Introduction
Stainless steel is a metal alloy that contains iron, carbon, and other elements such as chromium, nickel, and molybdenum. It is widely used for various purposes, such as automotive exhaust systems, catalytic converters, mufflers, and other equipment. However, there are different types of stainless steel that have different properties and characteristics.
In this blog post, we will introduce you to stainless steel SUS409L, which is a type of ferritic stainless steel that has improved oxidation and corrosion resistance compared to carbon steel. We will also answer some common questions about stainless steel SUS409L, such as its chemical composition, mechanical properties, physical properties, processing method, characteristics, and applications.
What is SUS409L?
Stainless steel SUS409L is also known as UNS S40900 or EN 1.4512. It is a stabilized ferritic stainless steel that contains chromium and some amount of nitrogen and carbon. It is a low-cost grade of stainless steel that is widely used in automotive exhaust systems and other applications that require good weldability and corrosion resistance.
What is the Chemical Composition of SUS409L?
The chemical composition of stainless steel SUS409L is given in the table below:
| Element | Content (%) |
| Iron | Balance |
| Chromium | 10.5-11.75 |
| Carbon | 0.03 max |
| Manganese | 1 max |
| Silicon | 1 max |
| Phosphorus | 0.045 max |
| Sulfur | 0.045 max |
| Nitrogen | 0.03 max |
| Titanium | 6xC min |
What are the Mechanical Properties of SUS409L?
The mechanical properties of stainless steel SUS409L are given in the table below:
| Property | Value |
| Tensile Strength (MPa) | 380 min |
| Yield Strength (MPa) | 170 min |
| Elongation (%) | 20 min |
| Hardness (Rockwell B) | 88 max |
What are the Physical Properties of SUS409L?
The physical properties of stainless steel SUS409L are given in the table below:
| Property | Value |
| Density (kg/m3) | 7800 |
| Elastic Modulus (GPa) | 200 |
| Coefficient of Thermal Expansion (μm/m/°C) | 10.8 (0-100°C) |
| Thermal Conductivity (W/m.K) | 25 (100°C) |
| Specific Heat Capacity (J/kg.K) | 460 (0-100°C) |
| Electrical Resistivity (μΩ.m) | 600 |
What is the Processing Method of SUS409L?
Stainless steel SUS409L can be processed by various methods, such as:
Hot forming: Stainless steel SUS409L can be hot formed at temperatures between 900°C and 1200°C. It should be cooled rapidly after forming to avoid cracking.
Cold forming: Stainless steel SUS409L can be cold formed by bending, drawing, or pressing. It has good ductility and formability.
Machining: Stainless steel SUS409L can be machined by conventional methods. It has good machinability due to its low hardness and sulfur content.
Welding: Stainless steel SUS409L can be welded by shielded fusion and resistance techniques. It has good weldability due to its low carbon and nitrogen content. Preheating and post-weld annealing are not required.
Annealing: Stainless steel SUS409L can be annealed at temperatures between 790°C and 900°C for improved ductility and toughness. It should be cooled rapidly after annealing to avoid grain growth.
What are the Characteristics of SUS409L?
Corrosion resistance: Stainless steel SUS409L has a high chromium content that forms a protective layer on the surface, preventing rust and oxidation. It has good resistance to exhaust gas and atmospheric corrosion.
Oxidation resistance: Stainless steel SUS409L has a titanium content that forms a stable oxide layer on the surface, preventing further oxidation at high temperatures. It has good resistance to scaling and thermal fatigue.
Weldability: Stainless steel SUS409L has a low carbon and nitrogen content that reduces the risk of intergranular corrosion and carbide precipitation in the weld zone. It has good weldability without preheating or post-weld annealing.
Cost: Stainless steel SUS409L is a low-cost grade of stainless steel that is widely available and easy to process. It has a lower nickel content than other stainless steels, which reduces its cost and price volatility.
What is the Application of SUS409L?
Stainless steel SUS409L is mainly used for automotive exhaust systems, such as mufflers, catalytic converters, tailpipes, and manifolds. It is also used for other applications that require good corrosion resistance and weldability, such as heat exchangers, boilers, gas heaters, and flanges.
| Application | Reason |
| Automotive exhaust systems | Good corrosion resistance and weldability, high chromium and titanium content, low cost |
| Heat exchangers | Good corrosion resistance and weldability, high chromium and titanium content, good thermal conductivity |
| Boilers | Good corrosion resistance and weldability, high chromium and titanium content, good thermal conductivity |
| Gas heaters | Good corrosion resistance and weldability, high chromium and titanium content, good thermal conductivity |
| Flanges | Good corrosion resistance and weldability, high chromium and titanium content, good strength and durability |
Conclusion
Stainless steel SUS409L is a type of ferritic stainless steel that has improved oxidation and corrosion resistance compared to carbon steel. It has good weldability and machinability, and it is a low-cost grade of stainless steel. It is widely used for automotive exhaust systems and other applications that require good corrosion resistance and weldability.
If you are looking for a stainless steel that has these characteristics, you should consider using stainless steel SUS409L for your project. You can find high-quality stainless steel SUS409L products at Metal Scope, a leading supplier of stainless steel products in India. Contact us today to get a quote or to learn more about our products and services.
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