SS400 ist eine weit verbreitete Kohlenstoffstahlsorte gemäß der Norm JIS G3101, geschätzt für seine ausgewogenen mechanischen Eigenschaften, Schweißbarkeit, und Wirtschaftlichkeit bei Hochbauprojekten. Ingenieure und Hersteller suchen häufig nach SS400-Materialeigenschaften, um Designs zu validieren, Äquivalente vergleichen, und stellen Sie sicher, dass alle internationalen Standards eingehalten werden. Dieser Leitfaden bietet einen umfassenden Überblick aus Herstellersicht, Wir helfen Ihnen bei der Auswahl und effektiven Anwendung von SS400 in realen Anwendungen.
Was ist SS400-Material??
SS400 stellt einen grundlegenden Kohlenstoffbaustahl in der Spezifikation JIS G3101 dar, werden hauptsächlich als warmgewalzte Bleche geliefert, Abschnitte, und Stangen für den allgemeinen Bau- und Maschinenbau. Der “SS” Präfix gibt an “Baustahl,” während “400” nähert sich seiner Mindestzugfestigkeit in MPa an, distinguishing it from higher grades like SS490 or SS540. This grade’s design philosophy prioritizes versatility over specialized performance, making it a staple in Japanese and exported structural projects since the 1970s.
Its chemical makeup as a low-carbon steel features no rigid caps on carbon (typically ≤0.25%) or manganese (≤1.50%), but stringent limits on phosphorus (P ≤0.050%) und Schwefel (S ≤0.050%) to curb brittleness and promote ductility. The resulting carbon equivalent (CE ≈0.35-0.40 per IIW formula) ensures low hardenability during welding, minimizing risks of cold cracking. Manufacturers appreciate this predictability, as it supports consistent fabrication without extensive pre- or post-weld treatments, even in multi-pass joints up to 40 mm thick.
Mechanical Properties of SS400 Material
Tensile, Yield Strength and Elongation
- Zugfestigkeit: 400–510 MPa, providing robust load capacity for beams and columns.
- Streckgrenze: Minimum 245 MPa (base value for thin sections), with actual values often 10-20% higher in modern mills.
- Verlängerung: 17–21% (gauge length 5.65√A), indicating sufficient ductility for seismic or impact-prone designs.
Thickness Effect on Yield Strength
Thickness profoundly influences SS400’s performance due to grain size and cooling rate variations in rolling. JIS G3101 mandates conservative minima to reflect real-world variability.
| Thickness (T) | Min. Streckgrenze (MPa) | Design Implication |
|---|---|---|
| ≤ 16 mm | ≥ 245 | Optimal for light frames; max allowable stress ~165 MPa (FS=1.5) |
| 16–40 mm | ≥ 235 | Common for beams; adjust buckling calcs downward |
| 40–100 mm | ≥ 215 | Heavy girders; increase section sizes for same load |
| > 100 mm | ≥ 205 | Foundations; verify with UT for laminations |
Ingenieure müssen die genaue Dicke anhand von Zeichnungen und MTRs angeben – wenn sie dies außer Acht lassen, können die Materialkosten in die Höhe getrieben oder die Sicherheitsmargen beeinträchtigt werden.
Physikalische Eigenschaften und Verarbeitbarkeit
Die physikalischen Eigenschaften des SS400 ermöglichen präzise technische Simulationen, während seine Verarbeitbarkeit die Fertigungsabläufe rationalisiert. Dichte bei 7850 kg/m³ ermöglicht genaue Massenschätzungen für Kräne und Fundamente, mit dem Elastizitätsmodul von 200-210 GPa liefert vorhersagbare Steifigkeit bei Durchbiegungsberechnungen. Wärmeausdehnungskoeffizient (11.7 × 10⁻⁶/K) und Leitfähigkeit (51-60 W/m · k) unterstützen die Modellierung thermischer Spannungen in beheizten Strukturen.
Für die Verarbeitbarkeit:
- Schweißbarkeit: CE <0.40 ermöglicht Mehrlagenschweißen ohne Vorwärmen (bis zu 20 mm); Verwenden Sie für Filets E4303-Elektroden.
- Verarbeitbarkeit: Vorschübe/Geschwindigkeiten ähnlich wie Weichstahl (120 m/min Hartmetalldrehen); geringer Werkzeugverschleiß für Prototypen.
- Formbarkeit: Biegeradien ≥2t für 90°-Bögen, kalt verarbeitbar bis 10 mm thick.
These traits reduce shop time by 20-30% versus higher-strength steels, per industry benchmarks.
Corrosion Protection and Surface Treatments
Unprotected SS400 corrodes at 50-100 µm/year in C3 atmospheres (urban/industrial), accelerating to 200+ µm/year near coasts due to chlorides. Pitting under coatings poses hidden risks, potentially halving design life without intervention. Standards like ISO 9223 classify exposures, guiding protection levels from rural (C2) to offshore (C5M).
Recommended strategies include:
- Galvanizing: 85 µm zinc (ISO 1461) for 25+ years in C4; duplex with paint for C5.
- Organic Coatings: Epoxy primer (80 µm) + PU topcoat (60 µm); inspect every 5 Jahre.
- Metallizing: Arc-sprayed aluminum (150 µm) for high-heat or abraded areas.
Prep via Sa 2.5 blasting ensures adhesion >5 MPa. Lifecycle analysis often favors galvanizing for 50-year bridges, balancing upfront costs with minimal maintenance.
Equivalent Grades and Global Standards
| Region/Standard | Grad | Key Similarities | Differences from SS400 |
|---|---|---|---|
| USA | ASTM A36 | Tensile 400-550 MPa; Yield ≥250 MPa (t≤200 mm) | More chemistry specs; optional NDT |
| China | GB/T 700 Q235B | Similar strength; good weldability | Impact tested; yield sub-grades (A/B/C/D) |
| Europa | IN 10025 S235JR | Yield ≥235 MPa; Tensile ~360-510 MPa | 27J Charpy at +20°C mandatory |
| Korea | KS D3503 SS400 | Direct match | Identical JIS alignment |
Ss400 material equivalent swaps work for 80% of cases but verify toughness, thickness effects, and welding consumables. A36 suits U.S. codes seamlessly; Q235D for cold regions.
Available Forms and Supply Specifications
SS400 ships in standardized forms optimized for structural efficiency:
- Plates/Sheets: 1.6-200 mm thick, widths 1.0-3.5 m, lengths 2-12 m.
- Sections: H-beams (100-900 mm height), Kanäle (50-400 mm), Winkel (25×25 to 200×200 mm).
- Barren: Rounds (10-250 mm dia.), flats (up to 300×40 mm).
Tolerances per JIS G3193: thickness ±0.5 mm (6-20 mm plates), width ±10-15 mm, flatness ≤1.5% of width. MTRs include chemistry, UT (per JIS G0303 Level 2), and marking (grade/heat/batch). Stock mills offer normalized or as-rolled; custom cut-to-length saves logistics. Specify EN 10204 3.1 certs for exports.
Typical Applications of SS400 Material
SS400’s balanced profile shines in structural roles demanding weldability and moderate strength. Key sectors include:
- Konstruktion: Welded beams and columns for warehouses, platforms, and multi-story frames; angle iron for bracing in seismic retrofits.
- Infrastructure: Bridge girders, approach slabs, and rail supports where fatigue resistance (~150 MPa at 10^7 cycles) handles traffic vibrations.
- Marine & Heavy Industry: Ship hull stiffeners and bulkhead frames enduring flexure; crane runway beams resisting cyclic hoist loads.
- Machinery & Herstellung: Bases for presses, conveyor frames, and storage racks—its machinability cuts setup time by 25%.
In die casting specifically, SS400 forms mold bases and non-core support fixtures. These low-stress components prioritize stability and cost over high polish, allowing premium tool steels (z.B., H13) for cavities. Paired with aluminum castings like A380 or ADC12, SS400 jigs enable precise production of EV motor housings and lighting shells without distortion.
Die Casting Manufacturer’s Perspective
Select SS400 when yield needs (205-245 MPa per thickness) align with budget and fabrication ease—ideal for mold bases, Rahmen, and prototypes. Escalate to higher grades for high-cycle fatigue or harsh environments; always calculate equivalents with site-specific factors like corrosion class.
Bei BIAN Die Cast, we leverage SS400 mold bases as reliable foundations for crafting A380, ADC12, and AlSi9Cu3 cavities—perfect for LED road lamp housings, automotive inverter shells, Und Industrielle Steuerung Gehege. Our integrated mold shop (10+ cold chamber die casters from 160-1250T, 100+ CNCs, in-house spray lines) produces full assemblies from steel frameworks to surface-finished castings.
Dual China-Mexiko facilities cut U.S. tariffs and delivery times. IATF 16949 certification ensures every component traces back with compliant MTRs and RoHS reports.
Seamless integration awaits
