Laser welding stainless steel: guide

Contents:

We continue to talk about metal welding, and in this article stainless steel is in the spotlight. What are this metal’s specifics, what to pay attention to, which parameters, gas, and wire to use—read here!

Steel and its characteristics

First thing first, we will be addressing stainless steel welding specifically, since there are many types, and each has its own parameters setting nuances in relation to the compound: there are magnetic and non-magnetic, mat and specular steels, etc. So, keep that in mind!

Stainless steel is a material with low thermal conductivity. In comparison with aluminum, it needs less laser power to be processed. Also, it has a higher infrared absorption. Overall, it is a little bit easier to work with it than with aluminum. Furthermore, pops or craters almost do not appear during welding, thus it’s easier to make beautiful welds.

Stainless steel is a corrosion- and rust-resistant, durable metal. Note that its surface usually has a chromium oxide layer on top.

This metal has various grades. Alloys are divided by additive component content.

• 200 series

These ones have chromium manganese in them. This type is used in automotive, cutlery, and appliance manufacturing.

• 300 series

Here, carbon and nickel are present. They increase corrosion resistance. This is the most often used series of stainless steel for welding. For example, 304 and 316 may be found in medical, jewelry, and automotive industries.

• 400 series

It stands for ferritic and martensitic stainless steel. These ones are rarely used for welding because they have lower resistance to corrosion. However, they still may be processed, with more challenges.
Overall, stainless steel is recommended to be welded with fast speed and low heating. Thus, laser welding is a great solution for this material since it can provide those exact conditions of work.

Working process

Pre-treatment

First of all, prepare the material to be welded: clean it from any impurities. And do not use brushes or other types of this since stainless steel is quite sensitive.

Welding

Now, let us give you setting examples for laser welding stainless steel of various thicknesses:

— 0.5 mm. Required power is 350 W, laser frequency is 5000 Hz, and vibration frequency is 50 Hz. Seam width has to be set at 2.0 mm and a wire speed feed—12.0 mm/sec. However, there is a nuance! Stainless steel of this thickness is very complicated to weld, and it’s necessary to feed material manually or use spot welding.

— 1.0 mm. All parameters stay the same, except power. We’ll have to use 500 W.

— 1.8 mm. Change power at 700 W, seam width at 2.5 mm, and leave everything else untouched.

Maximum welding thickness is based on the laser source power.

Post-treatment

Almost always stainless steel gives tarnishing colors, and this is inevitable. To get rid of this, you may use mechanical or chemical cleaning.

By the way, a cleaning function is present in 4in1 and 5in1 Wattsan laser welding machines, and it can help with this task.

Wire and Gas

Wire

While laser welding stainless steel, you may use wire, and to achieve success, you need to choose the one most similar to the workpiece by compound wire!

Laser welding equipment comes with an automatic wire feeding, and you need to install wire in there correctly:

— Make sure to use V-shaped rollers;

— Use the rainforced feeding tube.

Gas

For laser welding stainless steel, argon or argon-hydrogen mixtures are the best choice. They help to gain good-quality seams. But keep in mind that hydrogen by itself can make metal brittle, so clear argon is preferred.

Sometimes nitrogen is also used.

Machines for laser welding stainless steel

Wattsan has three lines of laser welding equipment: 4in1 G1, 4in1 G2, and 5in1 G2 Pro.

Machines may be equipped with laser sources for specific production tasks. Also, all models have an automatic wire feeding that accelerates the manufacturing process and makes the operator’s life easier.

Furthermore, laser welding machines have several functions: welding, cleaning, seam cleaning, and cutting. Sometimes an energy storage welding function is present as an additional one.

Conclusion

1. There are many types of stainless steel, and each has its own parameters setting nuances in relation to the compound.
2. Stainless steel is a material with low thermal conductivity; it needs less laser power to be processed. Also, it has a higher infrared absorption. Stainless steel is a corrosion- and rust-resistant, durable metal.
3. Overall, stainless steel is recommended to be welded with fast speed and low heating. Thus, laser welding is a great solution for this material since it can provide those exact conditions of work.
4. First of all, prepare the material to be welded: clean it from any impurities. And do not use brushes or other types of this since stainless steel is quite sensitive.
5. Almost always stainless steel gives tarnishing colors, and this is inevitable. To get rid of this, you may use mechanical or chemical cleaning. Or laser seam cleaning.
6. Choose the most similar to the workpiece by compound wire.
7. As for the gas, argon or argon-hydrogen mixtures are the best choice.