Een grotere Wobbling Spot Size helpt om grotere gaten te overbruggen
De vereiste tolerantie voor montage wordt verkleind en dus goedkoper
De lagere benodigde toleranties verlagen de bewerkingskosten drastisch
Niet-tolerante onderdelen kunnen nog steeds worden gebruikt: minder schroot, minder verliezen = grote besparingen
Maximale opbrengst en kwaliteit van gelast onderdeel
The ability to create products using different metals and alloys greatly increases both design and production flexibility. Optimizing properties such as corrosion, wear and heat resistance of the finished product while managing its cost, is a common motivation for dissimilar metal welding.
Joining stainless steel and zinc coated (galvanized) steel is a one example. Because of their excellent corrosion resistance, both 304 stainless steel and zinc coated carbon steel have found widespread use in applications as diverse as kitchen appliances and aeronautical components.
The process presents some special challenges, particularly since the zinc coating can present serious problems with weld porosity. During the welding process, the energy that melts steel and stainless steel will vaporize the zinc at approximately 900⁰C, which is significantly lower than the melting point of the stainless steel.
The low boiling (vaporization) point of zinc causes a vapor to form during the keyhole welding process. In seeking to escape the molten metal, the zinc vapor may become trapped in the solidifying weld pool resulting in excessive weld porosity. In some cases, the zinc vapor will escape as the metal is solidifying creating blowholes or roughness of the weld surface.
With proper joint design and selection of laser process parameters, cosmetic and mechanically sound welds are readily produced. As shown below, the top and bottom surfaces of an overlap weld of 0.6 mm thick 304 stainless steel and 0.5 mm thick zinc coated steel exhibit no cracking, porosity, or blowholes.
- left : Bottom bead (back side) of lap weld of 304 stainless steel and zinc coated steel. Shown is the zinc coated steel surface.
- right: Top bead of lap weld of 304 stainless steel and zinc coated steel. Shown is the stainless steel surface.
A material’s weldability is a factor. Most common materials a fab shop will process—be it carbon steel, stainless, or aluminum—have been successfully laser welded for years, using both continuous wave and pulsed modes. Lasers have performed dissimilar-metal welding ( Sample picture is copper joined with stainless steel by fiber laser welder), and specialized weld joint designs in galvanized material have even accounted for zinc outgassing. Moreover, a multikilowatt fiber laser has been shown to successfully weld even the most challenging of materials, including copper