Final answer:
The SMAW electrode restricted to horizontal and flat welding is the E4914, due to its coating and operating characteristics, although its designation suggests it could be used in all positions.
Step-by-step explanation:
The SMAW electrode that is restricted to horizontal and flat position welding is the E4914. SMAW, or Shielded Metal Arc Welding, utilizes different types of electrodes that are suited for various welding positions and metal types based on their designation. According to the AWS (American Welding Society) classification system, the '14' in E4914 indicates that the electrode can be used in all positions; however, due to its coating and operating characteristics, in practical applications, it is typically limited to flat and horizontal welding positions. Electrodes with a '16' as in E4916, or '18' as in EXX18, have a coating that is suitable for all-position welding, including vertical and overhead. EXX10 electrodes, on the other hand, are cellulosic electrodes designed for deep penetration, suitable for vertical down welding in addition to other positions.