The Benefits of High-Temperature Stainless Steel Sintering

The conventional stainless steel sintering process involves heating a part just below its melting point –  typically at temperatures between 2000°F to 2200°F (2100°F in DA or equivalent atmosphere for N1-grade stainless steel). As a stainless steel part nears its melting point, the powder metal particles diffuse to create strong material properties able to withstand extreme conditions. 

One variation of this method involves sintering at more extreme temperatures to create superior corrosion resistance, durability, and more. This process is known as high-temperature stainless steel sintering.

In this article, we’ll walk through high-temperature stainless steel sintering, how it’s unique from traditional sintering methods, and the benefits of the process.

What is High-Temperature Stainless Steel Sintering?

High-temp stainless steel sintering is a process in which a part goes through the traditional sintering process in a specialized furnace under more extreme conditions and higher control. This special furnace type is built for higher-temperature heating – generally above 2300℉ (1260℃).

However, the ultimate temperature for high-temperature stainless steel sintering depends on the stainless steel type. For N2 grade stainless steel, for example, high-temperature sintering occurs at 2300°F in DA or equivalent atmosphere. For L Grade stainless steel, high-temperature sintering takes place at 2300°F+ in a 100% purified, reducing atmosphere. 

This process is designed to create stainless steel parts with even more strength, durability, and corrosion resistance than traditional sintering can achieve. This process, paired with the already strong properties of stainless steel, makes high-temperature stainless steel sintering even more appealing for industrial applications. 

Want to learn more about stainless steel sintering? Check out our article on tolerances and dimensional control of sintered stainless steel.

How is High-Temperature Stainless Steel Sintering Different From Traditional Stainless Steel Sintering?

Now that we know what high-temperature stainless steel sintering is, it’s helpful to dive deeper into the characteristics that make it unique from traditional sintering. Here’s a breakdown of the most significant differences between high-temperature stainless steel sintering and traditional sintering: 

Overall, high-temperature sintering has the same capabilities as traditional sintering. Both processes can produce durable, dense, precise parts suitable for extreme conditions, but high-temperature sintering can enhance those properties even further. 

The Benefits and Drawbacks of High-Temperature Stainless Steel Sintering

When considering high-temperature stainless steel sintering with standard sintering methods, the pros and cons can help you decide which is better for your particular application. 

Benefits

As a whole, high-temperature sintering creates stronger, longer-lasting stainless steel materials than traditional sintering. This superior corrosion resistance and durability create the opportunity for these parts to be used in environments with extreme conditions, like the aerospace, medical, and defense industries. 

Another benefit of high-temperature sintering for stainless steels is its ability to obtain these superior properties in a similar cycle speed when compared to the traditional sintering process without compromising the part’s dimensional quality. 

Drawbacks

However, there are drawbacks to this type of sintering. One challenge of high-temperature sintering is the shrinkage that occurs post-compaction, which could alter the dimensions of a part after it’s sintered. This may require a part to be altered, leading to longer production times and additional costs. 

High-temperature sintering also has higher upfront costs than traditional sintering due to the special furnace and atmosphere required. This special technology leads to higher maintenance costs.

Fortunately, partnering with a skilled sintering company can address both of these challenges. Hiring a professional sintering company eliminates the upfront cost of special equipment. Plus, an educated engineer can design parts to minimize shrinkage from sintering. 

What Are High-Temperature Stainless Steel Parts Used For?

High-temperature sintered stainless steel parts are ideal for industrial applications where high corrosion resistance and durability are required. Below are some examples of industries these parts are used: 

• Agriculture (exhaust flanges, sensor bosses, retainer clips)
• Automotive (exhaust flanges, sensor bosses, urea flanges, exhaust marmons)
• Food/Processing (blender bearing cups)

Advancements in High-Temperature Sintering: Ultra High-Temperature Sintering

As technology in powder metallurgy continues to advance, sintering techniques do as well. High-temperature sintering has evolved to incorporate even higher temperatures – better known as ultra high-temperature sintering (UHTS). 

This type of sintering occurs at temperatures up to 2500℉ (over 1350℃). For L grade stainless steel specifically, UHTS occurs at over 2500°F in a 100% purified, reducing atmosphere.  

UHTS creates near full-density parts with even stronger mechanical properties, but it comes with limitations for suitable materials, costs, and part distortion. 

Conclusion

Depending on the grade of the stainless steel used and its application, HTS may be both feasible and cost-effective. However, it’s important to consider all factors and work with a trusted expert who can guide you through the process. 

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