For large or small orders for OEM parts, large volume orders or for prototype development, working with a reputable, established and experienced company to handle all your requirements for brazing stainless steel to copper is always the best option.
These companies have the professionals, the expertise and the years in the industry to be able to effectively design a brazing process to create an aesthetically pleasing joint and final component that is free from defects. This is often an extremely challenging task to complete for those not specializing in brazing.
An additional benefit to working with a brazing company is the cost factor. Not only will the price be lower than you can typically do in-house, but there will be virtually no waste. This means the parts will arrive to you looking as you expect. They will be bright, shiny and smooth without the need to pay for parts that don’t pass the quality control by the company.
You may find that you need to braze stainless steel to copper in your shop for a small part or component. If you do, there are a few considerations that can help to achieve a solid joint free when brazing stainless steel to copper that is from defects.
Martensitic and Austenitic Stainless Steels
The martensitic stainless steels are typically hardened as well as tempered. They can have up to 1.2% carbon and 12% chromium. The higher the level of chromium the more heating will impact the structure of the metal. Typically, after brazing these types of stainless steels they will be heat treated.
Similar in consideration are the austenitic stainless steels. These have chromium of up to 22% and nickel at up to 11%. Choosing the correct brazing alloy to keep heat at a minimum in the joint area will be essential to prevent the possibility of the area becoming less resistant to corrosion. Brazing, with its lower temperatures, reduces this risk, but without correct technique, it is possible to create high temperatures in the braze area.
It will be important when brazing stainless steel to copper in a natural environment with oxygen to use the right type of flux. The flux has to be matched to the brazing temperature required for the specific type of stainless as overheating the flux can create a reaction. This overheating of the flux causes a film to form on the stainless and prevents the braze alloy from properly bonding with the stainless, creating weak joint that will eventually fail.