Weld bronze

If you want to weld bronze, you should consider the properties and special features of copper and copper alloys when joining. Below we have put together for you how to weld bronze and what to pay attention to.

Bronze is a copper alloy

Bronze is an alloy known to humanity for many thousands of years. Although there are different bronze alloys, so also different base metals, which consists of bronze. But always included is a minimum share of 60 percent copper. As a result, bronze has similar welding properties to copper or other copper alloys.

Thus, welding properties of non-ferrous metals have to be considered

As a non-ferrous metal alloy, bronze is therefore generally easy to weld. However, during welding, the copper absorbs atmospheric gases. This results in a negative influence on the quality of quality compared to the starting alloy. As a result, it is preferable to use inert inert gas welding techniques, that is, TIG or MIG welding. This protects the molten bath for air.

In addition, it is difficult to achieve the necessary welding or melting temperature, since copper and thus bronze has a high thermal conductivity. As a result, a lot of heat is dissipated quickly and is no longer available for the process of melting. The phases have a special influence. Single-phase copper alloys are very easy to weld, but multiphase alloys are only limited. Stay (Pb), for example, forms its own phase.

Welding process for bronze (copper alloys)

When welding must therefore be distinguished according to the different bronze alloys. Otherwise, the following welding methods are basically possible, whereby they are no longer used equally intensively:

  • Gas welding such as gas welding
  • Arc welding such as electrical welding with electrode from welding filler
  • Inert gas welding with inert gases (TIG and MIG welding)

With craftsmen and thus also with do-it-yourselfers above all the protective gas welding techniques are of importance. Electric and gas welding play only a minor role. However, preheating is usually essential due to the high thermal conductivity.

Electric conductivity

Copper alloys are also less electrically conductive than pure copper and thus better to weld. For alloys containing copper, the weldability is extremely limited. From 0.03 percent lead content, heat cracks are hard to avoid.

Flux when welding bronze

Basically, the use of flux is recommended for all copper alloys (except MIG welding process). However, it should be noted that CuAl alloys (aluminum bronzes) require different fluxes. In addition, you must differentiate in the present copper alloy after the cold workability (copper Berrylium or copper-silicon would be cold deformable).

It must be distinguished after each bronze alloy

Copper-tin alloys are probably the most common home-made copper alloys (tin bronze) for welding. Again, the specific welding properties must be adapted to the metals contained beyond. This applies, for example, to CuSnPb alloys (copper tin lead). In particular, MIG and TIG welding is considered to be best practice today (outside of industrial applications).

Important standards for welding bronze and copper alloys

In addition to the welding processes, which must be adapted to the existing alloy, the compositions of the welding additives are also important. You should be familiar with the numerous standards. These include the following standards:

  • CEN / TS 13388: 2008: Overview and composition of copper and copper alloy products
  • DIN EN 1982: Copper and copper alloys
  • DIN 8552-3: Weld seam preparations, joint shapes for copper and copper alloys, gas fusion welding and arc welding
  • DIN ISO 15614: Gas welding and arc welding of copper and copper alloys (Part 6)

Of course there are also all standards (DIN, ISO DIN EN etc.), which are fundamentally important for welding processes and welding consumables.

Tips & Tricks

After welding, of course, the bronze must be further processed. Among other things, the grinding and polishing of bronze are important. In addition, of course, there are other methods of joining. Like the brazing and brazing of bronze.

Video Board: Bronze welding