Overview

Flanges and pipe fittings are vital connecting parts of industrial piping systems. Unified manufacturing, dimension, material and testing standards guarantee interchangeability, sealing performance and operational safety. Different regions and industries adopt distinct standard systems. Below introduces the most widely recognized international and domestic standards for flanges and pipe fittings.

1. Main Standards for Pipe Flanges

American Standard (ASME / ANSI System)

ASME B16.5

Covers pipe flanges and flanged fittings, NPS 1/2 ~ NPS 24, pressure classes Class150, 300, 600, 900, 1500, 2500. The most commonly used standard for oil, gas and chemical export projects.

ASME B16.47

Large diameter steel flanges, Series A and Series B, applicable for NPS 26 ~ NPS 60 large-size flanges.

European Standard (EN System)

EN 1092-1

Steel flanges for piping; specifies dimensions, pressure ratings PN6, PN10, PN16, PN25, PN40, PN63, PN100, widely used in European and Middle East projects.

Japanese Standard

JIS B2220

JIS standard steel pipe flanges, frequently adopted in Southeast Asian projects.

Chinese National Standard

GB/T 9113 ~ GB/T 9124

Series standards for steel pipe flanges and gaskets, widely used in domestic engineering projects.

2. Main Standards for Butt-Weld Pipe Fittings

(Elbows, tees, reducers, caps, crosses)

American Standard

ASME B36.10M: Welded and seamless wrought steel pipe

ASME B16.9: Factory-made wrought butt-welding fittings (NPS 1/2–NPS 48)

ASME B16.11: Socket-welding and threaded fittings

European Standard

EN 10253: Butt-weld pipe fittings (Part 1 non-alloy steel, Part 2 alloy steel)

Chinese Standard

GB/T 12459: Steel butt-welded seamless pipe fittings

GB/T 13401: Steel butt-welded welded pipe fittings

3. Material Standards

Standards define raw material chemical composition and mechanical properties:

Carbon steel: ASTM A105, A234 WPB

Stainless steel: ASTM A182 F304/F316, A403 WP304/WP316

Alloy steel: ASTM A182 F11, F22, A234 WP11, WP22

4. Key Testing & Non-destructive Testing Standards

ASTM, EN, GB standards cover visual inspection, dimension check, hardness test, tensile test, chemical analysis

NDT standards: UT, RT, MT, PT for crack and defect detection

Important Selection Reminders

Do not mix different standard systems randomly. ASME flanges cannot match EN flanges directly due to different outer diameters, bolt circle dimensions and sealing face sizes.

Confirm standard, pressure class, nominal diameter, sealing face type and material before ordering.

Clarify test requirements: heat treatment, third-party inspection certificates, MTR material test reports.

About Cangzhou Yunxinda International Trade Co., Ltd.

Cangzhou Yunxinda International Trade Co., Ltd. supplies full-series flanges and pipe fittings compliant with mainstream international standards including ASME B16.5, ASME B16.9, EN1092-1, GB and JIS.

Our product range includes weld neck flange, slip on flange, blind flange, threaded flange, lap joint flange, together with elbows, tees, concentric & eccentric reducers, pipe caps and crosses. Available materials: carbon steel, stainless steel and alloy steel.

We can provide complete MTR material test certificates and support third-party inspection. Products are exported to Southeast Asia, the Middle East, Europe and America for petrochemical, natural gas, power station, water treatment and construction pipeline projects.

We provide professional technical consultation for standard matching, model selection and customized drawing processing. Global buyers are welcome to send inquiries.