SUS441 ( 022Cr18NbTi ) ferritic stainless steel has a very low carbon and nitrogen content and a small amount of beneficial alloying elements Nb and Ti. The lattice structure of SUS441 ( 022Cr18NbTi ) ferritic stainless steel is body-centered cubic, and its octahedral gap radius is only 0.15 times the radius of Fe atom (the face-centered cubic is 0.414 times), and the ability to contain interstitial compound particles is poor. Therefore, the carbonitride particles of Nb and Ti are easily dispersed in the base metal, which improves the overall performance of the stainless steel.
Specification:
The affinity of Ti and N in stainless steel is greater than that of Nb. The affinity of Nb and C is greater than C. Therefore, there are a large number of dispersed TiN and NbC second phase particles in 022Cr18NbTi ferritic stainless steel. These particles not only play the role of second phase strengthening. At the same time, during the welding thermal cycle, these particles which are also stable at high temperatures play a role in suppressing excessive coarsening of the grains and improve the weldability of the material (3). Under the conditions of appropriate welding process parameters, the grain size of the weld and heat affected zone can be controlled to above grade 4, and has good mechanical properties to meet the requirements of use.
1. Summary Very low C, N, adding Ti and Nb to improve the high temperature strength, corrosion resistance, weldability and processability of the material. Steel grade specially developed by TISCO.
2. Characteristics 1) high temperature corrosion resistance; 2) weldability; 3) high temperature strength; 4) magnetic; 5) excellent processability.
3.The scope of application of the exhaust system of the exhaust system of the car, the front tube, CONVERTER and so on.
Futures:
Ferrite stainless steel performance requirements for high temperature end of automotive exhaust system The ambient temperature of the manifold and front tube of the automotive exhaust system can reach 750~900, and the local temperature may reach 950. The high temperature performance of the material such as high temperature strength and high temperature Fatigue performance requirements are high.
However, as the emission level increases, the engine performance increases, the exhaust temperature
rises, and because of the need to reduce the weight of components, especially for the three-way catalytic device, the use of ferritic stainless steel manifolds can quickly improve the catalytic efficiency.
Second, the high-temperature end of the exhaust system of the automobile exhaust (exhaust manifold) with ferritic stainless steel. The ferritic stainless steel currently used for the high-temperature end mainly has 429, 441, 444, of which Japanese cars mainly use 429 and 444, mainly in Europe and America. Use 441.
Surface and Application:
| Surface | Definition | Application |
| 2B | Those finished, after cold rolling, by heat treatment, pickling or other equivalent treatment and lastly by cold rolling to given appropriate luster. | Medical equipment, Food industry, Construction material, Kitchen utensils. |
| BA/8K mirror | Those processed with bright heat treatment after cold rolling. | Kitchen utensils, Electric equipment, Building construction. |
| NO.3 | Those finished by polishing with No.100 to No.120 abrasives specified in JIS R6001. | Kitchen utensils, Building construction. |
| NO.4 | Those finished by polishing with No.150 to No.180 abrasives specified in JIS R6001. | Kitchen utensils, Building construction, Medical equipment. |
| Hairline | Those finished polishing so as to give continuous polishing streaks by using abrasive of suitable grain size. | Building Construction. |
| NO.1 | The surface finished by heat treatment and pickling or processes corresponding there to after hot rolling. |
