How They’re Determined by the SAE, and How They’re Identified by the End User Automotive bolted joints operate under demanding cyclic loads, high temperatures, and increasingly lightweight designs. As a result, understanding bolt grades-and the standards behind them-is essential for fastener engineers working in OEM, Tier 1, and aftermarket applications.
When it comes to mechanical fastening, engineers often focus on bolt strength—after all, it’s doing the heavy lifting, right? But there’s more to the story. In a bolted joint, the relationship between bolt grade and nut grade plays a critical role in the strength, safety, and serviceability of the assembly.
Choosing the right bolt means knowing how it fails and when it bends too far to bounce back When designing or specifying fasteners, strength is everything, but not all strength is created equal. Two key properties – yield strength and tensile strength – tell very different stories about how a
