Step A involves melting the raw materials at a temperature of 930-960°C, allowing them to cool to 710-760°C, and then allowing them to stand for 5-10 minutes; step B involves melting the raw materials at a temperature of 930-960°C, allowing them to cool to 710-760°C, and then allowing them to stand for 5-10 minutes; step C involves melting the raw materials at a temperature of...