If you are new to stainless steel fabrication, then choosing a suitable SS grade is the most difficult task.
It is even challenging when you have to analyze over 20 grades of stainless steel available.
The good news – Tuolian engineers are giving you six practical factors for choosing the right stainless steel grade.
Let’s get started.
1. Know the Practical Applications of Stainless Steel or Components
These are environmental factors that may affect the stainless steel optimal performance. Such variables may include high temperature, acidic environments, workload, acidity, or alkalinity.
Therefore, choose grades of stainless steel that can withstand such environmental conditions. Take for example:
|Stainless Steel Grade||Unique Property||Recommended Applications|
|316 SS||Contain molybdenum for better corrosion resistance.||Main applications include seawater systems, chemical reactor tanks, medical equipment, etc.|
|309 SS||Excellent high-temperature resistance||High-temperature applications such as boiler systems, heat exchanger parts, etc.|
|420||Higher carbon content||Suitable for surgical equipment and instruments|
2. Evaluate Mechanical Strength Requirements
Whether you evaluate surgical grade stainless steel or just the general purpose options, mechanical strength is critical. Therefore, you must know the strength, ductility, and toughness your applications require.
Take for example:
- High ductility and toughness – nickel plays an important role
- Corrosion resistance – a combination of chromium, nickel, and molybdenum
A practical example is a petrochemical equipment. They require strong and heat-resistant material. Therefore, you will go for the Ferritic stainless steel grades such as 502.
3. Consider Stainless Steel Fabrication Processes
Fabricating stainless steel involves cutting, forming, welding, milling, drilling, etc. Of course, it includes post-fabrication operations such as heat treatment, and cold working, amongst others.
Besides, most stainless steel grade materials are available as sheets, bars, rods, or even plates. Therefore, you must fabricate the stainless material to get specific and useful products.
A fundamental question you must ask is – How will the fabrication process affect SS grades?
Have a look at this:
|SS Grade||Fabrication Process||Effects|
|304 SS or 316 L||Welding stainless steel||Their low carbon content makes them less susceptible to carbide formation. As a result, welded sections will not be brittle.
Some SS grades such as 347 SS have stabilizers such as niobium.
Ferritic SS is easy to weld, unlike the martensitic grades which are not easily weldable.
|309||Cold working||Suitable for drawing and stamping processes.
Also, cold working 309 stainless steel improves strength.
|304 SS and 430 SS||Good formability properties||You can make complex shapes without breaking them. It is not the case for martensitic stainless which are not readily formable.|
|303 SS||Machining||Most stainless steel grades are easy to machine, however, they are susceptible to work hardening.
Elements such as sulfur can be added to improve the machining properties.
|440c SS or 17-4 PH||Heat treatment||They are heat treatable|
From the above examples, you must know exactly how you are going to process stainless steel. With this information, you will choose a perfect stainless steel material grade.
4. Check Whether Grades of Stainless Steel Must Comply with Specific Standards
When fabricating critical components such as stainless steel boilers, or heat exchanger systems – choose SS grades conforming to set regulatory standards.
Usually, these regulations vary depending on the geographical location. A good example is the ASTM A213.
5. Cost Constraints are Critical when Choosing Stainless Steel Material Grades
The prices of stainless steel vary depending on the alloying materials. Again since the material is highly recyclable, the scrap metal price determines the prices.
Therefore, even when choosing the right stainless steel grades for your applications consider the prices. The truth is this:
Stainless steel 316 is more expensive than 304 SS. It is because the 316 has molybdenum.
So, if it is a normal application, you can go for the economical stainless steel grade 304. However, for applications in chloride areas or seawater, the best option is 316 grades of stainless steel.
6. Know the Degree of Corrosion Resistance You want to Achieve
There could be a certain degree of corrosion resistance you may wish to achieve. Consequently, you will find grades of stainless steel with varying chemical compositions.
And, this is evident from these simple explanations:
|SS Grade||Type of Corrosion Resistance|
|304 SS||High chromium content makes it a perfect choice for most corrosion-resistant applications.|
|316||Adding molybdenum improves corrosion resistance making it better than 304.
|Duplex stainless steel grades||Suitable for applications prone to stress corrosion cracking. They perform better here than austenitic stainless steel grades.|
At Tuolian Metal, we will help you choose the right stainless steel grades for all your applications. Simply tell us your application requirements and will help you get a high-performance, durable, and affordable stainless grade.
Stainless Steel Chart – Source: Tuolian
Choosing Grades of Stainless Steel – Source: Metal Supermarket
Stainless Steel Manufacturing – Source: Tuolian
Choosing SS Grade – Source: Regan Industrial
Grade of Stainless Steel Selection – Source: AZO Materials