ASTM A193 Standard Specification for Alloy-Steel and Stainless Steel Bolting Materials for High-Temperature Service
Grade: B7 — Ferritic Steels / Chromium-Molybdenum
Chemical Requirements (Composition, percent)
C: 0.38-0.48
Mn: 0.75-1.00
P: ≤0.035
S: ≤0.040
Si: 0.15-0.35
Cr: 0.80-1.10
Mo: 0.15-0.25
*For bar sizes over 3-1/2 in. [90 mm], inclusive, the carbon content may be 0.50 %, max.
Mechanical Requirements —Metric Products
Diameter, [mm] | Tensile Strength, min,MPa | Yield Strength, min, 0.2 % offset, MPa | Elongation in 4D, min, % | Reduction of Area, min, % | Hardness, max |
M64 and under | 860 | 720 | 16 | 50 | 321 HB or 35 HRC |
| over M64 to M100 | 795 | 655 | 16 | 50 | 321 HB or 35 HRC |
| over M100 to M180 | 690 | 515 | 18 | 50 | 321 HB or 35 HRC |
Minimum Tempering Temperature: 593℃
