Bushveld Vametco Alloys produces a steel-alloying vanadium carbon nitride product called Bushveld nitro-vanadium.
Bushveld nitro-vanadium is an efficient vanadium-nitrogen product that can significantly lower the strengthening costs of high-strength, low-alloy (HSLA) and other alloy steels.
When vanadium and nitrogen combine in the steel structure, they increase steel strengths more than vanadium by itself.
This allows steelmakers to reduce the amount of vanadium required to meet the strength specifications of the final product, which lowers costs by as much as 40% – depending on individual steelmaking practices and strength requirements.
Over the past 25 years, cost-conscious steelmakers all over the world have saved well over $100 million by using Bushveld nitro-vanadium.
Our flagship product has recently undergone a name change (from "Nitrovan" to "Bushveld nitro-vanadium") to be more aligned with the evolving brand and a new era of growth.
The new name removes any uncertainty about what the product does and how it is made. This certainty of brand aids in bolstering brand purpose and enables us to create messages of quality, prosperity, rooted in strategic intent.
Bushveld nitro-vanadium is available as briquettes packed in strong, moisture-resistant bags that can be added directly to molten steel in the ladle. The use of bags eliminates handling losses and simplifies weighing and inventory control.
With Bushveld nitro-vanadium, the same equivalent yield strengths are contained with less vanadium. It also equates to substantial cost and resource savings, enhancing both productivity and efficiency.
To put things in perspective, hot-rolled steel containing 100 parts per million of nitrogen requires only 0,04% vanadium to achieve a strength increase of 110 MPa (16 ksi).
When nitro-vanadium is added to steel, vanadium preferentially combines with nitrogen to form nitrogen-rich vanadium-carbonitride precipitates. The nucleation rate of these precipitates increases at higher nitrogen contents and produces a large number of small particles.
Grain refinement is the only mechanism that improves both strength and toughness while reducing the embrittling effects of precipitation. High-strength steels obtain good toughness by balancing grain refinement and precipitation hardening.
Key Features & Benefits:
Bushveld nitro-vanadium should be added to molten steel in the same manner as ferrovanadium. After adding deoxidants, such as aluminium and ferrosilicon, maximum vanadium recoveries are obtained by adding Bushveld nitro-vanadium. Aggressive agitation of the steel prevents localised super-saturation of nitrogen and leads to high-nitrogen recoveries.
Steelmakers using Bushveld nitro-vanadium have a choice of two vanadium-to-nitrogen ratios. Bushveld nitro-vanadium 16 introduces 30% more nitrogen than Bushveld nitro-vanadium 12. The low-carbon content of Bushveld nitro-vanadium 16 is also an advantage in low-carbon steels.
Bushveld nitro-vanadium is a high-purity product with low levels of residual elements. Its aluminium content is particularly low compared to ferrovanadium.
Strain ageing is virtually eliminated in vanadium-strengthened steels containing as much as 0,020% nitrogen.
Extensive research and technological studies have shown that the toughness of the heat-affected zone (HAZ) in vanadium-nitrogen steels depends on the transformation products and not on the nitrogen content. Excellent toughness can be obtained in these steels at heat inputs up to 4 kJ per mm used in many welding processes.
Bushveld Vanadium's Vametco processing facility employs the standard salt-roast and leach process to produce Bushveld nitro-vanadium.
Magnetite Concentrate:
Crushing, milling and magnetic separation to produce a magnetite concentrate with average grades of 2% V2O5 in-magnetite
Roasting:
Sodium salt roasting the concentrate in a kiln at ±1 150°C to form a water-soluble sodium vanadates material
Purification:
Leaching and purification, with dissolution of roasted vanadium concentrate in water, purification and precipitation of vanadium through the addition of ammonium sulphate, followed by drying and then processing in a reducing environment to produce a Modified Vanadium Oxide (MVO) product
Nitro-Vanadium:
Briquetting and feeding the MVO into a shaft induction furnace in a nitrogen atmosphere to produce nitro-vanadium, which is used as a micro-alloy in steel production