Description

AM Steel Flange Head Bolts feature a wide, integrated flange beneath the bolt head that acts like a built-in washer – spreading clamping force over a larger surface area, reducing the risk of surface damage, and eliminating loosening from over-torquing. Manufactured under the AM Steel brand, these flange bolts (also known as frame bolts or flanged hex bolts) are widely used wherever a strong, self-locking connection is needed without the extra step of fitting a separate washer.

Available with a plain flange or a serrated flange bolt design, AM Steel flange bolts are engineered for applications where vibration resistance is critical. The serrated underside bites into the mating surface, providing a locking action that keeps the joint tight under repeated stress or engine vibration – a key reason these are a go-to choice in automotive and machinery assembly. Crafted from carbon steel, alloy steel, or stainless steel flange bolts, they resist corrosion, rust, and wear, and hold up reliably in demanding industrial, outdoor, and high-vibration environments.

Whether it’s engine and transmission assembly, agricultural equipment, structural steel connections, or general machinery fastening, AM Steel flange head bolts deliver a faster, more secure installation than a standard hex bolt and washer combination. As with all AM Steel products, this flange bolt is available in metric flange bolt and imperial sizing, with multiple grades and finishes to suit both industrial-grade and everyday fastening needs.

Key features:

• Integrated flange head eliminates the need for a separate washer
• Wide bearing surface distributes clamping load and reduces surface damage
• Available in plain flange or serrated flange (anti-vibration) designs
• Corrosion-resistant finishes: zinc-plated, galvanized, and stainless steel flange bolts
• Available in metric flange bolt and imperial sizing
• Backed by the quality assurance of AM Steel

Note: This product, along with all other products in this catalog, is manufactured and supplied by AM Steel, a trusted name in industrial-grade fasteners and steel components.

Ideal For

AM Steel Flange Head Bolts are ideal for:

• Automotive technicians assembling engines, transmissions, and exhaust systems where vibration resistance is essential
• Agricultural and heavy equipment operators securing high-vibration machinery components
• Construction professionals fastening structural steel connections and equipment mounts
• Manufacturing & machinery applications requiring a self-locking, washer-free fastening solution
• DIY & maintenance work where a quick, secure fastening without loose washers is preferred

Choosing the Right Flange Head Bolt

Selecting the correct flange bolt from the AM Steel range depends on several factors:

1. Flange Type – Serrated flange bolts for high-vibration environments (engines, machinery); plain (unserrated) flange bolts for general assembly where surface marking isn’t a concern.
2. Material – Stainless steel flange bolts for corrosion resistance (outdoor/marine use), carbon steel for general strength, alloy steel for high-load-bearing needs.
3. Size & Thread Pitch – Match the bolt diameter and thread pitch (metric flange bolt or imperial) to your existing tapped hole or nut.
4. Length – Should fully engage the mating thread without excessive protrusion beyond the joint.
5. Grade/Strength Rating – Higher grades (e.g., Grade 8, Class 10.9) suit high-stress or high-vibration applications.
6. Flange Diameter – Ensure the flange size fits the available clearance and mounting surface without overlapping adjacent holes or components.

Strategies to Choose the Right Product

• Match the flange type to vibration levels – Choose serrated flange bolts for engines, machinery, and high-vibration joints; plain flange bolts for static, low-vibration assemblies.
• Check load and torque requirements – Use hex bolt torque specs and manufacturer torque charts to select the right grade for the application.
• Buy in matched sets – Since flange bolts replace a bolt-and-washer combination, ensure consistent grade and finish across a batch for uniform clamping performance.
• Prioritize certified standards – Look for ISO, ANSI, or DIN certification for guaranteed quality and safety compliance.
• Consider bulk vs. individual packs – Bulk packs of flange bolts offer cost savings for automotive or production-line assembly; smaller packs suit repairs.
• Read reviews and vibration/torque test data – Verify real-world locking performance before committing to a supplier for critical, heavy duty hex fasteners.

Mechanical Properties

AM Steel Flange Head Bolts are manufactured to meet stringent mechanical performance standards, ensuring reliability across automotive, structural, and industrial applications:

These hex bolt torque specs and mechanical ratings ensure every AM Steel flange head bolt performs reliably under the tensile, shear, and vibration loads demanded by automotive and industrial applications.

Frequently Asked Questions (FAQs)

1. What is a flange head bolt used for? A flange head bolt is used to fasten components together without requiring a separate washer, thanks to its wide, integrated flange that spreads clamping force and resists loosening – commonly used in automotive and machinery assembly.
2. What’s the difference between a flange bolt and a hex bolt? A flange bolt has a wide, built-in flange beneath the head that acts as a washer, while a standard hex bolt requires a separate washer to achieve the same load distribution.
3. What is a serrated flange bolt? A serrated flange bolt has small ridges on the underside of the flange that bite into the mating surface, providing extra locking power against vibration and loosening.
4. Are AM Steel flange bolts different from generic flange bolts? AM Steel flange head bolts are manufactured and quality-tested under the AM Steel brand, ensuring consistent mechanical properties, precise threading, and reliable flange geometry across every batch.
5. Do I need a washer with a flange bolt? No – the flange head is specifically designed to eliminate the need for a separate washer, simplifying installation while still distributing clamping load evenly.
6. What sizes do flange head bolts come in? AM Steel flange bolts are available in a range of sizes, typically from M5 to M20 in metric flange bolt sizing, and comparable imperial sizes, depending on the application.
7. Are flange bolts corrosion-resistant? Yes, especially AM Steel stainless steel flange bolts or those coated with zinc plating or hot-dip galvanization, which protect against rust and moisture damage.
8. Where are flange bolts most commonly used? Flange bolts are widely used in automotive engine and transmission assembly, agricultural machinery, and any application where vibration resistance and a compact washer-free design are needed.
9. What tools do I need to install flange head bolts? A wrench, socket set, or impact driver matching the bolt’s flange head size is typically required for proper installation.
10. What grade of flange bolt should I use for high-vibration applications? Grade 8 or Class 10.9 serrated flange bolts are commonly recommended for high-vibration environments such as engines and heavy machinery – see the Mechanical Properties table above for full specs.
11. Can flange bolts be reused? Yes, as long as the threads, flange, and serrations (if present) aren’t damaged or worn, flange bolts can typically be reused, though high-vibration or safety-critical applications may recommend replacement after removal.
12. What’s the difference between zinc-plated and stainless steel flange bolts? Zinc-plated flange bolts offer basic corrosion resistance at a lower cost, while stainless steel flange bolts provide superior long-term durability and resistance to rust, especially in harsh or outdoor environments.
13. What is the torque rating for flange head bolts? Torque ratings vary based on bolt size, grade, and material — refer to the hex bolt torque specs in the Mechanical Properties section above, or the AM Steel torque chart, to ensure correct tightening for the intended load.