Jis G3125 Spa H
JIS G3125 SPA-H steel è un ad alta resistenza, acciaio strutturale a bassa lega con:
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Balanced composizione chimica for toughness and weldability
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Proprietà meccaniche suitable for bridges, navi, and industrial frames
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Common applications in construction, shipbuilding, e macchinari pesanti
- Descrizione
JIS G3125 SPA-H è un ad alta resistenza, low-alloy structural steel standard widely used in construction, shipbuilding, and industrial engineering. It is the Japanese Industrial Standard (LUI) equivalent of high-strength structural plates, designed for elevata tenacità, saldabilità, and structural reliability.
1. Standard Overview
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Standard: SOLO G3125
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Grado: SPA-H (Structural Plate – High strength)
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Tipo: Low-alloy, high-strength steel plate suitable for welded structures
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Focus: Combines high yield strength with good toughness at ambient temperatures
2. Composizione chimica
| Elemento | Contenuto (%) | Funzione |
|---|---|---|
| Carbonio (C) | 0.12 – 0.18 | Fornisce forza |
| Manganese (Mn) | 1.0 – 1.5 | Migliora la tenacità e la temprabilità |
| Fosforo (P) | ≤ 0.035 | Controllo delle impurità |
| Zolfo (S) | ≤ 0.035 | Controllo delle impurità |
| Silicio (E) | ≤ 0.50 | Migliora la forza e la resistenza all'ossidazione |
| Rame (Cu) | ≤ 0.25 | Slightly improves corrosion resistance |
| Nichel (In) | Traccia | Improves toughness in some cases |
| Cromo (Cr) | Traccia | Contributes to strength and surface quality |
Key Feature: Low-alloy composition ensures alta resistenza, saldabilità, and good cold formability, while maintaining toughness.
3. Proprietà meccaniche
| Proprietà | Valore tipico |
|---|---|
| Forza di snervamento (MPa) | ≥ 355 |
| Resistenza alla trazione (MPa) | 470 – 630 |
| Allungamento (%) | ≥ 20 |
| Resistenza all'impatto | Good at ambient temperature |
| Durezza (HB) | 140 – 190 |
Highlights:
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High load-bearing capacity for structural use
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Good ductility for forming and bending
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Weldable without preheating in most applications
4. Key Applications
| Industria | Typical Use Cases |
|---|---|
| Costruzione | Ponti, travi strutturali, trusses, building frameworks |
| Shipbuilding | Hull plates, decks, offshore platform structures |
| Industrial & Engineering | Machinery frames, storage tanks, condutture |
| Attrezzatura pesante | Cranes, load-bearing frames, structural supports |
Advantages in Use:
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High strength allows thinner sections for same load
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Toughness ensures safety under dynamic loads
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Weldable for complex structural fabrication
5. Comparison with Other Structural Steels
| Grado | Forza di snervamento (MPa) | Primary Use |
|---|---|---|
| SPA-H (SOLO G3125) | ≥355 | High-strength welded structural plates |
| SPA-C | ≥315 | Medium-strength structural plates |
| S355 (IN) | 355 | European structural equivalent |
| ASTM A572 | 345–450 | High-strength structural steel |
Observation: SPA-H è ampiamente utilizzato in Japan and Asia for structural and shipbuilding plates where forza, saldabilità, and reliability sono critici.
