Answer:
Step-by-step explanation:
In the open hearth process for producing steel in a Siemens-Martin open hearth furnace, so called because the molten metal lies in a comparative shallow pool on the furnace bottom or hearth. The hearth is surrounded by a roof and walls of refractory bricks. The charge is fed through a charging door and heated to 1,600°C to 1,650°C mainly by radiation of heat from the burning of gaseous fuels above it. It is not the amount of heat but rather the high temperature heat that is essential for the purpose.