LESSON VII © COPYRIGHT 2000 THE ESAB GROUP, INC. 7.3    FEATURES OF FLUX CORED ELECTRODES Flux cored electrodes combine the advantages of several of the welding processes we have discussed earlier.  As with coated electrodes, the flux improves the weld metal chemi- cal composition and mechanical properties.  As in gas metal arc welding and submerged arc welding, productivity is increased because the electrode is continuous. Flux cored electrodes may be used for welding carbon steels, low alloy high strength steels, and the high strength quenched and tempered steels.  They are also used for welding stainless steels and abrasion resistant steels.  These will be covered in subse- quent lessons. 7.3.1 Functions of the Flux Ingredients - As with coated ingredients, each manufac- turer has his own formulas for the flux ingredients.  The composition of the flux core can be varied to provide electrodes for specific applications. The basic functions of the flux ingredients are: a) Deoxidizers and Denitrifiers - Since nitrogen and oxygen can cause porosity or brittleness, deoxidizers such as manganese and silicon are added.  In the case of self-shielded electrodes, denitrifiers such as aluminum are added.  Both help to purify the weld metal. b) Slag Formers - Slag formers such as oxides of calcium, potassium, silicon or so- dium are added to protect the molten weld puddle from the atmosphere.  The slag aids in improving the weld bead shape and “fast freezing” slags help hold the weld puddle for out-of-position welding.  The slag also retards the cooling rate, especially important when welding the low alloy steels. c) Arc Stabilizers - Elements, such as potassium and sodium, help produce a smooth arc and reduce spatter. d) Alloying Elements - Alloying elements, such as molybdenum, chromium, carbon, manganese, nickel, and vanadium, are used to increase strength, ductility, hardness and toughness. e) Gasifiers - Minerals, such as fluorspar and limestone, are usually used to form a shielding gas in the self-shielded type wires.

Lesson 1
The Basics of Arc Welding
Lesson 2
Common Electric
Arc Welding Processes
Lesson 3
Covered Electrodes for Welding
Mild Steels
Lesson 4
Covered Electrodes for Welding Low Alloy Steels
Lesson 5
Welding Filler Metals for Stainless Steels
Lesson 6
Carbon & Low Alloy
Steel Filler Metals -
Lesson 7
Flux Cored Arc Electrodes Carbon Low Alloy Steels
Lesson 8
Hardsurfacing Electrodes
Lesson 9
Estimating & Comparing Weld Metal Costs
Lesson 10
Reliability of Welding Filler Metals
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