High-Quality Neck Flange for Reliable Pipe Connections

Main Keyword: neck flange
Butt weld flange
Weld neck flange

Discover the latest advancements, meticulous manufacturing, and global applications of
neck flange components. This comprehensive guide by industry engineers fuses trusted data,
product specifications, and real-world expertise to ensure optimum selection and deployment for your projects.

1. Neck Flange & Butt Weld Flange: Overview and Industry Trends (2024)

The neck flange—often referenced as butt weld flange or weld neck flange—remains a critical component in the global piping industry, facilitating secure, leak-proof connections in pipelines under high pressure or temperature. According to the latest (Global Market Insights, 2023), the industrial flanges market surpassed
USD 6 billion and is projected to register over 4.8% CAGR from 2024 to 2030, majorly driven by increasing adoption in oil & gas, power generation, and chemical sectors.

Figure 1: Neck flange optimized for high-pressure systems

Core Parameters Table: **Neck Flange** Types (Butt Weld & Weld Neck)
Flange Type	Connection	Pressure Class (PN/ASME)	Main Materials	Dimension (inches/MM)	Certification/Standard
Weld Neck Flange	Welded (Butt Weld)	PN6~PN250 Class 150~2500	CS, SS, ASTM A105, A182 F304/316, Duplex	1”–48” / DN25–DN1200	ISO 7005, ANSI B16.5, EN 1092-1, JIS B2220
Butt Weld Flange	Welded (Butt Weld)	PN10~PN160 Class 150~1500	Carbon Steel, Alloy, Stainless Steel	2”–24” / DN50–DN600	ANSI B16.47, API 6A, GOST, DIN

Butt-weld neck flanges are renowned for their integral neck, which is welded directly to the pipe, providing superior mechanical strength and stress distribution at the base of the flange neck—making them an ideal solution for critical pipelines.

Market Adoption Across Sectors

Oil & Gas: Enhanced leak-proof performance for sour service lines.
Chemicals: High corrosion resistance, FDA/ISO compliance for process safety.
Water Treatment: Longevity in aggressive environments, low maintenance.
Power Generation: High-pressure, high-temperature sustainability.

2. Manufacturing Process of Neck Flange (With Flowchart)

The manufacturing quality of a neck flange is pivotal to its performance. Below is a stepwise graphical overview of the production of Butt-Weld Neck Flanges.

Raw Material Selection

Key grades: ASTM A105, 304/316L, F51, F53, etc.
Verification by PMI, chemical & mechanical testing.

Forging/Heat Treatment

Forged billet forms the grain, improved from casting. Normalizing or quenching increases toughness.

CNC Machining

Digital CNC lathes provide strict tolerance, precise bore & neck dimensions (±0.05mm).

Non-Destructive Testing

Ultrasonic/RT/MT as per API/ASME; verifies internal soundness, ISO/EN compliant.

Final Inspection & Marking

Dimensional, PMI, pressure & surface finish tests; marking for full traceability.

(See more: Production Video: Neck Flanges)

Figure 2: Forging & CNC process in neck flange manufacture

Technical Analysis: Material, Standards, and Performance

Material: Carbon steel for cost-effectiveness, stainless steel (304/316L) for corrosion resistance, duplex/super-duplex for critical services.
Standards Complied: ISO 7005, ANSI B16.5/B16.47, EN 1092-1, API 6A/B, NACE MR0175, GOST 12820.
Testing: PMI (Positive Material Identification), UT, RT, hydrostatic/air leak test.
Service Life: 25–40+ years in optimal conditions (Field Data: API RP 574, 2022).

3. Key Specifications & Data Visualization

Essential Technical Indices for Butt-Weld Neck Flanges

Pressure Classes (ASME): Class 150–2500

Material Usage Distribution (2024, Industry Survey)

Average Service Life by Material (years)

Figure 3: Internationally certified weld neck flange options

Product Specification Table: Butt-Weld Neck Flanges (Selected)

Model	Size (in/DN)	Pressure Rating	Facing	Material	Standard	Design Temp.(°C)
JYPN-150-6	6″/DN150	Class150 / PN20	RF	ASTM A105	ANSI B16.5	-29~345
JYPN-300-10	10″/DN250	Class300 / PN50	RTJ	ASTM F316L	EN 1092-1	-46~600
JYPN-600-12	12″/DN300	Class600 / PN100	RF	Duplex 1.4462	ASME B16.47	-50~650
JYPN-900-24	24″/DN600	Class900 / PN150	FM	ASTM A105N	DIN 2633	-29~400

4. Industry Competitor Comparison

Selecting a reliable neck flange supplier is crucial for project security and cost-effectiveness.
Below is a summarized review of major global and Chinese manufacturers, focusing on certification, lead time, and customization.

Key Competitor Matrix
Company	Certifications	MOQ	Delivery	Customization	Year Established
Jianyang Pipeline	ISO 9001:2015, PED, EN10204 API, CE, SGS, Bureau Veritas	1 piece	10–45 days	All (design+material+coating)	1998
Ulma Forge (Spain)	ISO, ASME, PED	5 pieces	25–60 days	Partial	1962
Bonney Forge (USA)	ASME, ISO	5 pieces	35–80 days	Limited	1876
Kofco (Korea)	ISO, MSS SP-44, API	10 pieces	40+ days	No	1981

Figure 4: Neck flange finished products inspected per ISO

5. Customization, Delivery, and Quality Promise

Tailored Solutions for Global Projects

Customizable material grades, facings (RF, RTJ, FM), coatings (PTFE, Xylan), and branding.
Full-size & non-standard dimensions as per client design—CAD drawings & 3D samples supported.
Extensive documentation: EN10204 3.1/3.2, radiography, pressure and finish certificates.

Lead Time: 1–2 weeks for stock, 3–6 weeks for engineered/custom orders.
Warranty: 24–60 months based on specification and service.
Support: 8D complaint process, on-site support, spare parts, field measurement & remote guidance.

Compliance & Authoritativeness

Verified by major EPCs: Sinopec, Shell, Aramco, BASF, PetroChina.
100% adherence to ISO 9001, CE, PED/97/23/EC, API, EN10204 standards.
Tested for compliance with FDA and ASME for food/pharma projects.

6. Application Cases & Customer Feedback

Case 1: Offshore Oil Platform (Saudi Aramco, 2023)

Project: Sulphur pipeline replacement under H2S conditions
Product: NACE duplex weld neck flanges DN400/16″, Class 600
Feedback: “Zero leakage after 30 months in service at 290°C. Inspection passed DNV/GL, surfaces had no corrosion. Outstanding quality.” — Project QA Lead

Case 2: Petrochemical Complex, Europe

Product: Butt-weld neck flanges, ASTM F316L, DN80–DN500
Certification: LRS, EN10204 3.2 TPI
Result: Service life exceeded 12 years in highly corrosive acid lines; quick-replacement feature reduced downtime by 36%.

Case 3: Water Treatment (Southeast Asia, 2022)

Flange: Epoxy-coated carbon steel neck flange, Class 150, DN250
Advantage: Cost-effective, with 8% higher flow efficiency after CAD optimization; zero failure in three years.

Contact Us for Tailored Neck Flange Solutions

7. Professional FAQ for Butt-Weld Neck Flanges

Q1: What are the main materials used for neck flange production?

A: Commonly, ASTM A105 (carbon steel), A182 F304/F316 (stainless steel), duplex 2205, and special alloys (for sour service) are used, depending on corrosion, temperature, and pressure demands.

Q2: How do I select the appropriate pressure class for my butt weld flange?

A: Pressure class is determined by system design pressure, operating temperature, and applicable standards (ASME/ANSI). For example: Class 300 (51.1 bar) is common for oil pipes; Class 600+ for higher-risk applications.

Q3: What is the welding process for a weld neck flange?

A: The preferred method is butt-welding using GTAW (TIG) or GMAW (MIG/MAG), followed by post-weld heat treatment (PWHT) for thicker/critical sections to reduce residual stress.

Q4: What international standards do you comply with?

A: Products are manufactured to ISO 7005, ANSI/ASME B16.5, EN 1092-1, API 6A, GB/T 9119, and GOST 12820. Each item is delivered with traceable test and inspection documents.

Q5: Is 100% NDT (Non-Destructive Testing) available?

A: Yes. Ultrasonic (UT), Magnetic Particle (MT), and Radiography (RT) are performed per client and standard requirements. NDT is mandatory for Class 600+ and critical services.

Q6: What post-delivery support and warranty do you offer?

A: All neck flanges come with a 2–5 year warranty. Support covers rapid claim handling, root-cause analysis (8D), on-site or remote technical support, and after-sales spare parts logistics.

Q7: Can I request custom markings or IDs on the flanges?

A: Yes. Laser/emboss engraving for logo, batch, project codes, or barcodes is available in compliance with international marking standards (ISO/EN/ANSI).

8. Conclusion: Why Choose Certified Neck Flange Solutions?

Opting for a certified and expertly manufactured neck flange guarantees:

Unmatched integrity in high-pressure, aggressive chemical, or cyclic temperature environments.
Backed by global certifications (ISO, ANSI, CE) and real performance data;
Endorsed by leading EPCs and subject to rigorous NDT & QA procedures.
Flexible customization and fast global delivery.

For more technical papers and peer experience on neck flanges, refer to:

Industry Source 1:
Weld Neck Flange Features & Best Practices
Industry Source 2:
Eng-Tips Forum – Neck and Butt Weld Flange Selection
Industry Source 3:
ScienceDirect – Investigation of High-Pressure Flange Joints

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