Welding A588 Steel
Welding A588 steel is a highly specialized process that requires the utmost expertise and skill. The steel alloy is known as weathering steel, due to its ability to form a protective layer against corrosion when exposed to environmental conditions.
As such, welding A588 steel provides its own set of challenges since the chemical composition of this type of steel can be affected by external elements.
When welding A588 steel it is important for welders to understand the properties of the material and select the appropriate technique for their particular application.
The most suitable method for welding A588 steel depends on many factors including thickness, size, shape, grade and degree of corrosion protection required.
Typically stick electrodes or metal arc welding processes are employed as they provide excellent penetration with minimal distortion.
Material Specification for A588 Steel
The material specification for A588 steel is ASTM A588. The UNS Number for A588 steel is K11430. ASME Section IX welding P Number for A588 Grade A & B is P-Number 3 and group No 1.
As per AWS D1.1, the strength group for ASTM A588 steel is Group II, and the toughness is Class C.
A588 Steel Chemical Compositions
A588 steel is a unique material that exhibits properties that make it suitable for a variety of applications. A588 steel is also called CORTEN-B steel.
This alloy has high strength, corrosion resistance, and excellent weldability and formability. It is often used in bridges, construction buildings, tanks, marine equipment, and more.
The chemical composition of A588 steel is listed in the below table:
| Element | Chemical Composition |
| C% | 0.19% maximum |
| Mn% | 0.80-1.25% |
| P% | 0.030% maximum |
| S% | 0.030% maximum |
| Si% | 0.03-0.65% |
| NIi% | 0.40% maximum |
| Cr% | 0.40-0.65% |
| Cu% | 0.25-0.40% |
| V% | 0.02-0.10% |
The mechanical properties of ASTM A588 are listed in the below table (Reference AWS D1.1). For thicknesses less than 4 inches, the minimum yield strength is 50 Ksi (345 MPa) and the minimum tensile strength is 70 Ksi (485 MPa).
Stick Welding of A588 Steel
Stick welding of A588 steel is carried out using E7018 or E7016 low hydrogen welding electrodes. According to the AWS D1.1, the base metal grouping of A588 steel is Group II.
As listed in Table 5.4 of AWS D1.1, stick welding rods for A588 steel welding are:
- E7015, E7016, E7018 and E7028 (AWS A5.1) and
- E7018-W1 and E8018-W2 (AWS A5.5).
The most commonly used electrodes are E7018-1 or E8018-W1; both provide excellent joint penetration and mechanical properties. E7018-W1 and E8018-W2 (AWS A5.5) give the best color match when properly executed.
TIG Welding of A588 Steel
TIG welding of A588 steel can be carried out using ER70S-2 and ER70S-6 tig filler wire. For higher thickness, you can use Nickel base filler wires that will provide good weld toughness. Examples of these wires are: ER80S-Ni1 and ER80S-Ni2.
No heat treatment is required for ER80S-Ni1 but PWHT is needed for ER80S-Ni2 weld.
MIG Welding of A588 Steel
MIG welding of A588 steel can be carried out using ER70S-2 and ER70S-6 tig filler wire.
Metal core welding for ASTM A588 is carried out using E80C-W2 cored wire.75-25 welding gas should be used when welding A588 steel with TIG or Metal core welding process.
Welding Preheat for A588 Steel Welding
Welding Preheat & interpass temperature for A588 Steel Stick Welding are given in the below table.
