Stainless Steel 304L Flanges
Stainless Steel 304L flanges are produced from UNS S30403, the low-carbon variant of the standard 304 grade. With carbon restricted to 0.030% maximum, these flanges resist carbide precipitation in heat-affected zones during and after welding. This makes them the preferred choice over standard 304 wherever flanges are welded into service without post-weld heat treatment. The composition and corrosion performance are otherwise similar to 304, covering atmospheric, mildly acidic, and food-grade environments across chemical processing, pharmaceuticals, water treatment, and food and beverage industries.
Approx Price Range
Price Range of SS 304L Flanges per kg and factors influencing their prices are explained below.
Price Per kg
SS 304L flanges are priced at roughly ₹175 to ₹240/kg. The 304L premium over standard 304 is typically marginal, as most mills supply dual-certified 304/304L material. Request per-piece pricing from your supplier for larger flange sizes.
Factors Affecting Price
Nickel and chromium market rates, flange type, pressure class, NPS size, dual certification requirements, surface finish, and order volume all affect the final cost of DIN 1.4307 flanges.
Types of Stainless Steel 304L Flanges
SS 304L flanges are available in the same full range of configurations as standard 304, covering all standard piping connection methods and pressure classes.
- Weld Neck Flanges (WNRF)
- Slip-On Flanges (SORF)
- Blind Flanges (BLRF)
- Socket Weld Flanges (SWRF)
- Threaded Flanges
- Lap Joint Flanges
- Orifice Flanges
- Reducing Flanges
- Long Weld Neck Flanges
- Spectacle Blind Flanges
- Ring Type Joint Flanges (RTJ)
- Flat Face Flanges (FF)
ASTM A182 F304L Flanges Specifications
The table below covers the key specification parameters for Stainless Steel 304L flanges as per international standards.
|
Parameter |
Details |
|
Standard |
ASTM A182 / ASME SA182 |
|
Dimensions |
ASME B16.5, B16.47 Series A & B, B16.48, DIN, BS4504, EN-1092, JIS B2220 |
|
Pressure Classes |
150#, 300#, 400#, 600#, 900#, 1500#, 2500# / PN6 to PN250 |
|
Size Range |
NPS 1/2" to 48" / DN15 to DN1200 |
|
Facing |
Raised Face (RF), Ring Type Joint (RTJ), Flat Face (FF), Tongue & Groove |
|
Manufacture |
Forged, Cast, Rolled, Plate |
|
Finish |
Plain, Pickled & Passivated, Electro-polished |
Chemical Composition of SS 304L Flanges
The composition below highlights the reduced carbon content of UNS S30403. Carbon at 0.030% maximum is the defining difference from standard 304, preventing sensitisation in welded joints.
|
Element |
Composition (%) |
|
Carbon (C) |
0.030 max |
|
Chromium (Cr) |
18.0 – 20.0 |
|
Nickel (Ni) |
8.0 – 12.0 |
|
Manganese (Mn) |
2.0 max |
|
Silicon (Si) |
0.75 max |
|
Phosphorus (P) |
0.045 max |
|
Sulphur (S) |
0.030 max |
|
Nitrogen (N) |
0.10 max |
|
Iron (Fe) |
Balance |
Mechanical Properties of UNS S30403 Flanges
The mechanical values below apply to ASTM A182 Grade F304L forged flange material. Note that the lower carbon content results in slightly reduced tensile and yield strength compared to standard F304.
|
Property |
Value |
|
Tensile Strength |
485 MPa (70,000 psi) min |
|
Yield Strength (0.2% offset) |
170 MPa (25,000 psi) min |
|
Elongation |
40% min |
|
Hardness |
Max 92 HRB |
Physical Properties of DIN 1.4307 Flanges
The physical properties below assist engineers in assessing thermal behaviour and material suitability for the intended service temperature range.
|
Property |
Value |
|
Density |
7.93 g/cm³ |
|
Melting Range |
1399 – 1454°C (2550 – 2650°F) |
|
Specific Heat |
500 J/kg·°C |
|
Thermal Conductivity |
16.2 W/m·K (at 100°C) |
|
Electrical Resistivity |
0.72 µΩ·m |
|
Modulus of Elasticity |
193 GPa |
|
Coefficient of Thermal Expansion |
17.2 µm/m°C (0–100°C) |
Dimension Chart of Stainless Steel 304L Flanges
The table below lists standard flange dimensions for SS 304L per ASME B16.5 Class 150.
|
NPS (in) |
DN (mm) |
OD (mm) |
Bore (mm) |
PCD (mm) |
Thickness (mm) |
Bolt Holes |
|
1/2 |
15 |
88.9 |
34.9 |
60.3 |
35.1 |
4 x 1/2" |
|
3/4 |
20 |
98.6 |
42.9 |
69.9 |
38.1 |
4 x 1/2" |
|
1 |
25 |
108.0 |
50.8 |
79.4 |
42.9 |
4 x 1/2" |
|
1.1/2 |
40 |
127.0 |
73.0 |
98.4 |
52.3 |
4 x 1/2" |
|
2 |
50 |
152.4 |
92.1 |
120.7 |
58.7 |
4 x 5/8" |
|
3 |
80 |
190.5 |
127.0 |
152.4 |
68.3 |
4 x 5/8" |
|
4 |
100 |
228.6 |
157.2 |
190.5 |
73.0 |
8 x 5/8" |
|
6 |
150 |
279.4 |
215.9 |
241.3 |
82.6 |
8 x 3/4" |
|
8 |
200 |
342.9 |
269.9 |
298.5 |
95.3 |
8 x 3/4" |
|
10 |
250 |
406.4 |
323.8 |
362.0 |
101.6 |
12 x 7/8" |
|
12 |
300 |
482.6 |
381.0 |
431.8 |
114.3 |
12 x 7/8" |
|
14 |
350 |
533.4 |
412.8 |
476.3 |
123.8 |
12 x 1" |
|
16 |
400 |
596.9 |
469.9 |
539.8 |
130.2 |
16 x 1" |
|
18 |
450 |
635.0 |
533.4 |
577.9 |
139.7 |
16 x 1.1/8" |
|
20 |
500 |
698.5 |
584.2 |
635.0 |
149.2 |
20 x 1.1/8" |
|
24 |
600 |
812.8 |
692.2 |
749.3 |
165.1 |
20 x 1.1/4" |
Size Chart of SS 304L Flanges
Stainless Steel 304L flanges are available across the same wide size range as standard 304, covering both ASME and metric international standards.
|
Standard |
Size Range (NPS) |
Size Range (DN) |
Pressure Classes |
|
ASME B16.5 |
1/2" – 24" |
DN15 – DN600 |
150# to 2500# |
|
ASME B16.47 Series A |
26" – 60" |
DN650 – DN1500 |
150# to 900# |
|
ASME B16.47 Series B |
26" – 60" |
DN650 – DN1500 |
75# to 900# |
|
DIN / EN 1092-1 |
DN15 – DN1200 |
DN15 – DN1200 |
PN6 to PN250 |
|
BS 4504 |
1/2" – 48" |
DN15 – DN1200 |
PN6 to PN64 |
|
JIS B2220 |
10A – 1500A |
DN10 – DN1500 |
5K to 63K |
Pressure Rating Chart of ASTM A182 F304L Flanges
The pressure-temperature ratings below apply to SS 304L (Group 2.3) flanges per ASME B16.5. Values are the maximum allowable working pressures in bar at the listed temperature. Note that 304L ratings are lower than standard 304 due to the reduced carbon content.
|
Temp (°C) |
Class 150 (bar) |
Class 300 (bar) |
Class 400 (bar) |
Class 600 (bar) |
Class 900 (bar) |
Class 1500 (bar) |
|
-29 to 38 |
15.1 |
39.8 |
53.0 |
79.5 |
119.3 |
159.1 |
|
50 |
14.8 |
39.0 |
52.0 |
77.9 |
116.9 |
155.8 |
|
100 |
13.8 |
36.4 |
48.5 |
72.7 |
109.1 |
145.5 |
|
150 |
12.6 |
33.2 |
44.3 |
66.5 |
99.7 |
132.9 |
|
200 |
11.5 |
30.4 |
40.5 |
60.7 |
91.1 |
121.5 |
|
250 |
10.4 |
27.6 |
36.8 |
55.2 |
82.7 |
110.3 |
|
300 |
9.4 |
24.9 |
33.2 |
49.8 |
74.7 |
99.6 |
|
375 |
7.9 |
21.0 |
27.9 |
41.9 |
62.8 |
83.8 |
|
425 |
6.5 |
17.2 |
23.0 |
34.5 |
51.7 |
69.0 |
|
450 |
5.6 |
14.8 |
19.8 |
29.6 |
44.5 |
59.3 |
Key Features of Stainless Steel 304L Flanges
SS 304L flanges are used in a similar wide-ranging manner as 304, but with the added advantage of weld-zone corrosion resistance. Here is what makes them the preferred choice for welded assemblies.
- Low carbon content (max 0.030%)
- Often supplied as dual-certified 304/304L material
- Reliable corrosion resistance in atmospheric, mildly acidic, oxidising, and food-grade environments
- Wide temperature service range
- Non-magnetic in the annealed condition
- Good weldability with standard austenitic filler metals
- No pre- or post-weld heat treatment required
- Electropolished surface finish options available for pharmaceutical and food-grade hygienic service
- Available in all standard flange types and pressure classes per ASME B16.5 and EN 1092-1
Applications of UNS S30403 Flanges
The weld-zone corrosion resistance of SS 304L makes these flanges the preferred choice wherever flanged joints will be welded into service without heat treatment.
- Chemical processing
- Pharmaceutical manufacturing
- Food, dairy, and beverages
- Water and wastewater treatment
- Cryogenic service
- Power generation
- Oil and gas
- Pulp and paper
How to Choose the Right Stainless Steel 304L Flanges Supplier?
Keep the following things in mind when choosing the right SS 304L flange supplier.
Supplier Selection Criteria
Check that stock is available in various flange types, sizes, and pressure classes. The most flexible supplier will have dual-certified 304/304L material for mixed specifications. Confirm that the supplier can supply WNRF, SORF, and blind flanges in Class 150 to Class 600 as ready stock for standard NPS sizes. For large-bore flanges to ASME B16.47 or special facings, confirm manufacturing lead times in advance.
Technical Considerations
Request mill test certificates for carbon content at 0.030% maximum per ASTM A182 F304L. This is critical for welded assemblies where standard 304 (max 0.08% C) would be insufficient. For dual-certified material, confirm that both UNS S30400 and S30403 are listed on the same MTC. Verify flange dimensions for your NPS. Check order specification documents for electropolish or passivation finish for pharmaceutical or food-grade service.
Quality and Certification Check
EN 10204 / 3.1 mill test certificates with full traceability of heat numbers are the minimum requirement. Request finished flange PMI test reports for critical process applications. For pharmaceutical or food applications, please request applicable documentation of 3A or EHEDG compliance. ISO9001 certification is a minimum standard for suppliers. For European PED applications, confirm dimensional compliance to EN 1092-1 and CE marking as applicable.
Procurement Tips for Bulk Orders
SS 304L prices track LME nickel closely. Lock in rates at order placement for long projects to avoid price movement exposure. For ongoing procurement, blanket orders reduce per-unit cost and maintain supply continuity. Always confirm written delivery timelines rather than verbal estimates. For pharmaceutical projects requiring full traceability and surface finish certification, allow additional lead time for test and documentation completion beyond standard forging and machining lead times.
Stainless Steel 304L flanges are produced from UNS S30403, the low-carbon variant of the standard 304 grade. With carbon restricted to 0.030% maximum, these flanges resist carbide precipitation in heat-affected zones during and after welding. This makes them the preferred choice over standard 304 wherever flanges are welded into service without post-weld heat treatment. The composition and corrosion performance are otherwise similar to 304, covering atmospheric, mildly acidic, and food-grade environments across chemical processing, pharmaceuticals, water treatment, and food and beverage industries.
Approx Price Range
Price Range of SS 304L Flanges per kg and factors influencing their prices are explained below.
Price Per kg
SS 304L flanges are priced at roughly ₹175 to ₹240/kg. The 304L premium over standard 304 is typically marginal, as most mills supply dual-certified 304/304L material. Request per-piece pricing from your supplier for larger flange sizes.
Factors Affecting Price
Nickel and chromium market rates, flange type, pressure class, NPS size, dual certification requirements, surface finish, and order volume all affect the final cost of DIN 1.4307 flanges.
Types of Stainless Steel 304L Flanges
SS 304L flanges are available in the same full range of configurations as standard 304, covering all standard piping connection methods and pressure classes.
- Weld Neck Flanges (WNRF)
- Slip-On Flanges (SORF)
- Blind Flanges (BLRF)
- Socket Weld Flanges (SWRF)
- Threaded Flanges
- Lap Joint Flanges
- Orifice Flanges
- Reducing Flanges
- Long Weld Neck Flanges
- Spectacle Blind Flanges
- Ring Type Joint Flanges (RTJ)
- Flat Face Flanges (FF)
ASTM A182 F304L Flanges Specifications
The table below covers the key specification parameters for Stainless Steel 304L flanges as per international standards.
|
Parameter |
Details |
|
Standard |
ASTM A182 / ASME SA182 |
|
Dimensions |
ASME B16.5, B16.47 Series A & B, B16.48, DIN, BS4504, EN-1092, JIS B2220 |
|
Pressure Classes |
150#, 300#, 400#, 600#, 900#, 1500#, 2500# / PN6 to PN250 |
|
Size Range |
NPS 1/2" to 48" / DN15 to DN1200 |
|
Facing |
Raised Face (RF), Ring Type Joint (RTJ), Flat Face (FF), Tongue & Groove |
|
Manufacture |
Forged, Cast, Rolled, Plate |
|
Finish |
Plain, Pickled & Passivated, Electro-polished |
Chemical Composition of SS 304L Flanges
The composition below highlights the reduced carbon content of UNS S30403. Carbon at 0.030% maximum is the defining difference from standard 304, preventing sensitisation in welded joints.
|
Element |
Composition (%) |
|
Carbon (C) |
0.030 max |
|
Chromium (Cr) |
18.0 – 20.0 |
|
Nickel (Ni) |
8.0 – 12.0 |
|
Manganese (Mn) |
2.0 max |
|
Silicon (Si) |
0.75 max |
|
Phosphorus (P) |
0.045 max |
|
Sulphur (S) |
0.030 max |
|
Nitrogen (N) |
0.10 max |
|
Iron (Fe) |
Balance |
Mechanical Properties of UNS S30403 Flanges
The mechanical values below apply to ASTM A182 Grade F304L forged flange material. Note that the lower carbon content results in slightly reduced tensile and yield strength compared to standard F304.
|
Property |
Value |
|
Tensile Strength |
485 MPa (70,000 psi) min |
|
Yield Strength (0.2% offset) |
170 MPa (25,000 psi) min |
|
Elongation |
40% min |
|
Hardness |
Max 92 HRB |
Physical Properties of DIN 1.4307 Flanges
The physical properties below assist engineers in assessing thermal behaviour and material suitability for the intended service temperature range.
|
Property |
Value |
|
Density |
7.93 g/cm³ |
|
Melting Range |
1399 – 1454°C (2550 – 2650°F) |
|
Specific Heat |
500 J/kg·°C |
|
Thermal Conductivity |
16.2 W/m·K (at 100°C) |
|
Electrical Resistivity |
0.72 µΩ·m |
|
Modulus of Elasticity |
193 GPa |
|
Coefficient of Thermal Expansion |
17.2 µm/m°C (0–100°C) |
Dimension Chart of Stainless Steel 304L Flanges
The table below lists standard flange dimensions for SS 304L per ASME B16.5 Class 150.
|
NPS (in) |
DN (mm) |
OD (mm) |
Bore (mm) |
PCD (mm) |
Thickness (mm) |
Bolt Holes |
|
1/2 |
15 |
88.9 |
34.9 |
60.3 |
35.1 |
4 x 1/2" |
|
3/4 |
20 |
98.6 |
42.9 |
69.9 |
38.1 |
4 x 1/2" |
|
1 |
25 |
108.0 |
50.8 |
79.4 |
42.9 |
4 x 1/2" |
|
1.1/2 |
40 |
127.0 |
73.0 |
98.4 |
52.3 |
4 x 1/2" |
|
2 |
50 |
152.4 |
92.1 |
120.7 |
58.7 |
4 x 5/8" |
|
3 |
80 |
190.5 |
127.0 |
152.4 |
68.3 |
4 x 5/8" |
|
4 |
100 |
228.6 |
157.2 |
190.5 |
73.0 |
8 x 5/8" |
|
6 |
150 |
279.4 |
215.9 |
241.3 |
82.6 |
8 x 3/4" |
|
8 |
200 |
342.9 |
269.9 |
298.5 |
95.3 |
8 x 3/4" |
|
10 |
250 |
406.4 |
323.8 |
362.0 |
101.6 |
12 x 7/8" |
|
12 |
300 |
482.6 |
381.0 |
431.8 |
114.3 |
12 x 7/8" |
|
14 |
350 |
533.4 |
412.8 |
476.3 |
123.8 |
12 x 1" |
|
16 |
400 |
596.9 |
469.9 |
539.8 |
130.2 |
16 x 1" |
|
18 |
450 |
635.0 |
533.4 |
577.9 |
139.7 |
16 x 1.1/8" |
|
20 |
500 |
698.5 |
584.2 |
635.0 |
149.2 |
20 x 1.1/8" |
|
24 |
600 |
812.8 |
692.2 |
749.3 |
165.1 |
20 x 1.1/4" |
Size Chart of SS 304L Flanges
Stainless Steel 304L flanges are available across the same wide size range as standard 304, covering both ASME and metric international standards.
|
Standard |
Size Range (NPS) |
Size Range (DN) |
Pressure Classes |
|
ASME B16.5 |
1/2" – 24" |
DN15 – DN600 |
150# to 2500# |
|
ASME B16.47 Series A |
26" – 60" |
DN650 – DN1500 |
150# to 900# |
|
ASME B16.47 Series B |
26" – 60" |
DN650 – DN1500 |
75# to 900# |
|
DIN / EN 1092-1 |
DN15 – DN1200 |
DN15 – DN1200 |
PN6 to PN250 |
|
BS 4504 |
1/2" – 48" |
DN15 – DN1200 |
PN6 to PN64 |
|
JIS B2220 |
10A – 1500A |
DN10 – DN1500 |
5K to 63K |
Pressure Rating Chart of ASTM A182 F304L Flanges
The pressure-temperature ratings below apply to SS 304L (Group 2.3) flanges per ASME B16.5. Values are the maximum allowable working pressures in bar at the listed temperature. Note that 304L ratings are lower than standard 304 due to the reduced carbon content.
|
Temp (°C) |
Class 150 (bar) |
Class 300 (bar) |
Class 400 (bar) |
Class 600 (bar) |
Class 900 (bar) |
Class 1500 (bar) |
|
-29 to 38 |
15.1 |
39.8 |
53.0 |
79.5 |
119.3 |
159.1 |
|
50 |
14.8 |
39.0 |
52.0 |
77.9 |
116.9 |
155.8 |
|
100 |
13.8 |
36.4 |
48.5 |
72.7 |
109.1 |
145.5 |
|
150 |
12.6 |
33.2 |
44.3 |
66.5 |
99.7 |
132.9 |
|
200 |
11.5 |
30.4 |
40.5 |
60.7 |
91.1 |
121.5 |
|
250 |
10.4 |
27.6 |
36.8 |
55.2 |
82.7 |
110.3 |
|
300 |
9.4 |
24.9 |
33.2 |
49.8 |
74.7 |
99.6 |
|
375 |
7.9 |
21.0 |
27.9 |
41.9 |
62.8 |
83.8 |
|
425 |
6.5 |
17.2 |
23.0 |
34.5 |
51.7 |
69.0 |
|
450 |
5.6 |
14.8 |
19.8 |
29.6 |
44.5 |
59.3 |
Key Features of Stainless Steel 304L Flanges
SS 304L flanges are used in a similar wide-ranging manner as 304, but with the added advantage of weld-zone corrosion resistance. Here is what makes them the preferred choice for welded assemblies.
- Low carbon content (max 0.030%)
- Often supplied as dual-certified 304/304L material
- Reliable corrosion resistance in atmospheric, mildly acidic, oxidising, and food-grade environments
- Wide temperature service range
- Non-magnetic in the annealed condition
- Good weldability with standard austenitic filler metals
- No pre- or post-weld heat treatment required
- Electropolished surface finish options available for pharmaceutical and food-grade hygienic service
- Available in all standard flange types and pressure classes per ASME B16.5 and EN 1092-1
Applications of UNS S30403 Flanges
The weld-zone corrosion resistance of SS 304L makes these flanges the preferred choice wherever flanged joints will be welded into service without heat treatment.
- Chemical processing
- Pharmaceutical manufacturing
- Food, dairy, and beverages
- Water and wastewater treatment
- Cryogenic service
- Power generation
- Oil and gas
- Pulp and paper
How to Choose the Right Stainless Steel 304L Flanges Supplier?
Keep the following things in mind when choosing the right SS 304L flange supplier.
Supplier Selection Criteria
Check that stock is available in various flange types, sizes, and pressure classes. The most flexible supplier will have dual-certified 304/304L material for mixed specifications. Confirm that the supplier can supply WNRF, SORF, and blind flanges in Class 150 to Class 600 as ready stock for standard NPS sizes. For large-bore flanges to ASME B16.47 or special facings, confirm manufacturing lead times in advance.
Technical Considerations
Request mill test certificates for carbon content at 0.030% maximum per ASTM A182 F304L. This is critical for welded assemblies where standard 304 (max 0.08% C) would be insufficient. For dual-certified material, confirm that both UNS S30400 and S30403 are listed on the same MTC. Verify flange dimensions for your NPS. Check order specification documents for electropolish or passivation finish for pharmaceutical or food-grade service.
Quality and Certification Check
EN 10204 / 3.1 mill test certificates with full traceability of heat numbers are the minimum requirement. Request finished flange PMI test reports for critical process applications. For pharmaceutical or food applications, please request applicable documentation of 3A or EHEDG compliance. ISO9001 certification is a minimum standard for suppliers. For European PED applications, confirm dimensional compliance to EN 1092-1 and CE marking as applicable.
Procurement Tips for Bulk Orders
SS 304L prices track LME nickel closely. Lock in rates at order placement for long projects to avoid price movement exposure. For ongoing procurement, blanket orders reduce per-unit cost and maintain supply continuity. Always confirm written delivery timelines rather than verbal estimates. For pharmaceutical projects requiring full traceability and surface finish certification, allow additional lead time for test and documentation completion beyond standard forging and machining lead times.
Stainless Steel 304L Flanges Suppliers
Stainless Steel 304L Flanges FAQ's
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