What was Germany's contribution to steel?

Answer 1

German engineer Carl Wilhelm Siemens pioneered experiments on the regenerative condenser, using hot steam. This laid the foundation for Open Hearth steelmaking, notably when adapted to the Siemens-Martin process, which can be used for the rapid production of large quantities of steel. This particular method has benefits over the Bessemer process, as the slower and easier to control Siemens-Martin process more efficiently extracts impurities, such as phosphorus. It is also more energy efficient, as the heated air that exits the furnace is recycled by passing it through solid bricks. These bricks are then used to heat air entering the furnace. In contemporary industry, however, this method is now obsolete, where its last use in the US stopped in 1992. Sources: http://en.wikipedia.org/wiki/Carl_Wilhelm_Siemens http://en.wikipedia.org/wiki/Siemens-Martin_process