Читать книгу Engineering Physics of High-Temperature Materials - Nirmal K. Sinha - Страница 72

Iron makes up approximately 8.1% by weight of Earth's crust (Lutgens and Tarbuck 2000) and is naturally found in the form of an ore, most often an iron oxide, such as magnetite (Fe₃O₄) or hematite (Fe₂O₃). The use of steel, an iron‐base alloy, dates far back to the Middle Ages, with the earliest known production of steel dating nearly 4000 years, from 1800 BCE (Akanuma 2005). Iron alloys are generally inexpensive compared to other materials and are highly versatile.