ThePipingMart Blog other Describe the Methods for Measuring Carbon Content in Steel.

Describe the Methods for Measuring Carbon Content in Steel.

The amount of carbon in steel is a standard criterion for classification. While adding more carbon to steel can make it stronger and tougher, it can also make it more brittle and difficult to weld. Most steels typically contain less than 0.45% carbon, while it is conceivable for there to be as much as 2%. The hardness of steel does not change after the carbon concentration exceeds 0.65%; however, extra carbon might increase the steel’s hardenability and enhance performance. Cast iron is classified according to its carbon content, which must be at least 1.8%.

It is crucial to employ a testing procedure that can precisely quantify the carbon content if you want to make sure that steel satisfies the requirements for each of the alloy classifications. The following methods for identifying metals and their ability to gauge steel’s carbon content are some of the most popular.

Visual Spark Analysis

Visual spark analysis, one of the more traditional methods, enables steel testing in the field, cutting down on the time needed to obtain the results. A piece of steel must be abraded with a high-speed grinding wheel to perform the visual spark test. The sparks released as the abrasive wheel spins against the steel are compared to a chart or another known sample. The type of steel is revealed by the way the sparks appear. A darker environment is required to see the sparks during this test. But this approach does not involve a quantitative study.

OES Sorting

One of the quickest ways to determine the composition of the metal is through arc sorting. Arc sorting analyzes a sample of air using an electrical discharge and a spectrometer, comparing the sample’s light intensity to that of a reference sample. An arc can sort steel without using argon in the process.

XRF Alloy Grade Identification

The sample does not need to be destroyed for this analysis to identify the alloy grade type.

The XRF carries out positive material identification, or PMI, using X-ray diffraction analysis rather than an electrical discharge. The study can be performed with handheld equipment and usually takes only a few seconds to complete. It has grown in popularity since exams can be taken anywhere.

Spark OES Analysis

Argon is used in this examination as a shielding gas to protect the spark and enable carbon measurement. While this process is more accurate than XRF or Arc sorting, it is slower due to the necessity to prepare the sample with a sanding disc or belt and the lengthy analysis time. But only this approach can deliver a precise, quantitative Carbon reading.


Training in the correct equipment use is necessary to measure carbon content. Inadequate testing can have a detrimental impact on the final results of a product or the decision of how to proceed with the materials at hand.

Making more intelligent selections about how to test your steel and ensuring that it satisfies the specifications for your planned use will benefit from your understanding of the advantages and disadvantages of each technique.


When working with steel, it’s critical to precisely quantify the carbon content to identify each piece of material and ensure traceability appropriately.

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