Friday, May 29, 2009

What is Welding Electrodes?

A device that emits, controls or receives electricity. Typically an end point or wire made of metal or some composite material, there are countless electrodes in electrical and electronics products. For example, in a vacuum tube, the cathode emitter is a "negative" electrode. The transparent wires made of indium-tin-oxide (ITO) that cross an LCD screen are electrodes.

ELECTRODE IDENTIFICATION


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.

  1. EXX1X is for use in all positions
  2. EXX2X is for use in flat and horizontal positions
  3. 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.
I won't describe the type of coatings of the various electrodes, but will give examples of the type current each will work with.

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+
  • EXX15 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+

CURRENT TYPES


SMAW is performed using either AC or DC current. Since DC current flows in one direction, DC current can be DC straight, (electrode negative) or DC reversed (electrode positive). With DC reversed,(DC+ OR DCRP) the weld penetration will be deep. DC straight (DC- OR DCSP) the weld will have a faster melt off and deposit rate. The weld will have medium penetration.
Ac current changes it's polarity 120 times a second by it's self and can not be changed as can DC current.

ELECTRODE SIZE AND AMPS USED


The following will serve as a basic guide of the amp range that can be used for different size electrodes. Note that these ratings can be different between various electrode manufactures for the same size rod. Also the type coating on the electrode could effect the amperage range. When possible, check the manufactures info of the electrode you will be using for their recommended amperage settings.

Electrode Table

ELECTRODE DIAMETER (THICKNESS)

AMP RANGE

PLATE


1/16"

20 - 40

UP TO 3/16"

3/32"

40 - 125

UP TO 1/4"

1/8

75 - 185

OVER 1/8"

5/32"

105 - 250

OVER 1/4"

3/16"

140 - 305

OVER 3/8"

1/4"

210 - 430

OVER 3/8"

5/16"

275 - 450

OVER 1/2"

Note! The thicker the material to be welded, the higher the current needed and the larger the electrode needed.

SOME ELECTRODE TYPES


This section will briefly describe four electrodes that are commonly used for maintenance and repair welding of mild steel. There are many other electrodes available for the welding of other kinds of metals. Check with your local welding supply dealer for the electrode that should be used for the metal you want to weld.

E6010 This electrode is used for all position welding using DCRP. It produces a deep penetrating weld and works well on dirty,rusted, or painted metals

E6011 This electrode has the same characteristics of the E6010, but can be used with AC and DC currents.

E6013 This electrode can be used with AC and DC currents. It produces a medium penetrating weld with a superior weld bead appearance.

E7018 This electrode is known as a low hydrogen electrode and can be used with AC or DC. The coating on the electrode has a low moisture content that reduces the introduction of hydrogen into the weld. The electrode can produce welds of x-ray quality with medium penetration. (Note, this electrode must be kept dry. If it gets wet, it must be dried in a rod oven before use.)

It is hoped that this basic information will help the new or home shop welder identify the various types of electrodes and select the correct one for their welding projects.

WELDING WIRE OR WELDING ROD


This invention relates to consumable welding rods or welding electrodes. More particularly, the invention relates to welding rods or welding electrodes of the type comprising a tubular metallic sheath enclosing a core or filling composed of grains or granules of inorganic welding materials belonging to one or more of the following groups: Alloying agents, fluxing agents, slag-forming agents, gas-forming agents and arc-stabilizing or electron-emitting agents.

Tubular welding wire or rods of the kind referred to are used in gas welding and in arc welding with nonconsumable electrode (carbon arc welding and TIG welding) as well as in the electroslag welding process (ES welding) and the consumable electrode welding process, in which last-mentioned processes the tubular wire or rod does itself constitute the consumable electrode. In automatic or semiautomatic consumable-electrode welding the wire is usually supplied as a coil, while in manual welding usually rod-shaped electrodes are employed. The wires or rods may be either bare or coated.

With the tubular wires or rods referred to, it is important to prevent material from dropping out at the electrode tip and to prevent voids from forming within the electrode. To secure this result it has been suggested to submit the core material to a high degree of compaction in the course of the manufacture, in order to convert it into a virtually solid body. This method does, however, not always secure the desired result. Also, it imposes particular restrictions on the manufacturing process. It has also been suggested to mix the powered material with a liquid bonding agent, for instance a sodium silicate solution, to a paste and to deposit or extrude a string of said paste in the trough-shaped strip. This method introduces, however, other complications.

Mild Steel Wire Rod 5.0mm, 6.0mm


Mild steel (MS) wire is a finished product which is directly used manufacture of various
engineering items. Generally, materials with diameter upto 4mm are considered to be
wire rods and materials below this size are classified as wire. MS wire has number of
applications such as for manufacturing fencing wire, wire nails, wire nettings, wire-ropes
etc.
Raw materials:
The major raw material required is mild steel wire rod of 6mm dia. or 8mm dia.