Tubería de acero de aleación sin costura ASTM A335
Alcance: Esta especificación cubre tuberías sin costura de cromo-molibdeno con espesor de pared nominal y mínimo para uso en las industrias petroquímica y de generación de energía. La tubería de acero sin costura ASTM A335 solicitada de acuerdo con esta especificación será adecuada para soldar, doblar, bridar (vanstoning) y operaciones de conformado similares. Con la adición de cromo y molibdeno, ASTM A335 tiene buena resistencia a la tracción, buena resistencia a las altas temperaturas y a la corrosión.
Nivel y aplicación:
Cubriendo los grados de acero P1 a P5, P9, P11, P12 y P91. Los grados P11/P22 y P91/92 se utilizan habitualmente en centrales eléctricas, mientras que los grados A335 P5 y P9 se utilizan principalmente en la industria petroquímica.
Especificaciones de tubos de acero sin costura ASTM A335:
Nombre: Tubería de acero de aleación ASTM A335
Diámetro: 16-1016 mm
Espesor: 2---120 mm
Grado de acero: P1 P2 P5 P9 P11 P12 P22
Superficie: aceitada y pintada de negro para evitar la oxidación.
Áreas de aplicación: calderas industriales, centrales eléctricas, centrales nucleares.
ASTM A335 Steel Pipe Chemical Composition:
| Material |
C |
Si |
Mn |
P |
S |
Mo |
Cr |
| |
% |
% |
% |
% |
Max |
% |
Max |
| A335 Grade P1 |
0.10---0.20 |
0.10---0.50 |
0.30---0.80 |
0.025 |
0.025 |
0.440.65 |
|
| A335 Grade P5 |
Max 0.15 |
Max 0.50 |
0.30---0.60 |
0.025 |
0.025 |
0.450.65 |
4.006.00 |
| A335 Grade P11 |
0.05---0.15 |
0.5---1.0 |
0.30---0.60 |
0.025 |
0.025 |
0.450.65 |
1.001.50 |
| A335 Grade P12 |
0.05---0.15 |
Max 0.50 |
0.30---0.61 |
0.025 |
0.025 |
0.450.65 |
0.801.25 |
| A335 Grade P22 |
0.05---0.15 |
Max 0.50 |
0.30---0.60 |
0.025 |
0.025 |
0.871.13 |
1.902.60 |
ASTM A335 Steel Pipe Mechanical Properties:
| Material |
Tensile N/mm2 |
Strength min N/mm2 |
Yield %min |
| A335 Grade P1 |
Min380 |
205 |
30 |
| A335 Grade P5 |
Min415 |
205 |
30 |
| A335 Grade P11 |
Min415 |
205 |
30 |
| A335 Grade P12 |
Min415 |
205 |
30 |
| A335 Grade P22 |
Min415 |
205 |
30 |
ASTM A335 Steel Pipe Heat Treatment Requirements
ASTM A335 steel pipe may be either hot finished or cold drawn with the finishing heat treatment noted below.
| ASTM A335 Grade |
Heat Treatment Type |
Normalizing Temperature Range F [C] |
Subcritical Annealing or Tempering
Temperature Range F [C] |
| P5 (b,c) |
Full or Isothermal Anneal |
|
|
| |
Normalize and Temper |
- |
1250 [675] |
| |
Subcritical Anneal (P5c only) |
- |
1325 - 1375 [715 - 745] |
| P9 |
Full or Isothermal Anneal |
|
|
| |
Normalize and Temper |
- |
1250 [675] |
| P11 |
Full or Isothermal Anneal |
|
|
| |
Normalize and Temper |
- |
1200 [650] |
| P22 |
Full or Isothermal Anneal |
|
|
| |
Normalize and Temper |
- |
1250 [675] |
| P91 |
Normalize and Temper |
1900-1975 [1040 - 1080] |
1350-1470 [730 - 800] |
| |
Quench and Temper |
1900-1975 [1040 - 1080] |
1350-1470 [730 - 800] |
ASTM A335 steel pipe Permissible Variation 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 |
20.0% |
12.5% |
| Above 2 1/2 [65], t/D < or = 5% |
22.5% |
12.5% |
| Above 2 1/2 [65], t/D > 5% |
15.0% |
12.5% |
| (t = Specified Wall Thickness; D = Specified Outside Diameter) |
ASTM A335 Steel Pipe Elongation Requirements:
| Calculated Minimum Elongation Values |
| Elongation in 2 in. or 50 mm, min % |
| Wall Thickness |
P5, P9, P11, P22 |
P91 |
| in. |
mm |
Longitudinal |
Transverse |
Longitudinal |
| 5/16 (0.312) |
8 |
30 |
20 |
20 |
| 9/32 (0.281) |
7.2 |
28 |
19 |
19 |
| 1/4 (0.250) |
6.4 |
27 |
18 |
18 |
| 7/32 (0.219) |
5.6 |
26 |
|
17 |
| 3/16 (0.188) |
4.8 |
24 |
|
16 |
| 5/32 (0.156) |
4 |
22 |
|
15 |
| 7/8 (0.125) |
3.2 |
21 |
|
14 |
| 3/32 (0.094) |
2.4 |
20 |
|
13 |
| 1/18 (0.062) |
1.6 |
18 |
|
12 |
ASTM A335 Steel Pipe Permissible Variations in Outside Diameter:
Outside Diameter at any point shall not vary from standard specified more than:
| NPS [DN] Designator |
Over |
Under |
| |
in. |
mm |
in. |
mm |
| 1/8 to 1 1/2 [6 to 40], incl. |
1/64 (0.015) |
0.40 |
1/64 (0.015) |
0.40 |
| 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 Steel Pipe Mechanical Tests Specified:
The steel material shall conform to chemical composition, tensile property, and hardness requirements. Each length of pipe shall be subjected to the hydrostatic test.
| Transverse or Longitudinal Tension Test and Flattening Test, Hardness Test, or Bend Test |
| For material heat treated in a batch-type furnace, tests shall be made on 5% of the pipe from each treated lot. For small lots, at least one pipe shall be tested. |
| For material heat treated by the continuous process, tests shall be made on a sufficient number of pipe to constitute 5% of the lot, but in no case less than 2 pipe. |
| Notes for Hardness Test: |
P91 shall not have a hardness not exceeding 250 HB/265 HV [25HRC]. |
| Notes for Bend Test: |
For pipe whose diameter exceeds NPS 25 and whose diameter to wall thickness ratio is 7.0 or less shall be subjected to the bend test instead of the flattening test. |
|
Other pipe whose diameter equals or exceeds NPS 10 may be given the bend test in place of the flattening test subject to the approval of the purchaser. |
|
The bend test specimens shall be bent at room temperature through 180 without cracking on the outside of the bent portion. |
|
The inside diameter of the bend shall be 1 inch [25 mm]. |
| Hydrostatic Test |
Each length of pipe shall be Hydro tested, at option of manufacture nondestructive electric testing can be used. |
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