Table 1: NOMINAL BOLT PROPERTIES
(Use these for calculations)
 Bolt  Grade Sizes UTS  100 x #1 Yield Stress  UTS x #2 / 10 Proof Load 90% x Yield Preload 80% x Proof Hardness  Rockwell mm diam MPa MPa MPa MPa Min 4.6 M5-M100 400 240 216 172 B67-95 4.8 M1.6-M16 400 320 288 230 B71-95 5.8 M5-M24 500 400 360 288 B82-95 8.8 M16-M72 800 640 576 460 C23-34 9.8 M1.6-M16 900 720 648 518 C27-46 10.9 M5-M100 1000 900 810 648 C33-49 12.9 M1.6-M100 1200 1080 972 777 C38-44

Proof Load:(MPa) Stress that the bolt must withstand without evidence of any permanent set, usually about 90% or Yield Strength..
Proof Stress:(MPa) The stress that produces a certain strain, typically 0.2%. Used for materials that do not have a definite yield point.
PreLoad Stress:(MPa) The stress that a bolt is normally tensioned up to. Typically 80% of the stress Proof Load, which is 72% of Yield.

Note: These are NOT THE SAME! Proof Stress is above the Yield Stress, but Proof Load is below it.

Table 2: MEASURED TYPICAL BOLT PROPERTIES:
Source: ISO 898-1, 1999, Sections 3 through 7, and App. A.
(Do NOT use these for calculations)

 Bolt  Grade Sizes UTS Yield Stress Proof Load Hardness  Rockwell mm diam MPa MPa MPa Min 4.6 M5-M100 400 240 225 B67-95 4.8 M1.6-M16 420 340 310 B71-95 5.8 M5-M24 520 420 380 B82-95 8.8 M16-M72 830 660 600 C23-34 9.8 M1.6-M16 900 720 650 C27-46 10.9 M5-M100 1040 940 830 C33-49 12.9 M1.6-M100 1220 1100 970 C38-44