Introduction to the Processing Performance of 409L
409L－022Cr11Ti
In order to improve workability, weldability, and corrosion resistance, a stabilizing element Ti is added, which has excellent weldability and workability and maintains a complete BCC structure at high and normal temperatures.
1. Features and Application:
| Grade | Characteristics | Application |
|---|---|---|
| Type 409L | High temperature strength and high temperature corrosion resistance, good weldability | Automobile exhaust pipe parts, heat exchangers, heat-resistant equipment, low-grade tableware |
2. Chemical composition:
| Distinguish | C | Si | Mn | P | S | Cr | Other |
|---|---|---|---|---|---|---|---|
| Type 409L | ≤0.03（0.009） | ≤1.00（0.6） | ≤1.0（0.2） | ≤0.040（0.021） | ≤0.03（0.002） | 10.5～11.75（16.2） | Ti：6*C%～0.75（0.2） |
3. Mechanical properties:
| Distinguish | YS（MPa） | TS（MPa） | EL（%） | Hv | Note |
|---|---|---|---|---|---|
| Type 409L | ≥175（230） | ≥360（425） | ≥25（34） | ≤175（135） | No.2D/0.6t |
4. Process performance:
Welding performance: 409L has excellent corrosion resistance in relatively weak corrosive environments, such as the atmosphere and fresh water. In a boiling solution containing trace amounts of HCl, its corrosion resistance is lower than 0Cr13, 00Cr13, and also lower than 0Cr17 steel. There is a wide range of acid resistance. In the simulated car muffler condensate environment, the corrosion rate decreases with the increase of Cr. When Cr≥11%, the corrosion rate drops very low. Therefore, 409L has replaced aluminized steel in modern automobile exhaust systems.
Oxidation resistance: 409L has better high-temperature oxidation resistance than mild steel (low carbon steel). The intermittent high-temperature use temperature is 815℃, and the continuous use temperature is 675℃. It is not suitable for use in harsh environments. The oxidation resistance of 409L is better than 0Cr13Al and 00Cr13.
Processing performance and heat treatment: the starting temperature of hot working is 1100~1150℃, the coiling temperature is ~600℃, and the hot-rolled strip is annealed 830~870℃X8h in the bell furnace. The cold-rolled strip is treated on the continuous annealing and pickling of the cold wire or mixed wire, and the temperature should be controlled at 860±10℃. The current input during welding should be small to avoid excessive crystal grain growth and reduce the plastic toughness of the weld and heat-affected zone.