Analysis Tolerances
Element | Ladle analysis | Check Analysis | |
Under | Over | ||
Carbon | 0.35 to 0.50 | 0.03 | 0.04 |
Manganese | 0.75 to 1.05 | 0.04 | 0.04 |
Phosphorus (max) | 0.035 | 0.01 | |
Sulphur (max) | 0.04 | 0.01 | |
Silicon | 0.15 to 0.35 | 0.02 | 0.03 |
Chromium | 0.80 to 1.15 | 0.05 | 0.05 |
Molybdenum | 0.15 to 0.25 | 0.02 | 0.02 |
S = [P(1.3D2 + 0.4d2)] / (D2 - d2)
Where:
S = Wall stress in psi;
P = Minimum test pressure, at least 5/3 service pressure;
D = Outside diameter in inches;
d = Inside diameter in inches.
S = Mc / I
Where:
S = Tensile stress in psi;
M = Bending moment in inch-pounds (wl2/8);
I = Moment of inertia-0.04909 (D4-d4) in inches fourth;
c = Radius (D/2) of cylinder in inches;
w = Weight per inch of cylinder filled with water;
l = Length of cylinder in inches;
D = Outside diameter in inches;
d = Inside diameter in inches.
S = A1 P / A2
Where:
S = Tensile stress in psi;
A1 = Internal area in cross section of cylinder in square inches;
P = Hydrostatic test pressure-psig;
A2 = Area of metal in cross section of cylinder in square inches.
Size of specimen (mm) | Average value for acceptance (3 specimens) | Minimum value (1 specimen only of the 3) |
10.0 * 10.0 | 25.0 ft. lbs. | 20.0 ft. lbs. |
10.0 * 7.5 | 21.0 ft. lbs. | 17.0 ft. lbs. |
10.0 * 5.0 | 17.0 ft. lbs. | 14.0 ft. lbs. |
49 C.F.R. §178.45