QUANTIFICATION OF SMITHING ACTIVITIES BASED ON THE INVESTIGATION OF SLAG AND OTHER MATERIAL REMAINS Vincent Serneels Sébastien Perret Mineralogy and Petrography.

QUANTIFICATION OF SMITHING ACTIVITIESBASED ON THE INVESTIGATION OF SLAG

AND OTHER MATERIAL REMAINS

Vincent Serneels

Sébastien Perret

Mineralogy and PetrographyDepartement of Geoscience

University of FribourgSwitzerland

[email protected] [email protected]/mineral/archmet

The Production Line of the Ancient Iron Metallurgy

V. Serneels, S. Perret Mineralogy and Petrography - University of Fribourg

Production line :

Sequence of technical steps from the raw material to the finished object.



Natural ore

Extracted ore

Extraction

Refuse



Natural ore

Extracted ore

Extraction

Refuse

Concentrated ore

Processing

Refuse



Natural ore

Extracted ore

Extraction

Refuse

Concentrated ore

Processing

Refuse

Raw iron

Reduction

Slag Direct method of reduction :

• Bloomery process

• Solid state

• FeO + CO Fe + CO2



Natural ore

Extracted ore

Extraction

Refuse

Concentrated ore

Processing

Refuse

Raw iron

Reduction

Slag Direct method of reduction :

• Bloomery process

• Solid state

• FeO + CO Fe + CO2



Natural ore

Extracted ore

Extraction

Refuse

Concentrated ore

Processing

Refuse

Raw iron

Reduction

Slag

Finished object

Smithing

Slag

• Plastic deformation (hammering / heating)

• Welding

• Heat treatment (annealing / quenching)

• Control of oxydation / carburization

Smithing


Smithing depends on :

• Quality of the metal

Physical characteristics :

• Compact / homogenous

bar iron

• Uncompacted / heterogeneous

bloom iron

• Small pieces

scrap

Chemistry : • % carbon

• % other elements : P, S, N, Mn, Ni, 0...

Smithing




• Type of object to produce

Kind of object :

• Simple nail

• Complex composite bladeiron + steel

Size of object :

• Small nail 10 g

knife 100 g

axe 1000 g

• Large anchor 10000 g

Sharpening, polishing, decoration

Smithing




• Type of object to produce

• Know-how of the smith

Qualification :

• Heat treatments

- annealing

- quenching

• Welding

• etc...

Smithing slags


Contribution to slag formation :

• Hot oxidation

FeO

• Related to time / temperature

• Related to the size of the section

Formation of a slag rich in iron oxides :

Smithing slags



• Hot oxidation

FeO

Formation of a slag rich in iron oxides :

• Related to time / temperature

• Related to the size of the section

Smithing slags



• Hot oxidation

FeO

• Poorly consolidated metal

Fe

Formation of a slag with iron particles :

Smithing slags


Formation of a slag rich in silica :Contribution to slag formation :

• Hot oxidation

FeO


Fe

• Use of flux

SiO2

Smithing slags


Other elements participate with various chemical elements :


• Hot oxidation

FeO


Fe

• Use of flux

SiO2

• Other effects

K2O, CaO, SiO2 , Al2O3...

Smithing slags


PCB : Plano-convex bottom slags

• Characteristic morphology

• Most typical smithing residue

Smithing slags



• Characteristic morphology

• Most typical smithing residue

• 1 cooling structure

Formed between lighthing and extinguishing of the fire

• 1 unit of work

1 day ?

Smithing slags


Variability of PCB slags :

• Dimensions and weight

As a general rule :

The weight is proportional to the quantity of work

Ø h weight

Small 5 cm 1 cm 50 gr

Normal 15 cm 3 cm 300 gr

Large 30 cm 10 cm 3000gr

Smithing slags




• Shape

Smithing slags




• Shape

Smithing slags




• Shape

• Composition

Smithing slags


Smithing slags



• Weight of PCB = quantity of work

• Composition of PCB = Type of work

Assembly of PCBs activity of a workshop

Examples of PCB assemblies from Switzerland


Examples of PCB assemblies from Switzerland


Vincent Serneels

Sébastien Perret

Mineralogy and PetrographyDepartement of Geoscience

University of FribourgSwitzerland

[email protected] [email protected]/mineral/archmet

QUANTIFICATION OF SMITHING ACTIVITIES BASED ON THE INVESTIGATION OF SLAG AND OTHER MATERIAL REMAINS Vincent Serneels Sébastien Perret Mineralogy and Petrography.

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