WLDG 1428 Unit #6 Introduction to SMAW Electrode Classification

STUDENT OBJECTIVES Describe what the American Welding Society (AWS) is and what it does. Specify the Title and Number Designation for AWS “Specification for Carbon Steel Electrodes for Shielded Metal Arc Welding” (A5.1). Recognize that the Specifications are revised occasionally and that the Specification Number will reflect the revision date—such as A5.1-9.

STUDENT OBJECTIVES Recognize that the Welding Electrodes for Carbon Steel SMAW Electrodes are Classified According to the following criteria: Type of Current Type of Covering The Mechanical Properties of the Weld Metal The Welding Position Capabilities of the Electrode Class.

STUDENT OBJECTIVES Specify the meaning of each Letter and Number used for Classifying Carbon Steel Shielded Metal Arc Electrodes. Identify the Two Current Determining Ingredients in Electrode Coverings. Identity the Four Major Categories of Electrode Coverings. Specify the Various Position Capabilities of the Electrodes.

STUDENT OBJECTIVES Specify the Storage Requirements of the Electrodes. Identify the Four Most Widely used Electrode Diameters. Recognize a Description of the Three Most Widely used Mechanical Tests for Testing Weld Metal by the AWS.

BACKGROUND Arc welding consumables are the materials used up during welding, such as electrodes, filler rods, fluxes, and externally applied shielding gases. Welding electrodes covered by the AWS A.5.1 Specification utilize a system based on U.S. Customary Units to classify the welding electrode.

BACKGROUND You as a weldor or welding technician must have the ability to decipher these letters and numbers identifying each electrode regardless whether it is a covered electrode, bare rod, spool, coil, etc.

The American Welding Society (AWS) is a private, non-profit organization which does the following: Develops and publishes filler metal specifications.

American Welding Society Develops and publishes welding codes for buildings, bridges, offshore drilling rigs, and railroad cars.

American Welding Society Develops and administers a national program of welding inspector, weldor, and welding educator certifications.

American Welding Society Publishes a monthly magazine.

American Welding Society Has a worldwide membership—of over 40,00 which meet as local chapters on a monthly basis.

Electrodes The welding electrodes (E6010, E7018, and E7024) that you are using this quarter are specified and classified by the American Welding Society in the following specification:

AWS Specification Title: AWS A5.1/A5.1M:2004 “Specification for Carbon Steel Electrodes for Shielded Metal Arc Welding”

AWS Specification The Specifications are revised maybe once or twice every ten years depending on new developments. The latest revision for the carbon steel electrodes was in 2004 as indicated by the specification number XXXXX:2004.

AWS Classification The AWS specifies and classifies the carbon steel electrodes according to the following criteria: Type of Current. Type of Covering.

AWS Classification The Mechanical Properties of the Weld Metal.

AWS Classification The Welding Position Capabilities of the Electrode.

Electrode Classification Electrode classifications are broken down as the following: (i.e. E6010) E – Stands for Electrode.

Electrode Classification The next two numbers of their classification (i.e. 60 or 70) refers to the minimum tensile strength of the weld metal in thousands of pounds per square inch of cross section.

Electrode Classification This classification could and is also be extended to 3 digits (i.e. 110, 120, . . .). In this case the electrode would have a 5 digit electrode classification.

Electrode Classification The third number of a 4 digit electrode classification refers to the electrode position capabilities. On a 5 digit electrode classification it would be the 4th digit. The break down would go as follows: 1 = All Position Welding (i.e. Flat, Horizontal, Vertical and Overhead) 2 = Flat and Horizontal Welding (i.e. Flat & Horizontal Groove Welds, Flat & Horizontal Fillet Welds, Flat & Horizontal . . .)

Electrode Classification The last two numbers together designate the type of current with which the electrode can be used and the type of covering on the electrode.

Flux Ingredients The two (2) current determining ingredients of SMAW electrode coatings are the following: Sodium (usually for DC use only). Potassium for AC and DC use.

Flux Ingredients The electrode coatings of SMAW have four major groups based on which ingredient is found in the greatest amount. They are listed as follows:

Flux Ingredients High cellulose (organic) electrodes (E6010 and E6011) – the cellulose produces C02 shielding gas which protects the molten puddle from oxygen and nitrogen.

High cellulose (organic) Electrodes E6010 DCEP (+) Only E6011 AC or DCEP (+)

Rutile Electrodes Rutile (titania) electrodes have a large relative percent of rutile (a mineral) which forms a heavy slag and produces a very smooth bead appearance due to the slower cooling rate of the weld metal because of the heavy slag.

Rutile Electrodes E6012 AC or DCEN (-) E6013 AC or DCEN (-) OR (DCEP(+) E6014 AC or DCEN (-) OR (DCEP(+) E6019 AC or DCEN (-) OR (DCEP(+)

Low Hydrogen Electrodes Low hydrogen electrodes have a lime (calcium carbonate) coating which produces CO2 shielding gas without producing water vapor as a by-product as do electrodes with cellulose or high cellulose and rutile electrodes.

Low Hydrogen Electrodes E7015 DCEP only (All position F,H, V, OH) E7016 AC or DCEP (All position F,H, V, OH) E7018 AC or DCEP (All position F,H, V, OH) E7018M* DCEP only (All position F,H, V, OH) * M = Military or Extra low moisture content. E7048 AC or DCEP (All position F,H, V, OH with special vertical down abilities)

High Iron Powder Electrodes High iron powder electrodes have very high relative percentages or iron powder in the chemical coating.

High Iron Powder Electrodes The iron powder adds extra weld metal and thus allows high welding speeds in the flat position.

High Iron Powder Electrodes Electrodes high in iron powder will use either cellulose or lime to produce the shielding gas and will usually have quantities of rutile or iron oxide to form a heavy slag. +

High Iron Powder Electrodes E6020 AC or DCEN (Flat groove and Flat and Horizontal Fillet Only) E6022 AC or DCEN (Flat groove and Flat and Horizontal Fillet Only) E6027 AC or DCEN (Flat groove and Flat and Horizontal Fillet Only) E7024 AC, DCEN, or DCEP (Flat groove and Flat and Horizontal Fillet Only) E7027 AC or DCEN (Flat groove and Flat and Horizontal Fillet Only) E7028 AC or DCEN (Flat groove and Flat and Horizontal Fillet Only)

AWS Recommendations AWS recommends the following storage requirements of electrodes:

AWS Recommendations

Electrode Diameters The four most widely used electrode diameters are: 3/32” 1/8” 5/32” 3/16”

Tensile Pull Mechanical testing used by AWS include the following: Tensile Test: A slow pulling test.

Guided Bend Test Guided Bend Test: A slow bending of a sample strap or coupon.

Charpy Impact Test Charpy Impact Test: A rapidly applied load swung on a pendulum which strikes a notched sample and is often conducted at temperatures at or below 0° F.

Evaluation: Student to be tested on Welding Program WLDG 1428 Test #3.

Summary: As a good weldor or welding technician you must have the ability and knowledge to recognize, analyze, recommend and implement corrective measures to a welding problem. As a professional weldor/technician, discontinuities are not acceptable nor in your job description.

Summary: Knowing how to eliminate and negotiate your way through welding defects will be one of your primary duties as a weldor. The welding industry at large is on a constant look out for welders and inspectors that can properly identify problematic weldments and make effective suggestions and corrections.