What Is The Tolerance Of ASTM A213 Tube?

What is ASTM A213 tube?

ASTM A213 is a standard specification applicable to seamless ferritic and austenitic alloy steel and stainless steel tubes intended for use in high-temperature and high-pressure service conditions, particularly in boilers, superheaters, and heat exchangers. Specific grades include TP304, TP304H, TP304L, TP310S, TP310HCbN, TP316, TP316H, TP316L, and others.

 

What is SA 213 equivalent to?

Equivalent Designations for this are EN 10216-2, ASTM A335, GOST 550-75, Grade T11 with Material T11, K11597, K11597 Seamless Tubes and Equivalent Material as P11.

 

What is the tolerance of ASTM A213 tube?

For ASTM A213 Seamless Alloy Tubes, the standard tolerance is +20% and -12.5% of the nominal wall thickness. This means that the actual wall thickness can be up to 20% thicker or 12.5% thinner than the specified nominal thickness.

Specification	Allowable Outside Diameter Variation in mm			Allowable Wall Thickness Variation		Exact Length Tolerance in mm
	Nominal Diameter	Over	Under	%Over	%Under	Over	Under
ASTM-A213 Seamless Boiler Superheater and Heat Exchanger Tubes	Under 25.4	.1016	.1016	+20	-0	3.175	0
	25.4-38.1 incl	.1524	.1524	+22	-0	3.175	0
	38.1-50.8 excl	.2032	.2032	+22	-0	3.176	0
	50.8-63.5 excl	.254	.254	+2	-0	4.46	0
	63.5-76.2 excl	.3048	.3048	+22	-0	4.76	0
	76.2-101.6 incl	.381	.381	+22	-0	4.76	0

 

Why does A213 emphasize "Minimum Wall" thickness?

In the ASTM A213 standard, unless "Nominal Wall" thickness is explicitly specified in the order, the default requirement is always "Minimum Wall" thickness. In the design of boilers and high-pressure heat exchangers, wall thickness directly relates to pressure-bearing safety. Utilizing the minimum wall thickness ensures a baseline level of safety in pressure calculations.

 

ASTM A213 tubes (seamless alloy and stainless steel boiler, superheater, and heat-exchanger tubes) must comply with the dimensional requirements specified in ASTM A1016/A1016M (General Requirements for Ferritic Alloy Steel, Austenitic Alloy Steel, and Stainless Steel Tubes).

Below are the technical tables for Outside Diameter (OD), Wall Thickness (WT), and Length tolerances.

 

Permissible Variations in Outside Diameter (OD)

These tolerances apply to the specified outside diameter of the tube.

Specified Outside Diameter (NPS / mm)	Over (Inches / mm)	Under (Inches / mm)
≤ 1.000" [25.4 mm]	0.004" [0.10 mm]	0.004" [0.10 mm]
> 1.000" to ≤ 1.500" [25.4 to 38.1 mm]	0.006" [0.15 mm]	0.006" [0.15 mm]
> 1.500" to < 2.000" [38.1 to 50.8 mm]	0.008" [0.20 mm]	0.008" [0.20 mm]
≥ 2.000" to < 2.500" [50.8 to 63.5 mm]	0.010" [0.25 mm]	0.010" [0.25 mm]
≥ 2.500" to < 3.000" [63.5 to 76.2 mm]	0.012" [0.30 mm]	0.012" [0.30 mm]
≥ 3.000" to < 4.000" [76.2 to 101.6 mm]	0.015" [0.38 mm]	0.015" [0.38 mm]
≥ 4.000" to ≤ 7.500" [101.6 to 190.5 mm]	0.015" [0.38 mm]	0.025" [0.64 mm]

Note: For hot-finished tubes, tolerances are slightly larger depending on the size and wall thickness.

 

Permissible Variations in Wall Thickness (WT)

ASTM A213/A1016 tubes are typically ordered to Minimum Wall Thickness. Therefore, the "Under" tolerance is always 0%.

Manufacturing Method	Outside Diameter (OD)	Tolerance Over (%)	Tolerance Under (%)
Cold-Finished Seamless	All Sizes	20%	0%
Hot-Finished Seamless	OD ≤ 4.000" [101.6 mm]	22% - 40%*	0%
Hot-Finished Seamless	OD > 4.000" [101.6 mm]	22% - 35%*	0%

*The "Over" percentage for hot-finished tubes varies based on the ratio of wall thickness to outside diameter (t/D ratio). Standard boiler tubes are usually +20% to +22%.

 

Permissible Variations in Cut Length

These tolerances apply to tubes with a length of 24 ft [7.3 m] or less.

Outside Diameter (OD)	Over (Inches / mm)	Under (Inches / mm)
All Sizes	1/8" [3 mm]	0" [0 mm]

Note: For lengths over 24 ft [7.3 m], an additional over-tolerance of 1/8" [3 mm] for each 10 ft [3 m] (or fraction thereof) is allowed, up to a maximum of 1/2" [13 mm].

 

Ordering Information

It shall be the responsibility of the purchaser to specify all requirements that are necessary for products under this specification. Such requirements to be considered include, but are not limited to, the following:

1.1 Quantity (feet, metres, or number of lengths),

1.2 Name of material (seamless tubes),

1.3 Grade (Tables 1 and 2),

1.4 Condition (hot finished or cold finished),

1.5 Controlled structural characteristics (see 6.3),

1.6 Size (outside diameter and minimum wall thickness, unless average wall thickness is specified),

1.7 Length (specific or random),

1.8 Hydrostatic Test or Nondestructive Electric Test (see 10.1),

1.9 Specification designation and year of issue,

1.10 Increased sulfur (for machinability, see Note B, Table 1, and 15.3), and

1.11 Special requirements and any supplementary require- ments selected.