People choose stainless steel for a variety of applications. Stainless steel is a favorite of many businesses and industries. Most appreciate its durability and anti-corrosion properties. However, if your project will require welding, it's important to know that all stainless steel isn't the same. Some stainless steel types can handle welding better than others can.
Why Some Grades Handle Welding Better Than Others Do
Stainless steel is an alloy. Different grades consist of differing amounts of metallic elements and chemicals. The composition of the stainless steel affects its weldability. Generally, the more carbon in the stainless steel, the less weldability it has.
Intergranular Corrosion and Hot Cracking
Some stainless steels can have good weldability to start, but lose efficacy over time due to intergranular corrosion. This can occur when chromium and carbon combine during the welding process. It creates an area where corrosion will set in given a little time.
Hot cracking is also a concern. It occurs when the stainless steel contains elements with lower melting points in it. These elements will become free and dig themselves into the steel during welding. As the stainless steel cools, those elements will cause it to crack.
Which Stainless Steel Grades Are Ideal for Welding Projects
Luckily, there are quite a few grades with good weldability. Mostly, the 300-series of austenitic stainless steels have the best ductility and carbon ratios. They can handle most types of welding, and some even have specific chemical makeups to help them hold up during and after the welding process.
300-series stainless steel grades with the L designation indicate low amounts of carbon. Two grades, in particular, stand out most when it comes to stainless steel welding:
- Grade 304L
- Grade 316L
The 304L works best for smaller stainless steel projects, such as creating instruments and utensils. The 316L can work best for more industrial applications, such as machinery parts. Others in the 300-series can accept welding as well, but it depends on the application and welding process involved.
Precipitation hardening stainless steel also has good weldability. PH stainless steel requires special pretreatment and posttreatment procedures but can work well in larger industrial projects. This type of stainless steel doesn't follow the typical grade numbering series scheme. The two most common grades with good weldability include:
Other stainless steel types can handle welding. In fact, just about all of them have at least some degree of weldability when properly prepared. The grades listed above tend to work with most welding methods. Going outside these grades may limit the types of welding methods available.
Even the grades with good weldability require unique handling dictated by that grade. If you must use a particular grade not listed here, you need to speak with an experienced welding service about how best to go about achieving a good weld.
What to Keep in Mind When Sourcing Your Stainless Steel
Contractors and others often choose stainless steel without considering weldability. You should choose based on your needs. But, you should always keep weldability in mind if you know you will require any type of welding for your stainless steel project.
You will also need the help of a welding service that knows stainless steel well. Even if you choose the perfect stainless steel grade for your project, your welding service must know how to handle it. Welding stainless steel requires experience, expertise and proper equipment.
Wilson's Welding Service Inc. has served businesses and industries on and off the Mississippi Gulf Coast for decades. We know how critical it is to get stainless steel welding right. Contact us about your stainless steel project today.