Flange bolts feature a broad surface under the head which acts like a washer. These fasteners are used in automobile and industrial manufacturing. Zinc plated fasteners have good corrosion resistant qualities and are a good choice for indoor and industrial applications. Property class: 10.9. Tensile strength 1040 MPa or about 150,000 p.s.i., similar to SAE grade 8. Made from alloy steel, quenched and tempered. Similar to grade 8 strength. Head marking 10.9.