Mechanical Properties of Low Chromium Ferritic Stainless Steel 0Cr11Ti(AISI409), 00Cr11Ti(AISI409L)

Low Chromium Ferritic Stainless Steel 0Cr11Ti (AISI 409) and 00Cr11Ti (AISI 409L) Introduction Low chromium ferritic stainless steels, 0Cr11Ti (AISI 409) and 00Cr11Ti (AISI 409L) are low carbon and low cost materials that are widely used in many industries. Different surface treatments can be used to enhance their corrosion resistance properties. These steels are suitable for a variety of automotive and industrial applications. This article provides an overview of the mechanical properties of 0Cr11Ti (AISI 409) and 00Cr11Ti (AISI 409L) and discusses the surface treatments that can be used to boost their corrosion resistance. Chemical Composition 0Cr11Ti (AISI 409) and 00Cr11Ti (AISI 409L) are low-chromium ferritic steels with the following chemical compositions (Table 1). Table 1. Chemical composition of 0Cr11Ti (AISI 409) and 00Cr11Ti (AISI 409L) AISI 409 0Cr11Ti AISI 409L 00Cr11Ti C 0.08 0.03 Si max. 1.00 max. 1.00 Mn max. 1.00 max. 1.00 P max. 0.040 max. 0.040 S max. 0.030 max. 0.030 Cr 4-6 ≤ 0.75 Ti 0.3 ≤ 0.75 N max. 0.1 max. 0.1 Mechanical Properties 0Cr11Ti (AISI 409) and 00Cr11Ti (AISI 409L) exhibit a range of mechanical properties that depend on their composition. The maximum tensile strength and yield strength of 0Cr11Ti (AISI 409) are 420 MPa and 325 MPa, respectively, and for 00Cr11Ti (AISI 409L), they are 395 MPa and 275 MPa, respectively. Both steels have an ultimate elongation of about 23%. The impact energy of 0Cr11Ti (AISI 409) is around 12 Joules and for 00Cr11Ti (AISI 409L) it is 10 Joules (Table 2). Table 2. Mechanical properties of 0Cr11Ti (AISI 409) and 00Cr11Ti (AISI 409L) AISI 409 0Cr11Ti AISI 409L 00Cr11Ti Tensile Strength 420 MPa 395 MPa Yield Strength 325 MPa 275 MPa Ultimate Elongation 23% 23% Impact Energy 12 Joules 10 Joules Surface Treatments 0Cr11Ti (AISI 409) and 00Cr11Ti (AISI 409L) exhibit a good combination of corrosion resistance and mechanical strength. However, their performance in corrosive environments can be further improved by using various surface treatments. These steels can be treated by passivation or pickling, electrochemical polishing, etc. In addition, these steels can also be coated with zinc, aluminium or other metals to improve their corrosion resistance.Conclusion Low chromium ferritic stainless steels, 0Cr11Ti (AISI 409) and 00Cr11Ti (AISI 409L) are low carbon and low cost materials that are widely used in many industries. They exhibit good mechanical properties and have a range of surface treatments available to enhance their corrosion resistance properties. These steels are suitable for a variety of automotive and industrial applications.

AISI409 and AISI409L are low chromium ferritic stainless steel. The American Iron and Steel Institute (AISI) uses a three-letter alphanumeric system for the identification of different grades of steel, and the first two digits specify the family of the steels. AISI409 (00Cr11Ti) and AISI409L (00Cr11Ti) are different from each other and are two low chromium ferritic stainless steels.

These two types of steels vary in their mechanical properties due to the differences in their chemical composition and heat treatment methods. AISI409 has a higher chromium content of 10.50-11.75 %, compared to the lower content of AISI409L which is 8.25-9.50 %. This variation in chromium content affects the corrosion resistance and mechanical properties of the two type of steels.

The tensile strength of AISI409 steel is 550MPa and its yield strength is 310MPa. This steel also offers 10-50 % improvement in formability as compared to low carbon ferritic stainless steel. AISI409L is stronger and more ductile as compared to AISI409. It has a tensile strength of 500MPa and its yield strength is 305MPa. Although softer due to its lower chromium content, AISI409L provides improved weldability and resistance to stress-corrosion cracking.

AISI409 and AISI409L are also susceptible to sensitization when exposed to temperatures greater than 700℃. The lower chromium content in AISI409L reduces its resistance to intergranular corrosion, which can be a problem if the steel is exposed to temperatures below 525-815 ℃.

In conclusion, AISI409 and AISI409L are two low chromium ferritic stainless steels with differing mechanical properties based on their chromium content. Both steels offer good corrosion resistance and formability, but are vulnerable to sensitization at high temperatures. They should both be used in low temperature applications.