Minerals and Metals in Ancient India v1.c22.s7: The Iron and Steel Objects at Taxila

Minerals and Metals in Ancient India v1.c22.s7

Language: English

The Iron and Steel Objects at Taxila

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The vast majority of the iron objects at Taxila were found in a severely corroded state. Of the 221 objects considered to be worthy of examination, less than one-fifth came from the Bhir Mound. The Śaka-Pārthian buildings of Sirkap and the later monasteries of Jaulian etc. were burnt out by the invading Kuṣāṇas and White Hūṇas respectively. Due to great heat and subsequent burial in wood ash, the iron objects in these buildings were better preserved aganist corrosion and disintegration.

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The objects which have survived may be classified under six groups: (a) household utensils, (b) arms and armour, (c) horse-bridles and elephant-goads, (d) carpenter’s and black-smith’s tools, (e) agricultural implements, and (f) miscellaneous articles like needles, plummets, unwrought ingots etc. Some of these objects are clearly of foreign origin such as ladles with vertical handles, candelabra, wheeled braziers, heavy iron javelins, helmet, snaffle-bits etc. which were not known/common amongst the Indians.

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The 108 ingots found in Sirkap came from the first century AD layer. These are hexagonal, long torpedo-shaped and shuttle-shaped pieces measuring between 4.75 and 7.12 inch in length and 1.3 to 2.5 inch in width at the middle. (Similar blooms were used for forging the iron beams at Koṇārka, several centuries later). The ingots weighed 1-1/2 to 4 lbs. and assayed in terms of elemental percentages: 0.1 C, 0.03 Si, 0.019 S, 0.077 P, trace Mn and 99.6 Fe.

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A complete longitudinal section showed the ingot to be very porous, some of the holes being 1/2 inch in maximum dimension. The standard diamond pyramid hardness figures over the section varied between 76 and 129, with an average of 95. The tensile test on a small testing bar showed the yield point and maximum stress in tons per sq. inch to be 16.1 and 22.8 respectively. These pure wrought iron pieces were evidently used as raw materials for the final carburized iron or steel products.

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Ten special specimens such as sword, dagger, adze, axe, chisel, knife etc., some of them carburised, were examined by the eminent metallurgist of Sheffield, U.K., Sir Robert Hadfield. The analytical results quoted by Marshall (1951, chapter 27, p. 536) are provided in Table 14.10.

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Hadfield noted the very low sulphur and phosphorus content of the Taxila samples and remarked:

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The chief feature of the present specimens is the high carbon percentage, 1.23, in No. 5. The Brinell hardness and the microstructure of Nos. 1 and 2 also indicate they are of similar high carbon. We have never come across any ancient specimens as high as this before. The highest was 0.7 carbon in the Khambāba specimen (100 BC Besnagar broken sword, also 0.04 Si, 0.02 P, 0.02 Mn, 0.008 S, rest Fe), and this was so exceptional that we thought at the time it must be a fluke.

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Evidently the Indians in this locality (Taxila), and at this period (first century AD), quite deliberately made high carbon steel. But apparently they did not know how to harden and temper. If they had, the two swords, specimens 1 and 2, and the adze (No. 5) would be just the articles to apply this treatment to. The micro gives no indication of anything more than the ordinary heating for forging, and of course the hardness is only ordinary.

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Marshall speculated that the ancient steel in Taxila (1.23% carbon) was probably produced by the crucible or wootz process, but no evidence could be obtained to that effect. It was really surprising that the specimens did not show any sign of having been tempered. Indians had produced quenched martensitic structure in the third century BC site of Pāṇḍu Rājār Dhibi (vide chapter 12). Great heat during fire carnage might have destroyed the martensitic structure. Marshall could have arranged metallographic examination of more samples from the Sirkap site.

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The correlation between the archaeological data with the historical or traditional is not a straight-forward task. However, the eminence of Taxila since the Early Historical Period is quite evident. Darius of Persia and Pradyota of Ujjain sent their armies to Taxila. The famous physician Jivaka, who was contemporary to Gautama Buddha, had received his training in Takṣaśilā or Taxila which was a seat of learning and a centre of medicine and surgery. The Persian and Greek influences in Taxila were evident even before Alexander's invasion. We have referred to the Kuṣāṇa era surgical instruments found at Taxila.

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Pāṇini was born in Śalātura (Lahur) near Taxila and flourished during the middle of the fifth century BC. He mentioned about furnaces having more than one bellow or bahubhastrikā (Aṣṭādhyāyī, 7.3.47). Bellow pipe and pair of bellows with nozzles have been found in the Parthian stratum of Sirkap during the excavations at Taxila. We have discussed the eminence of beryl or vaidūrya in Taxila. Pāṇini had explained (Aṣṭādhyāyī, 4.3.84) that the name of the mineral was derived from Vidura, the city where the gem was processed. Pāṇini's śatamāna coin (Aṣṭādhyāyī, 5.1.27) was probably the punch-marked, bent-bar silver coin unearthed from the fourth century BC stratum of Bhir Mound.

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The archaeological findings from the Maurya, Greek, Pārthian, Scythian and Kuṣāṇa layers at Taxila corroborate many aspects of written history. Minerals and metals found at Taxila indeed tell us the history of India and its contact with neighbouring countries over a long period of centuries.

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Table 14.10

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**Table of Analysis, Brinell Hardness and Micro-Examination of Some Iron/Steel Objects Found at Taxila**

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| Serial no. | Taxila reference | Description | Length (in.) | Brinell hardness Av. | Probable nature of the material |
| 1. 57 | Sk.'16-229; stratum II | Double-edged sword | 15 | 233 236 47 } 235 | High carbon material; about 1.3-1.5% carbon |
| 2. 58a | Ch. T.D. '21-3 | Copper guard | — | — | — |
| | | Fragmentary sword | 9.9 | 234 240 240 } 238 | High carbon material; about 1.5-1.7% carbon |
| 3. 62a | Sk.'12-96; stratum II | Dagger | 9.4 | 161 167 161 } 164 | Medium or low carbon material severely decarburised on the surface |
| | | End of blade near haft | | | |
| | | Micro piece from point-end of dagger | | | |
| 4. 59a | Bm.'24-897; stratum IV | Dagger | 9.6 | 134 128 } 131 | Probably iron |
| *5. 116 | Sk.'20-76; stratum II | Adze for carpenters | 5.75 | — | — |
| | | Away from edge | | 220 240 259 } 240 | High carbon steel (1.23%) |
| +6. 109 | | Near cutting-edge | | 236 | |
| | | Axe | 5.75 | 103 106 167 } 125 | Iron |
| | | | | | |

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| Specimen No. | | | | | | | | | Micro-examination |
| 7. 120 | Sk. '16-1, 124; stratum II | Chisel | 5-25 | 106 106 110 107 | Iron | | | | |
| 8. 126 | Sk. '15-294; stratum II | Knife | 5 | 122 118 120 | Iron | | | | |
| 9. 88a | Sk. '26-2, 847; stratum II | Arrowhead, three-flanged | 4.1 | 177 187 182 | Medium or low carbon steel | | | | |
| 10. 63 | Bm. '19-505; stratum I | Spearhead, double-edged | 7.5 | 105 121 113 | Iron | | | | |
| | Analysis | | | | | C | Si | S | P | Mn. | |
| | * 5, 116 | | | | | 1.23 | 0.28 | 0.004 | 0.024 | | |
| | + 6, 109 | | | | | 0.10 | 0.03 | 0.004 | 0.062 | Nil | |

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1. Micro No. 8134. Structure consists of small slightly elongated grains of ferrite and spheroidal carbide, the result of decomposition of the pearlite. The grains are outlined by cementite. Traces only of decarburisation round the outer surface. Non-metallic inclusions fairly small and comparatively few.

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2. Micro No. 8135. Structure similar to specimen 1, but cell walls of cementite thicker and grains larger and more elongated. Slight partial decarburisation of the surfaces. Non-metallic inclusions similar to those in specimen No. 1.

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³ Micro No. 8136. Shows a core of small ferrite and pearlite grains, corresponding to material of 0.15-0.25% C. surrounded by a skin 0.1-0.25 mm in thickness of coarse columnar-shaped grains of ferrite. Non-metallic inclusions moderately large and numerous.

Linked texts (2)

Aṣṭādhyāyī — Pāṇini, Sanskrit
Pandu Rajar Dhibi