Questions about single-pass welding

Single-pass welding joins a butt joint through its full plate thickness in one weld pass. Thick steel plate is usually welded in many passes — a root pass, filler passes and a cap pass, often from both sides. In a single pass, the beveled groove is no longer needed, and far less time, energy and filler material go into the seam.

We weld with ultra-high-power lasers in a laser-hybrid process, from one side and through the full thickness. Below the joint, a contactless electromagnetic weld pool support holds the molten metal in place so that it cannot drop through at the root. The background is explained in our guide to single-pass welding.

In thick plate, the molten metal forms a column as tall as the plate is thick. Its weight presses on the root, and surface tension alone can no longer hold it — without support, the melt drops through and the joint is not filled. The electromagnetic weld pool support produces an upward force in the melt from below, without touching the component, and keeps the root in shape.

Our machines are designed for sections up to 35 mm thick. The cross-sections on our home page show single-pass welds from 15 to 30 mm. Whether your component is suitable depends on material, joint and quality requirements — we check this with you, with trial welds if needed.

Our focus is on structural steels such as S355, as used in wind towers, pressure vessels and shipbuilding. In principle, we can weld a wide range of metallic materials, including carbon steels, high-strength steels, stainless steels, nickel-based alloys and aluminum alloys. Tell us your material, and we assess it with trial welds.

A square butt joint. A simple flame-cut edge is sufficient. Beveling the plate edges for a V, Y or X groove is no longer necessary.

Yes. We develop the welding procedure for your application and qualify it, so that the welds are reproducible and meet the standards that apply to your component.

Wherever thick steel plate is welded in many passes today. We currently work in wind energy (tower sections and tubes), pressure vessels (thick-walled vessels and shells) and shipbuilding (panels and thick-walled sections). Other components on request.

Yes. We integrate the machine into new or existing lines, independent of the equipment vendors you already work with.

You do not have to buy a machine at your own risk. Instead, you can pay for the welded, qualified meters of seam.

That depends on plate thickness, weld length per year, your current process and the number of passes. The ROI calculator gives a first estimate of the annual saving, throughput and welder-hours saved. For a worked example from wind-tower construction, request our case study.

Yes. In our application center we run trial welds on your material, with fiber lasers up to 45 kW, welding cells with external linear and rotary axes and seam lengths up to 3 m. Materials testing and metallography are available on request, and trials at your plant are possible too.

WeldNova GmbH is a team of welding engineers in Berlin and a spin-off of the Federal Institute for Materials Research and Testing (BAM). The technology comes from many years of research in BAM Division 9.3 Welding Technology. More on our about page.

Send us your welding task — plate thickness, material and approximate weld length per year. We assess feasibility and run the numbers on your case. Get in touch.