Overview
Engineering reference data for Steel Bolts ASTM Grades in material science and properties.
Key Formulas
Stress
Force per unit area.
Strain
Change in length per original length.
Hooke's Law
Stress proportional to strain in elastic region.
Thermal Expansion
Length change due to temperature.
Variables
| Symbol | Description | Unit |
|---|---|---|
| Stress | Pa | |
| Strain | — | |
| Young's modulus | Pa | |
| Thermal expansion coefficient | 1/°C | |
| Temperature change | °C |
ASTM Grade Properties
Material Properties & Heat Treatment
The abbreviation Q & T indicates that the steel has been quenched and tempered. This heat treatment process significantly increases the bolt's strength and hardness.
- Quenching: Rapid cooling from a high temperature locks the steel's crystalline structure into a hard, brittle state (martensite).
- Tempering: Reheating the quenched steel to a lower temperature and then cooling it again. This process relieves internal stresses and increases toughness, achieving the desired balance of strength and ductility.
Weathering Steel (used in Types 3 and A490 Type 3) is designed to form a stable, rust-like protective surface when exposed to the elements, reducing corrosion in unpainted applications.
Key Unit Conversions
For calculations involving these grades:
- Pressure/Stress:
- Length:
Proof Strength is the maximum tensile load a bolt can withstand without permanent deformation. It is typically 85-90% of the material's yield strength.