Think of it as the "general purpose" bolt. It is not the strongest bolt on the market (that honor goes to Grade 8.8 or 10.9), but it offers a unique combination of ductility, toughness, and cost-effectiveness that high-strength bolts simply cannot match. Choosing the right grade is critical. Using the wrong grade could lead to stripped threads or catastrophic joint failure.
Enter .
| Standard | Strength Level | Best For | Distinction | | :--- | :--- | :--- | :--- | | | Low | Plumbing, light fixtures | Very soft, high ductility | | A307M Gr B | Medium | Flanges, machinery | Controlled hardness range | | ISO 898-1 (8.8) | High | Automotive, heavy structures | Quenched & Tempered | | F568M Class 4.6 | Low-Medium | General metric steelwork | Very close to A307M Gr A |