Sphalerite is a sulfide mineral with formula (Zn,Fe)S. Discovered by Ernst Friedrich Glocker in 1847. Contains up to 40% iron content. Forms face-centered cubic zincblende crystal structure
Carburizing heats iron/steel by absorbing carbon from charcoal or carbon monoxide. Process creates hard surface while keeping core soft and tough. Carbon diffuses into metal surface layers through solution or carbide formation
Old Copper Complex in North America dates to 9500 BP. Copper smelting technology enabled Copper Age and Bronze Age. 80% of global primary copper production was from copper-iron-sulfur minerals until 20th century
Ferrosilicon contains 15-90% silicon by weight. Produced by reducing silica with coke in presence of iron. Available in 15%, 45%, 75%, and 90% silicon formulations. Contains about 2% iron and other elements like aluminum and calcium
EN 10305 covers seamless cold drawn steel pipes for hydraulic and pneumatic systems. Tubes must have precisely defined dimensions and specified surface roughness. Manufactured from hot finished tubes through cold drawing. Delivery conditions include +N (normalized) and NBK (protective heat-treating)
Specification covers chromium, chromium-nickel, and chromium-manganese-nickel stainless steels. Applies to pressure vessels and general applications. Values must be used independently of inch-pound and SI units