EN 1.4307 Stainless Steel: Guide to Properties, Uses & Fabrication

If you need a stainless steel that resists intergranular corrosion—especially after welding—EN 1.4307 stainless steel is an excellent choice. As the low-carbon version of EN 1.4301 (AISI 304), it’s perfect for industries like food processing and pharmaceuticals where corrosion resistance and hygiene matter most. This guide covers everything from its specs to real-world applications, helping you make informed decisions for your projects.

1. EN 1.4307 Stainless Steel: Overview & Key Specifications

Let’s start with the basics of EN 1.4307 stainless steel—its composition, standards, and core properties.

Chemical Composition

The EN 1.4307 composition is defined by its low carbon content (max 0.03%), which sets it apart from EN 1.4301. It also contains 18–20% chromium (for corrosion resistance) and 8–12% nickel (for its austenitic structure), plus small amounts of manganese (max 2.0%) and silicon (max 1.0%). This low-carbon blend is the key to its resistance to intergranular corrosion.

Industry Standards & Equivalents

EN 1.4307 follows strict global standards to ensure consistency:

• 1.4307 AISI 304L equivalent: It’s the direct European counterpart to AISI 304L, so they can be used interchangeably in most projects.
• 1.4307 UNS S30403: The Unified Numbering System identifier, used in North America.
• 1.4307 ASTM A240: ASTM standard for plates and sheets, and 1.4307 EN 10088-2: European standard for flat products (sheets/plates).

Physical & Mechanical Properties

Below is a table of critical properties that make EN 1.4307 stainless steel ideal for corrosion-sensitive applications:

Example: A dairy processor uses EN 1.4307 stainless steel for milk storage tanks. Its low-carbon austenitic structure resists corrosion from milk acids, and its smooth surface is easy to clean—meeting food safety standards.

2. Corrosion Resistance & Environmental Performance

EN 1.4307 stainless steel’s biggest advantage is its strong corrosion resistance, especially against intergranular corrosion.

Key Corrosion Behaviors

• 1.4307 intergranular corrosion immunity: Its low carbon content prevents carbide precipitation at grain boundaries, so it won’t corrode along grain edges—even after welding.
• 1.4307 sensitization prevention: Unlike EN 1.4301, it doesn’t become “sensitized” (prone to intergranular corrosion) when heated, making it ideal for welded parts.
• 1.4307 PREN ~18: The Pitting Resistance Equivalent Number (PREN) of ~18 means it handles mild chlorides (e.g., indoor plumbing) well.
• 1.4307 atmospheric corrosion: Excellent resistance to dry, humid, and urban air. It’s used for architectural cladding that stays rust-free for decades.

Critical Corrosion Considerations

• 1.4307 chloride pitting resistance: Low risk in clean, low-chloride environments, but avoid high-chloride settings (e.g., saltwater pools) — use EN 1.4404 (AISI 316L) for those.
• 1.4307 crevice corrosion threshold: Avoid tight crevices (e.g., unsealed bolts) in wet areas—they can trap moisture and cause pitting.
• 1.4307 seawater limits: Can handle occasional seawater splashes (e.g., coastal building trim) but not full submersion.
• 1.4307 vs 1.4301 corrosion comparison: Both offer similar general corrosion resistance, but EN 1.4307 is far better at resisting intergranular corrosion after welding.

Case Study: A pharmaceutical company uses EN 1.4307 stainless steel for drug mixing tanks. The tanks are welded, and EN 1.4307’s intergranular corrosion immunity ensures no rust forms in weld areas—critical for keeping drugs pure.

3. Heat Treatment & Microstructure Stability

Proper heat treatment helps maintain EN 1.4307 stainless steel’s corrosion resistance and microstructure stability.

Common Heat Treatment Processes

Critical Considerations

• 1.4307 carbide precipitation avoidance: Its low carbon content means carbide precipitation (which causes intergranular corrosion) is almost impossible—even if heat treatment is slightly off.
• 1.4307 grain growth control: Solution annealing at 1000–1100 °C keeps grain sizes small (ASTM 5–8), balancing strength and ductility.
• 1.4307 cold working strain hardening: Cold working (like bending) increases hardness, but it won’t reduce corrosion resistance—unlike some other grades.
• 1.4307 magnetic permeability after cold work: It may become slightly magnetic after heavy cold working, but this doesn’t affect its corrosion resistance or strength.

Example: A manufacturer of heat exchanger tubes uses EN 1.4307 stainless steel. They solution anneal the tubes at 1050 °C and water quench to ensure carbide precipitation avoidance—the tubes resist corrosion from coolants for 10+ years.

4. Welding, Fabrication & Machining Guidelines

EN 1.4307 stainless steel is easy to weld and fabricate, making it popular for complex parts.

Welding Tips

• 1.4307 weldability rating: Excellent (rated 9/10)—it welds well with TIG, MIG, and stick methods.
• 1.4307 no preheat required: Unlike martensitic grades (e.g., 410), it doesn’t need preheating, saving time and money.
• 1.4307 filler metal ER308L: Use this low-carbon filler to match the base metal’s corrosion resistance—avoid high-carbon fillers like ER308.
• 1.4307 post-weld cleaning passivation: While not mandatory (thanks to its intergranular corrosion immunity), passivation (with nitric acid) boosts general corrosion resistance by 30–40%.

Machining & Fabrication

• 1.4307 machining speeds and feeds: Use speeds of 150–250 m/min (turning) and feeds of 0.1–0.3 mm/rev—avoid overheating, which can reduce tool life.
• 1.4307 tool life with carbide inserts: Carbide tools last 2–3x longer than high-speed steel (HSS) when machining EN 1.4307.
• 1.4307 formability deep drawing: Excellent—its austenitic structure lets it be deep-drawn into shapes like food cans or sink basins without cracking.
• 1.4307 distortion control techniques: Use clamps during welding and uniform heating during forming to minimize distortion.

Case Study: A kitchen appliance maker uses EN 1.4307 stainless steel for dishwasher interiors. They deep-draw the metal into curved shapes (thanks to its formability deep drawing) and weld seams without preheating—producing 10,000+ interiors per month with no defects.

5. Product Forms, Sizes & Supply Chain

EN 1.4307 stainless steel is available in many forms to fit different applications—here’s what you can find.

Common Product Forms

• 1.4307 stainless steel plate thicknesses: 3–200 mm (used for chemical storage tanks, structural parts).
• 1.4307 sheet gauge chart: 26 gauge (0.45 mm) to 8 gauge (4.0 mm) (used for kitchen appliances, pharmaceutical equipment).
• 1.4307 seamless pipe EN 10216-5: Sizes ½–24 inches (used for pharmaceutical and food processing piping).
• 1.4307 welded tube EN 10217-7: Sizes ½–12 inches (used for plumbing, brewery lines).
• 1.4307 round bar stock: Diameters 5–300 mm (used for fasteners, shafts).

Supply Chain Tips

• 1.4307 angle iron sizes: Common sizes include 20x20x3 mm to 100x100x10 mm (used for structural supports in food facilities).
• 1.4307 coil slit widths: 50–1600 mm (used for mass-produced parts like heat exchanger fins).
• 1.4307 flat bar tolerances: Most suppliers offer tolerances of ±0.1 mm for thickness—ideal for precision parts like pharmaceutical equipment components.
• 1.4307 hollow bar suppliers: Look for ISO 9001-certified suppliers to ensure consistent wall thickness and corrosion resistance.

6. Industry Applications & Case Studies

EN 1.4307 stainless steel is used in industries where corrosion resistance (especially after welding) and hygiene are critical.

Key Applications

• 1.4307 food processing equipment: Mixers, conveyors, and storage bins—its corrosion resistance handles food acids, and it’s easy to sanitize.
• 1.4307 brewery tanks: Stores beer and wort without adding metallic tastes—resists corrosion from hops and yeast.
• 1.4307 pharmaceutical piping: Transports drugs and solvents—meets strict hygiene standards and resists chemical corrosion.
• 1.4307 dairy processing: Milk tanks and pipelines—its smooth surface prevents bacterial growth.
• 1.4307 cryogenic vessels: Stores liquids at very low temperatures (down to -196 °C)—its austenitic structure stays ductile even in cold.

Real-World Example: A brewery uses EN 1.4307 stainless steel for 10,000-liter fermentation tanks. The tanks are welded, and EN 1.4307’s sensitization prevention ensures no rust forms in welds. After 5 years of use, the tanks still look new and produce consistent-tasting beer.

Yigu Technology’s Perspective on EN 1.4307 Stainless Steel

At Yigu Technology, we supply EN 1.4307 stainless steel to food, pharmaceutical, and dairy clients globally. Its low-carbon design and intergranular corrosion immunity make it perfect for welded parts like tanks and piping. We offer custom cuts (e.g., mirror finish sheets for architectural projects) and provide certification documents to meet industry standards. For food clients, we ensure our EN 1.4307 meets FDA requirements, so their equipment is safe and durable.

FAQ About EN 1.4307 Stainless Steel

1. Is EN 1.4307 stainless steel magnetic?
   No—unless it’s heavily cold-worked. Its 1.4307 low-carbon austenitic structure is non-magnetic, but heavy bending or stamping can make it slightly magnetic. This doesn’t affect its corrosion resistance or strength.
2. When should I use EN 1.4307 instead of EN 1.4301?
   Use EN 1.4307 if your project involves welding. EN 1.4307’s intergranular corrosion immunity means it won’t corrode along welds, while EN 1.4301 may become sensitized and prone to intergranular corrosion after welding.
3. Can EN 1.4307 be used in high-temperature applications?
   Yes—it has good 1.4307 oxidation resistance up to 870 °C. It’s used for heat exchanger tubes and oven parts, but avoid temperatures above 900 °C for long periods—this can reduce its strength.