Comprehensive Guide to ASTM A193 Grade B7 Fasteners

1. Comprehensive Guide to ASTM A193 Grade B7 Fasteners: Properties, Applications, and Standards Introduction ASTM A193 Grade B7 Fasteners are high-performance alloy steel fasteners designed to endure extreme pressure and temperature conditions. Manufactured from chromium-molybdenum (Cr- Mo) steel and heat-treated through quenching and tempering, these fasteners offer exceptional tensile strength and durability. They are widely used in petrochemical plants, refineries, power generation, and oil & gas industries, particularly for bolting flanges, valves, and pressure vessels. Because of their availability in multiple dimensions and international compliance, Grade B7 remains one of the most specified fastener grades in the engineering world. Types of ASTM A193 Grade B7 Fasteners ASTM A193 B7 is available in different forms depending on project requirements: Hex Bolts / Heavy Hex Bolts Stud Bolts (Continuous Thread & Double End Studs) Threaded Rods Nuts (usually ASTM A194 2H or Grade 7) Hardened Washers (ASTM F436) Socket Cap Screws Anchor Bolts

2. Use-Case Classification Stud Bolts: Flange-to-flange connections in pipelines Heavy Hex Bolts: Structural assemblies in plants & power stations Threaded Rods: Suspended equipment & support structures Applications Industries using ASTM A193 B7 Fasteners: Oil & Gas Exploration and Processing Petrochemical and Refinery Units Thermal and Nuclear Power Plants Marine and Offshore Engineering Chemical Processing Units Construction & Heavy Engineering Example Use Cases: High-pressure steam pipeline bolting Securing heat exchangers and reactors Fastening valves and compressors in refineries Offshore rig equipment where high strength is critical Standards and Grades Primary Standard: ASTM A193 (alloy & stainless bolting materials) Related Standards: ASME B18.2.1 / B18.2.2– Bolt & nut dimensions DIN 933 / ISO 898-1– Global equivalents BS 4882 & BS 1769– UK standards Nut & Washer Pairing: Nuts: ASTM A194 Grade 2H, 2HM, or Grade 7 Washers: ASTM F436

3. Technical Specifications Mechanical Properties Tensile Strength: Min 125 ksi Yield Strength (0.2% offset): Min 105 ksi Elongation (2”): Min 16% Hardness: Max 321 HB Reduction of Area: Min 50% Service Temperature Effective range: -40°C to +450°C (-40°F to +842°F) Chemical Composition Carbon (C): ≤ 0.35% Manganese (Mn): 0.65–1.10% Silicon (Si): 0.15–0.35% Chromium (Cr): 0.75–1.20% Molybdenum (Mo): 0.15–0.25% Phosphorus (P): ≤ 0.035% Sulfur (S): ≤ 0.040% Dimensional & Weight Chart Bolt Diameter Length Approx. Weight per 100 pcs (kg) 1/2" 2" 3.1 5/8" 3" 6.5 3/4" 4" 12.4 1" 6" 25.8 1-1/4" 8" 52.6 1-1/2" 10" 87.4 (Custom sizes and coatings available on request.)

4. Manufacturing Process 1.Raw Material Sourcing– Certified Cr-Mo steel bars 2.Forging & Cutting– Shape formation under controlled heat 3.Threading– Rolled or cut threads as per ASME/DIN 4.Heat Treatment– Quenching & tempering for strength 5.Surface Treatment– Black oxide, zinc plating, PTFE, hot-dip galvanizing 6.Quality Testing oMechanical testing (tensile, hardness, impact) oNDT (ultrasonic, magnetic particle) oDimensional & hydrostatic checks Advantages High Strength: Ideal for critical bolting applications Temperature Resistant: Performs at high operating temperatures Versatile: Standardized across industries Durable: Resistant to stress & fatigue failure Cost-Effective: Economical compared to exotic alloys How to Select the Right ASTM A193 B7 Fasteners Key Criteria: Verify ASTM & ASME compliance Confirm nut/washer compatibility (ASTM A194 2H/Grade 7 + ASTM F436) Match fastener size & strength with design codes Consider corrosion protection (plating or coating if required) Ensure supplier certifications Quick Checklist: ☑ Mechanical property certification (MTC EN 10204 3.1) ☑ Heat treatment traceability ☑ Dimensional conformity (ASME/DIN) ☑ Relevant compliance (ISO, API, PED, IBR)

5. Certifications & Compliance ISO 9001:2015– Quality management PED 2014/68/EU– EU pressure equipment compliance IBR (Indian Boiler Regulations)– Boiler & steam application approval API– Oil & gas industry acceptance CE– European market conformity Importance: Certifications ensure safe, reliable, and internationally accepted fasteners, reducing project risks. ASTM A193 Grade B7 vs Alternatives Feature B7 (Standard) Cr-Mo Steel L7 (Low Temp) Low-Temp Alloy Steel B16 (High Temp) Cr-Mo-V Steel Material Temperature Range -40°C to 450°C -101°C to 593°C Up to 593°C Pressure vessels, pipelines Cryogenic & low-temp service High-temp boilers, turbines Common Use FAQs Q1: What nuts are used with ASTM A193 Grade B7 fasteners? A: Typically, ASTM A194 Grade 2H or Grade 7 nuts are paired. Q2: Can ASTM A193 B7 fasteners resist corrosion? A: Base material has limited resistance; coatings like PTFE, zinc, or galvanizing are applied for corrosion protection. Q3: What is the hardness range? A: Maximum hardness is 321 HB. Q4: Are B7 fasteners suitable for cryogenic applications? A: No, ASTM A320 L7 is better for low-temperature services. Q5: What finishes are available? A: Black oxide, hot-dip galvanizing, PTFE coating, and zinc plating.

6. Q6: Where are B7 fasteners most commonly used? A: In petrochemical plants, power plants, refineries, and oil & gas pipelines. About Us We are one of the leading ASTM A193 Grade B7 Fasteners Manufacturers, Suppliers, Stockists, and Exporters in India, delivering products that meet global standards. Our fasteners are manufactured with state-of-the-art machinery, rigorous testing, and ISO-certified processes to ensure reliability in critical applications ?Contact Us Today Email: info@dalloyedbolts.com Phone: +91-7666996996 Address:1/B, Ground Floor, Siddhi Apartment, 10th Khetwadi Back Road, Mumbai - 400 004. .Request a quote, download our datasheet, or connect with our sales team to discuss your project requirements