Types of Classification of electrode : Types of Classification of electrode Electrode and Filler Rod Identification of electrode : Identification of electrode Arc welding electrodes are identified using the A.W.S, (American Welding Society) numbering system and are made in sizes from 1/16 to 5/16 . An example would be a welding rod identified as an 1/8" E6011 electrode.
The electrode is 1/8" in diameter
The "E" stands for arc welding electrode.
Next will be either a 4 or 5 digit number stamped on the electrode. The first two numbers of a 4 digit number and the first 3 digits of a 5 digit number indicate the minimum tensile strength (in thousands of pounds per square inch) of the weld that the rod will produce, stress relieved. Examples would be as follows:
E60xx would have a tensile strength of 60,000 psi E110XX would be 110,000 psi
The next to last digit indicates the position the electrode can be used in.
EXX1X is for use in all positions
EXX2X is for use in flat and horizontal positions
EXX3X is for flat welding
The last two digits together, indicate the type of coating on the electrode and the welding current the electrode can be used with. Such as DC straight, (DC -) DC reverse (DC+) or A.C.ELECTRODES AND CURRENTS USED
EXX10 DC+ (DC reverse or DCRP) electrode positive.
EXX11 AC or DC- (DC straight or DCSP) electrode negative.
EXX12 AC or DC-
EXX13 AC, DC- or DC+
EXX14 AC, DC- or DC+
EXX16 AC or DC+
EXX18 AC, DC- or DC+
EXX20 AC ,DC- or DC+
EXX24 AC, DC- or DC+
EXX27 AC, DC- or DC+
EXX28 AC or DC+ Storing and caring of electrode : Storing and caring of electrode Welding rods must be kept dry. Moisture destroys the characteristics of the rod coating. It causes excessive spattering, leads to the formation of cracks in the weld, and causes poor penetration and operating characteristics such as an uneven arc.
Low hydrogen welding rods exposed to humid air for more than two or three hours should be placed in a "Rod Oven." Even a small amount of moisture in low hydrogen welding rods leads to major weld problems Slide 4: After drying, the rods should be transferred to a portable holding Rod Oven and kept there at proper temperature until supplied to the individual weldor. Do not use rods if any part of the core wire is exposed. Do not bow a welding rod. It can cause the coating to break loose from the core wire or cause tiny cracks that cause poor performance
Low Hydrogen welding rods, such as E7018 and E8018-C3, must be kept very dry because hydrogen induced cracking can easily occur, especially in steels of 80,000 psi and higher yield strengths. Here are some suggestions: Slide 5: Purchase welding rods in sealed containers
Do not open the sealed containers until the welding rods are needed
When the cans are opened, rods that will not be immediately used should be placed in a welding rod holding cabinet
Welding rods should be supplied to the weldors in small quantities that can be used within set time limits
Check the standards for welding rods before using because they differ. For example, a E7018 welding can be exposed to the atmosphere for 4 hours, but a standard E11018 welding rod is only good for 30 minutes. Slide 6: Re-drying Low Hydrogen
When the seal is broken, by choice or by accident, a container of low hydrogen welding rods needs to be re-dried. Even when the rods have been exposed to the atmosphere for a few days, they need to be re-dried. Follow these procedures:
To re-dry, remove welding rods from the container and place them in a Rod Oven. Spread the rods out on the shelf. Don't put the container in the oven; the cardboard liners will char the rods
When the rods are initially placed in the oven follow the chart on this page for proper time and temperature settings
Be sure to check with the manufacturer's recommendations and follow them
Do not dry electrodes at higher temperatures. In addition, several hours at a lower temperature is not equivalent to using the specified requirements
Discard any welding rods if excessive re-drying causes the coating to become fragile or if it flakes or breaks off while welding. Get rid of welding rods if there is a noticeable difference in handling of arc characteristics such as insufficient arc force. Slide 7: Storing and exposure, non-low hydrogen
Welding Electrodes such as E6010 and E7014 are not low hydrogen, but it is important that these electrodes also be properly stored to avoid welding defects. Unlike the low hydrogen electrodes that always must be kept dry, most of the non-low hydrogen rods need some moisture in the coatings to work well. If these rods are too dry, they may not function properly. On the other hand, excessively moisture may cause other problems. The following procedures should be followed:
Store these non-low hydrogen electrodes from the freshly opened containers in heated cabinets at 100 degrees - 120 degrees F.
Do not use higher temperatures. For more information, see the chart on this page for proper time and temperature. Welding positions : Welding positions Welding position gives an idea of the location of the workpiece which is to be welded. Flat Position : Flat Position flat position welding is when your job is in a horizontal position the easiest and best position to do welding, then you get vertical up position where the trick is to weave your arc in a V formation, vertical down is used on thin material if its possible at an angle of 45 degrees last overhead that is the most difficult the opposite of flat welding where the job is upside down
anytime you look directly down on your weld joint, it is a flat weld, flat position weld are not affected by gravity, as opposed to horizontal, vertical, and overhead, all of which the puddle tends to "sag" as you weld Horizontal position : Horizontal position The plane of the workpiece is vertical, and the deposited weld bead is horizontal. In this position, slope does not exceed 10 degrees, but rotation can vary from 10-90 degrees. Vertical position : Vertical position plane of the workpiece is vertical and the deposited weld bead is also vertical. In vertical position slope remains between 45 and 90 degrees and rotation may have any value from 0 to 180 degrees. Overhead position : Overhead position The plane of the workpiece is horizontal; welding is carried out from the underside, electrode pointing upward. In this position slope and rotation can vary from 0 to 45 and 90 to 180 degrees respectively. Basic operations : Basic operations Cutting and welding operations (commonly referred to as hot work) are associated with machine shops, maintenance, and construction activities, as well as certain laboratory-related activities, such as glass blowing and torch soldering. Potential health, safety, and property hazards result from the fumes, gases, sparks, hot metal and radiant energy produced during hot work. Hot work equipment, which may produce high voltages or utilize compressed gases, also requires special awareness and training on the part of the worker to be used safely. The hazards associated with hot work can be reduced through the implementation of effective control programs. Program Description : Program Description Cutting and welding operations often are found in maintenance, but can also occur in research settings. Adequate controls and procedures must be used to minimize the hazards associated with these activities. General Cutting and Welding Controls : General Cutting and Welding Controls Areas where hot work is done should be properly designated and prepared. Combustible and flammable materials within the work area should be protected against fire hazards and the operation should not pose a hazard to others in nearby areas. To help achieve this, the following controls should be used:
Cutting and welding operations restricted to authorized, properly trained individuals;
If possible, hot work performed in a properly designed shop area equipped with all necessary controls and adequate ventilation;
Move combustible materials at least 35 feet from the work site. If this is not possible, protect combustible materials with metal guards or by flameproof curtains or covers (other than ordinary tarpaulins);
Cover floor and wall openings within 35 feet of the work site to prevent hot sparks from entering walls or falling beneath floors or to a lower level;
Fire resistant curtains and /or tinted shields used to prevent fire, employee burns, and ultra-violet light exposure. Fire Protection : Fire Protection A person other than the operator should perform fire watch duties and remain at the work site for at least 30 minutes after hot work operations have ended. Additionally, the following steps should be taken:
A fire extinguisher rated at not less than 2-A:20-B:C must be available in shop areas where hot work is performed;
A fire extinguisher rated at not less than 2-A:10-B:C must be attached to all portable cutting and welding carts;
If a building or area is equipped with a sprinkler system, then that system must be operational when hot work is performed;
A fire code permit, which may be obtained from the local fire official, is required for all cutting and welding operations. Hot Work Permits : Hot Work Permits Hot work permits should be developed by departments where cutting or welding is performed. Hot work permits can help minimize the risk of fire during cutting and welding activities by serving as a checklist for operators and those performing fire watch duties. The person responsible for issuing permits should be qualified to examine the work site and ensure that appropriate protective steps, such as those listed in this section, have been taken. A hot work permit should be issued at the beginning of each shift for each specific operation. Welding problems : Welding problems