Projection Welding Defects

UNDERCUT Cause- High amperage wrong electrode angle long arc length rust Prevention- Set machine on scrap metal to correct parameters clean metal before welding Repair- Weld with smaller electrode sometimes must be low hydrogen with preheat. Projection welding has fewer variables that affect the resistance welding process as compared to spot welding.

Mechanical Engineering Resistance Projection Welding Rpw Advantages And Disadvantages

The metal mostly used on building or engineering may not be rigid enough to support the projections.

Projection welding defects. When the projections make contact at the same time but they are different sizes they can heat at different rates. Only a skilled person can form projections of different required shape like spherical projections. Metal thickness and composition is a significant matter here.

40 Weld Schedules 41 Weld Tables - Three-ply Weld Schedule 50 Weld Quality Defects Spot and Projection Welds 51 Surface Defects - Indentation - Surface Deformation Surface Burning - Surface Expulsion Whiskers - Cracks - Blow Holes 52 Weld Nugget Defects - Undersize Nugget - Low Penetration - Porosity - Expulsion - Misshapen Weld Nugget. 1 start of operation contact between parts is at projections. One projection can overheat which could lead to expulsion.

Some of the defects may be allowed if the defects are under permissible limits but other defects. Failures in resistance projection welded nuts used in automotive components especially those located in structural areas or that compromises the safety of the occupants may be considered catastrophic since in most cases rework these bodies is extremely difficult. Even some coppers and brasses cannot be welded using projection welding.

Welding Defects can be defined as the irregularities formed in the given weld metal due to wrong welding process or incorrect welding patterns etc. High weld current high weld force and long squeeze and hold times may cause deep indentations that do not meet specifications. ExpulsionBurn-Through Issues with high electrode follow-up high current and welds too close to the edge may cause the expulsion of molten metal during welds.

Disadvantages of Projection Welding. Disadvantages of Projection Welding. Resistance projection welding RPW.

PROJECTION SIZE OR SHAPE. Welding defects are generated in a welding job due to the faulty or poor technique used by the inexperienced or unskilled welder or due to fundamental difficulties in the welding operation. When welding multiple projections if the projections are not the same size shape or missing there is a potential for inconsistent welding.

Welding defects may occur either outside or inside the weld metal. The defect may differ from the desired weld bead shape size and intended quality. 1 Projection formation in projection welding is a complicated process and it takes time.

However one potential difficulty for the success of projection welding is the cleanliness of the parts or presence of surface films that can inhibit bonding. The most important variables of this assembly technique are the quality of the projections and the response of the cylinder as the projection collapses during the welding time. Resistance Projection Welding A resistance welding process in which coalescence occurs at one or more small contact points on parts Contact points determined by design of parts to be joined May consist of projections.

A significant aspect of projection welding is the limited distortion associated with it which is certainly advantageous in terms of geometrical stability. You cannot apply this welding method on every type of materials. 2 when current is applied weld nuggets similar to spot welding are formed at the projections.

An ideal weld or good weld should be such that adequate fusion exists between the filler metal and edge preparation together with good penetration.

Types Of Welding Defects Qa Qc Professionals