Welding process of A588 weathering steel plate

A588 weathering steel plate is a high-strength low-alloy steel plate with superior corrosion resistance, especially suitable for bridges. It has long been used in bridge construction due to its resistance to corrosion and its ability to withstand the elements. The chemical composition of A588 weathering steel plate makes it ideal for use in structural applications such as bridges, buildings, and other structures that are exposed to the elements.

There are some caveats for welding A588 weathering steel, as this grade of steel has a higher resistance to atmospheric corrosion and welding of weathering steel can be done without any additional shielding or protection. However, if you plan to weld such steels in acidic or otherwise corrosive conditions, you should take extra precautions to avoid potential corrosion.

There are a number of factors to consider when welding A588 weathering steel plate. The first step is to preheat the material prior to welding; this helps to reduce the chance of cracking. Preheating should be done to a minimum temperature of 150 degrees Fahrenheit (66 degrees Celsius) prior to welding. After preheating, the temperature should not exceed 200 degrees Fahrenheit (93 degrees Celsius).

The type of weld joint and welding process should be selected carefully to ensure the weld properties meet the desired requirements, as the weld joint strength of weathering steel is lower than that of the base metal. The base metal thickness, joint geometry, type of welding process, welding speed, arc length, etc should all be taken into account.

Various welding processes such as oxyacetylene welding/brazing, shielded metal arc welding, gas metal arc welding, flux-core arc welding, and gas tungsten arc welding can be used when welding A588 weathering steel plate. The selection should primarily be based on the joint design and welding application. For example, a flat position and limited access welding application would require oxyacetylene welding/brazing, while arc welding processes are used when welding in the flat, horizontal, and overhead positions.

To ensure a high-quality weld, the right filler alloy should be selected. For example, the AWS A5.1 or A5.5 specification is recommended when joining ASTM A588 grades. The electrode should also be selected based on the joint design and welding application. A rutile coated electrode is typically used to make general and low stress applications, while an iron-powder electrode should be used for joints with high stress and out of position welding.

In addition to the welding process, post-weld treatments should also be considered in order to obtain optimal properties. For example, PWHT (Post Weld Heat Treatment) may be used to reduce hardness and ensure the uniformity of the welded joint.

Welding of A588 weathering steel requires some additional consideration due to its corrosion resistance rating. Preheat, the correct welding process and the correct filler alloy should be selected to ensure the highest quality welded joints. Additionally, post-weld treatments should be considered to ensure optimum performance. With proper preparation and technique, weathering steel can be successfully welded to provide the desired results.