Common Stainless Steel Grades & Performance: High-Quality Materials for Diverse Industrial Needs

Introduction

Stainless steel is a remarkable material that has gained widespread popularity across numerous industries, thanks to its exceptional corrosion resistance, impressive strength, and attractive aesthetics. Each grade of stainless steel boasts unique performance characteristics, making it suitable for a wide range of specific application scenarios. In this article, we will delve into some of the most commonly used stainless steel grades and explore their key properties.

I. Popular Stainless Steel Grades and Their Key Features

1. 304. It is one of the austenitic stainless steels with the largest application volume and the widest range of usages, It is suitable for manufacturing deep-drawn parts and acid pipelines, containers, structural parts, various instrument bodies, etc. It can also manufacture non-magnetic and low-temperature equipment and parts.

2. 304L. An ultra-low carbon austenitic stainless steel developed to solve the problem that 304 has a serious tendency to intergranular corrosion under some conditions due to the precipitation of Cr23C6. Its sensitized intergranular corrosion resistance is significantly better than 304. Except for slightly lower strength, other properties are the same as 321.

3. 304H. An internal branch of 304, with a carbon mass fraction of 0.04%-0.10%, and high-temperature performance is better than 304.

4. 316. Mo element is added to 10Cr18Ni12 steel to make the steel have good resistance to reducing media and pitting corrosion.

5. 316L. Ultra-low carbon steel, with good resistance to sensitized intergranular corrosion, is suitable for manufacturing thick section welding parts and equipment utilized in petrochemical equipment.

6. 316H. The internal branch of 316, the carbon mass fraction is 0.04%-0.10%, and the high-temperature performance is better than 316.

7. 317. It has better pitting and creep resistance than 316L, used in organic acid corrosion conditions.

8. 321. Ti element stabilized austenitic stainless steel. Adding Titanium improves intergranular corrosion resistance and has good high-temperature mechanical properties,It is generally not recommended for use except for special occasions such as high temperature or hydrogen corrosion resistance.

9. 347. Niobium-stabilized austenitic stainless steel. Adding Ni element improves intergranular corrosion resistance. It is mainly used in thermal power and petrochemical fields.

10. 904L. Super fully austenitic stainless steel, invented by Outokumpu of Finland. Its carbon mass fraction is less than 0.02%. It has good resistance to crevice corrosion and stress corrosion and is suitable for various concerntrations of sulfuric acid below 70°C.

The original standard ASME SB-625 classified it as a nickel-based alloy, and the new standard classifies it as stainless steel.

China only has similar grade 015Cr19Ni26Mo5Cu2 steel. A few European instrument manufacturers use 904L stainless steel as the key material. For example, the measuring tube of E+H's mass flow meter is made of 904L stainless steel, and the case of Rolex watches is also made of 904L.

11. 440C. Martensitic stainless steel has the highest hardness (HRC57). It is mainly used to make nozzles, bearings, valve cores, valve seats, sleeves, valve stems etc.

12. 17-4PH. Martensitic precipitation hardening stainless steel with a hardness of HRC44, and cannot be used at temperature above 300°C. It is used to manufacture offshore platforms, turbine blades, valve cores, valve seats, sleeves, valve stems, etc.

13. 300 Series-Chromium-Nickel Auustenitic Stainless Steel

(1) 301- Good ductility, used for molded products. Can also be hardened quickly by machining, good weldability. Wear resistance and fatigue strength are better than 304.

(2) 302- Essentially a variant of 304 with a higher carbon content, it can be made to have higher strength by cold rolling.

(3) 302B- With a higher silicon content, it has high resistance to high temperature oxidation.

(4) 303 &303Se- Free-cutting stainless steel containing sulfur and selenium respectively, used in occasions where free-cutting and high surface finish are mainly required. 303Se stainless steel is also used to make parts that require hot upsetting because of good hot workability.

(5) 304N- A nitrogen-containing stainless steel, nitrogen is added to increase the strength of the steel.

(6) 305 &384- It contains high nickel content and have low work hardening rates, making them suitable for various applications that require high cold formability.

(7) 308- Used to make welding rods.

(8) 309 & 310 & 314 & 330- They have high nickel and chromium content, to improve the steel's oxidation resistance and creep strength at high temperatures.

(9) 30S5 and 310S are variants of 309 and 310 stainless steels, the only difference being that they have a lower carbon content in order to minimize the carbides that precipitate near the weld. 330 stainless steel has particularly high resistance to carburization and thermal shock.

2. Appropriate options for stainless steel grades

Different application scenarios impose unique performance requirements on stainless steel, making it crucial to carefully select the appropriate grade based on factors such as corrosion resistance, strength, processing performance, and cost. For instance, food processing equipment and medical devices typically demand highly corrosion-resistant and non-magnetic materials like 304 and 316 stainless steel. These grades offer excellent protection against corrosion and ensure the safety and hygiene of food and medical products.

In contrast, applications such as automobile exhaust pipes and decorative items can opt for more cost-effective options like 403 stainless steel. While 403 stainless steel may not provide the same level of corrosion resistance as 304 or 316, it still offers sufficient durability and aesthetic appeal for these specific uses, making it a practical choice for balancing performance and budget.

Conclusion

In summary, the diverse grades of stainless steel provide modern industry with a rich selection of materials, ensuring that various equipment and components can operate stably in different environments. Understanding the performance characteristics of different grades will help you choose the most suitable material in your project, thereby improving the quality and service life of your products.