ST12 cold rolled steel coil can often be identified by the following characteristics:

• Cold rolled steel has better, more finished surfaces with closer tolerances
• Smooth surfaces that are often oily to the touch in CR steel sheet
• Bars are true and square, and often have well-defined edges and corners
• Tubes have better concentric uniformity and straightness,made from cold rolled material.
• Cold
  rolled steel coil with better surface characteristics than hot rolled
  steel, it’s no surprise that cold rolled steel is often used for more
  technically precise applications or where aesthetics are important. But,
  due to the additional processing for cold finished products, they come
  at a higher price.