A193 Grade B8M VS Grade B8
ASTM A193 Grade B8 and Grade B8M are both stainless steel Grade for stud bolts used for high-temperature and high-pressure applications. However, Just like the difference between SS316 and SS304,the main difference between them are from the material composition and corrosion resistance.
- ASTM A193 B8 Material: This grade is made from AISI 304 stainless steel, which provides good corrosion resistance in general environments but is less resistant to chloride-induced pitting and crevice corrosion compared to Grade B8M.
- Grade B8M (AISI 316 Stainless Steel): Material: This grade is made from AISI 316 stainless steel, which has added molybdenum (Mo) for enhanced corrosion resistance, especially against chlorides, making it ideal for marine, offshore, and chemical applications.
Comparison Table of B8 and B8M Stud bolt
| Property | Grade B8 (AISI 304) | Grade B8M (AISI 316) |
|---|---|---|
| Material | 304 Stainless Steel | 316 Stainless Steel (with Mo) |
| Corrosion Resistance | Moderate | Superior (resistant to chlorides) |
| Composition | 18% Cr, 8% Ni | 16-18% Cr, 10-14% Ni, 2-3% Mo |
| Applications | General industrial, food, pharma | Marine, offshore, chemical, pharma |
| Cost | Ecconomic | More expensive |
| Tensile Strength | 75 ksi (515 MPa) min | 75 ksi (515 MPa) min |
| Yield Strength | 30 ksi (205 MPa) min | 30 ksi (205 MPa) min |
How to chose the material between B8M and B8M fasteners?
Grade B8 is suitable for general industrial use where corrosion resistance is not critical
Grade B8M, with the addition of molybdenum, is specifically designed for harsh, chloride-rich environments, such as offshore, marine, and chemical processing industries, where superior corrosion resistance is critical.
