ISO 15350 Steel and Iron - Determination of Total Carbon and Sulfur Content - Infrared Absorption Method After Combustion in Induction Furnace (Routine Method)

In the standard “ISO 15350 Steel and iron - Determination of total carbon and sulfur content - Infrared absorption method after combustion in an induction furnace (routine method)” developed by the International Organization for Standardization (ISO), combustion in an induction furnace for the determination of the total carbon and sulfur content in steel and iron Afterwards, the infrared absorption method is explained.

This method is applied to the carbon content of the mass fraction between 0,005 percent and 4,3 percent and the sulfur content of the mass fraction between 0,0005 and 0,33 percent.

This method can be used in single element mode, i.e., independent determination of carbon and sulfur, or in simultaneous mode, i.e., simultaneous determination of carbon and sulfur.

The test method described is intended for use in normal manufacturing operations and laboratories that will perform the tests are expected to meet generally accepted good laboratory practices of the type expected by accreditation bodies. Such laboratories use commercially available equipment, its calibration is verified using certified reference materials of steel and iron, and its performance is checked using normal statistical process control practices.

In principle, when performing the test, carbon is burned in a stream of oxygen and converted into carbon monoxide and carbon dioxide. The measurement is performed by infrared absorption of carbon monoxide and carbon dioxide carried by a stream of oxygen. Sulfur is converted into sulfur dioxide by burning in the flow of oxygen. The measurement is performed by infrared absorption of sulfur dioxide carried by a stream of oxygen.

Determination of carbon and sulfur content in solids is a routine practice in laboratories and manufacturing. Different analyzers are used in these tests depending on the sample material. Organic samples are generally characterized by high carbon content (60-100 percent) and flammability (e.g. coal, coke, wood). Complete release of carbon and sulfur occurs at temperatures of approximately 1.300 degrees. Analyzers with resistance furnaces are suitable for this purpose.

However, inorganic sample materials have fairly low carbon content (a few ppm to a maximum of 10 percent) and are generally not flammable. Carbon-sulfur is released at high temperatures above 2.000 degrees, which can only be achieved with an induction furnace.

In the induction furnace, the sample is melted in an atmosphere of pure oxygen, allowing sulfur to react with sulfur dioxide and carbon to react as a mixture of carbon monoxide and carbon dioxide. Combustion gases pass through a dust filter and moisture absorber to be purified. In the next step, sulfur dioxide is detected in infrared cells. Infrared cells with different sensitivities, high or low, can be adapted to the user's requirements.

Sulfur measurement is followed by the oxidation of carbon monoxide to carbon dioxide and sulfur dioxide to sulfur trioxide. Sulfur trioxide gas is removed, the carbon content is detected by infrared cells that can be individually customized. Analyzers that do this job can be equipped with up to four independent infrared cells.

Infrared spectroscopy is the analysis of infrared light interacting with a molecule. This can be analyzed in three ways by measuring absorption, emission and reflection. The main use of this technique is in organic and inorganic chemistry. It is used by chemists to identify functional groups in molecules. Infrared spectroscopy measures the vibrations of atoms and based on this it is possible to determine functional groups. Generally, stronger bonds and lighter atoms vibrate at a higher stretching frequency (wave number).

The infrared absorption method after combustion in an induction furnace is a standard method that enables the analysis of trace amounts of carbon and sulfur in metals, ores, ceramics and other inorganic materials. Many industries utilize this technique to accurately determine the carbon and sulfur content of purchased or manufactured products. This technique is based on the principle that the combustion gases carbon dioxide and sulfur dioxide absorb infrared energy at unique wavelengths within the infrared spectrum.

Among the numerous testing, measurement, analysis and evaluation studies carried out for businesses in various sectors, our organization, with its trained and expert staff and advanced technological equipment, has established "ISO 15350 Steel and iron - Determination of total carbon and sulfur content - Infrared absorption method after combustion in the induction furnace" It also provides testing services in accordance with the “(routine method)” standard.