ASTM A608 High-Alloy Tubing
ASTM A608/A608M – 06
Standard Specification for Centrifugally Cast Iron-Chromium-Nickel High-Alloy Tubing for Pressure Application at High Temperatures
1. Scope
1.1 This specification covers iron-chromium-nickel, high-alloy tubes made by the centrifugal casting process intended for use under pressure at high temperatures.
1.2 The grades of high alloys detailed in Table 1 are intended for applications requiring strength and resistance to corrosion and scaling at high temperatures.
1.3 Optional Supplementary Requirements S1 to S11 are provided; these call for additional tests to be made if desired.
1.4 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used independently of each other. Combining values from the two systems may result in nonconformance with the specification.
2. Referenced Documents
2.1 ASTM Standards:
A 342/A 342M Test Methods for Permeability of Feebly Magnetic Materials
A 488/A 488M Practice for Steel Castings, Welding, Qualifications of Procedures and Personnel
A 999/A 999M Specification for General Requirements for Alloy and Stainless Steel Pipe
E 8 Test Methods for Tension Testing of Metallic Materials
E 21 Test Methods for Elevated Temperature Tension Tests of Metallic Materials
E 94 Guide for Radiographic Examination
E 139 Test Methods for Conducting Creep, Creep-Rupture,and Stress-Rupture Tests of Metallic Materials
E 142 Method for Controlling Quality of Radiographic Testing
E 151 Recommended Practice for Tension Tests of Metallic Materials at Elevated Temperatures With Rapid Heating and Conventional or Rapid Strain Rates
E 165 Test Method for Liquid Penetrant Examination
E 340 Test Method for Macroetching Metals and Alloys
3. Ordering Information
3.1 Orders for material to this specification should include the following, as required, to describe the desired material adequately:
3.1.1 Quantity (feet, centimetres, or number of lengths),
3.1.2 Name of material (centrifugally cast tubing),
3.1.3 Specification number and grade (Table 1),
3.1.4 Size (outside or inside diameter and minimum wall thickness, see Section 8).
3.1.5 Condition (see Section 9, as cast or as cast with machining on outside or inside surfaces, or machined; see 5.1,8, and 9),
3.1.6 Length (specific or random), (Permissible Variations in Length Section of Specification A 999/A 999M),
3.1.7 End finish (Ends Section of Specification A 999/A 999M),
3.1.8 Optional requirements (see 8.2.3 regarding the manufacturer’s wall thickness allowance for as cast tubing and Supplementary Requirements S1 to S11),
3.1.9 Test report required (see Section 13), and
3.1.10 Special requirements to be added to the specification.
4. General Requirements
4.1 Material furnished under this specification shall conform to the applicable requirements of the current edition of Specification A 999/A 999M, unless otherwise provided herein.
5. Materials and Manufacture
5.1 The tubing may be supplied in the as cast condition or as cast with machining on the outside or inside surfaces, or machined, as agreed upon between the manufacturer and the purchaser.
5.2 Heat treatment of the tubing shall not be required under this specification.
6. Chemical Requirements
6.1 The material shall conform to the requirements as to chemical composition as prescribed in Table 1.
7. Tensile Properties
7.1 Tension tests at room temperature are not recommended as acceptance criteria under this specification since the alloys are intended for elevated-temperature service, and room-temperature tests do not have a dependable relationship to elevated-temperature properties. (Where the design of the tubing is based on an assumption of certain minimum creep-rupture properties, one of the supplementary requirements of this specification may be stipulated on the order to ascertain the ability of the material to meet the design properties.)
8. Permissible Variation in Dimensions
8.1 Machined Tubing (Tubing Machined on Inside and Outside):
8.1.1 The tolerances given in Specification A 999/A 999M shall govern, except that the wall thickness shall not vary over the specified minimum wall thickness by more than 10 % or 1 ⁄ 16 in. [1.6 mm], whichever is greater. There shall be no variation under the specified minimum wall thickness.
8.2 As-Cast Tubing (No Machining or Machined on Inside or Outside):
8.2.1 Outside Diameter (For Tubes Ordered to Outside Diameter):
8.2.1.1 Tubes machined on the outside shall meet the requirements of Specification A 999/A 999M.
8.2.1.2 Tubes not machined on the outside shall meet the permissible variations of Table 2.
8.2.2 Inside Diameter (For Tubes Ordered to Inside Diameter):
8.2.2.1 Tubes machined on the inside shall meet the requirements of Specification A 999/A 999M.
8.2.2.2 Tubes not machined on the inside shall have permissible variations as agreed upon by the purchaser and the manufacturer.
8.2.3 Wall Thickness—The wall thickness shall not exceed the calculated minimum as cast wall thickness by more than the limits shown in Table 3. The calculated minimum wall thickness shall be equal to the specified minimum wall thickness plus the manufacturer’s allowance for “inside surface feed metal” and outside surface roughness. Upon request, the manufacturer’s allowance shall be furnished to the purchaser.There shall be no variation under the calculated minimum as cast wall thickness. For tubes over 24 up to and including 54 in.[600 to 1350 mm] in diameter the “permissible variations over specified minimum as cast wall thickness” shall be agreed upon by the manufacturer and the purchaser.
8.2.4 Length—If definite lengths are ordered, no length of tubing shall be under the length specified and not longer than the tolerance shown in Table 4.
9. Finish
9.1 Machined Tubing—All tubes shall be reasonably straight and free of rejectable indications. All visual irregularities shall be explored for depths. When the depth encroaches on the specified minimum wall thickness, such irregularities shall be considered rejectable indications.
9.2 As-Cast Tubing:
9.2.1 The outside surface shall be adequately cleaned (such as by shotblasting, sandblasting, wire brushing, grinding, or machining). The metal surface so revealed shall be visually inspected and shall be free of linear discontinuities or other imperfections that encroach on the specified minimum wall of the tube.
9.2.2 Various degrees of surface roughness occur on unmachined tubing. If a specific surface finish is required, it shall be a matter of agreement between the manufacturer and the purchaser.
9.3 Surface Irregularities Not Classified as Rejectable—Visual surface defects that have been explored and that do not encroach on the minimum sound wall thickness shall be blended either by machining or grinding the surface into the surrounding unaffected surface area of the tubing.
9.4 Repair by Welding—Repair of injurious defects by welding shall be permitted and major weld repairs shall be permitted only subject to the approval of the purchaser. Weld repairs shall be considered major if the depth of the cavity prepared for welding exceeds 20 % of the required minimum wall thickness or if the total surface area exceeds 10 in. 2 [65cm 2 ]. Defects shall be completely removed before welding. If defects are linear, complete removal shall be checked by liquid penetrant inspection (Practice E 165). Only qualified operators and procedures in accordance with Practice A 488/A 488M shall be used. All weld repairs shall be subjected to the same inspection standard as the tubing.
10. Pressure Test
10.1 All tubing shall be subjected to an internal air pressure of at least 75 psi [515 kPa] for at least 1 min either while submerged in clear water or with the entire outer surface coated with sulfur-free soap suds at the discretion of the manufacturer.In the usable portion of the tube, leaks are not permitted. If the Hydrostatic Test, Supplementary Requirement S6, is invoked,the exact details of the test and testing procedure shall be clearly defined and made a part of the Ordering Information(3.1.8).
10.2 Leaks may be repaired by welding only if such repair is approved by the purchaser.
11. Flattening Test
11.1 Flattening tests are not required since material covered by this specification is not intended to be bent, flanged, or otherwise formed.
12. Mechanical Tests Required
12.1 Air Pressure Test—Each length of tubing shall be subjected to the pressure test described in Section 10.
13. Certification
13.1 Upon request of the purchaser in the contract or order,a manufacturer’s certification that the material was manufactured and tested in accordance with this specification together with a report of the test results shall be furnished at the time of shipment.
14. Product Marking
14.1 In addition to the marking prescribed in Specification A 999/A 999M, the marking shall include the length, an additional symbol “S” if the tubing conforms to the supplementary requirements specified in Supplementary Requirements S1 to S11, and the heat number or manufacturer’s number by which the tube can be identified, and, when as cast (see 8.2), the notation “AS CAST.”
15. Keywords
15.1 alloy; centrifugal casting; high temperatures; pressure containing parts; steel tube; temperature service applications
Standard Specification for Centrifugally Cast Iron-Chromium-Nickel High-Alloy Tubing for Pressure Application at High Temperatures
1. Scope
1.1 This specification covers iron-chromium-nickel, high-alloy tubes made by the centrifugal casting process intended for use under pressure at high temperatures.
1.2 The grades of high alloys detailed in Table 1 are intended for applications requiring strength and resistance to corrosion and scaling at high temperatures.
1.3 Optional Supplementary Requirements S1 to S11 are provided; these call for additional tests to be made if desired.
1.4 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used independently of each other. Combining values from the two systems may result in nonconformance with the specification.
2. Referenced Documents
2.1 ASTM Standards:
A 342/A 342M Test Methods for Permeability of Feebly Magnetic Materials
A 488/A 488M Practice for Steel Castings, Welding, Qualifications of Procedures and Personnel
A 999/A 999M Specification for General Requirements for Alloy and Stainless Steel Pipe
E 8 Test Methods for Tension Testing of Metallic Materials
E 21 Test Methods for Elevated Temperature Tension Tests of Metallic Materials
E 94 Guide for Radiographic Examination
E 139 Test Methods for Conducting Creep, Creep-Rupture,and Stress-Rupture Tests of Metallic Materials
E 142 Method for Controlling Quality of Radiographic Testing
E 151 Recommended Practice for Tension Tests of Metallic Materials at Elevated Temperatures With Rapid Heating and Conventional or Rapid Strain Rates
E 165 Test Method for Liquid Penetrant Examination
E 340 Test Method for Macroetching Metals and Alloys
3. Ordering Information
3.1 Orders for material to this specification should include the following, as required, to describe the desired material adequately:
3.1.1 Quantity (feet, centimetres, or number of lengths),
3.1.2 Name of material (centrifugally cast tubing),
3.1.3 Specification number and grade (Table 1),
3.1.4 Size (outside or inside diameter and minimum wall thickness, see Section 8).
3.1.5 Condition (see Section 9, as cast or as cast with machining on outside or inside surfaces, or machined; see 5.1,8, and 9),
3.1.6 Length (specific or random), (Permissible Variations in Length Section of Specification A 999/A 999M),
3.1.7 End finish (Ends Section of Specification A 999/A 999M),
3.1.8 Optional requirements (see 8.2.3 regarding the manufacturer’s wall thickness allowance for as cast tubing and Supplementary Requirements S1 to S11),
3.1.9 Test report required (see Section 13), and
3.1.10 Special requirements to be added to the specification.
4. General Requirements
4.1 Material furnished under this specification shall conform to the applicable requirements of the current edition of Specification A 999/A 999M, unless otherwise provided herein.
5. Materials and Manufacture
5.1 The tubing may be supplied in the as cast condition or as cast with machining on the outside or inside surfaces, or machined, as agreed upon between the manufacturer and the purchaser.
5.2 Heat treatment of the tubing shall not be required under this specification.
6. Chemical Requirements
6.1 The material shall conform to the requirements as to chemical composition as prescribed in Table 1.
TABLE 1 Chemical Requirements
| Grade | Composition, % | |||||||
| Carbon | Manganese | Silicon | Chromium | Nickel | Phosphorus | Sulfur | Molybdenum | |
| HC30 | 0.25–0.35 | 0.5–1.0 | 0.50–2.00 | 26–30 | 4.0 max | 0.04 max | 0.04 max | 0.50 max |
| HD50 | 0.45–0.55 | 1.50 max | 0.50–2.00 | 26–30 | 4–7 | 0.04 max | 0.04 max | 0.50 max |
| HE35 | 0.30–0.40 | 1.50 max | 0.50–2.00 | 26–30 | 8–11 | 0.04 max | 0.04 max | 0.50 max |
| HF30 | 0.25–0.35 | 1.50 max | 0.50–2.00 | 19–23 | 9–12 | 0.04 max | 0.04 max | 0.50 max |
| HH30 | 0.25–0.35 | 1.50 max | 0.50–2.00 | 24–28 | 11–14 | 0.04 max | 0.04 max | 0.50 max |
| HH33 A | 0.28–0.38 | 1.50 max | 0.50–2.00 | 24–26 | 12–14 | 0.04 max | 0.04 max | 0.50 max |
| HI35 | 0.30–0.40 | 1.50 max | 0.50–2.00 | 26–30 | 14–18 | 0.04 max | 0.04 max | 0.50 max |
| HK30 | 0.25–0.35 | 1.50 max | 0.50–2.00 | 23–27 | 19–22 | 0.04 max | 0.04 max | 0.50 max |
| HK40 | 0.35–0.45 | 1.50 max | 0.50–2.00 | 23–27 | 19–22 | 0.04 max | 0.04 max | 0.50 max |
| HL30 | 0.25–0.35 | 1.50 max | 0.50–2.00 | 28–32 | 18–22 | 0.04 max | 0.04 max | 0.50 max |
| HL40 | 0.35–0.45 | 1.50 max | 0.50–2.00 | 28–32 | 18–22 | 0.04 max | 0.04 max | 0.50 max |
| HN40 | 0.35–0.45 | 1.50 max | 0.50–2.00 | 19–23 | 23–27 | 0.04 max | 0.04 max | 0.50 max |
| HT50 | 0.40–0.60 | 1.50 max | 0.50–2.00 | 15–19 | 33–37 | 0.04 max | 0.04 max | 0.50 max |
| HU50 | 0.40–0.60 | 1.50 max | 0.50–2.00 | 17–21 | 37–41 | 0.04 max | 0.04 max | 0.50 max |
| HW50 | 0.40–0.60 | 1.50 max | 0.50–2.00 | 10–14 | 58–62 | 0.04 max | 0.04 max | 0.50 max |
| HX50 | 0.40–0.60 | 1.50 max | 0.50–2.00 | 15–19 | 64–68 | 0.04 max | 0.04 max | 0.50 max |
7. Tensile Properties
7.1 Tension tests at room temperature are not recommended as acceptance criteria under this specification since the alloys are intended for elevated-temperature service, and room-temperature tests do not have a dependable relationship to elevated-temperature properties. (Where the design of the tubing is based on an assumption of certain minimum creep-rupture properties, one of the supplementary requirements of this specification may be stipulated on the order to ascertain the ability of the material to meet the design properties.)
8. Permissible Variation in Dimensions
8.1 Machined Tubing (Tubing Machined on Inside and Outside):
8.1.1 The tolerances given in Specification A 999/A 999M shall govern, except that the wall thickness shall not vary over the specified minimum wall thickness by more than 10 % or 1 ⁄ 16 in. [1.6 mm], whichever is greater. There shall be no variation under the specified minimum wall thickness.
8.2 As-Cast Tubing (No Machining or Machined on Inside or Outside):
8.2.1 Outside Diameter (For Tubes Ordered to Outside Diameter):
8.2.1.1 Tubes machined on the outside shall meet the requirements of Specification A 999/A 999M.
8.2.1.2 Tubes not machined on the outside shall meet the permissible variations of Table 2.
TABLE 2 Permissible Variations in As-Cast Outside Diameter
| Specified Outside Diameter of Tubing | Permissible Plus or Minus Variations from Specified Outside Diameter | ||
| in. | mm | in. | mm |
| From 2 to 4 | 50 to 100 | 0.08 | 2.0 |
| Over 4 to 12 | 100 to 300 | 0.10 | 2.5 |
| Over 12 to 24 | 300 to 600 | 0.12 | 3.0 |
| Over 24 to 36 | 600 to 900 | 0.16 | 4.1 |
| Over 36 to 54 | 900 to 1350 | 0.25 | 6.4 |
8.2.2 Inside Diameter (For Tubes Ordered to Inside Diameter):
8.2.2.1 Tubes machined on the inside shall meet the requirements of Specification A 999/A 999M.
8.2.2.2 Tubes not machined on the inside shall have permissible variations as agreed upon by the purchaser and the manufacturer.
8.2.3 Wall Thickness—The wall thickness shall not exceed the calculated minimum as cast wall thickness by more than the limits shown in Table 3. The calculated minimum wall thickness shall be equal to the specified minimum wall thickness plus the manufacturer’s allowance for “inside surface feed metal” and outside surface roughness. Upon request, the manufacturer’s allowance shall be furnished to the purchaser.There shall be no variation under the calculated minimum as cast wall thickness. For tubes over 24 up to and including 54 in.[600 to 1350 mm] in diameter the “permissible variations over specified minimum as cast wall thickness” shall be agreed upon by the manufacturer and the purchaser.
TABLE 3 Permissible Variations in As-Cast Wall Thickness
| Specified Outside Diameter of Tubing | Permissible Plus or Minus Variations from Specified Outside Diameter | ||
| in. | mm | in. | mm |
| From 2 to 4 | 50 to 150 | 0.08 | 2.0 |
| Over 4 to 12 | 150 to 300 | 0.10 | 2.5 |
| Over 12 to 24 | 300 to 600 | 0.13 | 3.3 |
8.2.4 Length—If definite lengths are ordered, no length of tubing shall be under the length specified and not longer than the tolerance shown in Table 4.
TABLE 4 Excess Length Tolerances for Centrifugally Cast Tubes
| Outside Diameter of Tube | Permissible Excess Length | ||
| in. | mm | in. | mm |
| From 2 to 12 | 50 to 300 | 1 ⁄ 4 | 6.4 |
| Over 12 to 24 | 300 to 600 | 1 ⁄ 2 | 13 |
| Over 24 to 54 | 600 to 1350 | 1 | 25 |
9. Finish
9.1 Machined Tubing—All tubes shall be reasonably straight and free of rejectable indications. All visual irregularities shall be explored for depths. When the depth encroaches on the specified minimum wall thickness, such irregularities shall be considered rejectable indications.
9.2 As-Cast Tubing:
9.2.1 The outside surface shall be adequately cleaned (such as by shotblasting, sandblasting, wire brushing, grinding, or machining). The metal surface so revealed shall be visually inspected and shall be free of linear discontinuities or other imperfections that encroach on the specified minimum wall of the tube.
9.2.2 Various degrees of surface roughness occur on unmachined tubing. If a specific surface finish is required, it shall be a matter of agreement between the manufacturer and the purchaser.
9.3 Surface Irregularities Not Classified as Rejectable—Visual surface defects that have been explored and that do not encroach on the minimum sound wall thickness shall be blended either by machining or grinding the surface into the surrounding unaffected surface area of the tubing.
9.4 Repair by Welding—Repair of injurious defects by welding shall be permitted and major weld repairs shall be permitted only subject to the approval of the purchaser. Weld repairs shall be considered major if the depth of the cavity prepared for welding exceeds 20 % of the required minimum wall thickness or if the total surface area exceeds 10 in. 2 [65cm 2 ]. Defects shall be completely removed before welding. If defects are linear, complete removal shall be checked by liquid penetrant inspection (Practice E 165). Only qualified operators and procedures in accordance with Practice A 488/A 488M shall be used. All weld repairs shall be subjected to the same inspection standard as the tubing.
10. Pressure Test
10.1 All tubing shall be subjected to an internal air pressure of at least 75 psi [515 kPa] for at least 1 min either while submerged in clear water or with the entire outer surface coated with sulfur-free soap suds at the discretion of the manufacturer.In the usable portion of the tube, leaks are not permitted. If the Hydrostatic Test, Supplementary Requirement S6, is invoked,the exact details of the test and testing procedure shall be clearly defined and made a part of the Ordering Information(3.1.8).
10.2 Leaks may be repaired by welding only if such repair is approved by the purchaser.
11. Flattening Test
11.1 Flattening tests are not required since material covered by this specification is not intended to be bent, flanged, or otherwise formed.
12. Mechanical Tests Required
12.1 Air Pressure Test—Each length of tubing shall be subjected to the pressure test described in Section 10.
13. Certification
13.1 Upon request of the purchaser in the contract or order,a manufacturer’s certification that the material was manufactured and tested in accordance with this specification together with a report of the test results shall be furnished at the time of shipment.
14. Product Marking
14.1 In addition to the marking prescribed in Specification A 999/A 999M, the marking shall include the length, an additional symbol “S” if the tubing conforms to the supplementary requirements specified in Supplementary Requirements S1 to S11, and the heat number or manufacturer’s number by which the tube can be identified, and, when as cast (see 8.2), the notation “AS CAST.”
15. Keywords
15.1 alloy; centrifugal casting; high temperatures; pressure containing parts; steel tube; temperature service applications