Iron Bloom Research Articles

Analysis of Ancient Slag Inclusion-Metal Systems as a Method to Disclose Processing Thermo-chemical Parameters: The Case Study of a Medieval Lombard Steel Bar from Northern Italy

An archaeometallurgical characterization of a VI to VII century Lombard steel bar from Ponte di Val Gabbia I site (northern Italy) was performed to reconstruct its manufacturing process and extract processing thermochemical parameters (i.e., temperature and oxygen chemical potential) from the slag inclusion-metal systems. Metallographic observations by optical microscopy and Vickers microhardness measurements indicated that the steel bar was forged from a heterogeneous steel lump, most probably an iron bloom, which was cooled in the air after the forging process. The chemical composition of non-metallic inclusions was determined by scanning electron microscopy coupled with X-ray dispersive spectroscopy. A multivariate statistical analysis of the smelting-derived non-metallic inclusions chemistry allowed to conclude that the steel bar was obtained by the direct or bloomery method. Under the hypothesis of local near-equilibrium conditions for the slag inclusion-metal systems, a thermodynamic-based strategy was adopted to estimate the firing conditions in the bloomery furnace in terms of both temperature and oxygen chemical potential of the reducing gas atmosphere. In particular, the computed temperatures are in the range of 1003 °C to 1171 °C, whereas the values of oxygen chemical potential vary between − 447.47 and − 385.79 kJ/mol.

ARCHAEOLOGICAL EXPERIMENTS OF IRON SMELTING AT SUNGAI BATU ARCHAEOLOGICAL COMPLEXES, BUJANG VALLEY, KEDAH, MALAYSIA

This archaeological experiment study of furnace, tuyere and bellow making to conduct iron smelting experiments is aimed at obtaining information related to the iron smelting process that is likely to have been carried out in Sungai Batu Archaeological Complex. This archaeological experiment study was conducted through a knowledge transfer program (KTP) at the Sungai Batu Complex conducted in 2013 involving 18 participants and two instructors. This experiment involves the use of soil taken in the Sungai Batu river to produce furnaces and tuyere while bellow are made from wood, plywood and cloth. The raw material of iron smelting, namely iron ore, was taken after the survey activities were carried out near Kampung Batu 5, UiTM Merbok and Tupah Hill areas while the charcoal for iron smelting was used by rubber wood in the rubber plantation near the Sungai Batu Archaeological Complexs. The iron smelting experiments conducted have shown the difference in smelting results with the discovery of iron bloom which explains the possible differences in smelting techniques and technology to produce the iron ingots. Although the results of the experiments show differences with the actual results at the iron smelting site but the data can be used in the development of archeotourism at the Sungai Batu Archaeological Complex to provide a overview of iron smelting techniques that may be used in this area in the past.

Distribution and Precipitation Mechanism of TiN in Industrial Pure Iron Bloom

The size and distribution of TiN particles have a great influence on the properties of industrial pure iron. It is necessary to understand TiN precipitation behavior in bloom. Herein, inclusions in industrial pure iron cast billets are observed. The temperatures and conditions for TiN precipitation are calculated using thermodynamics and kinetics. The results show a large number of TiN inclusions in the bloom, and the quantity density is the largest at the inner arc of the bloom. This is caused by the large cooling rate at the inner arc and the homogeneous nucleation of inclusions. According to the thermodynamic calculations, during the solidification of industrial pure iron, TiN begins to precipitate at a solidification fraction greater than 0.82. The amount of TiN precipitated during solidification is 93%, with TiN continuing to precipitate from the solid phase after the solidification is complete. The results of TiN particle growth kinetics reveal that MgO is the most effective in promoting TiN nucleation, followed by δ‐Fe, CaS, and MgAl2O4, the effectiveness of Al2O3 as a heterogeneous nucleation core is relatively poor. The radius of the TiN particles decreases with a decrease in the N and Ti content and an increase in the cooling rate.

First Archaeometrical Approach of the Examinations of Iron Age Ferrous Fragments from Regöly and Bükkábrány (Hungary) – The Inception of Iron Working in the Carpathian Basin?

The emergence, spread and development of iron working in the Carpathian Basin is an essential and interdisciplinary research field, an important stage of which being the results of the archaeometallurgical-archaeomaterial examinations presented in this article. The excavation site of Regöly (Hungary) represents a special source from the earliest Iron culture of the Carpathian Basin, and using the results of metallographic analysis our aim is to place the examined objects in their proper context with regard to the process of iron working. One fragment found in the tumulus of Regöly during the excavation 2011–2012 has been presumed part of an iron bloom; this may be the earliest example of iron working in the Carpathian Basin (630–600 BC). From both an historical and technological point of view this raises several questions. One aim of our study is to characterise the fragments in order to figure out what kind of processing has been applied and ultimately see how the ‘iron bloom’ fragment can be connected in any way to the other iron objects found at the site. Examinations were carried out by optical microscopy (OM) and scanning electron microscopy (SEM-EDS) on both the iron objects and the bloom fragment. Metallographic analysis revealed a very specific microstructure, indicating that the bloom fragment is not a direct product that came directly from the bloomery furnace; it could be a secondary or even tertiary product (prefabricated) instead. However, regarding the bloom fragment, there is evidence of a forging method. During the tests, slag inclusions were also examined. The results from Regöly were also compared with other finds from a Celtic workshop-type site (Bükkábrány, 320–200 BC). Although a direct connection between the examined iron objects and the iron bloom fragment (as possible raw material) cannot be confirmed, the iron artefacts and fragments of Regöly might easily have been made from some basic material as represented by the fragment of an iron bloom or bar. Even though the find from Regöly does not definitively provide the earliest evidence for iron smelting technology in the Carpathian Basin area, it does give evidence for some form of iron forging from a semi-finished product.

Investigating the Iron-Making Process through the Scientific Analysis of By-products Obtained during Iron-Making from Songdu-ri Site in Jincheon, Korea

The study, iron-making process was examined through the scientific analysis of six by-products that were obtained during iron making at the Songdu-ri site in Jincheon. The total Fe content of the slags excavated from the Songdu-ri site was 36.29–54.61 wt%, whereas the deoxidation agent was 26.48–49.08 wt%. The compound analysis result indicated that fayalite and wüstite are the main compounds in slag. Furthermore, the microstructure analysis result confirmed the presence of fayalite and wüstite in the slag. It can be inferred from the flat shape in a bright matrix structure of the hammer scales that forging was performed in the latter stage. The Raman micro-spectroscopy results confirmed that the surface was hematite (Fe<sub>2</sub>O<sub>4</sub>), middle layer was magnetite (Fe<sub>3</sub>O<sub>4</sub>), and inner layer was wüstite (FeO). The presence of smelting and smithing slags, spheroid hammer scales, and flake hammer scales suggests that at the Songdu-ri site, iron-making process is carried out by division of labor into producing iron bloom through direct smelting, refining and forge welding, and ingot production.

Research of the efficiency of the one-step process for producing carbon steels on the territory of modern Belarus in the pre-industrial period. Foundry production and metallurgy

The article describes experiments on the reconstruction of the technology of the one-step process of obtaining iron-carbon alloys in furnaces based on archaeological sources. It contains the description of furnace design, metallurgical process technology and raw materials preparation. The process of refining the iron bloom by forging is described. Scientifically grounded assumptions are made about possible technological methods of obtaining steels in the pre-industrial period on the territory of modern Belarus.

Neutron imaging for metallurgical characteristics of iron products manufactured with ancient Korean iron making techniques

This paper demonstrates the possible nondestructive analysis of iron artifacts’ metallurgical characteristics using neutron imaging. Ancient kingdoms of the Korean Peninsula used a direct smelting process for ore smelting and iron bloom production; however, the use of iron blooms was difficult because of their low strength and purity. For reinforcement, iron ingots were produced through refining and forge welding, which then underwent various processes to create different iron goods. To demonstrate the potential analysis using neutron imaging, while ensuring artifacts’ safety, a sand iron ingot (SI–I) produced using ancient traditional iron making techniques and a sand iron knife (SI–K) made of SI–I were selected. SI–I was cut into 9 cm2, whereas the entirety of SI–K was preserved for analysis. SI–I was found to have an average grain size of 3 μm, with observed α-Fe (ferrite) and pearlite with a body-centered cubic (BCC) lattice structure. SI–K had a grain size of 1–3 μm, α-Ferrite on its backside, and martensite with a body-centered tetragonal (BCT) structure on its blade. Results show that the sample’s metallurgical characteristics can be identified through neutron imaging only, without losing any part of the valuable artifacts, indicating applicability to cultural artifacts requiring complete preservation.

Ironworking slags from Late Iron Age sites in Hungary - composition, microstructure and function

ABSTRACT Numerous slag samples and a piece of iron bloom with slag from excavations of Celtic settlements (La Téne C and D) at Ordacsehi, Szilvásvárad and Jászberény (Hungary) were examined. The main objectives of the investigations were to study the material and structural properties of the slag specimens, the definition of the metallurgical functions of the different pieces of slag. Analytical techniques are wet chemical analysis (ICP-OES complemented with carbon determination, moreover using titration for separating the Fe2+ and Fe3+), textural-chemical investigations with SEM-EDS microanalysis and mineralogical analysis with XRD. Chemical investigations can be supplemented by ED-XRF. Most of the examined slags can be originated from the purification hammering process, where in an oxidizing atmosphere intended to separate the slag from the iron after reheating the bloom, or the forging of the iron tool. Some of the slag samples with fine dendrites remind metallurgical slag, although there have not been found traces of bloomery at the excavation sites. The examined slaggy bloom-fragment interlocks to the beginning of the technological line of forging as the first (by)product after the smelting formed in the bloomery furnace. Most of the examined slag samples are by-products of smithy workshop working in buildings.

COLLECTIONS OF FINDS FROM THE ARCHAEOLOGICAL STUDIES ON THE ST. MICHAEL GOLDEN-DOMED MONASTERY YARD IN 1940s—1960s

The Scientific Repository of the Institute of Archaeology of the NAS of Ukraine has three collections of archaeological finds coming from excavations on the St. Michael Golden-domed Monastery yard. These are the materials from the excavation of 1940 led by Mikhail Karger, the survey of 1944 led by David Blifeld and observations over the earthworks of Volodymyr Diadenko in 1967. The excavations of 1940 revealed two Old Rus dwellings and several pits on the site between St. Michael Cathedral and the Refectory, as well as the previously unknown Old Rus temple of the 11th century, associated with the St. Dmitro Cathedral. The field inventory books stored in the Scientific Archive of the Institute of Archaeology allow to clarify the locations of excavated sections where the works were carried out, as well as to compile a list of finds with a preserved collection that is about much smaller than the total amount found during excavations. A significant part of it is building remains such as fragments of frescos (some with graffiti), bricks, floor tiles, tiles, acoustic jars, molten lead roof sheets. The collection contains also household items such as fragmented ceramic dishes, amphora containers, grinding stones, and remains of manufacture: a fragment of an iron bloom and the glassware production refuse. In addition, there are some artefacts from graves: fabric, leather shoe details. The finds dated to a wide chronological range from the 10th—11th to the 18th—19th centuries and display the life in the monastery during all this time, without chronological lacunae.
 The survey of David Blifeld in 1944 was caused by construction of a vegetable store on the courtyard of the former monastery, and the works of Volodymyr Diadenko in 1967 were apparently related to the supervision over earthworks in the Upper city of Kyiv. There are neither publication, no archive data about the last two stages of research, so collections of archaeological finds are the only source of information about these studies. Both collections are small. The collection of the year 1944 contains the 18th century pottery, as well as three fragments of vessels of the 12th—13th centuries from cultural layer. The collection is incomplete because of significant gaps of inventory numbers.
 Observations of Volodymyr Diadenko in 1967 revealed the dwelling of Old-Rus time, which can be dated to the 12th — early 13th century by the available materials (fragments of pots and a big pottery container). The collection also included a half of brick of the 17th—18th centuries and a sherd of acoustic jar that may indicate the location of the site close to any architectural object.

Assessing the Quality of Iron Ores for Bloomery Smelting: Laboratory Experiments

There is fragmentary knowledge of iron ore sources exploited in the past for many regions including the Southern Levant. This missing information has the potential to shed light on political, economic, craft-production, and trading patterns of past societies. This paper presents the results of smelting experiments performed in graphite crucibles and a muffle furnace, using 14 iron ore samples from the Southern Levant, in an attempt to determine their suitability for smelting using ancient techniques. A range of analytical techniques, including optical and electron microscopy, Fourier-transform infrared spectroscopy, X-ray powder diffraction, and portable X-ray fluorescence were used to comparatively investigate the mineralogy and composition of the precursor iron ores and their smelting products: Iron bloom and slag. Several parameters attesting to the ability of a given ore to be successfully reduced and consolidated into a solid metal mass were quantified. The generated results highlight the significance of a ‘correct balance’ between iron oxides and other major elements in the smelting system in order to form fluid slag and a well-consolidated bloom. These data contribute to the understanding of factors, potentially influencing choices of iron ore exploitation by past human societies in the Southern Levant.

Analysis of Iron Production Technology of Army against Japanese through Slag from Saengsoegol Iron Production Site

Slag was collected from the iron-producing furnace site in Saengsoegol, Baegun mountain, where iron was manufactured by a righteous army against Japan in the Gwangyang region; then, the iron-manufacturing technique of the early modern period was investigated through scientific analysis. In the microstructure analysis results of the selected samples, iron bloom was mainly observed together with magnetite and fayalite. In the component analysis results of the compounds, it was confirmed that the furnace was built by using gangue of alkali feldspar or plagioclase series, and the ironmaking work was performed at a high temperature of at least 1050°C, because mullite was identified together with cristobalite and hercynite. Based on the chemical composition, it was speculated that low-grade iron ores were used as raw materials, and it seemed that the yield was low, because the total Fe content of the smelting slag samples was 37.72-49.93%. It was difficult to confirm whether a slag former was used, and it seemed that materials easily obtained nearby were used when the furnace was built, without considering the corrosion resistance. It appeared that the ironmaking work was performed at the Gwangyang Saengsoegol iron-producing furnace based on the direct ironmaking method in an environment that could escape the vigilance of the Japanese Empire to produce weapons that would be used for the resistance against Japan. It seemed that there was neither an advanced ironware production system nor a mass production system, and small-scale works were performed in short periods of time.

Slag-pit bloomery furnace of the Tarchalice type

The paper presents the results of the first stage of experimental research on reconstruction of the bloomery process in the slag-pit furnace of the Tarchalice type. The phenomenon of bloomery furnaces from the Przeworsk culture settlement in Tarchalice (Tarxdorf), Lower Silesia, Poland, has been known to the scientific community since 1903. With regard to ancient slag-pit furnaces discovered in the second half of the twentieth century in the Świętokrzyskie Mountains and Mazovia region, these features had two-times larger diameter of slag-pits and almost four-times greater weight of slag blocks. The large sizes of the slag-pits suggested dissimilarity of conditions of running the process, formation of iron bloom and block of slag in relation to quite well known from scientific experiments the bloomery process from the Świętokrzyskie Mountains.

Material Characteristic of Slags and Iron Bloom Produced by Smelting Process Using Sand Iron

본 연구에서는 ì „í†µ ì œë ¨ë²•ì„ í† ëŒ€ë¡œ ì‚¬ì² ì„ 이용해 ê´´ë ¨ì² ìƒì‚°ì„ ìž¬í˜„í•˜ê³ ìŠ¬ëž˜ê·¸ 및 ê´´ë ¨ì² ì„ 분석하여 ìž¬ë£Œí•™ì  특성을 알아보았다. 원료는 ê³ ë¬¸í—Œì„ í† ëŒ€ë¡œ ê²½ì£¼ì‚¬ì² ê³¼ í¬í•­ì‚¬ì² ì„ 이용했다. WD-XRF 및 XRD ê²°ê³¼ 경주 ì‚¬ì² ì€ ì €í‹°íƒ„ì‚¬ì² ì˜ Magnetite이며 í¬í•­ì‚¬ì² ì€ ê³ í‹°íƒ„ì‚¬ì² ì˜ Magnetite와 Ilmenite가 혼합됨을 확인하였다. 슬래그 의 XRD 및 미세조직 분석결과 ê²½ì£¼ì‚¬ì² ìŠ¬ëž˜ê·¸ëŠ” Fayalite와 Wüstite, í¬í•­ì‚¬ì² ìŠ¬ëž˜ê·¸ëŠ” Titanomagnetite와 Fayalite가 확인되어 ì‚¬ì² ì˜ Ti 함량에 따른 조직의 차이를 확인하였다. ê´´ë ¨ì² ì˜ 미세조직의 분석결과 ê²½ì£¼ì‚¬ì² ê´´ë ¨ì² ì€ 표면에 공석강에 가까운 탄소함량을 보이는 Pearlite가 우세하며, 내부는 Ferrite와 Pearlite가 혼재된 아공석강이었다. í¬í•­ì‚¬ì² ê´´ë ¨ì² ì€ ìˆœì² ì— 가까운 Ferrite이었다. ê´´ë ¨ì² ì˜ ì² ë¬¼í™”ë¥¼ 위해서는 내부 불순물 ì œê±°, 조직을 치밀하게 하는 ì •ë ¨ 및 ë‹¨ì ‘ì´ 필요함을 확인하였다. 향후 다양한 조건의 ì „í†µ ì œì² ì‹¤í—˜ì„ 통해 ì œì² ë¶€ì‚°ë¬¼ì˜ 성격을 ê·œëª í•˜ê³ ì œì² ìœ ì ì˜ 특징을 알아보는데 중요한 데이터로 활용 ê°€ëŠ¥í• ê²ƒì´ë‹¤. 중심어: ì‚¬ì² , ê³ ëŒ€ ì œë ¨, 슬래그, ê´´ë ¨ì² , ì œì²

Striking Iron: The Art of African Blacksmiths

Striking Iron: The Art of African Blacksmiths

Characteristic of Iron Bloom and Slag Block from Experimental Iron Smelting Process

Characteristic of Iron Bloom and Slag Block from Experimental Iron Smelting Process

Bladesmithing at South Dakota School of Mines and Technology

A Damascus-style layered blade was made by incorporating bloomery iron and crucible steel. A bloomery furnace was constructed and charged with Black Hills, SD bog iron ore, alloys, and hardwood charcoal. At sufficient temperature, the furnace was bottom-tapped to produce a low carbon iron bloom. A high-carbon crucible steel was made in a natural gas-fired furnace using commercial hematite pellets and coke. The steel was cast into sand molds. The two types of iron/steel were forged together using traditional blacksmithing techniques in a coke-fired forge. The forging process continued until the metal could be evenly worked, signifying the homogenization of the two metals. Once homogenized, the metal was shaped into a blade and subsequently ground into near-final shape, heat-treated, and finish-machined. The microstructure and mechanical properties of the blade were characterized using optical microscopy, hardness and tensile testing. The grain structure of the material varied widely and was not entirely homogenous at the welded layers, but the layers themselves were well-homogenized. The finished blade was compared to a common steel (1095) used for bladesmithing and was found to have similar hardness but significantly lower tensile strength.

Experimental smelting of iron ores from Elba Island (Tuscany, Italy): Results and implications for the reconstruction of ancient metallurgical processes and iron provenance

Iron deposits from Elba Island (Tuscan Archipelago) were extensively exploited since the 1st millennium BC: both raw iron ore and smelted blooms were extensively traded through the Mediterranean region. Within the frame of the multidisciplinary research Project “AITHALE” (from the Greek name for Elba Island), we have performed a series of archaeometallurgical experiments primarily to investigate the traceability of Elban iron ores during the various steps of the chaîne opératoire of bloomery iron production. Results of experiments performed both in the field (reconstruction of a bloomery furnace) and in the laboratory (smelting experiments carried out in a gas mixing furnace) are discussed in the text. Slags produced by smelting of W-Sn-rich iron (hematite) ores, like those from Elba island, show the presence of these elements in phases of their own, either relic (scheelite, ferberite, cassiterite) and/or newly formed (iron-tin alloys). Iron bloom obtained from this kind of iron ore could also bear evidence of the peculiar geochemistry of smelted ore, with tungsten preferentially associated with slag inclusions and tin eventually enriched in the metallic phase.

Extracting phosphoric iron under laboratorial conditions smelting bog iron ores

In recent years it has been indicated by archaeometric investigations that phosphoric-iron (P-iron, low carbon steel with 0,5-1,5wt% P), which is an unknown and unused kind of steel in the modern industry, was widely used in different parts of the world in medieval times. In this study we try to explore the role of phosphorus in the arhaeometallurgy of iron and answer some questions regarding the smelting bog iron ores with high P-content. XRF analyses were performed on bog iron ores collected in Somogy county. Smelting experiments were carried out on bog iron ores using a laboratory model built on the basis of previously conducted reconstructed smelting experiments in copies of excavated furnaces. The effect of technological parameters on P-content of the resulted iron bloom was studied. OM and SEM-EDS analyses were carried out on the extracted iron and slag samples. On the basis of the material analyses it can be stated that P-iron is usually extracted but the P-content is highly affected by technological parameters. Typical microstructures of P-iron and of slag could also be identified. It could also be established that arsenic usually solved in high content in iron as well.

Thermodynamics applied to iron smelting techniques

Thermodynamics allows us to understand the chemical reactions occurring inside an experimental archaeometallurgical shaft furnace for iron smelting. The production of an iron bloom, with the so-called direct process, is described in a daily pyrometallurgical cycle. The experiences suggest that, as higher and better blown furnaces were built for improving the production, different reactions have been involved and a new material, pig iron, has been obtained

A new species of Wellsopsyllus (Copepoda, Harpacticoida, Paramesochridae) from the deep Southern Ocean and remarks on its biogeography

The new deep-sea copepod species of the family Paramesochridae (Copepoda, Harpacticoida) presented here was collected during the scientific ANtarctic benthic DEEP-sea biodiversity cruise II (ANDEEP II) to the Weddell Abyssal Plain and western Weddell Sea and the CROZet natural iron bloom and EXport experiment (CROZEX cruise) to the Crozet Isles in the Indian Ocean. The new species has been allocated to the subgenus Wellsopsyllus within the genus Wellsopsyllus Kunz, 1981, based on the 1-segmented endopods and 3-segmented exopods of swimming legs 2–4. Furthermore, the new species shows a 1-segmented exopod of the antenna. Wellsopsyllus (W.) antarcticus sp. n. can be distinguished from its congeners by its small body size, the presence of two setae on the distal segment of the endopod of the first swimming leg, by the very small furcal rami, the extremely reduced endopods of second and third swimming legs, the reduced mandibular palp and maxillula, as well as by the size and armature of the fifth and sixth swimming legs in both sexes. Difficulties of the placement of the new species into a suitable genus show an insufficiency in the present family classification. In the future, a revision of the genus Wellsopsyllus is essential. With its presence in the western Weddell Sea and the Indian Ocean, the new species may have a wide distribution range. Furthermore, it is the first abyssal species of the genus Wellsopsyllus sampled outside of the Scotia Sea.