Basic Knowledge Of Welding - Yeswelder CT2050 Operator's Manual

BASIC KNOWLEDGE OF WELDING

Basic Knowledge of Stick
Manual metal arc welding (MMA/Stick) is arc welding by manually operating electrodes. Stick requires simple equipment and is a
convenient, flexible, and adaptive welding processing type. Stick is applied to various metal materials with thicknesses of more than
2mm. It's suitable for various material structures, particularly for workpieces with complex structures and shapes, short weld joints
or bending shapes, as well as weld joints in various spatial locations.
Welding Process of Stick
Connect the two output terminals of the welder to the workpiece and electrode holder respectively, and then clamp the electrode by
the electrode holder. When welding, the arc is ignited between the electrode and the workpiece, and the end of the electrode and
part of the workpiece is fused to form a welding crater under the high-temperature arc. The weld crater is quickly cooled and con-
densed to form a weld joint that can firmly integrally connect two separate pieces of the workpiece. The coating of the electrode is
fused to produce slag to cover the weld crater. The cooled slag can form a slag crust to protect the weld joint. The slag crust is re-
moved at last, and the joint welding is finished.
Tools for Stick
Common tools for Stick include electrode holder, welding mask, slag hammer, wire brush (see Fig 5.8), welding cable, and labor pro-
tection supplies.
a) Electrode Holder b) Welding Mask c) Slag Hammer d) Wire Brush
Fig 18 Tools for Stick
a) Electrode holder: a tool for clamping electrode and conducting current, mainly including 300A type and 500A type.
b) Welding mask: a shielding tool for protecting eyes and face from injury due to arc and spatter, including hand holding type and
helmet type. Colored chemical glass is installed on the viewing window of the mask to filter ultraviolet rays and infrared rays. Arc
burning condition and weld crater condition can be observed from the viewing window during welding. Thus, welding can be carried
out by operators conveniently.
c) Slag hammer (peen hammer): for the use of removing slag crust on the surface of the weld joint.
d) Wire brush: for the use of removing dirt and rust at the joints of the workpiece before welding, as well as cleaning the surface of
the weld joint and the spatter after welding.
e) Welding cable: generally cables formed from many fine copper wires. Both YHH type arc welding rubber sleeve cable and
THHR type arc welding rubber sleeve extra-flexible cable can be used. The electrode holder and welding machine are connected
via a cable, and this cable is named as welding cable (live wire). The welding machine and workpiece are connected via another ca-
ble (earth wire). The electrode holder is covered with insulating material performing insulation and heat insulating.
Basic Operation of Stick
1) Welding joint cleaning
Rust and greasy dirt at the joint should be removed completely before welding in order to implement arc igniting and arc stabilizing
conveniently as well as ensure the quality of the weld joint. A wire brush can be used for conditions with low requirements for dust
removal; a grinding wheel can be used for conditions with high requirements for dust removal.
2) Posture in operating
Take flat welding of butt joint and T-shaped joint from left to right as an example. The operator should stand on the right side of the
working direction of the weld joint with a mask in the left hand and an electrode holder in the right hand. The left elbow of the opera-
tor should be put on his left knee to prevent his upper body from following downwards, and his arm should be separated from the
costal part so as to stretch out freely.
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