SUS410L Stainless Steel: Low-Carbon Martensitic Grade for High-Toughness Applications

SUS410L is a low-carbon martensitic stainless steel (C≤0.03, Cr=11.5%-13.5%) with good weldability and toughness. Compared with standard SUS410, its lower carbon content reduces the risk of cold cracking after welding, and it can obtain balanced strength and toughness through tempering treatment.

Core Parameters

Chemical Composition (wt%): C≤0.03, Si≤1.00, Mn≤1.00, P≤0.040, S≤0.030, Cr=11.50-13.50, Fe=Balance

Mechanical Properties (Quenched & Tempered): Tensile Strength ≥550MPa, Yield Strength ≥380MPa, Elongation ≥20%, Hardness 25-30HRC

Service Temperature: -40℃ to 400℃ (continuous service)

Equivalent Grades: EN 1.4003, UNS S41003, GB 022Cr12

Performance Advantages: Low carbon content ensures excellent weldability without preheating or post-weld heat treatment; good toughness at low temperatures (impact toughness ≥40J at -40℃); moderate corrosion resistance in atmospheric environments; magnetic, suitable for magnetic component applications.

Typical Applications: Low-pressure valve bodies, pump casings, hydraulic components, food machinery parts, surgical instrument trays, magnetic separators, automotive brake components.

Practical Q&A

Q1: What is the difference between SUS410L and SUS410? A1: The core difference is carbon content: SUS410L (C≤0.03%) vs. SUS410 (C=0.15%-0.25%). SUS410L has better weldability and toughness, while SUS410 can obtain higher hardness (up to 45HRC) after heat treatment, with better wear resistance.

Q2: Can SUS410L be used in low-temperature environments? A2: Yes. It can be used stably at -40℃, with impact toughness ≥40J, which is much higher than SUS410 (impact toughness ≤20J at -40℃). It is suitable for low-temperature mechanical components in cold regions.

Q3: What heat treatment process is suitable for SUS410L? A3: For high toughness: annealing at 780-830℃, air cooling, hardness ≤180HB; for balanced strength and toughness: quenching at 950-1000℃, oil cooling + tempering at 200-300℃, hardness 25-30HRC.

Q4: Is SUS410L suitable for food contact applications? A4: Yes. It meets the food safety standards (such as FDA 21 CFR 175.300) after passivation treatment. It is suitable for food machinery parts such as mixing blades and storage tanks that do not contact acidic foods for a long time.

Q5: How to improve the corrosion resistance of SUS410L? A5: Perform passivation treatment with 20% nitric acid solution (room temperature, 30 minutes) after processing to form a dense chromium oxide film; apply anti-rust oil or paint for surface protection in humid environments; avoid contact with chloride ion-containing media.