What do the numbers on welding rods mean?

Among the numerous things you will need to learn when you begin stick welding is distinguishing one stick electrode from another. You can determine what type of stick welding electrode you have by learning a few numbers and letters printed on the base of the electrode. 

Every stick electrode is unique,e with some working well on rusty metal while others require clean steel. Some are good for any welding position,n but others are restricted to flat welding. Identifying a stick electrode is relatively easy when you know how to interpret the four or 5-digit alphanumerical code that tells you what you need to know.

Here is an example of a welding rod number:

E7018

The first letter stands for “electrode,” the consumable, conductive part of the welding circuit creating the arc.

The first two numbers identify the tensile strength of the electrode’s filler material. The tensile strength is given in thousand pounds per square inch reading, so this electrode would contain 70,000 lb. or be identified as 70. The tensile strength of a material refers to the maximum amount of tensile stress it can withstand before failing.

The third digit on the electrode identification number is 1, indicating that this electrode is suitable for all welding positions. If the number were a 2, that would tell you this electrode is appropriate for flat and horizontal welding only. And skipping the number 3, a number 4 identifies the electrode as correct for welding only flat, horizontal, vertical down, and overhead positions.

The fourth numerical digit in the electrode identification number indicates coating type and current. The following table explains:

The electrode identification number tells you that the electrode (E) has 70,000 pounds of tensile strength (70) and is suitable for all welding positions (1). From the chart above, the coating is low hydrogen potassium and iron powder with AC, DC, or DC- welding currents.