ASTM A511 / A511M – 16: Standard Specification for Seamless Stainless Steel Mechanical Tubing and Hollow Bar
ASTM A511 / A511M – 16
Standard Specification for Seamless Stainless Steel Mechanical Tubing and Hollow Bar
1. Scope
1.1 This specification covers seamless stainless tubing for use in mechanical applications or as hollow bar for use in the production of hollow components such as, but not limited to nozzles, reducers, and couplings by machining where corrosion-resistant or high-temperature strength is needed. The grades covered are listed in Table 1, Table 2, and Table 3.
(A) For small diameter or thin wall tubing or both, where many drawing passes are required, a maximum of 0.040 % carbon is necessary in grades MT-304L and MT-316L. Small outside diameter tubes are defined as those under a 0.500 in. [12.7 mm] outside diameter and light-wall tubes as those under a 0.049 in. [1.2 mm] average wall thickness (0.044 in. [1.1 mm] min wall thickness).
(B) Iron shall be determined arithmetically by difference of 100 minus the sum of the other specified elements.
(C) The range of (Al + Ti) shall be within 0.85–1.20 %.
(D) The terms Niobium (Nb) and Columbium (Cb) are alternate names for the same element.
(A) MT446-2 is a lower carbon version of MT446-1, that has a lower tensile strength but improved ductility and toughness.
(B) Carbon plus nitrogen = 0.025 max %.
(A) Maximum, unless a range or minimum is indicated. Where ellipses (…) appear in this table, there is no requirement and analysis for the element need not be determined or reported.
(B) % Cr + 3.3 X % Mo + 16X % N ≥ 40.
1.2 This specification covers seamless cold-finished mechanical tubing and hollow bar and seamless hot-finished mechanical tubing and hollow bar in sizes up to 123/4 in. [325 mm] in outside nominal diameter (for round tubing) with wall thicknesses or inside diameters as required.
1.3 Tubes for mechanical applications shall be furnished in one of the following shapes, as specified by the purchaser: round, square, rectangular, or special. Tubes to be used as hollow bar shall be furnished in round shape.
1.4 Optional supplementary requirements are provided and when desired, shall be stated in the order.
1.5 The values stated in inch-pound units are to be regarded as the standard. Within the text, the SI units are shown in square brackets. The values stated in each system are not exact equivalents; therefore, each system shall be used independently of the other.
2. Chemical Requirements of Austenitic Stainless Steels：
Grade | Composition, % | ||||||||||
Carbon | Mn | P | S | Si, max | Ni | Cr | Mo | Ti | Columbium plus Tantalum | Se | |
max | max | max | |||||||||
MT 302 | 0.08 to 0.20 | 2 | 0.04 | 0.03 | 1 | 8.0–10.0 | 17.0–19.0 | … | … | … | … |
MT 303 | 0.15 max | 2 | 0.2 | 0.15 min | 1 | 8.0–10.0 | 17.0–19.0 | … | … | … | … |
MT 303Se | 0.15 max | 2 | 0.04 | 0.04 | 1 | 8.0–11.0 | 17.0–19.0 | … | … | … | 0.12–0.2 |
MT 304 | 0.08 max | 2 | 0.04 | 0.03 | 1 | 8.0–11.0 | 18.0–20.0 | … | … | … | … |
MT 304L | 0.035 maxA | 2 | 0.04 | 0.03 | 1 | 8.0–13.0 | 18.0–20.0 | … | … | … | … |
MT 305 | 0.12 | 2 | 0.04 | 0.03 | 1 | 10.0–13.0 | 17.0–19.0 | … | … | … | … |
MT 309S | 0.08 max | 2 | 0.04 | 0.03 | 1 | 12.0–15.0 | 22.0–24.0 | … | … | … | … |
MT 310S | 0.08 max | 2 | 0.04 | 0.03 | 1 | 19.0–22.0 | 24.0–26.0 | … | … | … | … |
MT 316 | 0.08 max | 2 | 0.04 | 0.03 | 1 | 11.0–14.0 | 16.0–18.0 | 2.0–3.0 | … | … | … |
MT 316L | 0.035 maxA | 2 | 0.04 | 0.03 | 1 | 10.0–15.0 | 16.0–18.0 | 2.0–3.0 | … | … | … |
MT 317 | 0.08 max | 2 | 0.04 | 0.03 | 1 | 11.0–14.0 | 18.0–20.0 | 3.0–4.0 | … | … | … |
MT 321 | 0.08 max | 2 | 0.04 | 0.03 | 1 | 9.0–13.0 | 17.0–20.0 | … | B | … | … |
MT 347 | 0.08 max | 2 | 0.04 | 0.03 | 1 | 9.0–13.0 | 17.0–20.0 | … | … | C | … |
A For small diameter or thin wall tubing or both, where many drawing passes are required, a maximum of 0.040 % carbon is necessary in grades MT-304L and MT-316L. Small outside diameter tubes are defined as those under a 0.500 in. [12.7 mm] outside diameter and light-wall tubes as those under a 0.049 in. [1.2 mm] average wall thickness (0.044 in. [1.1 mm] min wall thickness).
B The titanium content shall be not less than five times the carbon content and not more than 0.60 %.
C The columbium plus tantalum content shall be not less than ten times the carbon content and not more than 1.00 %.
3. Permissible Variations in Outside Diameter, Ovality, Wall Thickness, and Cut-Length Variations
(Cold-Finished Round Tubing)A
Outside | Outside Diameter, Tolerance,B | Ovality,B Double | Wall Thickness | Permissible Variations | ||
Over | Under | Over | Under | |||
Under 1⁄2 | 0.005 | less than 0.015 in. | 15 | 15 | 1⁄8 | 0 |
1⁄2 to 11⁄2 , excl | 0.005 | less than 0.065 in. | 10 | 10 | 1⁄8 | 0 |
11⁄2 to 31⁄2 , excl | 0.01 | less than 0.095 in. | 10 | 10 | 3⁄16 | 0 |
31⁄2 to 51⁄2 , excl | 0.015 | less than 0.150 in. | 10 | 10 | 3⁄16 | 0 |
51⁄2 to 8, exc | 0.03 | less than 0.240 in. | 10 | 10 | 3⁄16 | 0 |
8 to 85⁄8 , excl | 0.045 | less than 0.300 in. | 10 | 10 | 3⁄16 | 0 |
85⁄8 to 123⁄4 , incl | 0.062 | less than 0.350 in. | 10 | 10 | 3⁄16 | 0 |
4. Permissible Variations in Outside Diameter, Wall Thickness, and Cut-Length Variations
(Hot-Finished Round Tubing)
Specified Size, Outside | Ratio of Wall | Outside Diameter and Wall Thickness Tolerances | Permissible Variations | ||||||||||
Wall Thickness, % | |||||||||||||
Outside | 0.109 in. | 0.109 to | Over 0.172 to | Over 0.203 in. | |||||||||
over | under | over | under | over | under | over | under | over | under | ||||
Under 3 | all wall thicknesses | 0.023 | 0.023 | 16.5 | 15 | 15 | 15 | 14 | 14 | 12.5 | 12.5 | 3⁄16 | 0 |
3 to 51⁄2 , excl | all wall thicknesses | 0.031 | 0.031 | 16.5 | 15 | 15 | 15 | 14 | 14 | 12.5 | 12.5 | 3⁄16 | 0 |
51⁄2 to 8, excl | all wall thicknesses | 0.047 | 0.047 | … | … | … | … | 14 | 14 | 12.5 | 12.5 | 3⁄16 | 0 |
8 to 103⁄4 , excl | 5 % and over | 0.047 | 0.047 | … | … | … | … | … | … | 12.5 | 12.5 | 3⁄16 | 0 |
103⁄4 to 123⁄4 , incl | under 5 % | 0.063 | 0.063 | … | … | … | … | … | … | 12.5 | 12.5 | 3⁄16 | 0 |
A These tolerances apply to cut lengths up to and including 24 ft (7.3 m). For lengths over 24 ft, an additional over tolerance of 1⁄8 in. (3.1 mm) for each 10 ft (3 m) or faction thereof shall be permissible, up to a maximum tolerance of 1⁄2 in. (12.7 mm).
5. Straightness Tolerances (Cold-/Finished or Hot-/Finished Round Tubing)A
Size Limits | Max Curvature | Max Curvature in Total Lengths, in. | Max Curvature for |
OD 5 in. and smaller. Wall thickness, over 3 % of OD but not over 0.5 in. | 0.03 | 0.030 3 [(Number of feet of length)/3] | Ratio of 0.010 in./ft |
OD over 5 in. to 8 in., incl. Wall thickness, over 4 % of OD but not over 0.75in. | 0.045 | 0.045 3 [(Number of feet of length)/3] | Ratio of 0.015 in./ft |
OD over 8 in. to 123⁄4 , incl. Wall thickness, over 4 % of OD but not over 1 in. | 0.06 | 0.060 3 [(Number of feet of length)/3] | Ratio of 0.020 in./ft |
A The usual procedure for measuring straightness is by means of a 3-ft (0.9 m) straight edge and feeler gage. If determined by the dial indicator method, the values obtained will be approximately twice those determined by the straightedge feeler gage method.
6. Permissible Variations in Outside Dimensions for Square and Rectangular Seamless Mechanical TubingAB
Largest Outside Dimension Across | Tolerances, Outside Dimension Seamless Mechanical Tubing Plus and Minus, in. | |
| For Wall Thickness, Given, in. | Tolerance for Outside Dimension (Including Convexity or Concavity) Plus and Minus, in. |
To 3⁄4 , incl | 0.065 and lighter | 0.015 |
To 3⁄4 , incl | over 0.065 | 0.01 |
Over 3⁄4 to 11⁄4 , incl | all thicknesses | 0.015 |
Over 11⁄4 to 21⁄2 , incl | all thicknesses | 0.02 |
Over 21⁄2 to 31⁄2 , incl | 0.065 and lighter | 0.03 |
Over 21⁄2 to 31⁄2 , incl | over 0.065 | 0.025 |
Over 31⁄2 to 51⁄2 , incl | all thicknesses | 0.03 |
Over 51⁄2 to 71⁄2 , incl | all thicknesses | 1% |
A The wall thickness tolerance is plus and minus 10 % of nominal wall thickness.
B The straightness tolerance is 0.075 in. 3 ft. using a 3-ft straight edge and feeler gage
