company news about Why is ferrosilicon added during steel deoxidation?

Ferrosilicon is added during steel deoxidation because it removes dissolved oxygen efficiently, economically, and metallurgically safely, while also improving downstream casting and steel quality. Its role is both chemical and process-critical, not optional.

Below is a steelmaking-practice-based explanation.

After BOF, EAF, or IF steelmaking, molten steel contains excess dissolved oxygen, which causes:

• Blowholes and porosity

• Non-metallic inclusions

• Poor surface quality

• Reduced mechanical properties

• Casting instability

If oxygen is not removed, steel cannot be cast or meet quality standards.

Silicon reacts readily with oxygen:

This reaction:

• Occurs rapidly at steelmaking temperatures

• Produces thermodynamically stable silica

• Removes oxygen from the molten steel phase

Compared with aluminum:

• Ferrosilicon provides moderate deoxidation strength

• Avoids excessive formation of hard alumina clusters

• Produces more fluid inclusions that can float out easily

This makes FeSi ideal for:

• Initial or intermediate deoxidation

• Combined deoxidation systems (Si–Mn, Si–Al)

Ferrosilicon deoxidation results in:

• Fewer sharp, solid inclusions

• More rounded, low-melting inclusions

• Better flotation and slag absorption

Practical benefits:

• Cleaner steel

• Lower defect rate

• Reduced nozzle clogging during continuous casting

Because ferrosilicon contains iron:

• It dissolves smoothly into molten steel

• Silicon recovery is higher than pure silicon metal

• Less oxidation loss during addition

This makes FeSi:

• More cost-effective

• More predictable in silicon yield

Ferrosilicon:

• Adds silicon without increasing carbon significantly

• Does not introduce harmful alloying side effects

• Works across explanation:

• Carbon steel

• Low-alloy steel

• Structural and engineering steel

Steelmakers use ferrosilicon because it:

• Is easy to handle and feed

• Works in BOF, EAF, and ladle refining

• Supports stable and repeatable steel chemistry

• Integrates well with other deoxidizers

Ferrosilicon is added during steel deoxidation to:

• ✔ Remove dissolved oxygen effectively

• ✔ Improve steel cleanliness and quality

• ✔ Control inclusion morphology

• ✔ Increase silicon recovery

• ✔ Maintain stable casting and production efficiency

Without ferrosilicon, steel deoxidation would be less controllable, more expensive, and more defect-prone.