17-4 vs 17-7 Stainless Steel – What’s the Difference

17-4 vs 17-7 Stainless Steel

When choosing the right type of stainless steel for your particular needs, there are so many options available that it can be overwhelming. Two popular types of stainless steel are 17-4 and 17-7. Whilst these two types of steel may look similar, some important differences could affect your decision. In this blog post, we’ll deeply dive into the differences to help you decide which is right.

Difference Between 17-4 and 17-7 Stainless Steel


Their composition is the main difference between 17-4 and 17-7 stainless steel. 17-4 is a precipitation-hardening steel comprising around 17% chromium and 4% nickel. The remaining makeup is mostly iron. 17-7, on the other hand, has a slightly different makeup, including 17% chromium and 7% nickel. This may seem like a small difference, but adding extra nickel gives 17-7 stainless steel better corrosion resistance properties.


When it comes to strength, there is no clear winner. Both 17-4 and 17-7 stainless steel are known for their strength and durability. However, 17-7 stainless steel is known to have higher tensile strength, which makes it a good choice for devices such as springs and washers.


Welding is an important consideration when choosing a material. Welding 17-4 stainless steel can be challenging due to its high hardness. To combat this issue, consider preheating the material before welding. Welding 17-7 stainless steel, on the other hand, is easier thanks to its lower carbon content. This means that it can be welded without requiring preheating.


Whichever material you choose will depend on the application you need it for. 17-4 stainless steel is often used in applications where high strength and corrosion resistance are paramount, including aircraft components, turbines and medical equipment. 17-7 stainless steel is often used in springs, washers, and other similar components.


Lastly, cost is an important consideration when choosing any material. 17-4 stainless steel is generally cheaper than 17-7 stainless steel. However, as mentioned above, the choice of material will depend on many factors, not just cost.


As you can see, while 17-4 and 17-7 stainless steel may seem similar at first glance, there are some important differences. By understanding the differences in composition, strength, welding characteristics, application, and cost, you can decide which material is right for you. Whatever your decision, 17-4 and 17-7 are great and reliable options in various applications. So, whether you’re looking for a material for medical equipment, aircraft components, or springs and washers, you now know what to consider when choosing between these popular types of stainless steel.



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