Cold-rolled steel is hot-rolled steel that has been further processed, making it a more expensive steel product. After the hot-rolled steel has cooled, it is temper rolled, which essentially means that it is rolled with a very low reduction. This process of temper rolling makes the finished product look smooth and flat, and it also increases the hardness of the steel. In fact, cold-rolled steel is up to 20 percent stronger than hot-rolled steel!