Weldability of A588 Grade K Weathering Steel

Weldability refers to a material’s ability to be welded without suffering weld metal cracking and without compromising mechanical properties of the weld joint. A588 Grade K weathering steel is a high-strength, low-alloy (HSLA) steel with improved atmospheric corrosion resistance due to its chemical composition. This grade is a manganese-chromium-copper alloy steel and is colloquially known as “Corten®”. Due to its corrosion resistance properties, this steel is often used in bridge and other large structural applications. The weldability of A588 Grade K weathering steel is generally considered to be good.

Welding of A588 Grade K weathering steel should be done only after pre-heating the base metal above the pre-heat requirements for the selected filler metal. The most suitable electrodes for welding this grade of steel are either the 7018 low-hydrogen electrodes or the E-7018 low-hydrogen electrodes. These electrodes are suitable for welding A588 Grade K as they minimize the risk of hydrogen cracking in the weld while providing good toughness and strength.

As with most welding operations, proper joint preparation is always important when welding A588 Grade K. To minimize the potential for cracking, it is best to pre-heat the steel or use a lower current and higher voltage settings. Using a pre-heat temperature of at least 150°F (65°C) is recommended for applications with thicknesses above 5/8” (16 mm). The pre-heat temperature should be increased in heavier sections.

In some cases, the weldment may require post weld heat treatment (PWHT) after welding is complete. While PWHT is not required for all operations, it may help reduce stress in the weldment and enhance corrosion resistance. After welding and post weld heat treatment, if necessary, the welded joint should be inspected for porosity, cracking, and other defects.

Weldability of A588 Grade K can be improved by taking proper measures to ensure that the weldment is properly prepared, pre-heated, and post weld heat treated (if necessary). It is also important to ensure that the electrodes used are appropriate for the application and that all welding parameters are followed to help minimize the risk of weld defects. By following the right welding techniques and implementing the appropriate precautions, good weldability can be achieved with A588 Grade K weathering steel.