ASTM A333 Grade 6 Pipes VS ASTM A106 Grade B Pipes
We may always heard the questions from some people,
Can they use ASTM A106 B pipes to replace ASTM A333 Grade 6 Pipes?
Here we would like to introduce both ASTM A106 B pipes and ASTM A333 Grade 6 Pipes,and try to get the answer.
ASTM A106 grade B Seamless Pressure Pipe (ASME SA106) is used in power plants, boilers, petrochemical plants, oil and gas refineries, and ships where the piping must transport fluids and gases that exhibit high pressures and temperatures.
Chemistry Composition of ASTM A106/ASME SA106 Grade B
| C, % | Mn, % | P, % | S, % | Si, % | Cr, % | Cu, % | Mo, % | Ni, % | V, % |
| 0.30 max | 0.29-1.06 | 0.035 max | 0.035 max | 0.10 min | 0.40 max | 0.40 max | 0.15 max | 0.40 max | 0.08 max |
Mechanical Properties of ASTM A106/ASME SA106 Grade B
| Tensile Strength , MPa | Yield Strength, MPa | Elongation, % |
| 415 min | 240 min | 22 min |
While ASTM A333 is the standard specification for seamless and welded carbon and alloy steel pipe for low temperature service or other applications requiring notch toughness.
Chemical Composition of ASTM A333 Grade 6 Seamless Pipes & Tubes
| Element | Composition, wt. % |
|---|---|
| C | ≤0.30 |
| Mn | 0.29-1.06 |
| P | ≤0.025 |
| S | ≤0.025 |
| Si | ≥0.10 |
| Ni | ≤0.40 |
| Cr | ≤0.30 |
| Cu | ≤0.40 |
| V | ≤0.08 |
| Nb | ≤0.02 |
| Mo | ≤0.12 |
*For each reduction of 0.01% carbon below 0.30%, an increase of 0.05% manganese above 1.06% would be permitted to maximum of 1.35% manganese.
In terms of the influence on low temperature impact toughness, phosphorus (P) is the most detrimental element among C, Si, P, Si and N to the Charpy toughness of ASTM A333 Gr.6. Their amount shall be reduced to the smallest. Manganese, as well as the addition of small traces of nickel, vanadium, copper and niobium, can significantly reduce the critical brittle-ductile transition temperature and refine the grain, therefore, improve the impact toughness.
ASTM A333 Grade 6 Seamless Pipes Mechanical Properties at Room Temperature
| Tensile Properties | Requirements (Longitudinal) |
Requirements (Transverse) |
|---|---|---|
| Tensile Strength min. MPa [ksi] |
415 [60] | 415 [60] |
| Yield Strength min. MPa [ksi] |
240 [35] | 240 [35] |
| Elongation in 2″, min. % |
30 | 16.5 |
*Tensile requirements for ASTM A333 Gr.6 at room temperature.
ASTM A333 Grade 6 Seamless Pipes Charpy V-Notch Impact Test
Toughness, or ductility, is the ability of a material to resist impact, to withstand repeated reversals of stress, or to absorb energy when stressed beyond the elastic limit. Steel is normally considered to be a ductile material, however, it may shatter just as glass at certain low temperatures. The critical ductile-to-brittle transition temperature (CDBTT) for any steel is the temperature above which the steel behaves in a predominantly ductile manner and below which it behaves in a predominantly brittle manner. The low alloy steel pipe of ASTM A333 Gr.6 with a low CDBTT can be used at temperatures down to -45°C [-50°F]. It is important to verify that the pipe materials are impact tested and exhibit a sufficient high Charpy toughness.
Equivalent Grade to ASTM A333 GR6
The equivalent grade to ASTM A333 GR6 is often EN 10216-4 P265NL or DIN 17173 TT St 35N. These grades share similar mechanical properties and are suitable for low-temperature service applications.
| Material | Pipes | Buttweld Fittings | Forged Steel Fittings | Valves | Bolts and Nuts |
| Low Temp Carbon Steel | A333 GR6 | A420 WPL6 | ASTM A350 LF2 | A352 LCB | A320 Gr L7 /A194 Gr 7 |
Obviousy we can see that the difference between A106 Gr B and A333 Gr 6 Pipes.
Chemical composition: The chemical composition of A106 Gr B and A333 Gr 6 is only slightly different in terms of maximum values for elements like Phosphorus, Sulfur, Chromium, and Molybdenum. In A106-B material the maximum allowed range for these elements are slightly higher than that of A333-6 material.
Mechanical properties: The mechanical properties of the two grades are also the same. Both A106 Gr B and A333 Gr 6 have a minimum tensile strength of 60,000 psi and a minimum yield strength of 35,000 psi.
Temperature range: A106 Gr B pipes are designed to be used at high temperatures and pressures, while A333 Gr 6 pipes are designed for use at low temperatures.
We do all testing for our products on A106 Grade B pipes and with this assume that results with A333 Gr. 6 will be equivalent or better.
We have bought copies of both standards, and they are indeed very similar. Only real difference is impact testing.
We can easily understand that A333 Gr. 6 pipe is equal or stricter than A106 Gr. B pipes.
However, If you want to use A106 B at a low temperature enviorement,it is not suitable.
It is recommended to use A333 Gr. 6 pipe grade instead of A106 B
