What are the different types of numbers found on welding rods and how do they indicate the characteristics of the rod?

Welding rods are labeled with numbers that indicate their characteristics. The numbers typically represent the type of coating, tensile strength, and welding position of the rod. For example, a number like E6010 indicates that the rod has a high cellulose sodium coating and can be used in all welding positions. The numbers help welders choose the right rod for the specific welding job based on its properties.