An atmospheric corrosion-resistant weldable notch-tough steel plate grade specified within G40.21 of the Canadian Standards Association (CSA). This plate is utilized primarily in structural applications such as bridges and buildings. When properly exposed to the atmosphere, this steel plate can be utilized in its bare condition (unpainted). It is also referred to as 350A, which is its metric designation. This material is also available as Charpy tested when referenced with a “T”, such as 50AT / 350AT. When Charpy tests are required, the category will be indicated. The values of these categories are outlined below in mechanical properties.