Zhejiang Chengjiu Pipeline Co., Ltd. is one of the most reliable manufacturers and suppliers of stainless steel plate flanges in China, also supports customized service. Please feel free to buy high quality stainless steel plate flanges from our factory. Good service and reasonable price are available.
The flange standards of the PN series
The PN Flange series stainless steel Plate flanges are widely used in industrial piping systems around the world. Their standardized design mainly follows general systems such as EN (European standards), ISO (International standards), etc. Meanwhile, national or regional standards such as DIN (German standards), BS (British standards), GOST (Russian standards), AS (Australian standards), UNI (Italian standards), etc. are also commonly applicable in corresponding markets.
Standard details
| EN092-1 TYPE 01 Flat flange |
| EN092-1 TYPE 02/32 Loose flanges |
| EN092-1 TYPE 02/35 Loose flanges |
| EN092-1 TYPE 02/36 Loose flanges |
| EN092-1 TYPE 02/37 Loose flanges |
| EN092-1 TYPE 04/34 Loose flanges |
| EN092-1 TYPE 05 Blind Flanges |
| EN092-1 TYPE 11 Welding neck Flange |
| EN092-1 TYPE 12 Slip on flange |
| EN092-1 TYPE 13 Thread flange with neck |
| BS T/D Flange |
| BS T/E Flange |
| BS 4504 PN16 Flange |
| BS 4504 PN25 Flange |
| BS 4504 PN40 Flange |
| BS 4504 PN64 Flange |
| ISO 9624 Flange |
| ISO 7005-1 Flange |
| XFE 29203 Flange |
| AS/NZS 4331.1 Flange |
| AS 4087 PN16/21 Flange |
| AS 2129 T/D. T/E Flange |
| NS Flange |
| SABS / SANS 1123 T600 /2 /3 /4 /5 /8 Flange |
| SABS / SANS 1123 T1000 /2 /3 /4 /5 /8 Flange |
| SABS / SANS 1123 T1600 /2 /3 /4 /5 /8 Flange |
| SABS / SANS 1123 T2500 /2 /3 /4 /5 /8 Flange |
| SABS / SANS 1123 T4000 /2 /3 /4 /5 /8 Flange |
| SABS / SANS 1123 1000/3 Backing Ring Flange |
| SABS / SANS 1123 1600/3 Backing Ring Flange |
| SABS / SANS 1123 T/D Backing Rins Flange |
| UNI 2276 PN6 Plate flange |
| UNI 2277 PN10 Plate flange |
| UNI 2278 PN16 Plate flange |
| UNI 6083 PN25 Plate flange |
| UNI 6084 PN40 Plate flange |
| UNI 2280 PN6 Welded neck Flange |
| UNI 2281 PN10 Welded neck Flange |
| UNI 2282 PN16 Welded neck Flange |
| UNI 2283 PN25 Welded neck Flange |
| UNI 2284 PN40 Welded neck Flange |
| UNI 2253 PN6 Threaded Flange |
| UNI 2254 PN16 Threaded Flange |
| UNI 6091 PN6 Blank Flange |
| UNI 6092 PN10 Blank Flange |
| UNI 6093 PN16 Blank Flange |
| UNI 6094 PN25 Blank Flange |
| UNI 6095 PN40 Blank Flange |
| UNI 6088 PN6 Loose flanges |
| UNI 6089 PN10 Loose flanges |
| UNI 6090 PN16 Loose flanges |
| DIN2527 Blind Flanges |
| DIN 2501 Plate Flange |
| DIN 2502 Plate Flange |
| DIN 2503 Plate Flange |
| DIN 2543 PN16 Plate Flange |
| DIN 2544 PN25 Plate Flange |
| DIN 2545 PN40 Plate Flange |
| DIN 2573 PN6 Flat flange for welding |
| DIN 2576 PN10 Flat flange for welding |
| DIN2630 Welding neck Flange |
| DIN 2631 PN6 Welding neck Flange |
| DIN 2632 PN10 Welding neck Flange |
| DIN 2633 PN16 Welding neck Flange |
| DIN 2634 PN25 Welding neck Flange |
| DIN 2635 PN40 Welding neck Flange |
| DIN 2636 PN64 Welding neck Flange |
| DIN 2637 PN100 Welding neck Flange |
| DIN 2638 PN160 Welding neck Flange |
| DIN 2628 PN250 Welding neck Flange |
| DIN 2629 PN320 Welding neck Flange |
| DIN 2627 PN400 Welding neck Flange |
| DIN 2641 PN6 Lapped Flange, Plain collars |
| DIN 2642 PN10 Lapped Flange, Plain collars |
| DIN 2652 PN6 Loose flanges and rings with neck |
| DIN 2653 PN10 Loose flanges and rings with neck |
| DIN 2655 PN25 Loose flanges and rings with neck |
| DIN 2656 PN40 Loose flanges and rings with neck |
| DIN 2673 PN10 Loose flanges and rings with neck |
| DIN 2558 PN6 Oval plain threaded flanges |
| DIN 2561 Oval flanges, with neck threaded |
| DIN 2561 PN10 Oval flanges, with neck threaded |
| DIN 2561 PN16 Oval flanges, with neck threaded |
| DIN 2565 PN6 Thread flange with neck |
| DIN 2566 PN10/16 Thread flange with neck |
| DIN 2567 PN25/40 Thread flange with neck |
| DIN 2568 PN64 Thread flange with neck |
| DIN 2569 PN100 Thread flange with neck |
| DIN 28115 Long neck welding flanges |
| DIN 86030 PN16 Slip on flange |
| DIN 2554 PN16 Slip on flange |
How to choose the type of flat flange
Flat flange weld beveling
1. Improves welding quality and strength
2. Applicable to pipes with a thickness of ≥ 5mm
3. Enhances structural load-bearing capacity
4. Ensures sealing performance and safety
5. Reduces welding deformation
Flat Flange Weld Without Beveling
1. Easy installation
2. Suitable for thin-walled pipes
3. Reduces the risk of welding deformation
4. Applicable to low-pressure, normal-temperature, non-corrosive media
FLANGE FACE FINISH TYPES
STOCK FINISH
It is the most widely used of any flange surface finish, because practically, is suitable for all ordinary service conditions. Under compression, the soft face from a gasket will embed into this finish, which helps create a seal, and a high level of friction is generated between the mating surfaces. The finish for these flanges is generated by a 1.6 mm radius round-nosed tool at a feed rate of 0.8 mm per revolution up to 12 inch. For sizes 14 inch and larger, the finish is made with 3.2 mm round-nosed tool at a feed of 1.2 mm per revolution.
SPIRAL SERRATED
This is also a continuous or phonographic spiral groove, but it differs from the stock finish in that the groove typically is generated using a 90-° tool which creates a "V" geometry with 45° angled serration.
CONCENTRIC SERRATED
As the name suggests, this finish is comprised of concentric grooves. A 90° tool is used and the serrations are spaced evenly across the face.
SMOOTH FINISH
This finish shows no visually apparent tool markings. These finishes are typically utilized for gaskets with metal facings such as double jacketed, flat steel and corrugated metal. The smooth surfaces mate to create a seal and depend on the flatness of the opposing faces to effect a seal. This is typically achieved by having the gasket contact surface formed by a continuous (sometimes called phonographic) spiral groove generated by a 0.8 mm radius round-nosed tool at a feed rate of 0.3 mm per revolution with a depth of 0.05 mm. This will result in a roughness between Ra 3.2 and 6.3 micrometers (125 – 250 micro inch).
STOCK FINISH
SPIRAL SERRATED
CONCENTRIC SERRATED
SMOOTH FINISH
FLANGE FACE TYPES
RAISED FACE FLANGE (RF)
A raised face flange (RF) is easy to recognize as the gasket surface area is positioned above the bolting line of the flange. A raised face flange is compatible with a wide range of flange gaskets, ranging from flat to semi-metallic and metallic types (as, for example, jacketed gaskets and spiral wound gaskets), either ring or full face.
FLAT FACE FLANGE (FF)
Flat face flanges (FF) have a contact surface having the same height as the bolting line of the flange. Full face gaskets, generally of the soft type, are used between two flat face flanges. According to ASME B31.3, a flat face flange should never be mated with a raised face flange as the resulting flanged joint would definitely leak.
RING JOINT FLANGE (RTJ)
A ring joint flanges (RTJ) is used when a metal-to-metal seal between the mating flanges is required (which is a condition for high-pressure and high-temperature applications, i.e. above 700/800 C°). A ring joint flange features a circular groove to accommodate a ring joint gasket (oval, or rectangular). RTJ flanges can be sealed by RTJ gaskets of different styles (R, RX, BX) and profiles (example: octagonal/oval for the R style).
LAP JOINT FLANGE
A lap joint flange has a flat face, which is not used to seal the flanged joint but simply hosts the back of a stub end. The sealing surface is actually on the stub end itself and may be either flat face or raised face.
TONGUE AND GROOVE FLANGE (T AND G)
Two tongue and groove flanges (T&G face) perfectly fit one into the other: one flange has a raised ring, the other a groove and they can be mated easily (the tongue enters the groove and seals the joint).
MALE AND FEMALE FLANGE (M AND F)
Similarly to tongue and groove flanges, male and female flanges (M&F face type) match one to the other as well. One flange has an area extended beyond its face area, the male flange, the other flange has a matching depression machined on the facing surface, the female flange. The female face is 3/16" deep, while the male face is 1/4″ high, and both of them are smooth finished. The outer diameter of the female face retains the gasket.
Marking of flange
PACKAGING
sHIPPING
Process Flow of Flanges
Material Selection
The raw material of stainless steel (SUS304, 316L, 321, 904L, 2205, etc.) is verified by spectrometer analysis, guaranteeing 100% chemical composition accuracy.
Heat Treatment
Forging ensures high product density. Process complies with ASTM A961/A182 for mechanical properties.
ASTM A961 (general requirements for forged steel components) and ASTM A182 (specifics for alloy/stainless steel forgings).
Material grades (e.g., F304, F316, F91) with certified chemistry.
Mechanical properties: Tensile/yield strength, elongation, hardness per grade (e.g., F304: ≥485 MPa tensile, ≥170 MPa yield).
Forging & heat treatment: Hot-forged, then annealed/quenched/tempered for density and strength.
Testing: Mandatory mechanical tests; optional NDT (e.g., UT, PT).
CNC Machining
Precision-turned on CNC lathes for accurate specifications.
Standard tolerance ±0.05mm
Final Inspection
Material Test Certification (EN 10204 3.1 MTC) or PMI (Positive Material Identification) reports are provided free of charge upon delivery.
Additional Testing Services (Charged Separately)
Radiographic Testing (RT)
Ultrasonic Testing (UT)
Magnetic Particle Testing (MT)
Penetrant Testing (PT)
Quality Guarantee
We strictly comply with ISO 9001:2015 Quality Management System, and we openly welcome all third-party factory inspections.
An ISO 9001 certification in a stainless steel flange/fittings factory signifies top-tier quality management, ensuring:
Consistent compliance with ASTM/ASME standards (e.g., A182, A961).
Traceability from raw materials to finished products.
Reliable mechanical performance (strength, corrosion resistance).
company profiles of CNCJ
ZheJiang Chengjiu Pipeline Co., Ltd.
With 12 years of expertise in manufacturing flanges and pipe fittings, we deliver unmatched professionalism. Our robust quality control, high production capacity, and competitive pricing provide you with a distinct advantage in the industry. Choosing us is the smart choice for reliability and value.
12
years
We have been working in the industry since 2012.
120+
equipments
We have over 120+ equipments, showcasing our strong production capabilities and commitment to high-quality production. This extensive range allows us to efficiently meet diverse project requirements and maintain a competitive edge in the industry.
10,000
ANNUAL PRODUCTION VALUE
We have an annual production value of 10,000 tons, demonstrating our strong output capacity and ability to meet market demands effectively.
Stainless steel flange forging process
Precision forging, quality guaranteed
Utilizing advanced forging techniques, we produce high-strength and high-precision stainless steel flanges, ensuring that every product meets the stringent industrial standards.
Professional team, exquisite craftsmanship
With experienced technical teams working in conjunction with modern equipment, we create corrosion-resistant and high-pressure-tolerant high-quality flanges, meeting the needs of various industries.
Strict quality inspection, reliable durability
From raw materials to finished products, we strictly control the entire process to ensure stable performance and long service life of the flanges, providing customers with reliable solutions.
Ready-to-Ship Stainless Steel Flanges – In Stock Now
ANSI, EN, DIN, JIS,GOST, RF, FF, RTJ,150# 300# 600#,900#,1500#, PN10, PN16, PN25, 5K, 10K, etc.
Bulk Stock Available – No MOQ
From standard sizes (1/2" to 48")
Stainless Steel Flanges: ASTM A182 304/304L, 316/316L, 321, 2205,2207, 904L,etc.
Certifications
These certificates demonstrate our commitment to quality, compliance and industry standards.
Unauthorized use or reproduction will be strictly prohibited.
CNCJ Trademark
Malaysia Trademark
Vietnam trademark
CHINJIU Trademark
ISO 9001:2015 Quality Management System
PED 4.3 2014/68/EU (CE EN10204 TYPE 3.1)
Customer visit & Exhibition Display
Certificate of Origin Selection
| Short Name | Full Name | Applicable Countries |
| CO | CERTIFICATE OF ORIGIN THE PEOPLE' S REPUBLIC OF CHINA | United Arab Emirates, Saudi Arabia, Africa |
| FORM A | GENERALIZED SYSTEM OF PREFRENCES CERTIFICATE OF ORIGIN | United Kingdom, France, Germany, Italy, Netherlands, Luxembourg, Belgium, Ireland, Denmark, Greece, Spain, Portugal, Austria, Sweden, Finland, Poland, Hungary, Czech Republic, Slovakia, Slovenia, Estonia, Latvia, Lithuania, Cyprus, Malta, Bulgaria, Romania, Switzerland, Liechtenstein, Norway, Russia, Belarus, Ukraine, Kazakhstan, Japan, Australia, New Zealand, Canada, Turkey |
| FORM B | CERTIFICATE OF ORIGIN Asia-Pacific Trade Agreement | China, India, Sri Lanka, Bangladesh, Laos and South Korea |
| FORM E | ASEAN-CHINA FREE TRADE AREAPREFERENTIAL TARIFFCERTIFICATE OF ORIGIN | China, Laos, Vietnam, Thailand, Myanmar, Cambodia, the Philippines, Brunei, Indonesia, Malaysia and Singapore |
| FORM P | CERTIFICATE OF ORIGIN Form for China-Pakistan FTA | Pakistan |
| FORM F | CERTIFICATE OF ORIGIN Form for China-Chile FTA | Chile |
| FORM N | CERTIFICATE OF ORIGIN Form for China-New Zealand FTA | New Zealand |
| FORM X | CERTIFICATE OF ORIGIN Form for China-Singapore FTA | Singapore |
| FORM S | CERTIFICATE OF ORIGIN Form for China-Switzerland FTA | Switzerland |
| FORM R | CERTIFICATE OF ORIGIN Form for China-Peru FTA | Peru |
| FORM L | CERTIFICATE OF ORIGIN Form for China-Costa Rica FTA | Costa Rica |
| FORM H | Free Trade Agreement between the Two Sides of the Taiwan Strait Origin Certificate | China |
| FORM AU | CERTIFICATE OF ORIGIN Form for China-Australia FTA | Australia |
| FORM KO | CERTIFICATE OF ORIGIN Form for China-Korea FTA | Korea |
FAQ
Q: What types of flanges do you manufacture?
A: We produce a wide range of flanges, including:
- Weld Neck Flanges (WN)
- Slip-On Flanges (SO)
- Plate Flanges (PL)
- Blind Flanges (BL)
- Threaded Flanges (TH)
- Lap Joint / loose Flanges (LJ)
- Socket Weld Flanges (SW)
Materials: stainless steel (304/316/321), alloy steel, Duplex Steel, etc.
Q: What standards do your flanges comply with?
A: Our flanges meet international standards such as:
- ASME B16.5 / B16.47(ANSI/ASME)
- EN 1092-1 (DIN) (UNI)
- JIS B2220
- BS 4504
- GOST 33259
- AS2129
- ISO7005-1
- SABS/SANS 1123
Q: Can you customize flanges (non-standard sizes/materials)?
A: Yes! We offer customized flanges with specific dimensions, materials.
Q: What is your minimum order quantity (MOQ)?
A: MOQ varies by product type. Standard flanges & pipe fittings: one piece; Custom orders: negotiable.
Q: What payment terms do you accept?
A: We accept:
- T/T (Bank Transfer)
- LC (Letter of Credit)
Q: How long is your production lead time?
A: - Standard flanges & pipe fittings: 7–15 days.
- Custom flanges & pipe fittings: 15–30 days (depending on complexity).
Q: What quality certifications do you have?
A: We are certified with:
- ISO 9001:2015
- PED 4.3 2014/68/EU (for CE-marked flanges)
- EN10204 Type 3.1 MTC (Material Test Certificates) provided.
Q: What is your warranty policy?
A: We offer 12 months warranty against manufacturing defects. Damage due to improper installation is excluded.
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