Nitrogen Application in Steel Brands
Enhancement of requirements to steel quality and properties in power engineering, shipbuilding, oil and gas industry and medicine resulted in the application of nitrogen as an alloying element in the manufacture of steels. Nitrogen in steel, in the form of interstitial solution rather than in the form of nitrides, hardens steel substantially stronger than carbon, as plasticity increases simultaneously. Nitrogen also enhances wear and corrosion cracking resistance of steel. Introduction of nitrogen into steel allows to substitute or reduce the content of expensive, not readily available and environmentally dangerous austenite–forming alloying elements – nickel and manganese. It is not needed to destroy the surface and interior of the Earth when obtaining nitrogen from the atmosphere. At present output production of high–nitrogen alloyed steels (HNAS), alongside the traditionally–produced steels, is being brought to the design figure. Their application enables to decrease high–nitrogen alloyed steels output by 15..20% at a sacrifice in reduced net sections of elements of machines, mechanisms and structures resulting in the reduction of specific consumption of materials.
Nitrided metallic manganese and chromium or nitrided ferroalloys – ferromanganese, ferrochromium, some complex alloys – are specially manufactured for the introduction of soluble nitrogen into steel. Traditional means of their production are distinguished by a prolonged process cycle, high power consumption and low content of nitrogen (no more than 8%). The Nitrided Materials – 10, Ltd produces the nitrided ferroalloys by the most advanced technique of Self – propagating high – temperature synthesis (SPHTS).
Nitrogen – bearing materials obtained by the SPHTS – technique are distinguished by the highest possible content of nitrogen (10…40%) with the possibility of obtaining alloys, not only having various pre–set chemical compositions but also having optimum physical properties for consumer purposes–density and melting temperature, as well as a pre–set state of aggregation – in the form of sintered lumpy material used for the introduction under a jet of metal when emptied from the steel – making unit into the ladle, or in the powdered form used for a precise dosage by powder wire when introduced into steel. We can produce nitrided alloys not only of traditionally used components – metallic manganese and chromium or their rich ferroalloys but on the basis of any ferroalloys, silicium and complex alloys inclusive.
The unique combination of high content of nitrogen and chemical composition of the composite alloys, state of aggregation and physical properties of the nitrided alloys ensures a high rate of dissolution at a maximum rate of nitrogen assimilation and of all other alloying elements. The introduction of lumpy nitrided ferroalloys under a jet of metal when emptied from a steel–making unit into the ladle, allows making nitrogen–based steel alloying effectively without using a special equipment. Fast and full dissolving of alloying composition introduced by powdered wire provides a reliable acquisition of a required nitrogen concentration in steel at minimal consumption of alloys.