Quality, inspection and standards in stud welding

The quality of a stud weld is assessed using the inspections specified for the application. DIN EN ISO 13918 describes welding studs and ceramic ferrules; DIN EN ISO 14555 covers arc stud welding and its associated inspection requirements. Torque testing was removed in edition DIN EN ISO 14555:2026-01. For suitable welding tasks, Bolzenschweißtechnik bsk + BTV GmbH offers reliable stud welders with digital system monitoring and appropriate welding elements . These technical standards help specifically avoid common sources of error such as magnetic arc blow or shrinkage cavities.

DIN EN ISO 13918 applies to welding studs. It describes welding studs and ceramic ferrules, including their geometry, materials and designations. The equipment and welding elements from Bolzenschweißtechnik bsk + BTV GmbH are designed accordingly.

DIN EN ISO 14555 applies to the stud welding process, covering arc stud welding, including requirements, testing and quality assurance. Equipment and welding elements from Bolzenschweißtechnik bsk + BTV GmbH are designed accordingly.

Welding elements from Bolzenschweißtechnik bsk + BTV GmbH comply with DIN EN ISO 13918.

DIN EN ISO 14555 is the process standard for arc stud welding. Among other matters, it regulates requirements for the process, procedure qualification and quality assurance. Equipment and welding elements from Bolzenschweißtechnik bsk + BTV GmbH are designed accordingly.

Stud weld quality is checked by visual inspection of the weld collar and bend testing, and for safety-relevant joints by procedure qualification according to DIN EN ISO 14555. Process monitoring covers both mechanical and electrical values and compares actual values with setpoints. If a deviation falls outside the tolerance, the unit displays an error message. Equipment and welding elements from Bolzenschweißtechnik bsk + BTV GmbH are designed accordingly.

Common methods include visual inspection, bend testing and tensile testing, as well as procedure qualification according to DIN EN ISO 14555. Process monitoring additionally documents each weld. Equipment and welding elements from Bolzenschweißtechnik bsk + BTV GmbH are designed accordingly.

Visual inspection assesses externally visible characteristics of the welded joint. In a bend test, the stud is loaded under specified test conditions. Bend testing that causes permanent deformation cannot generally be classified as non-destructive. Whether continued use is permissible depends on the testing method and applicable requirements. Supplementary testing tables do not replace an inspection plan according to the current standard. Bolzenschweißtechnik bsk + BTV GmbH provides the associated test torque table and offers suitable torque wrenches and bend testing tools from M3 to M10.

Use the test method, loading and acceptance criteria specified for the particular joint and applicable inspection plan. Values from an older torque table must not be treated as universal bending-test values or as a current DIN EN ISO 14555 requirement. The DIN EN ISO 14555:2026-01 revision removed torque testing.

Inspection scope and sample size must be defined for the application, applicable standard, quality requirements and agreed inspection plan. The inspection of incoming studs and the testing of completed welded joints are separate tasks.

For bend testing, the stud is loaded with a specified test torque, requiring a suitable torque wrench and bend testing tool. Bolzenschweißtechnik bsk + BTV GmbH offers suitable torque wrenches and bend testing tools from M3 to M10 in its range, together with the test torque table.

Magnetic fields deflect the arc, usually towards the greater mass of material, resulting in one-sided weld collars and more porosity. Remedies include symmetrical earth connections on both sides, compensating masses at the edge, steady cable routing and rotation of the gun. Reversing polarity helps with strongly magnetised parts.

Shrinkage cavities are voids in the centre of the stud, occurring particularly from approximately 16 mm diameter when the lift is too small. The weld pool solidifies from the outside, isolates the liquid centre and shrinkage opens up cavities. The remedy is a generally larger lift height matched to the diameter and tip shape.

The notch effect results from the abrupt change in cross-section at the weld collar. Under static loading it is generally uncritical, with fracture occurring outside the welding location. Under cyclic loading it significantly reduces fatigue strength; flat collars and the flange used in capacitor discharge welding are more favourable here.

The error rate in automated lines is very low: approximately 0.3 per thousand in vehicle construction, and single-digit figures per million in fully automatic processes. Process monitoring displays an error message if actual values deviate from setpoints beyond the tolerance. Bolzenschweißtechnik bsk + BTV GmbH offers systems with process monitoring.

The welding location must be bare metal and free of scale, rust, oil, paint and moisture. Contamination causes porosity and lack of fusion, immediately in the very short capacitor discharge process. Clean surfaces are therefore the basis for a strong joint.

Design in construction must use the design rules applicable to the specific structure, for example DVS 0967 and Eurocode 4 for relevant headed-stud applications in composite construction. DIN EN ISO 14555 for the process and DIN EN ISO 13918 for the elements are also decisive. Bolzenschweißtechnik bsk + BTV GmbH supplies headed studs conforming to standards.

Questions about this topic or your application? Email info@stud-welding.de; the team at Bolzenschweißtechnik bsk + BTV GmbH will be happy to help.