SUS410L Stainless Steel: Low-Carbon Martensitic Grade with Excellent Weldability & Toughness

SUS410L is a low-carbon martensitic stainless steel (C≤0.03%) based on SUS410, with chromium content of 11.5%-13.5%. The low carbon design greatly improves its weldability and low-temperature toughness, avoiding cold cracking after welding without complex preheating or post-weld heat treatment. It is a cost-effective material for low-corrosion, high-toughness mechanical components.

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%, Brinell Hardness ≤180HB (annealed) / 25-30HRC (quenched-tempered)

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

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

Performance Advantages: Outstanding weldability, no preheating required for thin plates (≤6mm) welding; excellent low-temperature toughness, impact toughness ≥40J at -40℃, avoiding brittle fracture in cold regions; moderate corrosion resistance in atmospheric and fresh water environments; magnetic, suitable for magnetic component applications; low cost, easy to process in annealed state.

Typical Applications: Low-pressure valve bodies and bonnets, pump casings and impellers for clean water, hydraulic system components, food machinery brackets and trays, surgical instrument accessories, automotive brake calipers, magnetic separators in mining industry.

Practical Q&A

Q1: What is the core difference between SUS410L and standard SUS410? A1: The key is carbon content: SUS410L (C≤0.03%) vs. SUS410 (C=0.15%-0.25%). SUS410L eliminates the risk of cold cracking after welding, has 2-3 times higher low-temperature toughness, but lower maximum hardness (≤30HRC vs. ≤45HRC of SUS410) and slightly weaker wear resistance.

Q2: Can SUS410L be used in low-temperature outdoor equipment in cold regions? A2: Yes. It can stably work at -40℃, and its impact toughness at this temperature is ≥40J, which meets the requirements of low-temperature mechanical components. It is suitable for outdoor hydraulic valves and pump parts in alpine regions.

Q3: What welding materials and processes are recommended for SUS410L? A3: Use ER410L welding wire (for TIG/MIG welding) or E410L-16 electrode (for SMAW welding). Control welding heat input ≤150J/mm to avoid grain coarsening; no preheating for thin plates, preheat to 100-150℃ for thick plates (≥8mm); no post-weld heat treatment is required.

Q4: How to adjust the heat treatment process of SUS410L to balance strength and toughness? A4: For high toughness demand: Anneal at 780-830℃, air cool, hardness ≤180HB. For balanced strength and toughness: Quench at 950-1000℃, oil cool + temper at 200-300℃, air cool, hardness 25-30HRC. Avoid tempering at 350-500℃ to prevent temper brittleness.

Q5: Is SUS410L suitable for food contact applications? A5: Yes. After passivation treatment with 20% nitric acid solution, it meets food safety standards (such as FDA 21 CFR 175.300). It is suitable for food machinery parts that do not contact strong acids for a long time, such as mixing tank brackets and conveying roller shafts.