SA423/A423M Grade 1 , Grade 2 , Grade 3 electric welded steel pipe
, Electric-Welded Low-Alloy Steel Tubes
Standard Specification for
Seamless and Electric-Welded Low-Alloy Steel Tubes1
1. Scope
1.1 This specification2 covers minimum-wall-thickness, seamless and
electric-resistance welded, low-alloy steel tubes
for pressure containing parts such as economizers or other
applications where corrosion resistance is important.
1.2 The tubing sizes and thicknesses usually furnished to this
specification are 1⁄2 to 5 in. [12.7 to 127 mm] in outside
diameter and 0.035 to 0.500 in. [0.9 to 12.7 mm] inclusive, in
minimum wall thickness. Tubing having other dimensions may
be furnished, provided such tubes comply with all other
requirements of this specification.
1.3 Mechanical property requirements do not apply to tubing smaller
than 1⁄4 in. [3.2 mm] in inside diameter or 0.015
in. [0.4 mm] in thickness.
1.4 An optional supplementary requirement is provided and, when
desired, shall be so stated in the order.
1.5 The values stated in either SI units or inch-pound units are to
be regarded separately as standard. Within the text, the
SI units are shown in brackets. The values stated in each system
may not be exact equivalents; therefore, each system
shall be used independently of the other. Combining values from the
two systems may result in non-conformance with the
standard. The inch-pound units shall apply unless the “M”
designation of this specification is specified in the order.
2. Referenced Documents
2.1 ASTM Standards:3
A450/A450M Specification for General Requirements for Carbon and
Low Alloy Steel Tubes
E213 Practice for Ultrasonic Testing of Metal Pipe and tubing
E273 Practice for Ultrasonic Testing of the Weld Zone of Welded
Pipe and Tubing
8. Tensile Requirements
8.1 The material shall conform to the requirements as to tensile
properties prescribed in Table 3.
9. Hardness Requirements
9.1 The tubes shall have a hardness number not exceeding 170 HB or
87 HRB.
10. Forming Operations
10.1 Tubes when inserted in the boiler shall stand expanding and
beading without showing cracks or flaws.
| | Composition,% | | Grade 1 and | Grade 3 |
| | Grade 1 | Garde 2 | Grade 3 | | 2 | |
| Carbon,max | 0.15 | 0.15 | 0.06 | Tensile strength,min,ksi(Mpa) | 60(415) | 55(380 |
| Manganese | 0.55 max | 0.50-1.00 | 0.70-1.40 | Yield strength,min,ksi(Mpa) | 37(255) | 33(230) |
| Phosphorus | 0.06-0.15 | 0.04 max | 0.020 max | Elongation in 2 in.or 50 mm,min,% | 25 | 35 |
| Sulfur,max | 0.060 | 0.05 | 0.020 | For longitudinal strip tests a | 1.25A | 1.25A |
| Silicon | 0.10 min | … | 0.55 max | deduction for each 1/32 in.(0.8 mm) | | |
| Copper | 0.20-0.60 | 0.30-1.00 | 0.25-0.45 | decrease in wall thickness below | | |
| Chromium | 0.24-1.31 | … | … | 5/16 in.(8 mm)from the basic | | |
| Nickel | 0.20-0.70 | 0.40-1.10 | 0.50 max | minimum elongation of the following | | |
| Molybdenum | … | 0.10 min | 0.20 max | percentage points shall be made | | |
| Antimony | … | … | 0.05-0.15 | | | |
