How to choose welding current according to the shape of stainless steel electric heating ring?

Common shapes of stainless steel electric heating rings include round, square and special shapes. Different shapes have different requirements for welding current during welding. The following are some basic selection methods:
Circular electric heating ring
Girth welding: Circular electric heating rings usually have the need for girth welding. When welding the girth, since the welding process is a continuous circular motion, the heat distribution is relatively uniform and the welding current can be relatively stable. For circular electric heating rings with smaller diameters (such as diameters less than 100mm), the welding current is generally 10% - 20% smaller than that of flat plate welding of the same thickness. This is because its circumference is shorter, the welding speed is relatively fast, and the heat dissipation is relatively slow, so a smaller current can meet the welding requirements and prevent overheating. For example, when welding the girth of a circular electric heating ring with a thickness of 3mm and a diameter of 80mm, tungsten inert gas arc welding is used, and the welding current can be selected between 100 and 120A. For circular electric heating rings with larger diameters (such as diameters greater than 100mm), the welding current can be close to the welding current of a flat plate of the same thickness, but attention should be paid to controlling the welding speed to ensure the fusion quality of the weld.
Spiral weld welding: If the circular electric heating ring is a spiral weld, the welding current needs to be adjusted according to the pitch and pitch of the spiral. When the pitch is small and the pitch is large, the welding current can be appropriately reduced, because there are more weld overlaps per unit length and the heat accumulation is large; conversely, when the pitch is large and the pitch is small, the current can be appropriately increased. For example, the welding current of a circular electric heating ring with a spiral pitch of 10mm and a pitch of 30mm can be 10% - 20% larger than that of a circumferential weld of the same diameter.
Square electric heating ring
Fillet weld welding: When welding the corner weld of a square electric heating ring, the heat is easily concentrated at the corner, which is prone to overheating and burn-through, so the welding current should be smaller than that of a flat butt weld. Generally speaking, for a square electric heating ring corner weld with a thickness of 3 - 5mm, the welding current is 20% - 30% smaller than that of a flat butt weld. For example, when the welding current of the flat plate butt weld is 150A, the welding current of the fillet weld can be adjusted to 100-120A. At the same time, when welding fillet welds, appropriate welding angles and rod feeding methods should be used to ensure good fusion at the root of the weld and avoid defects such as incomplete penetration.
Straight seam welding: The straight seam welding of square electric heating rings is similar to that of flat plate welding, but it should be noted that the heat dissipation of the edge of the square electric heating ring is different from that of the flat plate. The heat dissipation of the edge of the square electric heating ring is relatively fast, so the welding current can be slightly larger than the current when welding the flat plate. For the straight seam of the square electric heating ring with a thickness of 4mm, when using electrode arc welding, the welding current can be 140-160A, which is 10-20A larger than the welding current of the flat plate of the same thickness.
Special-shaped electric heating ring
Complex shape weld: The weld shape of the special-shaped electric heating ring is complex, which may include curves, broken lines and other shapes. When welding, the welding current needs to be adjusted according to the specific shape and size of the weld. For parts with large curvature, the welding current should be appropriately reduced to prevent heat concentration from causing local overheating; for parts with long straight sections, the current can be appropriately increased. For example, when welding a special-shaped electric heating ring with a semicircular protrusion, the welding current of the semicircular protrusion should be 15% - 25% smaller than the surrounding straight section weld.
Irregular size: If the size of the special-shaped electric heating ring is irregular, there is a change in thickness or different widths, the welding current should be adjusted according to the thickness and width of different parts. In thicker or wider parts, the welding current should be increased accordingly; in thinner or narrower parts, the current should be reduced. For example, the thickness of one end of the special-shaped electric heating ring is 5mm and the thickness of the other end is 3mm. When welding a 5mm thick part, the welding current should be 30% - 50% larger than that of welding a 3mm thick part.
When selecting the welding current according to the shape of the stainless steel electric heating ring, it is necessary to comprehensively consider factors such as the shape, size, heat dissipation and welding method of the weld, and continuously adjust the current through trial welding to obtain the best welding quality.