Marzouk Steel, headquartered in Tunis, Tunisia, is a trusted manufacturer and supplier of premium steel products, serving industries that require strength, precision, and durability. Among its specialized offerings are Alloy Steel GR B5 Fasteners, designed for high-pressure, high-temperature, and critical mechanical applications. Manufactured using advanced technology and stringent quality control, GR B5 fasteners provide exceptional tensile strength, toughness, and corrosion resistance. Marzouk Steel ensures that every GR B5 fastener meets international standards, offering engineers and fabricators reliable fastening solutions for power plants, petrochemical facilities, oil and gas equipment, and heavy industrial machinery.
Alloy Steel GR B5 Fasteners are made from high-grade chromium-molybdenum alloy steel, engineered for superior tensile strength, hardness, and thermal resistance. Their chemical composition, including carbon, chromium, and molybdenum, enhances toughness, fatigue resistance, and corrosion resistance. GR B5 fasteners respond well to heat treatment, optimizing mechanical properties such as yield strength, tensile strength, and impact resistance. With excellent structural integrity under extreme conditions, GR B5 fasteners are ideal for critical applications requiring long-term durability, safety, and consistent performance.
Specification :Â ASTM A 194 ASME SA 194
Standard :Â DIN, ASTM, BS and all International Standards
Length :Â 3 mm to 2 mm
Size : M3 – M56 | 3/6″ to 2″ | Custom Sizes
Types :Â Nuts, Bolts, Screws, Sockets, Studs, Screw, Hex Set Screw, Socket Screw, Cap Screw, Pan Head Screw, Socket Head Cap Screw, Washers, Spring Washers, Studs, Anchors
| Alloy Steel B5 | C | Mn | P | S | Si | Ni | Cr |
| 0.40% min | 1.00% max | 0.040% | 0.050% | 0.40% max | – | – |
| Specification | Material | Nominal Size, In. | Tempering Temp. °F | Proof Load Stress, ksi | Hardness Rockwell | See Note | |
|---|---|---|---|---|---|---|---|
| Min | Max | ||||||
| ASTM A194 Grade B5 | Medium Carbon Steel, Quenched and Tempered | 1/4 – 4 | 1000 | 150 | 159 | 237 | 1,2,3 |
We provide products that come with both mill test certificates and third-party test certificates, ensuring the highest standards of quality and compliance.
Hexagon Bolts / Set Screws | Stud Bolts | Hexagon Nuts | Socket Capscrews |
|---|---|---|---|
DIN 931 | BS4882 | DIN 934 | DIN 912 |
DIN 933 | DIN 976 | BS 1768 | DIN 6912 |
BS 1768 | Â | BS 1769 | DIN 7984 |
UNI 5731 | Â | BS 1083 | ANSI B18.3 |
UNI 5739 | Â | BS 3692 | ISO 4762 |
ISO 4014 | Â | ISO 4032 | UNI 5931 |
ISO 4017 | Â | ISO 4033 | BS 2470 |
BS 1769 | Â | ANSI B18.2.2 | BS 4168 |
BS 3692 | Â | Â | Â |
ANSI B18.2.1 | Â | Â | Â |
Socket & Slotted Set Screws | Socket & Slotted Countersunk Screws | Studs | Washers |
DIN 913 | DIN 963 | DIN 938 | DIN 125 |
DIN 914 | DIN 7991 | DIN 939 | DIN 9021 |
DIN 915 | BS 4168 | DIN 2510 | BS 4320 |
DIN 916 | BS 1981 | BS 4439 | BS 3410 |
DIN 551 | BS 483 | BS 2693 | Â |
DIN 553 | BS 2470 | Â | Spring Washers |
DIN 438 | Â | Â | DIN 127 |
BS 4168 | Â | Â | BS 4464 |
 |  |  | BS 1802 |
Alloy Steel GR B5 Fasteners are widely used in industries that require strong, reliable, and durable fastening solutions. They are commonly applied in boilers, heat exchangers, turbines, petrochemical plants, oil and gas pipelines, and heavy industrial machinery. Designed to withstand high pressures, elevated temperatures, and cyclic loads, GR B5 fasteners maintain structural integrity and provide secure, leak-proof connections. Engineers and fabricators rely on these fasteners for critical applications where safety, durability, and operational efficiency are essential. Their combination of toughness, thermal stability, and mechanical strength ensures dependable performance in 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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