ASTM A335 P11 Seamless Welded Pipe for High-Temperature Service
1. About ASTM A335 P11 Pipe
Trade Name: 1 ¼ Chrome
Grade: P11
UNS #: K11597
Pipe: A335/SA335
Forged/Bored Pipe: A369/SA369
Chromium and molybdenum are important elements of P11. Chromium, or
chrome, improves high-temperature strength, increases oxidation
resistance and raises the tensile, yield and hardness at room
temperatures. Molybdenum increases the strength, elastic limit,
resistance to wear, impact qualities and hardenability. It
increases the resistance to softening, restrains grain growth and
makes chromium steel less susceptible to embrittlement. Moly is
also the most effective additive for increasing high temperature
creep strength, or creep resistance. It also enhances the corrosion
resistance of steel and inhibits pitting.
2. Outside Diameter & Tolerance
ASTM A450 | Hot rolled | Outside Diameter, mm | Tolerance, mm |
OD≤101.6 | +0.4/-0.8 |
101.6<OD≤190.5 | +0.4/-1.2 |
190.5<OD≤228.6 | +0.4/-1.6 |
Cold Drawn | Outside Diameter, mm | Tolerance, mm |
OD<25.4 | ±0.10 |
25.4≤OD≤38.1 | ±0.15 |
38.1<OD<50.8 | ±0.20 |
50.8≤OD<63.5 | ±0.25 |
63.5≤OD<76.2 | ±0.30 |
76.2≤OD≤101.6 | ±0.38 |
101.6<OD≤190.5 | +0.38/-0.64 |
190.5<OD≤228.6 | +0.38/-1.14 |
ASTM A530 & ASTM A335 | NPS | Outside Diameter, inch | Tolerance, mm |
1/8≤OD≤1-1/2 | ±0.40 |
1-1/2<OD≤4 | ±0.79 |
4<OD≤8 | +1.59/-0.79 |
8<OD≤12 | +2.38/-0.79 |
OD>12 | ±1% |
3. P11 Pipe Chemical Requirements
- Carbon - 0.05% - 0.15%
- Manganese - 0.30% - 0.60%
- Phosphorus, max - 0.025%
- Sulfur, max - 0.025%
- Silicon – 0.50% - 1.00%
- Chromium - 1.00% - 1.50%
- Molybdenum - 0.44% - 0.65%
4. Enhanced properties of A335/SA335 P11
- Toughness
- Strength
- Hardness
- Wear resistance
- Hardenability
- Hot hardness
- Corrosion resistance
Heat treating can be required to achieve some of these properties.
5. P11 Pipe Specifications
- Tensile strength, min, PSI, (MPa) – 60,000 (415)
- Yield Strength, min, (MPa) – 30,000 (205)
6. P11 Pipe Applications
Due to the ferrimagnetic characteristics of iron, a few steel
alloys in A335 P11 pipes can be used in applications where their
reactions to magnetism are important. This includes transformers
and electric motors. P11 is also a popular grade for many different
applications such as:
- Spacecraft
- Turbine blades of jet engines
- Nuclear reactors