A588 Method for Chemical Composition Analysis of Grade C Weathering Steel

A588 is a type of weathering steel used in a range of projects to provide added protection against corrosive environments. A588 grade C weathering steel is a high strength, low alloy steel, often referred to as Cor Ten® steel, that exhibits increased corrosion resistance in the presence of atmospheric oxygen thanks to its unique chemical composition.

In order to evaluate the corrosion resistance of grade C weathering steel, the chemical composition analysis of the material is necessary. Major elements in A588 grade C steel are carbon, manganese, phosphorus, sulfur, silicon, nickel, chromium, vanadium and copper. The concentrations of these elements determine the mechanical properties and corrosion resistance of the material.

The chemical composition of A588 grade C weathering steel is divided into different elements, each of which has different concentration limits as specified by ASTM's specification A588/A588m. The elements and their concentration limits are as follows:

Carbon : 0.19% - 0.75%
Manganese : 0.80% - 1.25%
Phosphorus : 0.04% max
Sulfur : 0.05% max
Silicon : 0. 15% - 0.50%
Nickel : 0.40% max
Chromium : 0.40% - 0.65%
Vanadium : 0.02% - 0.10%
Copper : 0.20% max

The above elements, along with Alloying Elements, apply to the structural and mechanical properties of A588 grade C weathering steel to improve their corrosion resistance.

In order to analyze the chemical composition of grade C weathering steel, both destructive and non-destructive testing methods such as optical emission spectrometry (OES) and x-ray fluorescence (XRF) can be used. The OES method is excellent for identifying elements, hence providing proof of compliance with ASTM's requirements. The XRF technique enables fast and accurate cloud measurements to be taken.

Therefore, when undertaking a chemical composition analysis on A588 grade C weathering steel, non-destructive spectrometer testing methods are suitable, enabling accurate and detailed measurements to be taken. This ensures that the material is compliant with ASTM A588/A588M and is suitable for use in the intended application.