary strength is its service-oriented approach. They understand the pain points of their customers, such as the need for on-time delivery and adherence to industry standards. Their extensive inventory of carbon steel flanges, ranging from 1/2" to 36" and covering various pressure classes, ensures they can meet a wide variety of project requirements quickly and efficiently.

Specializations:
As a distributor, Mattsco specializes in providing a comprehensive piping solution. They supply high-quality carbon steel flanges that are durable and cost-effective for industries like oil and gas, water treatment, and construction. Their value proposition is centered on being a one-stop shop that simplifies procurement and ensures projects stay on track.

Eastern Steels

Company Overview:
Eastern Steels is a prominent manufacturer, supplier, and exporter of flanges based in Mumbai, India. The company has carved out a significant position in the global market by offering a wide range of competitively priced, high-quality flanges. They serve a diverse international client base across the Middle East, Southeast Asia, and beyond.

Strengths:
The company's main advantage is its ability to produce a vast array of flanges conforming to all major international standards (ASME, EN, DIN, BS) at a competitive price point. Their integrated manufacturing facility allows for tight quality control, from raw material sourcing to final inspection. This combination of quality and cost-effectiveness makes them an attractive option for large-volume orders.

Specializations:
Eastern Steels specializes in producing a comprehensive range of flange types, including weld neck, slip-on, socket weld, and blind flanges in carbon steel, alloy steel, and stainless steel. They are particularly adept at serving the needs of the chemical, fertilizer, and oil & gas industries. Their flexibility in manufacturing and ability to meet diverse international standards is a key part of their service.

Bebitz GmbH

Company Overview:
Located in Germany, Bebitz is a classic example of German engineering and manufacturing prowess. As a family-owned company with a long history, they are a leading European manufacturer of flanges and forged fittings. Their reputation is built on precision, quality, and adherence to the highest technical standards.

Strengths:
Bebitz's core strength is its highly automated and efficient production process, which guarantees consistent quality and dimensional accuracy. They are known for their reliability and adherence to delivery schedules. Their products are manufactured strictly according to DIN, EN, and ASME standards, making them a trusted name in industries where precision is critical.

Specializations:
Bebitz specializes in the production of standard flanges according to DIN and EN specifications, which are widely used throughout Europe and in projects specified with European standards. They are a major supplier to the chemical industry, plant engineering, and power generation sectors. Their focus is on producing flawless, standard-compliant carbon and stainless steel flanges rather than highly exotic custom work.

HYDAC Technology Corporation

Company Overview:
HYDAC is a global giant in fluid power technology, with a significant manufacturing presence in the United States and worldwide. While their portfolio is vast, their flange offerings are highly specialized and integral to their hydraulic systems. They are a large-revenue company known for innovation and system-integrated solutions.

Strengths:
As a large, vertically integrated manufacturer, HYDAC's strength lies in its systems-based approach. Their flanges are designed to work seamlessly with their other hydraulic components, such as tanks, filters, and accumulators. They hold numerous certifications, including ASME and OHSAS 18001, reflecting their commitment to quality and safety on a global scale.

Specializations:
HYDAC specializes in tank welding flanges made from low-carbon steel. These are not standard pipe-to-pipe connection flanges but are instead designed for mounting components onto hydraulic reservoirs and tanks. Their products are essential for applications in mobile and industrial hydraulics, serving industries from construction and agriculture to factory automation.

Weldbend Corporation

Company Overview:
For over 70 years, Weldbend has been a leading US domestic manufacturer of carbon steel fittings and flanges. Based in Illinois, the company is fiercely committed to producing 100% American-made products. They are a cornerstone of the domestic supply chain for industrial piping components.

Strengths:
Weldbend's greatest strength is its unwavering commitment to domestic manufacturing. This provides customers with an assurance of quality, material traceability, and insulation from the volatility of international supply chains. Their massive inventory and efficient distribution network mean they can deliver standard fittings and flanges across the country with very short lead times.

Specializations:
Weldbend focuses exclusively on producing the most commonly used carbon steel butt-weld fittings and flanges. Their product line is straightforward and centered on quality over breadth of materials. They are a primary supplier for projects that specify or prefer domestically manufactured components, particularly in the power generation, pipeline, and mechanical contracting industries.

Octal Flange

Company Overview:
Octal Flange is a China-based supplier that concentrates on providing a diverse range of steel flanges to industrial companies globally. Their business model is built around large, multi-location inventories and rapid response times. They represent the agile and service-focused segment of the modern industrial supply market.

Strengths:
The primary advantage of Octal Flange is its extensive in-stock material, which allows them to fulfill urgent requirements quickly. They are highly responsive, promising quick quotations and leveraging their inventory in both northern and southern China to optimize logistics. This agility is a major benefit for buyers needing standard flanges without long manufacturing lead times.

Specializations:
Octal Flange specializes in supplying carbon steel flanges made to common standards like ASTM A105N and MSS SP-44, with pressure ratings from Class 150 to 2500. They serve as a flexible source for a wide variety of standard flange types. Their model is particularly well-suited for distributors and end-users who value speed and inventory availability for standard maintenance and project work.

Making the Final Decision: Your Actionable Checklist

Choosing the right carbon steel flange supplier is a strategic decision that safeguards the integrity of your industrial systems. The ideal partner is not merely a vendor but a collaborator who understands your technical requirements, respects your project timelines, and is committed to delivering certified, high-quality products. The diverse companies listed above—from large-scale domestic manufacturers to specialized international producers—offer a range of solutions to fit nearly any application.

As you make your final selection, move beyond the quote and evaluate the supplier's holistic value. A partner who provides robust technical support, transparent documentation, and a reliable supply chain will deliver greater long-term benefits than one who simply offers the lowest price. By making a well-informed choice, you secure not just a flange, but peace of mind.

To finalize your decision, use this practical checklist:

• Verify Certifications: Insist on seeing current ASME, ASTM, and ISO certifications. Request Material Test Reports (MTRs) for full traceability.
• Match Flange to Application: Confirm the material grade (e.g., ASTM A105) and pressure class are appropriate for your system's operating pressure and temperature.
• Assess Technical Support: Gauge the supplier's ability to answer technical questions and guide you to the correct product.
• Confirm Logistics: Inquire about current inventory levels, typical lead times for your required items, and their track record for on-time delivery.