Carbon content in steel, it is one of the key parameters that determine its mechanical properties and applications. There are several methods for determining the chemical composition of steels and alloys, and one of the quickest and easiest is the spark method. It was developed by American blacksmith John Francis Keller in 1921 and later described in the world's first welding encyclopedia.
The spark method is based on observing the glowing particles that form when the sandwheel contacts the surface of various types of steel. The heating process causes the release of particles exposed to atmospheric oxygen, which leads to various visual effects.
When the sandwheel comes into contact with the metal surface, friction heats up. This results in the emission of tiny particles all around. When steel or alloy contains up to 0.02% carbon, particles move along expanding straight lines and become brighter until they completely disappear. This phenomenon is presumably due to the effect of air oxygen on hot particles.
To observe the behavior of the material, it is recommended to only slightly touch the sandwheel with the test sample, as well as monitor the behavior of sparks on a black or other dark background.
Low-carbon steel with a carbon content of 0.02 to 0.25% can be determined by the separation of luminous bands. As the carbon content decreases, the number of sparks decreases and the spatial distance between them increases.
Medium-carbon materials contain from 0.3 to 0.65% carbon and are characterized by a unique branching of glowing lines when in contact with the sandwheel. This is due to the presence of an increased amount of carbon, which, under the influence of heat from iron sparks, forms flashes that interrupt the initially thick lines.
Steel, which contains more than 0.65% carbon, is characterized by an abundance of frequent star-shaped flares. Those present in the material iron and carbon is easily oxidized by oxygen, which puts steel at risk of burning. It should be noted that as the amount of carbon in steel increases, the frequency of outbreaks also increases, and the distance between them is significantly reduced.
The chemical composition of steel plays a crucial role in its mechanical and thermal properties. The spark method described in this article provides a quick estimate of carbon content, but it is approximate. In case precision alloys, the accuracy of determining the chemical composition is critical. In the laboratories of modern metallurgical enterprises, the composition of steels and alloys is assessed using spectral analysis methods to ensure the high quality of finished products.
The PZPS has a spectral laboratory that uses modern equipment and accurate analysis methods to determine not only the amount of carbon, but also the content of other chemical elements in steels and alloys. This ensures high quality manufactured products, and ensure the exact chemical composition of the smelted precision alloys. The laboratory also conducts customer material research and helps to obtain all the necessary information about prototypes.
