ASTM A335 P23 Seamless Alloy Steel Pipe For Power Plant Boiler
ASTM A335 P23 Seamless Alloy Steel Pipe For Power Plant
Specification
ASTM A335 P23 Alloy Steel Pipe is a seamless alloy steel pipe designed for high-temperature service, featuring chromium, molybdenum, and vanadium for enhanced strength, creep resistance, and corrosion resistance, making it ideal for power plants, boilers, and superheaters, bridging the gap between P22 and higher alloy grades like P91. It offers excellent thermal stability, durability, and weldability, with required minimum tensile strength of 510 MPa (73.9 ksi) and yield strength of 400 MPa (58 ksi).
| American Standard | Standard Name |
| A335 / A335M | Standard Specification for Seamless Ferritic Alloy-Steel Pipe for High-Temperature Service |
ASTM A335 P23 Alloy 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 | Others |
| P23 | K40712 | 0.04-0.1 | 0.1-0.6 | 0.03 | 0.01 | 0.5 | 1.9-2.6 | 0.05-0.3 | V 0.20-0.30 Nb F 0.02-0.08 B 0.0010-0.006 N 0.015 max Al 0.030 max W 1.45-1.75 Ni 0.40 max Ti 0.005-0.060 Ti/N ≥3.5 C |
| A New designation established in accordance with Practice E527 and SAE J1086, Practice for Numbering Metals and Alloys (UNS). B Grade P5c shall have a titanium content of not less than 4 times the carbon content and not more than 0.70 %; or a niobium content of 8 to 10 times the carbon content. C Alternatively, in lieu of this ratio minimum, the material shall have a minimum hardness of 275 HV in the hardened condition, defined as after austenitizing and cooling to room temperature but prior to tempering. Hardness testing shall be performed at mid-thickness of the product. Hardness test frequency shall be two samples of product per heat treatment lot and the hardness testing results shall be reported on the material test report. D Applies to both heat and product analyses. E Chromium-Nickel Balance is defined as CNB = (Cr + 6Si + 4Mo + 1.5W + 11V + 5Nb + 9Ti + 12Al) – (40C + 30N + 4Ni + 2Mn + 1CU). F The terms Niobium (Nb) and Columbium (Cb) are alternate names for the same element. |
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ASTM A335 P23 Alloy 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 | |||||
| P23 | K40712 | 58/400 | 74/510 | 20 | 220HBW | 220HV | 97HRBW |
ASTM A335 P23 Alloy 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] |
| P23 | normalize and temper | 1900-1975[1040-1080] | air or accelerated cooling | 1350-1470[730-800] |
| A Where ellipses (_) appear in this table there is no requirement. | ||||
ASTM A335 P23 Alloy 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 P23 Alloy 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 P23 Alloy Steel Pipe Manufacturing Proces
ASTM A335 P23 Alloy Steel Pipe Application
- Power Plant Boiler Components
- Water Wall Panels in High-Pressure Boilers
- Main Steam and Hot Reheat Piping
- Boiler Headers and Manifolds
- Retrofit and Life Extension Projects
- Heat Recovery Steam Generator (HRSG) High-Temperature Sections
- Industrial and Utility Boilers for High-Efficiency Operation
- Fossil Fuel-Fired Boiler Critical Pressure Parts
- Advanced Heat Exchanger Tubing
ASTM A335 P23 Alloy 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.
→Alloy Steel Pipes is transported in containers
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