Alloy Steel ASTM A335 P9 Pipe Seamless For Petrochemical
ASTM A335 P9 Boilar Steel Pipe For Petrochemical
Specification
ASTM A335 P9 Alloy Steel Pipe is a seamless ferritic alloy steel pipe designed for high-temperature service, featuring 8-10% Chromium and 0.9-1.1% Molybdenum for enhanced strength, oxidation resistance, and toughness at extreme temperatures, making it ideal for power plants, petrochemicals, and refineries. It meets strict chemical and mechanical specs, requiring hydrostatic and NDT testing, and offers superior performance over carbon steel in demanding industrial environments.
| American Standard | Standard Name |
| A335 / A335M | Standard Specification for Seamless Ferritic Alloy-Steel Pipe for High-Temperature Service |
ASTM A335 P9 Boilar Steel Pipe Chemical Composition
Sources American Standard A335 / A335M TABLE 1 Chemical Requirements
| ASTM A335 Grades |
UNS Designation |
C | Mn | P | S | Si | Cr | Mo |
| P9 | K90941 | 0.15 | 0.30-0.60 | 0.025 | 0.025 | 0.25-1.00 | 8.00-10.00 | 0.9-1.1 |
ASTM A335 P9 Boilar Steel Pipe Mechanical Properties
Sources American Standard A335 / A335M TABLE 3 Tensile Requirements
| ASTM A335 Grade |
UNS Designation |
Yield strength, Min:ksi/MPa |
Tensile strength, Min:ksi/MPa |
Elongation Requirements % (Min) | Hardness Requirements (Max) | ||
| Brinell | Vickers | Rockwell | |||||
| P9 | K90941 | 30/205 | 60/415 | 30 | – | - | – |
ASTM A335 P9 Boilar Steel Pipe Heat Treatment
Sources American Standard A335 / A335M TABLE 2 Heat Treatment Requirements A
| ASTM A335 Grade | Heat Treatment Type | Normalizing Temperature Range F [C] | Cooling Media | Subcritical Annealing or Tempering Temperature,min or range“F[°C] |
| P9 | full or isothemmal anneal or | - | - | - |
| normalize and temper or | - | - | 1250 [675] | |
| A Where ellipses (_) appear in this table there is no requirement. | ||||
ASTM A335 P9 Boilar Steel Pipe Permissible Variations in Outside Diameter
Sources American Standard A335 / A335M TABLE 7 Permissible Variations in Outside Diameter
|
NPS [DN] Designator |
Over | Under | ||
| in. | mm | in. | mm | |
| 1/8 to 1 1/2 [6 to 40], incl. | 1/64 (0.015) | 0.4 | 1/64 (0.015) | 0.4 |
| Over 1 1/2 to 4 [40 to 100], incl. | 1/32 (0.031) | 0.79 | 1/32 (0.031) | 0.79 |
| Over 4 to 8 [100 to 200], incl. | 1/16 (0.062) | 1.59 | 1/32 (0.031) | 0.79 |
| Over 8 to 12 [200 to 300], incl. | 3/32 (0.093) | 2.38 | 1/32 (0.031) | 0.79 |
| Over 12 [300] | +/- 1% of the specified outside diameter | |||
ASTM A335 P9 Boilar Steel Pipe Permitted Variations in Wall Thickness
Sources American Standard A335 / A335M TABLE 8 Permitted Variations in Wall Thickness
| NPS [DN] Designator | Tolerance, % from Specified | |
| Over | Under | |
| 1/8 to 2 1/2 [6 to 65] incl., all t/D ratios | 20.00% | 12.50% |
| Above 2 1/2 [65], t/D < or = 5% | 22.50% | 12.50% |
| Above 2 1/2 [65], t/D > 5% | 15.00% | 12.50% |
| (t = Specified Wall Thickness; D = Specified Outside Diameter) | ||
ASTM A335 P9 Boilar Steel Pipe Manufacturing Proces
ASTM A335 P9 Boilar Steel Pipe Application
- Petrochemical Cracking Furnace Tubes
- Hydrogen Reformer Furnace Components
- Direct-Fired Process Heater Tubes
- Refinery High-Temperature Piping
- Power Generation Boiler Components
- Heat Exchanger Tubing for Aggressive Services
- Sulfur Recovery Unit (SRU) Critical Piping
ASTM A335 P9 Boilar Steel Pipe Packing & Loading
a. 1/2"-2"Plain end with black oil paint, caps both ends, bundles with loading belt.
b. 2"-4"Beveled end with black oil paint, caps both ends, bundles with loading belt.
c. 10"-20"Beveled end with black oil paint, caps both ends, loose packed in to container.
→Boilar Steel Pipe is transported in containers
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