HEAT, SEPARATE AND DETECT ONH IN METALS
DETECTION OF GASEOUS ELEMENTS (OXYGEN / NITROGEN / HYDROGEN)
Oxygen, nitrogen and hydrogen strongly influence the properties of metals (like steel, titanium, and copper), which makes a reliable and precise measurement of these elements an important part of the quality control process.
Inert gas fusion is a method of determining the quantitative content of gas in ferrous and nonferrous materials where gas, such as hydrogen, nitrogen, and Oxygen, are physically and chemically adsorbed by the materials and later removed and swept from the fusion area by an inert carrier gas. A high-temperature furnace is used to rapidly heat the sample and convert certain elements into volatile forms to separate, detect and measure them.
Oxygen
Oxygen is undesirable in steel. Combines with other elements (manganese, silicon, aluminium, titanium, etc.) to form oxide inclusions that can degrade toughness and fatigue resistance. It is usually minimized in steel by deoxidation with aluminium and silicon and vacuum degassing.
Nitrogen
Nitrogen is used as an alloying element, substituting the expensive and allergenic element nickel in austenitic stainless steels to improve their mechanical properties and corrosion resistance. High nitrogen content in stainless steels enhances the hardness, yield strength, tensile strength, wear resistance, and fatigue resistance of stainless steels.
HYDROGEN
Hydrogen is not ideal for metals like steel, aluminium, and magnesium. It can make these metals brittle; the ductility of the metal becomes reduced. Its durability deteriorates. This can lead to the sudden failure of parts and components.
WORKING PRINCIPLE
Our expert chemical testing team uses LECO ONH Determinator to carry out the inert gas fusion technique. The technique is to fuse the sample in a high-purity graphite crucible inside a furnace by taking it to very high temperatures (~3000°C) in an inert gas environment to release the target gas from within the sample efficiently.
The graphite crucibles are effectively resistors that supply the heat necessary to fuse the sample, as well as Carbon for reducing Oxygen in the sample. An inert carrier gas, purified Helium gas, sweeps the liberated analyte gas out of the furnace through a Mass Flow Controller and to a series of detectors.
Oxygen in the sample reacts with the graphite crucible to form CO and CO2, which are detected using non-dispersive infrared (NDIR) cells. The gas then flows through a reagent heater where the CO is oxidized to form CO2, and H2 is oxidized to form H2O. The gas continues through another set of NDIR cells where H2O and CO2 are detected.
These analytes are then scrubbed out of the carrier gas stream. The final component in the flow stream is a Thermal Conductivity (TC) detector used to detect nitrogen.
APPLICATION OF INERT GAS FUSION TECHNIQUE
Provide simultaneous wide-range measurement of Oxygen, nitrogen, and hydrogen content in steel, refractory metals, and other inorganic materials
Satisfy stringent material QC requirements
Provide researchers with accurate and precise data in material development
COMMON TEST METHODS
ASTM E1019
ASTM E1447
ASTM E1409
Talk to us today
We can perform routine LECO analysis in our state-of-the-art chemical analysis laboratory. Our expert chemical team will apply the inert gas fusion Technique for your chemical analysis test.
For more information about our chemical composition Test, call us or send us an enquiry today.
