Weldability of A588 Grade B Weathering Steel

A588 Weldability of Grade B Weathering Steel

Weldability is an important aspect to consider when describing any material, and A588 Grade B weathering steel is no exception. Although this material is known for its extreme corrosion resistance, it can be welded depending on how the procedure is performed and how the material is prepared prior to welding. In order to properly weld A588 Grade B weathering steel, the following considerations must be considered.

1. The preheat and interpass temperature: Preheat and interpass temperatures are, in many cases, the most important factor in successful welding of A588 Grade B weathering steel. To properly weld the material, a preheat of 15099°F is required to help pre-condition the material and prevent cracking during cooling. To further reduce cracking during cooling, the minimum interpass temperature should be 335°F.

2. Choice of filler metal: With the proper preheat and interpass temperature, the choice of filler metal will ultimately decide the success of the weld. The most common filler metal to use when welding A588 Grade B is an AWS (American Welding Society) specification A 5.5 E7018 electrode. This electrode can typically be used with shielding gas such as 100 percent CO2 or 75 percent argon and 25 percent CO2.

3. Pre-treatment prior to welding: The metal should be clean and dry prior to welding to ensure optimal weld integrity. All rust, oil, dirt, and mill scale should be removed prior to welding. Additionally, it is necessary to remove any previous coatings from the metal.

4. Post welding heat treatment: Post-weld heat treatment is recommended to all welded A588 Grade B weathering steel. The optimum time to perform the heat treatment is when the temperature of the weld is above 1250°F. The post-weld heat treatment should involve a stress relief at between 1050°F and 1100°F to reduce the risk of cracking due to stress.

Welding A588 Grade B weathering steel is a difficult task, but it can be accomplished with the correct procedure, the correct filler metal, and proper preheat and post-weld heat treatment. Despite the high corrosion resistance of this material, pre-treatment of the metal prior to welding and post-weld heat treatment are still required to further ensure structural integrity. Following these procedures will help ensure that welding and construction of A588 Grade B weathering steel is as successful as possible.