ANSI/ASME B18.2.1 automotive hexagonal flange bolts are designed with a hexagonal head and an integral flange to increase the bearing surface, reduce the compressive stress between the bolt and the connected parts, and improve the stability of the connection. The size range is from 1/4 inch to 6 inches. ANSI/ASME B18.2.1 automotive hexagonal flange bolts are widely used in the automotive industry, especially in the fastening connection of engines, chassis and structural components to ensure high-strength and high-reliability assembly requirements. The bolts are usually made of high-strength alloy steel and heat-treated to meet the automotive industry's strict requirements for mechanical properties, fatigue resistance and corrosion resistance. In addition, its threads comply with the unified thread standards (UNC/UNF), and can provide surface treatments such as galvanizing, electroplating or Dacromet according to different use environments to enhance corrosion resistance and extend service life. Key Advantages for Your Applications: Increased Bearing Surface: The integral flange distributes clamping force over a larger area, reducing stress on connected parts. Improved Connection Stability: The wider bearing surface enhances resistance to loosening, especially under vibration. Simplified Assembly: Eliminates the need for separate washers, reducing part count and assembly time. High Strength and Reliability: Manufactured from high-strength alloy steel and heat-treated to meet stringent automotive industry standards. Excellent Fatigue Resistance: Engineered to withstand the cyclic loading and stresses common in automotive applications. Enhanced Corrosion Resistance: Available with various surface treatments like galvanizing, electroplating, or Dacromet to suit different operating environments and extend service life. Standardized Threads: Compliance with UNC/UNF thread standards ensures compatibility and ease of use. Wide Size Availability: Offers a broad range of sizes to accommodate diverse automotive fastening needs. Ideal for: Engine Assembly: Securing critical engine components such as cylinder heads, manifolds, and brackets. Chassis Fastening: Connecting frame members, suspension components, and body mounts. Structural Components: Joining load-bearing parts of the vehicle body and frame. Transmission Assembly: Fastening housings, covers, and internal components. Axle and Drivetrain Components: Securing hubs, differentials, and related parts. Exhaust Systems: Connecting exhaust manifolds, pipes, and mufflers. Automotive Interiors: Securing seats, dashboards, and trim components where a wider bearing surface is beneficial. Product NameStandardMaterialDiameter (Shank)Length (Shank)Hexagon Flange BoltDIN 69218.8 Grade Steel, Zinc PlatedM620 mmHexagon Flange BoltDIN 692110.9 Grade Steel, PlainM825 mmHexagon Flange BoltDIN 6921A2-70 Stainless SteelM1030 mmHexagon Flange BoltDIN 6921A4-80 Stainless SteelM1240 mmHexagon Flange BoltISO 41628.8 Grade Steel, Hot-Dip GalvanizedM1650 mmHexagon Flange BoltISO 416210.9 Grade Steel, Black OxideM2060 mmHexagon Flange BoltANSI B18.2.6ASTM A325, Zinc Plated1/4"1" (25.4 mm)Hexagon Flange BoltANSI B18.2.6ASTM A490, Plain3/8"1.5" (38.1 mm)Hexagon Flange BoltANSI B18.2.6ASTM F593 (Stainless 304)1/2"2" (50.8 mm)Hexagon Flange BoltJIS B1189SCM435 Alloy Steel, Zinc PlatedM620 mmHexagon Flange BoltJIS B1189S45C Carbon Steel, PlainM825 mmHexagon Flange BoltJIS B1189SUS316 Stainless SteelM1030 mmHexagon Flange BoltGB/T 5789-20168.8 Grade Steel, ElectroplatedM620 mmHexagon Flange BoltGB/T 5789-201610.9 Grade Steel, Dacromet CoatedM825 mmHexagon Flange BoltASME B18.2.6ASTM A193 B7, Zinc Plated5/8"3" (76.2 mm)Hexagon Flange BoltASME B18.2.6ASTM A320 L7, Plain3/4"4" (101.6 mm)Hexagon Flange BoltBS EN 14399-48.8 Grade Steel, HDGM1250 mmHexagon Flange BoltBS EN 14399-410.9 Grade Steel, PlainM2080 mm