In the middle of the 19th century; relatively large amounts of high quality wire were being drawn in the United States and United Kingdom from iron billets made in Sweden. After adoption of the pneumatic and open-hearth methods for making steel, chemistry laboratories were set up, and chemical analyses evolved into the definitive means of grading steel. The importance of the billet marks declined immediately. This archival paper explains the Swedish billet marking system and its significance to wiremakers, c.1850.
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