A335 Chrome Alloy Steel Pipe, Fittings & Flanges
Scope
This specification covers nominal wall and minimum wall seamless ferritic alloy-steel pipe intended for high temperature service. Pipe ordered to this specification shall be suitable for bending, flanging and similar forming operations, and for fusion welding.
Material & Manufacture
Pipe may be either hot finished or cold drawn with the finishing heat treatment noted below.
Chemical Requirements
|
Grade |
P-5 |
P-9 |
P-11 |
P-22 |
P-91 |
P-91 shall also include the following: |
||
| Element |
UNS Designation |
K41545 |
S50400 |
K11597 |
K21590 |
K91560 |
||
| Carbon |
0.15 max |
0.15 max |
0.05 – 0.15 |
0.05 – 0.15 |
0.08 – 0.12 |
V at 0.18 – 0.25 |
||
| Manganese |
0.30 – 0.60 |
0.30 – 0.60 |
0.30 – 0.60 |
0.30 – 0.60 |
0.30 – 0.60 |
N at 0.030 – 0.070 |
||
| Phosphorous, max |
0.025 |
0.025 |
0.025 |
0.025 |
0.020 |
Ni at 0.40 max |
||
| Sulfur, max |
0.025 |
0.025 |
0.025 |
0.025 |
0.010 |
Al at 0.02 max |
||
| Silicon |
0.50 max |
0.25 – 1.00 |
0.50 – 1.00 |
0.50 max |
0.20 -0.50 |
Cb at 0.06 – 0.10 |
||
| Chromium |
4.00 – 6.00 |
8.00 – 10.00 |
1.00 – 1.50 |
1.90 – 2.60 |
8.00 – 9.50 |
Ti at 0.01 max |
||
| Molybdenum |
0.45 -0.65 |
0.90 – 1.10 |
0.44 – 0.65 |
0.87 – 1.13 |
0.85 – 1.05 |
Zr at 0.01 max |
||
Tensile Requirements
|
Seamless |
||||||||
|
P-5 |
P-9 |
P-11 |
P-22 |
P-91 |
P91 shall not have a hardness not exceeding 250 HB/265 HV [25HRC]. | |||
| Tensile Strength, min., psi | ||||||||
| ksi |
60 |
60 |
60 |
60 |
85 |
|||
| MPa |
415 |
415 |
415 |
415 |
585 |
|||
| Yield Strength, min., psi | ||||||||
| ksi |
30 |
30 |
30 |
30 |
60 |
|||
| MPa |
205 |
205 |
205 |
205 |
415 |
|||
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) | ||||
Elongation Requirements
|
Calculated Minimum Elongation Values |
|||||
|
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 |
||
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 |
|||
Heat Treatment Requirements
| P5, P9, P11, and P22 | |||
|
Grade |
Heat Treatment Type |
Normalizing Temperature Range F [C] |
Subcritical Annealing or Tempering |
|
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] |