Introduction to the properties and applications of SUH409L stainless steel

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1. To improve workability, weldability, and corrosion resistance, low-carbon and stabilizing elements are added. It is a ferrite-based heat-resistant steel containing 11% Cr that maintains a complete BCC structure at both high and room temperatures, offering excellent workability and weldability. It also possesses suitable high-temperature properties and corrosion resistance at room temperature; its main use is as a material for heat-resistant equipment. Properties and Practical Applications: Characteristics of the SUH409L steel grade – high-temperature strength and corrosion resistance at high temperatures, as well as good weldability. Applications – automotive exhaust system components (font pipe, converter shell, center pipe, tail pipe), heat exchangers, heat-resistant equipment, low-grade tableware, electronic components (FDD, casings). Chemical composition: (units: wt%) Specification CSiMnP SCr Others TYPE 409L ≤0.030 ≤1.00 ≤1.00 ≤0.040 ≤0.030 10.50–11.75 Ti: 6×C% – 0.75 Mechanical properties: Specification YS (Mpa) TS (Mpa) EL (%) Hv TYPE 409L ≥175 ≥360 ≥25 ≤175 Density (g/cm3) Magnetic resistance (10-6·W·cm) Specific heat at 250°C (J/kg·°C) Thermal conductivity at 1000°C (W/m·°C) Coefficient of thermal expansion from 20 to 1000°C (10-6/°C) Young’s modulus N/mm2 (10^3) 7.74 59 468 32.91 1.42 01 2. Scope of application: Heat exchangers, heat-resistant equipment, automotive exhaust system components (font pipe, converter shell, center pipe, tail pipe), low-grade tableware, electronic components, containers, etc. 1) Annealed solution-treated states: NO.1, 2D, 2B, and various other surface treatment states. 2) Rolled hard state. 3. Precautions for use 1) Magnetism may occur after cold working ； 2) Among all stainless steels, the grade with the lowest Cr content has relatively poor corrosion resistance ； 3) Although 409L used for containers and 409L used for exhaust pipes have similar chemical compositions, their mechanical properties differ due to variations in the manufacturing processes at steel mills. The elongation rate of stainless steel used for containers is relatively low, making it unsuitable for use in exhaust pipes ； As for the exhaust pipe grade 409L, due to its relatively low hardness and yield strength, it is also not suitable for use in container applications; the two should not be used interchangeably.