Stainless steel is growing in popularity due to its versatility and durability. This material is in high demand for building construction and appliance projects, although welders need to take a different approach when working on stainless steel welding.
Here are our expert top tips on working with stainless steel for the best results and highest quality.
Consider Stainless Steel Properties
One of the keys to successful stainless steel welding is understanding the unique properties of this material and how to best work with these surfaces. For example, these are the main differences between stainless steel and mild steel:
- Lower heat transfer coefficient – stainless steel welding needs lower heat input and slow, steady conduction.
- Higher expansion coefficient – there is more distortion with stainless steel, and popular austenitic stainless steel expands 50% more.
- Lower electrical conductivity – the best welders keep the stick-out distance consistent for stainless steel welding, while a higher wire speed is required for the same current.
Prepared Work Area
While stainless steel offers impressive heat retention and is overall a long-lasting material, it does require some careful preparation before welding gets underway. Welding companies should maintain a separate work area for stainless and carbon steels, including segregated tools for each material. The best welders know this is because carbon steel contamination can cause rust and other welding defects on stainless steel.
For the best stainless steel welding quality, it’s important to thoroughly clean joint surfaces before welding. Any excess oil, grease, or dirt should be removed, and the filler wire must be totally clean too. While preparing the joints, welders should also check to confirm the joint gap is properly designed to accommodate the higher expansion rate stainless steel is known for.
Selecting Filler Material
One step to pay particular attention to is filler material selection. While the base metal is usually used for filler material, sometimes there may not be a match for certain stainless steels, especially if you are welding two different varieties. It’s important to carefully select a durable filler material that lowers the likelihood of hot cracking and intergranular corrosion.
Welding companies can prevent stainless steel warping by clamping a brass or copper piece behind the weld seam. This acts as a heat sink, absorbing the heat to cool the surface and prevent burn-through. It may also help with continuous welding for the entire seam. Another simple way to protect against warping and other damage to the weld is to always wear gloves whenever touching stainless steel to keep natural hand oils off the surface.
Cleaning and passivation should be top priorities after weld completion to maximise corrosion resistance on stainless steel surfaces. A mechanical brush, grinder, or blaster can ensure a smooth, high-quality finish while pickling agents and similar chemicals also help with the protection process.
Comprehensive Welding Inspection and Management Solutions
At Technoweld, our team is made up of the best welders and now supervisors who understand stainless steel welding and how to best manage, supervise, and consult Australian welding companies.
Call 1300 00 WELD today or send us a message online to learn more about our stainless steel welding support services.