Examples Of Weldable Parts; Weldability Of Typical Combinations Between Stud And Base Metal For Welding By Capacitor Discharge - CEVIK TSW1000CAR Manual De Instrucciones

EXAMPLES OF WELDABLE PARTS

The following parts: pins, bushes, fastons, etc., to be used with capacitor discharge welders, must be of high quality,
supplied by the same supplier and made of the same material. Pins of different characteristics require different
adjustments and therefore parts consisting of different batches and suppliers must absolutely never be mixed together.
WELDABILITY OF TYPICAL COMBINATIONS BETWEEN STUD AND BASE METAL FOR
WELDING BY CAPACITOR DISCHARGE.
A brief arc initiates the melting both of the stud and the base metal and the smelting baths mix as soon as the joint
is formed. Even the properties of the area affected by the heat are subjected to changes.
Generally speaking the material of the stud melts more than the base metal.
Usually the welding area on the base metal is wider than the crosswise section of the stud. Therefore the resistance
and deformation at the welding point between the stud and the base metal must be very closely examined. As far
as steel is concerned, pay special attention to its fragility caused by the hardening process.
The material and resistance of the stud are subject to limited tolerance. The carbon contents inside steel studs must
be less than or equal to 0.20% (ladle analysis). The weldability of the various materials and the combinations allowed
between the stud and the base metals are illustrated in table 1.
Table 1 : WELDABILITY OF THE BASE METAL/STUD METAL COMBINATIONS
Good weldability: A Fair weldability: B Not weldable: -
The surface of the base metal must be clean. Any residues of paint, rust, dross, grease or coatings of non-weldable
metals must be removed from the welding area using suitable equipment. The base metals with layers of dross and
rust must be perfectly clean.
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