Marzouk Steel, headquartered in Tunis, Tunisia, is a trusted manufacturer and supplier of premium steel products, serving industries that demand strength, precision, and long-term reliability. Among its specialized offerings are Alloy Steel F91 Flanges, designed for high-pressure, high-temperature, and critical mechanical applications. Manufactured with advanced technology and strict quality control, F91 flanges provide exceptional strength, toughness, and corrosion resistance. Marzouk Steel ensures that every F91 flange meets international standards, providing engineers and fabricators with a dependable solution for power generation, petrochemical, oil and gas, and heavy industrial systems.
Alloy Steel F91 Flanges are made from chromium-molybdenum-vanadium (Cr-Mo-V) alloy steel, engineered for superior tensile strength, creep resistance, and thermal stability. The chemical composition, including carbon, chromium, molybdenum, and vanadium, enhances hardness, impact resistance, and fatigue strength. F91 flanges respond well to heat treatment, optimizing mechanical properties such as yield strength, tensile strength, and toughness. With excellent structural integrity under high-pressure and high-temperature conditions, F91 flanges are ideal for demanding industrial, power generation, and petrochemical applications.
Alloy Steel Flanges Specification :Â ASTM A182 / ASME SA182
Dimension Standard :Â ANSI/ASME B16.5, B 16.47 Series A & B, B16.48, BS4504, BS 10, EN-1092, DIN, etc.
Standard :Â ANSI Flanges, ASME Flanges, BS Flanges, DIN Flanges, EN Flanges, etc.
Size :Â 1/2″ (15 NB) to 48″ (1200NB)
Class / Pressure :Â 150#, 300#, 600#, 900#, 1500#, 2500#, PN6, PN10, PN16, PN25, PN40, PN64 etc.
Flange Face Type :Â Flate Face (FF), Raised Face (RF), Ring Type Joint (RTJ)
DIN Flanges :Â DIN 2527, 2566, 2573, 2576, 2641,2642, 2655, 2656, 2627, 2628, 2629, 2631, 2632, 2633, 2634, 2635, 2636, 2637,2638, 2673.
JIS Flanges :Â JIS B2220 5K, JIS B2220 10K, JIS B2220 16K, JIS B2220 20K
BS Flanges :Â BS4504 PN 6, BS 4504 PN 10, BS4504 PN 16, BS4504 PN 25, BS4504 PN 40, BS 4504 PN 64, BS 4504 PN 100, BS 4504 PN 160, BS 4504 PN 250, BS 10, BS Table D, BS Table E, BS Table F, BS Table H.
| Grade | C | Mn | P | S | Si | Ni | Ch | Mo | Cb | N |
|---|---|---|---|---|---|---|---|---|---|---|
| F91 | 0.08-0.12 | 0.30-0.60 | 0.020 | 0.010 | 0.20-0.50 | 0.40 | 8.0-9.5 | 0.85-1.05 | 0.06-0.10 | 0.03-0.07 |
| Grade | Tensile Strength (MPa) min | Yield Strength 0.2% Proof (MPa) min | Elongation (% in 50mm) min | Hardness | |
|---|---|---|---|---|---|
| Rockwell B (HR B) max | Brinell (HB) max | ||||
| F91 | 585 | 415 | 20 | – | 248 max |
| STANDARD | UNS | WERKSTOFF NR. |
|---|---|---|
| Alloy Steel F91 | K90901 | 1.4903 |
We provide products that come with both mill test certificates and third-party test certificates, ensuring the highest standards of quality and compliance.
|
Pipe Normal Diam. |
O.D. Flange |
Thk. Of Flange Min |
Diam.
of
Hub |
Diameter of Raised Face |
Length Hub.Y |
Thread Length |
Diam.
of Bolt
Circle |
Diam.
of Bolt
Holes |
Number
of Bolts |
Diam. of
Bolts
(inch) |
KG |
LB |
|
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
inch |
dn |
O |
C |
X |
G |
Y |
T |
BC |
BH |
BN |
BD |
||
|
1/2″ |
15 |
89.00 |
11.20 |
30.20 |
35.10 |
15.70 |
15.70 |
60.50 |
15.80 |
4 |
1/2″ |
0.4 |
0.9 |
|
3/4″ |
20 |
98.50 |
12.70 |
38.10 |
42.90 |
15.70 |
15.70 |
69.90 |
15.80 |
4 |
1/2″ |
0.7 |
1.5 |
|
1″ |
25 |
108.00 |
14.20 |
49.30 |
50.80 |
17.50 |
17.50 |
79.30 |
15.80 |
4 |
1/2″ |
0.8 |
1.8 |
|
1-1/4″ |
32 |
117.50 |
15.70 |
58.70 |
63.50 |
20.60 |
20.60 |
88.90 |
15.80 |
4 |
1/2″ |
1.2 |
2.6 |
|
1-1/2″ |
40 |
127.00 |
17.50 |
65.00 |
73.20 |
22.40 |
22.40 |
98.60 |
15.80 |
4 |
1/2″ |
1.5 |
3.3 |
|
2″ |
50 |
152.50 |
19.10 |
77.70 |
91.90 |
25.40 |
25.40 |
120.70 |
19.10 |
4 |
5/8″ |
2.3 |
5.1 |
|
2-1/2″ |
65 |
178.00 |
22.40 |
90.40 |
104.60 |
28.40 |
28.40 |
139.70 |
19.10 |
4 |
5/8″ |
3.7 |
8.1 |
|
3″ |
80 |
190.50 |
23.90 |
108.00 |
127.00 |
30.20 |
30.20 |
152.40 |
19.10 |
4 |
5/8″ |
4.1 |
9 |
|
3-1/2″ |
90 |
216.00 |
23.90 |
122.20 |
139.70 |
31.80 |
31.80 |
177.80 |
19.10 |
8 |
5/8″ |
5.1 |
11.2 |
|
4″ |
100 |
228.50 |
23.90 |
134.90 |
157.20 |
33.30 |
33.30 |
190.50 |
19.10 |
8 |
5/8″ |
5.9 |
13 |
|
5″ |
125 |
254.00 |
23.90 |
163.60 |
185.70 |
36.60 |
36.60 |
215.90 |
22.40 |
8 |
3/4″ |
7 |
15.4 |
|
6″ |
150 |
279.50 |
25.40 |
192.00 |
215.90 |
39.60 |
39.60 |
241.30 |
22.40 |
8 |
3/4″ |
8.4 |
18.5 |
|
8″ |
200 |
343.00 |
28.40 |
246.10 |
269.70 |
44.50 |
44.50 |
298.50 |
22.40 |
8 |
3/4″ |
13 |
28.6 |
|
10″ |
250 |
406.50 |
30.20 |
304.80 |
323.90 |
49.30 |
49.30 |
362.00 |
25.40 |
12 |
7/8″ |
18 |
39.5 |
|
12″ |
300 |
482.50 |
31.80 |
365.30 |
381.00 |
55.60 |
55.60 |
431.80 |
25.40 |
12 |
7/8″ |
29 |
64 |
|
14″ |
350 |
533.50 |
35.10 |
400.10 |
412.80 |
57.20 |
57.20 |
476.30 |
28.50 |
12 |
1″ |
39 |
86 |
|
16″ |
400 |
597.00 |
36.60 |
457.20 |
469.90 |
63.50 |
63.50 |
539.80 |
28.50 |
16 |
1″ |
47 |
103 |
|
18″ |
450 |
635.00 |
39.60 |
505.00 |
533.40 |
68.30 |
68.30 |
577.90 |
31.80 |
16 |
1 1/8″ |
57 |
126 |
|
20″ |
500 |
698.50 |
42.90 |
558.80 |
584.20 |
73.20 |
73.20 |
635.00 |
31.80 |
20 |
1 1/8″ |
76 |
167 |
|
24″ |
600 |
813.00 |
47.80 |
663.40 |
692.20 |
82.60 |
82.60 |
749.30 |
35.10 |
20 |
1 1/4″ |
97 |
214 |
Marzouk Steel is a top manufacturer and supplier of high-quality Alloy Steel F91 Flanges products in Tunis, Tunisia. Specializing in steel solutions, we provide a wide range of products, including Carbon Steel, Alloy Steel, Mild Steel and Galvanized Steel. Our offerings include Pipes, Tubes, Flanges, Pipe Fittings, Forged Fittings, Sheets and Plates. Known for our reliable delivery and superior customer service, we are committed to offering top-tier steel materials that ensure durability and performance across a wide range of industrial applications. We strive to meet the highest standards, making us a trusted partner for all your steel needs.
Alloy Steel F91 Flanges are widely used in industries requiring high-strength, durable, and reliable connections in piping systems. They are commonly applied in ultra-supercritical boilers, heat exchangers, turbines, high-pressure pipelines, petrochemical plants, and heavy industrial machinery. Engineered to withstand extreme pressure, elevated temperatures, and cyclic stress, F91 flanges maintain structural integrity and provide leak-proof connections. Engineers and fabricators rely on these flanges for critical applications where durability, safety, and operational efficiency are essential. Their combination of toughness, thermal stability, and mechanical strength ensures dependable performance in the most demanding industrial environments.
Marzouk Steel is a leading manufacturer, supplier and exporter of high-quality Carbon Steel, Alloy Steel, Mild Steel and Galvanized Steel products. Our extensive product range includes Pipes, Tubes, Flanges, Pipe Fittings, Forged Fittings, Sheets and Plates, catering to various industries in Tunis, Tunisia.
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