Understanding Sintered Stainless Steel Corrosion Resistance: Key Factors & Benefits
The sintering process is a step where a material is heated almost to the point of liquefaction, leading to the diffusion of powder particles in a specific material. This process creates a finished piece with strong chemical properties and, under certain sintering conditions, enhancement of corrosion resistance.
While sintering can be used with several different materials, it particularly benefits stainless steel. That’s because it combines the strong chemical properties of stainless steel – corrosion resistance and durability – with the benefits of traditional powder metallurgy – creating precise, complex metal parts with the ability to alter the piece’s final properties.
In this article, we’ll take a look at sintered stainless steel corrosion resistance, along with the benefits and applications of the process.
What is Sintered Steel Corrosion Resistance?
Sintered stainless steel corrosion resistance is the material’s ability to withstand external elements without degradation. In other words, corrosion resistance measures how well a stainless steel part is protected from elements like extreme temperatures and extended exposure to moisture, certain acids, or chemicals.According to WorldStainless, there are different types of corrosion stainless steel is susceptible to. These include:
- Uniform: the entire metal surface uniformly weakens or thins due to the corroding elements
- Galvanic: electrochemical process where two different metals (an anode and a cathode) come into contact with water or another electrolyte to cause the anode to corrode at a faster rate
- Pitting: centralized corrosion in the form of deep cavities or pits caused by a weakening in the oxide layer of stainless steel
- Crevice: crevices or gaps between two different metals causes a trap where solution builds up, causing a difference in oxygen concentration that leads to electrochemical corrosion
- Intergranular: corrosion between the grain boundaries of stainless steel
- Stress cracking: cracking or failure due to excess weight or pressure on the steel, extreme temperatures, or high chloride levels
This guide from Xometry dives deeper into the different stainless steel types, grades, properties, and applications.
How Does Sintering Affect Stainless Steel Corrosion Resistance?
Stainless steel is one of the most corrosion-resistant materials due to its chemical composition and the forming an external chromium based layer that makes it extremely strong and durable. Sintering preserves stainless steel’s corrosion resistance – it’s an added layer of protection against corroding elements. Sintering techniques aim to reduce the porosity of stainless steel and increase density, which can sustain their durability and increase longevity.Atmosphere can also play a role in the protective properties of stainless steel. A stainless steel part will outperform an iron component when sintered in a standard nitrogen/hydrogen atmosphere. However, sintering in a purified, reducing atmosphere, like high-temperature stainless steel sintering, will protect the chromium from forming any oxides/nitrides allowing for superior corrosion resistant performance.
Factors Affecting Corrosion Resistance of Stainless Steel
Several factors will impact the corrosion resistance of stainless steel. These factors include (but aren’t limited to):- The composition of alloying elements
- Porosity
- Environmental conditions
- The amount of welds or bends
- External pressure or weight
Which Stainless Steel is the Most Corrosion-Resistant?
Austenitic stainless steels, such as 304, 316, and 316L offer the highest corrosion resistance among stainless steel types. Their elevated chromium content enhances durability and provides superior protection against corrosion.Which Applications and Industries Does Corrosion-Resistant Sintered Stainless Steel Benefit?
As we established, sintered stainless steel has corrosion resistance built to withstand harsh conditions. But what is it used for? Below are some applications of sintered stainless steel:- Chemical processing equipment
- Food processing equipment
- Pharmaceuticals
- Automotive industry
- Aerospace and defense industry
- Filtration systems
Conclusion
The benefits of sintering combined with the chemical properties of stainless steel make for highly-durable, corrosion-resistant materials used across a wide variety of industries.To learn more about how stainless steel is used in powder metallurgy, check out this blog that explores its advantages.