From Standard Industrial Flanges to Custom Flanges, we offer a wide variety of Stainless Steel flanges made from high-quality materials including carbon steel, stainless steel, alloy steel, duplex stainless steel, and other specialized metals. Our SS flanges are designed to meet various industry standards, including AWWA, ANSI, ASME, DIN, JIS, GB and BS. Trust us to provide reliable, customized solutions to protect your piping system.
Stainless Steel Flanges come in several key types, selection depends on factors like pressure, temperature, ease of maintenance, and system requirements, each designed for specific applications:
Weld neck flange: Offers superior strength for high-pressure and high-temperature systems
Slip on flange: Easy to install and align, cost-effective for lower pressure applications
Blind flange: Solid disc used to seal off pipe ends or openings
Threaded flange: Allows quick assembly without welding, suitable for low-pressure systems
Lap joint flange: Accommodates thermal expansion and frequent dismantling
Our custom flanges are made to specific sizes and materials for unique applications. Can be modified from standard designs or created from scratch to meet various industry requirements.
Available Stainless Steel Flange Grades & Composition
Type
Grade of Steel
Chemical component(mass fraction)%
C
Si
Mn
Cr
Ni
Mo
Cu
Ti
Nb
N
P
S
Austenitic
S30408
≤0.08
≤1.00
≤2.00
18.00-20.00
8.00-10.50
—
——
——
—
—
≤0.035
≤0.020
S30403
≤0.030
≤1.00
≤2.00
18.00-20.00
8.00-12.00
—
—
—
—
—
≤0.035
≤0.020
S30409
0.4-0.10
≤1.00
≤2.00
18.00-20.00
8.00-10.50
—
—
—
—
—
≤0.035
≤0.020
S32168
≤0.08
≤1.00
≤2.00
17.00-19.00
9.00-12.00
—
—
5xC-0.70
—
—
≤0.035
≤0.020
S34779
0.04-0.10
≤1.00
≤2.00
17.00-19.00
9.00-12.00
—
—
—
8xC-1.10
—
≤0.035
≤0.020
S31608
≤0.08
≤1.00
≤2.00
16.00-18.00
10.00-14.00
2.00-3.00
—
—
—
—
≤0.035
≤0.020
S31603
≤0.030
≤1.00
≤2.00
16.00-18.00
10.00-14.00
2.00-3.00
—
—
—
—
≤0.035
≤0.020
S31609
0.04-0.10
≤1.00
≤2.00
16.00-18.00
10.00-14.00
2.00-3.00
—
—
—
—
≤0.035
≤0.020
S31668
≤0.08
≤1.00
≤2.00
16.00-18.00
10.00-14.00
2.00-3.00
—
5xC-0.70
—
—
≤0.035
≤0.020
S31703
≤0.030
≤1.00
≤2.00
18.00-20.00
11.00-15.00
3.00-4.00
—
——
—
—
≤0.035
≤0.020
S31008
0.04-0.08
≤1.00
≤2.00
24.00-26.00
19.00-22.00
—
—
—
—
—
≤0.035
≤0.020
S39042
≤0.020
≤1.00
≤2.00
19.00-21.00
24.00-26.00
4.00-5.00
1.20-2.00
—
—
≤0.10
≤0.030
≤0.010
Austenitic Monotonic Type
S21953
≤0.030
1.30-2.00
1.00-2.00
18.00-19.50
4.50-5.50
2.50-3.00
—
—
——
0.05-0.12
≤0.030
≤0.020
S22253
≤0.030
≤1.00
≤2.00
21.00-23.00
4.50-6.50
2.50-3.00
—
—
—
0.08-0.20
≤0.030
≤0.020
S22053
≤0.030
≤1.00
≤2.00
22.00-23.00
4.50-6.50
3.00-3.50
—
—
—
0.14-1.10
≤0.030
≤0.020
Our Austenitic Stainless Steel Flange in Grading Systems
No.
China
America
Korea
European Union BSEN
India IS
Australia AS
Taiwan,China CNS
Old Brand
New Brand (07.10)
Japan
ASTM
UNS
KS
1
1Cr17Mn6Ni5N
12Cr17Mn6Ni5N
SUS201
201
S20100
STS201
1.4372
10Cr17Mn6Ni4N²⁰
201-2
201
2
1Cr18Mn8Ni5N
12Cr18Mn9Ni5N
SUS202
202
S20200
STS202
1.4373
—
—
202
3
1Cr17Ni17
12Cr17Ni7
SUS3014
301
S30100
STS301
1.4319
10Cr17Ni7
301
301
4
0Cr18Ni9
06Cr19Ni10
SUS304
304
S30400
STS304
1.4301
07Cr18Ni9
304
304
5
00Cr19Ni10
022Cr19Ni10
SUS304L
304L
S30403
STS304L
1.4306
02Cr18Ni11
304L
304L
6
0Cr19Ni9N
06Cr19Ni10N
SUS304N1
304N
S30451
STS304N1
1.4315
—
304N1
304N1
7
0Cr19Ni10NbN
06Cr19Ni9NbN
SUS304N2
XM21
S30452
STS304N2
—
—
304N2
304N2
8
00Cr18Ni10N
022Cr19Ni10N
SUS304LN
304LN
S30453
STS304LN
—
—
304LN
304LN
9
1Cr18Ni12
10Cr18Ni12
SUS305
305
530500
STS305
1.4303
—
305
305
What are Industry Standards of Pipe Flanges?
ANSI (American National Standards Institute):
Sizes: Typically from 1/2″ to 24″ for ANSI B16.5; larger sizes for ANSI B16.47.
Pressure Ratings: Ranges from 150 LB to 2500 LB.
ASME (American Society of Mechanical Engineers):
Sizes: ASME B16.5 NPS 1/2 through NPS 24; ASME B16.47 NPS 26 through NPS 60.
The 304 and 304L stainless steel flanges differ mainly in carbon content (0.08% vs 0.03%). 304 serves general industrial use in food and chemical equipment, while 304L excels in welded systems. Both contain 18% chromium and 8% nickel, with 304L preventing weld point corrosion, making it better for maintenance-heavy applications.
316L Series Stainless Steel Flange
316L steel flanges is the premium choice for harsh environments. It’s got 2% molybdenum added to the mix, making it tougher against corrosion than 304. The low carbon content (0.03%) means better welding properties. Marine equipment, chemical processing, and pharmaceutical plants use this grade extensively. When you need flanged stainless steel fittings that can handle aggressive chemicals or saltwater, 316L delivers.
2205 (F51) Duplex Metal Flange
2205 is the workhouse of the duplex range. With 22% chromium and 5% nickel, it’s twice as strong as regular stainless steel flanges. It resists corrosion better than 304 or 316L and costs less than super duplex options. Oil rigs, chemical plants, and high-pressure systems rely on 2205 flanges. It’s the sweet spot between performance and price for demanding applications.
2507 (F53) Super Duplex Steel Pipe Flange
2507 is the tank of flange materials. 25% chromium and 7% nickel make it virtually bulletproof against corrosion. It’s the strongest option in the lineup. Offshore platforms, desalination plants, and high-pressure chemical systems use 2507 flanges. When failure isn’t an option, and budget isn’t your primary concern, this is your material.
TP310S Stainless Steel Flange
TP310S handles extreme heat like a champion. With 25% chromium and 20% nickel, it’s built for high-temperature applications. You’ll find these flanges in furnaces, heat exchangers, and hot chemical processing. When your system runs hot enough to make other grades sweat, TP310S keeps its cool.
TP321 Stainless Steel Pipe Flange
TP321 is the titanium-enhanced version of 304. The titanium addition prevents corrosion issues during welding and high-temperature use. Aircraft parts, chemical processors, and pressure vessels use this grade. It’s the go-to choice when you need a ss flange that can handle both heat and frequent welding without compromising strength or corrosion resistance.
Compliance Certificates
Why Choose LONGAN Flange?
Expertise in Flange Manufacturing: Longan Flange specializes in producing a wide range of flanges and custom non-standard products, ensuring we meet diverse industry needs with precision.
Advanced Manufacturing Capabilities: With over 100 CNC lathes, 10 machining lathes, and 16 high-precision machining centers, we leverage advanced technology for efficient and high-quality production.
Rigorous Quality Assurance: Our independent laboratory equipped with 15 testing devices ensures extensive testing of each flange, guaranteeing they meet specifications and providing reliable performance.
Commitment to Customization and Standards: We offer tailor-made solutions while adhering to established industry standards, ensuring seamless compatibility and exceptional quality tailored to your project requirements.
Yes, we provide certifications. We have obtained many domestic and international certifications, including CE, Quality Management System, and Environmental Management System certifications.
When you buy forged flange parts, you don’t have to buy a certain amount. But if you want a length that’s more than 2 meters, you’ll need to buy at least 10 pieces.
We package our big, heavy flanges in wooden crates and the small, light ones in cardboard boxes. The choice depends on what kind of flange it is, its size, weight, and how far it needs to be transported.
When making flanges, we mainly use stainless steel, but we also use other special materials based on what the flange is for and what the customer wants.
Get In touch
Address
620 Kongo Mingzhu Road, Yongxing Street, Longwan District, Wenzhou City, Zhejiang Province, China.