Technical Overview of the ASTM A210 / A210M Standard
The ASTM A210 / A210M specification establishes strict requirements for the manufacture of seamless boiler tubes and flue tubes with regulated minimum wall thickness. Medium-carbon steel is used as the primary material, ensuring the reliability of components operating under high-temperature and high-pressure conditions, including superheater elements, arches, and support structures.
Note: These steel grades are not intended for forge welding.
The standard is optimized for a wide range of dimensions: the outside diameter ranges from 1/2 to 5 inches (12.7–127 mm), with a minimum wall thickness from 0.035 to 0.500 inches (0.9–12.7 mm). For products exceeding these parameters, the general requirements of the specification apply unless otherwise agreed upon at the time of order. Mechanical property requirements are not mandatory for tubes with an outside diameter of less than 1/8 inch or a wall thickness of less than 0.015 inches.
EV Group China supplies Grade A-1 and Grade C tubes, which differ in chemical composition and strength characteristics. Hardness control is a critical parameter: for Grade A-1, the limit is 79 HRBW or 143 HBW, and for Grade C, it is 89 HRBW or 179 HBW.
This specification allows for the use of both inch-pound and SI units. When placing an order with EV Group China, it is important to specify the appropriate designation (e.g., “M” for the metric system), as values in different systems are not direct mathematical equivalents and must be applied independently according to international WTO standardization rules.
Table 1. Chemical Composition of Steel, %
| Grade | C, max | Mn | P, max | S, max | Si, min |
| A-1 | 0.27 | 0.93 max | 0.035 | 0.035 | 0.10 |
| C | 0.35 | 0.29–1.06 | 0.035 | 0.035 | 0.10 |
Note: For each reduction of 0.01% below the specified carbon maximum, an increase of 0.06% manganese above the specified maximum will be permitted up to a maximum of 1.35%.
Table 3. Tensile Requirements
| Parameter | Grade A-1 | Grade C |
| Tensile Strength (min), ksi [MPa] | 60 [415] | 70 [485] |
| Yield Strength (min), ksi [MPa] | 37 [255] | 40 [275] |
| Elongation (min), % | 30 | 30 |
| Elongation for proportional specimen (4D) | 22 | 20 |
Table 4. Calculated Minimum Elongation Values
| Wall Thickness, in [mm] | Elongation (min), % |
| 5/16 (0.312) [8] | 30 |
| 9/32 (0.281) [7.2] | 28 |
| 1/4 (0.250) [6.4] | 27 |
| 7/32 (0.219) [5.6] | 26 |
| 3/16 (0.188) [4.8] | 24 |
| 5/32 (0.156) [4] | 22 |
| 1/8 (0.125) [3.2] | 21 |
| 3/32 (0.094) [2.4] | 20 |
| 1/16 (0.062) [1.6] | 18 |
| 0.062–0.035 [1.6–0.9] | 17 |
| 0.035–0.022 [0.9–0.6] | 16 |
| 0.022–0.015 [0.6–0.4] | 16 |