NB6965 Iron Niobium Master Alloy

Iron Niobium Master Alloy Description

Iron Niobium Master Alloy (FeNb), typically containing 60–70% Nb and 30–40% Fe with controlled impurities (Ta ≤1.0%, Al/Si ≤0.5%, C ≤0.1%, S/P ≤0.05%), is used to refine grain size and to induce precipitation hardening in steel production. When added to molten steel (standard dosage: 0.03–0.1% Nb), niobium forms stable carbides (NbC) and nitrides (NbN) during solidification. These compounds limit austenite grain growth at temperatures ≥1 100°C, reducing the final ferrite grain size to 5–15 μm (up to four times finer than unmodified steel). This modification increases yield strength by 50–100% (for example, from 250 MPa to 400–500 MPa in HSLA steels) and enhances low-temperature impact toughness (for instance, maintaining over 100 J at –60°C). Nb precipitates also reduce electrochemical reactions at grain boundaries, thereby increasing resistance to corrosion in acidic or damp environments (for example, in offshore pipelines). The alloy’s high melting point (approximately 1 550°C) permits gradual dissolution in steel melts without significant vapourisation losses, and its density (approximately 7.2 g/cm³) assists in achieving even dispersion. FeNb-modified steels exhibit improved weldability (with reduced heat-affected zone cracking) and improved creep resistance at temperatures up to 600°C, which is critical for energy pipelines and structural components. Limitations include the possibility of slag formation if added improperly and sensitivity to niobium price fluctuations.

Iron Niobium Master Alloy Applications

FeNb is employed in high-strength steel manufacturing, where its addition (0.03–0.1% Nb) refines grains and produces NbC/NbN through precipitation hardening. This adjustment results in yield strengths that are 50–100% higher (attaining up to 550 MPa) in steel grades used for energy pipelines (API X70–X120), which must operate under conditions of sour gas and sub-zero temperatures (–60°C). In the automotive sector, FeNb-modified steels allow a weight reduction of 20–30% while satisfying Euro NCAP standards. In structural engineering, FeNb is incorporated in the production of reinforcements used in high-rise buildings, crane booms and offshore oil rigs, thereby reducing the incidence of defects in the heat-affected zones during welding. Additionally, tool steels incorporating FeNb for applications such as hot-work dies and extrusion equipment demonstrate creep resistance at 600°C that extends service life threefold compared with conventional alloys. The use of FeNb can also lead to a material consumption reduction of approximately 15% in wind turbine foundations, thereby lowering CO₂ emissions. Research is ongoing into the use of FeNb in additive manufacturing powders for aerospace components that require microstructural stability at high temperatures.

Iron Niobium Master Alloy Packaging

Our products are packaged in customised cartons of various sizes, depending on the material dimensions. Small items are securely placed in PP boxes, while larger items are accommodated in custom wooden crates. We adhere strictly to packaging customisation and use appropriate cushioning materials to ensure optimal protection during transportation.

Packaging: Carton, Wooden Box, or Customised.

Kindly review the packaging details provided for your reference.

Manufacturing Process

1.       Testing Method

(1)    Chemical Composition Analysis is performed using techniques such as GDMS or XRF to verify that purity requirements are met.

(2)    Mechanical Properties Testing is conducted to measure tensile strength, yield strength and elongation.

(3)    Dimensional Inspection checks the thickness, width and length to ensure compliance with specified tolerances.

(4)    Surface Quality Inspection is carried out through visual and ultrasonic examinations to detect defects, including scratches, cracks or inclusions.

(5)    Hardness Testing is undertaken to ascertain the material’s hardness and confirm its consistency.

Please refer to the SAM testing procedures for further details.

Iron Niobium Master Alloy FAQs

Q1. Key steel applications?

High-strength pipelines (API X70–X120 grades) are used in environments containing sour gas and operating at sub-zero temperatures.

Automotive chassis and suspension components may achieve a weight reduction of 20–30%.

Structural steel members in high-rise buildings, cranes and offshore rigs benefit from reduced heat-affected zone defects.

Tool steels for extrusion dies can exhibit a service life that is three times longer at 600°C.

Q2. Why use FeNb instead of pure Nb?

FeNb dissolves more slowly in molten steel, thereby reducing the loss of Nb through vapourisation. The iron base enhances dispersion and cost efficiency.

Q3. Critical impurity limits?

Carbon (C): ≤0.1% to avoid the excessive formation of carbides.

Sulphur (S)/Phosphorus (P): ≤0.05% to prevent brittleness.

Aluminium (Al)/Silicon (Si): ≤0.5% to minimise oxide inclusion formation.

Related Information

1.       Common Preparation Methods

FeNb master alloy is produced via aluminothermic reduction in refractory-lined reactors. A blended charge containing niobium pentoxide (Nb₂O₅) concentrate (typically 55–65% Nb₂O₅), iron oxide (Fe₂O₃) and aluminium powder (used as a reductant) is ignited to trigger an exothermic reaction reaching temperatures of 2 200–2 400°C. The reaction, Nb₂O₅ + 2Al → 2Nb + Al₂O₃ + Fe (with Fe₂O₃ reduced to Fe), results in two molten layers. The denser FeNb alloy layer (60–70% Nb) settles at the bottom, while a lighter alumina slag layer remains on top. Following controlled cooling, the slag is removed and the solidified FeNb ingot is fragmented into lumps ranging from 10 to 50 mm. Impurity levels (Al, Si, Ta) are controlled by adjusting the Nb₂O₅/Al ratio and by adding lime/fluorspar fluxes to improve slag fluidity. The final products are then graded by size and subjected to magnetic separation to remove any residual slag. Chemical analysis confirms an Nb content of 60–70% and that impurity limits (Ta ≤1.0%, Al ≤0.5%, C ≤0.1%, S/P ≤0.05%) are maintained. Alternative methods, such as carbothermic reduction in electric arc furnaces or plasma smelting, are available for higher-purity grades; however, aluminothermy is generally preferred given its cost efficiency and scalability. The alloy’s density (approximately 7.2 g/cm³) and crystalline structure ensure consistent dissolution in steel melts during microalloying.