QN1803 stainless Steel
In the traditional stainless steel industry, 304 stainless steel has long dominated. However, its relatively high nickel content (approximately 8%) presents two major issues: high cost and limited strength.
QN1803 stainless steel is a new high-performance nickel-saving austenitic stainless steel developed under these circumstances by Tsingshan Group, aiming to achieve superior overall performance compared to 304 at a lower cost. The core design concept is to replace the conventional "high-nickel" approach with a "high-nitrogen, low-nickel" composition, significantly enhancing strength and reducing costs while maintaining or even improving corrosion resistance. This article systematically introduces the composition design, mechanical properties, corrosion resistance, processability, and application prospects of QN1803.
Chemical composition: Replace nickel with nitrogen
The basic chemical composition of QN1803 stainless steel:Cr:18.2%、Ni:3.0%、Mn:6.2%、Cu:1.65%、N:0.24%.Compared with 304 (8.0%Ni), the nickel content of QN1803 has decreased by approximately 60%. This is the direct reason for the cost reduction of QN1803.
The reduction of nickel is not a simple subtraction process; instead, it is precisely compensated through three key elements:
N: Nitrogen is a strong element for forming austenite and also a solid solution strengthening element. With a nitrogen content of 0.24%, not only does it compensate for the loss of austenite stability caused by the reduction of nickel, but it also provides significant solid solution strengthening and fine-grain strengthening effects.
Mn: Manganese is a relatively weak element for forming austenite. Its main function is to increase the solubility of nitrogen in the molten steel, making it possible to have high nitrogen content.
Cu: The addition of copper is to improve the corrosion resistance in reducing acids (such as dilute sulfuric acid).
Mechanical properties: Strength doubles
The mechanical properties are the most outstanding feature of QN1803 stainless steel. The yield strength of QN1803 is 1.5 times that of 304 stainless steel, reaching the level of carbon steel Q355. Meanwhile, the elongation rate remains above 50%.
| Performance | QN1803 stainless steel | 304 stainless steel |
| YS | 425 MPa | 285 MPa |
| TS | 755 MPa | 680 MPa |
| EL | 51% | 58% |
| HV | 215 | 165 |
Corrosion Resistance:compare with 304 stainless steel
Corrosion resistance is the most important characteristic of stainless steel. The QN1803 stainless steel has a lower nickel content, and thus its overall corrosion resistance is not as good as that of 304 stainless steel. However, in certain conditions, its corrosion resistance is higher than that of 304 stainless steel. For example:
- After undergoing 60% cold rolling deformation, the pitting corrosion resistance of QN1803 stainless steel is 1.15 times that of 304 stainless steel .
- In a 5% dilute sulfuric acid solution, a copper protective film forms on the surface of QN1803 stainless steel , and its corrosion resistance is 6.6 times that of 304 stainless steel.
Good industrial applicability
Cold working performance: QN1803 stainless steel is a steady-state austenitic stainless steel with low cold work hardening degree. The risk of stress cracking in the products is lower than that of 304 stainless steel.
Strength regulation potential: Through cold rolling and low-temperature annealing treatment, QN1803 stainless steel can achieve heterogeneous structures ranging from nanometer to micrometer scales, and the yield strength can be further increased to 1130 MPa while maintaining a certain degree of ductility.
Welding performance: Research on the pulsed TIG welding joints has confirmed that QN1803 stainless steel has excellent weldability and has been widely applied in fields such as architectural decoration, medical devices, and household appliances.
The application of QN1803 stainless steel
At present, QN1803 stainless steel has been widely used in architectural decoration, household appliances, kitchen and bathroom facilities, engineering equipment, fire protection and air conditioning water systems, and fasteners, etc.
Conclusion
QN1803 stainless steel is a new generation of nickel-reducing austenitic stainless steel developed based on the concept of "replacing nickel with nitrogen". It has a nickel content approximately 60% lower than that of 304, yet it achieves a yield strength increase of about 50% and an elongation rate of no less than 50%. Moreover, in some cases, its corrosion resistance is even better than that of 304 stainless steel.
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Post time: Jul-07-2026
