notícias da empresa sobre Turkey | How Can Automotive Foundries Control MgFeSi Reaction During Spheroidization to Improve Process Stability?

A stable spheroidization reaction is a time controlled one. When MgFeSi reacts, the magnesium vapour stirs the ladle for a period that should last 60 to 120 seconds and end before pouring begins; if that period swings by more than about thirty seconds between heats, nodularity will swing with it. Turkish automotive foundries that hold process capability tight do four things: they fix the alloy weight against tapped weight, they keep a single particle band per treatment station, they control ladle freeboard and cover, and they log the reaction time for every heat.

Automotive castings leave little room for a heat that is nearly right. Safety parts, turbo housings and brake components are bought against process capability evidence, so a foundry that cannot show a stable magnesium recovery cannot hold the nomination. The reaction in the ladle is the point where variability is either created or removed.

Magnesium boils at 1090 degrees Celsius, so every MgFeSi treatment is a vapour driven mixing event rather than a simple dissolution. The alloy heats, magnesium vaporises, the vapour rises through the iron, and the rising gas stirs the bath while magnesium dissolves into the metal.

The mixing is useful and the escape is not. Magnesium that reaches the surface leaves through the slag, and the amount that leaves is decided by how violent the plume is, how deep the ladle is, and how much freeboard the ladle offers.

Six variables set the reaction, and each can be fixed in advance.

Fixing the first two is administrative work and costs nothing. Foundries that change grade between heats to chase a defect usually lose the stability they were trying to gain.

Recovery is the ratio of magnesium retained in the iron to magnesium delivered in the alloy, and it is the only number that shows whether the reaction behaved.

A recovery that falls from one heat to the next, with the same grade and weight, points to temperature or sulfur rather than to the alloy. A recovery that falls across the whole shift points to particle size, moisture or a change of ladle.

Instability usually enters after the reaction, not during it.

• Pouring delay beyond the fixed window, so magnesium fades in the ladle

• Inoculant added before the boil ends, so it is consumed by the reaction

• Slag left on the bath, giving magnesium a surface to burn against

• Ladle lining that is cold or damp, chilling the first iron and slowing solution

• Alloy stored in humid conditions, so surface moisture drives a violent start

Each of these is visible in the heat record if the record is kept properly, which is why automotive auditors ask for treatment logs rather than for certificates alone.

The casting tells the story before the laboratory does, and matching the defect to the reaction is a fast diagnostic.

Two signals in one casting is common, and the pair usually resolves to a single lever: the treatment was too energetic for the ladle it was run in.

Process stability depends on receiving the same alloy every shipment, so the agreement carries process clauses rather than price clauses alone.

1. One grade code and composition range per treatment station, with no substitution without approval

2. A particle band with sieve tolerances on undersize and oversize

3. Moisture protection in packing, delivered dry, in 1 MT big bags

4. Lot level certificates naming the analytical method

5. A written magnesium recovery expectation for the agreed treatment method

6. Advance notice of any change in raw material source or production line

The sixth item matters most in practice. A supplier that changes its own raw materials can shift reaction behaviour without changing the certificate, and the foundry discovers it through a casting defect rather than through paperwork.

A boil lasting roughly 60 to 120 seconds suits covered ladle treatments at 1450 to 1500 degrees Celsius. What matters more than the absolute figure is that the same station repeats the same time within a narrow band.

Almost always temperature or sulfur. A hotter tap raises vapour pressure and pushes more magnesium out through the slag, and extra sulfur consumes magnesium before it can nodulize graphite.

It can reduce the swing but not remove it. Particle size sets reaction speed, while freeboard, cover, temperature and sulfur set how much magnesium survives. All of them have to sit inside a range.

No. A violent boil is magnesium leaving the ladle. The useful reaction is energetic but contained, with the plume staying under the slag rather than breaking through it.

Fade begins immediately and becomes visible in nodularity within minutes of holding. The practical response is a fixed maximum pour time per heat rather than an alloy change.

After. Inoculant added while magnesium is still boiling is partly consumed by the reaction and partly lost to the slag, which wastes both additions.

With a heat record showing alloy weight, grade, particle band, tapping temperature, reaction time, residual magnesium and nodularity at a fixed sample position across a run of consecutive heats.

Yes. Freeboard, bath depth and pocket geometry decide how much of the vapour plume stays in the iron, and they are fixed plant assets that either support the treatment or fight it.

ZhenAn produces FeSiMg grades from 5 percent to 11 percent magnesium with rare earth from 0.5 to 8 percent, in 10 to 50 mm and 50 to 100 mm lump or granule form, packed in 1 MT big bags at 20 to 25 MT per 20 foot container and dispatched 7 to 10 working days after payment. Send the treatment method and ladle data, and the grade and particle band can be matched to the station.

RFQ details to include: grade, size band, monthly volume, port of discharge, and the date the first container is needed.

For ladle work the 10-50 mm and 50-100 mm FeSiMg lump page shows the two size bands used in covered treatments, while the 10-50 mm FeSiMg lump specification covers the standard automotive band. Foundries moving to in-mould treatment can compare the 3-6 mm FeSiMg granule for spheroidizing.