Metallurgical coal is low in ash, moisture, sulfur and phosphorus content, and its rank is usually bituminous. Some grades of anthracite coal are used for sintering, pulverized coal injection, direct blast furnace charge, pelletizing, and in production of ferro-alloys, silicon-manganese, calcium-carbide and silicon-carbide. Metallurgical coal produces strong, low-density coke when it is heated in a low-oxygen environment. On heating, the coal softens, and volatile components evaporate and escape through pores in the mass. During coking, the material swells and increases in volume.

The coking ability of coal is related to its physical properties such as its rank, but laboratory testing is required to completely evaluate the coking ability of a coal. The strength and density of coke are particularly important when it is used in a blast furnace, as the coke supports part of the ore and flux burden inside the furnace. Metallurgical coal contrasts with thermal coal, which does not produce coke when heated. Because of their different end-uses, prices for the two types of coal are usually quite different.

The suitability of coal for conversion to coke is also referred to as the caking ability.

Characteristics of Hot Rolled Steel

Hot rolled steel tends to have a scaly finish which can be removed by pickling, grinding, or sand-blasting. This steel is essentially normalized, meaning free from internal stresses that can arise from quenching or work-hardening processes, because it is allowed to cool at room temperature. Other properties may include:

• Slightly rounded edges and corners for plate products (due to shrinkage and less precise finishing)

• Slight distortions

• More malleable and able to be turned into various shapes

• Increased ductility and toughness

Applications of Hot Rolled Steel

One of the many differences between hot and cold rolled steel is price. Hot rolled steel tends to be cheaper than cold rolled steel because it is manufactured without any delays in the process and does not require reheating like cold rolled steel. It can be used in applications where precise shapes and tolerances are not required, such as:

• Structural Components (Railroad Tracks, I-Beams, Sheet Metal)

• Agricultural Equipment

• Metal Buildings

• Stampings

• Automotive Frames