Si vous travaillez sur une construction à charge moyenne, machinerie, or infrastructure projects, ST35 structural steel est un fiable, choix rentable. Connu pour sa bonne formabilité, soudabilité, et une force équilibrée, il est utilisé dans tout, des cadres de construction aux systèmes de convoyeurs. Ce guide explique ce qu'est le ST35, comment ça marche, and where it adds the most value—so you can make confident material decisions.
1. Material Properties of ST35 Structural Steel
ST35’s performance is rooted in its carefully controlledchemical composition and predictable physical, mécanique, and functional traits. Below’s a detailed breakdown:
Composition chimique: Simple, Balanced, and Cost-Effective
ST35 is a low-alloy structural steel—its composition focuses on basic elements to deliver reliability without extra alloy costs.
| Élément | Gamme de contenu | Rôle clé |
|---|---|---|
| Carbone (C) | 0.14–0.22% | Provides moderaterésistance à la traction while keeping the steel easy to weld |
| Manganèse (Mn) | 0.35–0.65% | Enhances toughness and prevents cracking duringhot rolling |
| Silicium (Et) | Jusqu'à 0.40% | Acts as a deoxidizer (removes oxygen to avoid porous defects in beams/columns) |
| Soufre (S) | Max 0.050% | Strictly limited (high levels reducesoudabilité and cause brittleness) |
| Phosphore (P.) | Max 0.040% | Controlled to avoid cold brittleness (protects performance in cool climates) |
| Chrome (Cr), Nickel (Dans), Molybdène (Mo), Vanadium (V), Cuivre (Cu) | Trace amounts or absent | Kept low to keep costs down (ST35 prioritizes affordability over extreme strength) |
Propriétés physiques: Consistent for Easy Design
ST35’s physical traits are consistent across batches, making it simple to integrate into projects:
- Densité: ~7850 kg/m³ (same as most structural steels—easy to calculate weight for beams or vehicle frames)
- Conductivité thermique: 50–60 W/(m·K) (spreads heat evenly—reduces warping when welding industrial structures)
- Specific heat capacity: ~490–500 J/(kg·K) (resists temperature spikes—reliable for outdoor infrastructure like ponts routiers)
- Coefficient of thermal expansion: 12–13.5 µm/(m·K) (low enough to handle seasonal temperature swings in transmission towers)
- Magnetic properties: Ferromagnétique (easy to inspect with magnetic particle testing for defects in bâtis de machines)
Propriétés mécaniques: Balanced for Mid-Load Projects
ST35’s mechanical strength is tailored for applications that don’t require ultra-high strength—but still need durability.
| Mechanical Property | Valeur typique | Why It Matters for ST35 Users |
|---|---|---|
| Résistance à la traction | 335–435 MPa | Handles moderate pulling forces (ideal forbuilding columns ousystèmes de convoyeurs) |
| Yield strength | ~235 MPa | Maintains shape under load (prevents bending incomposants de suspension ouequipment supports) |
| Elongation at break | 25–35% | Stretches easily without breaking (simple to form intopoutres ouchâssis de véhicules) |
| Reduction of area | 40–50% | Indicates high ductility (avoids snapping infermes oupièces de moteur) |
| Dureté | 130–190 HB (Brinell); 85–100 HRB (Rockwell) | Soft enough for easyusinabilité (cuts quickly into custom parts) |
Other Key Properties
- Résistance à la corrosion: Faible (needs paint, galvanisation, or coating for outdoor use—critical for marine structures ou tours d'éoliennes)
- Fatigue resistance: Modéré (handles repeated stress in systèmes de convoyeurs ou châssis de véhicules for years)
- Weldability: Bien (requires minimal pre-heating—perfect for on-site welding of bridge girders ou factory frames)
- Usinabilité: Fair to good (cuts easily with standard tools—saves time when making pièces de moteur ou safety structures)
- Formabilité: Bien (bends with basic press brakes—ideal for shaping highway barriers ou building trusses)
2. Applications of ST35 Structural Steel
ST35’s balance of affordability, formabilité, and strength makes it a top choice across industries. Here’s where it shines:
Construction
ST35 is a workhorse for mid-rise buildings, ponts, and industrial structures:
- Beams, colonnes, and frames: Supports floors and roofs in 5–15 story buildings (par ex., office buildings, small apartment complexes).
- Bridge girders and trusses: Used in medium-span bridges (50–100 meters) for local roads or rural highways.
- Industrial structures: Frames for factories, warehouses, or workshops (handles light-to-moderate equipment loads).
- Exemple: A European construction firm used ST35 for a 12-story office building—its formabilité let them create custom beam shapes, et soudabilité cut on-site construction time by 15%.
Infrastructure
ST35 keeps critical infrastructure running smoothly:
- Railway tracks and supports: Holds rail lines in place (c'est résistance à la fatigue handles repeated train loads).
- Highway bridges and barriers: Makes up guardrails and small bridge components (affordable enough for large-scale projects).
- Marine structures (piers, docks): Used in low-salt areas (with galvanizing) for small pier frames or walkways.
- Exemple: A Southeast Asian DOT used ST35 for highway guardrails—they cost 30% less than stainless steel, and with paint, lasted 10 years without rust.
Génie mécanique
Machinery makers rely on ST35 for easy-to-shape, pièces durables:
- Bâtis de machines: Holds motors and components in place for small-to-medium machines (par ex., packaging equipment).
- Equipment supports: Bases for generators, compresseurs, or pumps (c'est yield strength prevents tipping).
- Systèmes de convoyeurs: Frames and rollers for moving grain, gravel, or packaged goods (ductilité handles minor impacts).
- Exemple: Un États-Unis. manufacturing plant used ST35 for conveyor frames—they were 20% cheaper than Grade 50 steel and lasted 8 years with no repairs.
Automobile & Énergie
ST35 plays a role in vehicle and energy projects where cost and formability matter:
- Automobile: Vehicle frames for small cars, composants de suspension for trucks, and low-stress pièces de moteur (par ex., parenthèses).
- Énergie: Secondary components in tours d'éoliennes (par ex., access ladders) et power plant structures (par ex., pipe supports).
- Exemple: A Chinese automaker used ST35 for compact car frames—its formabilité let them create aerodynamic shapes, et usinabilité speeded up production.
3. Manufacturing Techniques for ST35 Structural Steel
Producing ST35 is straightforward—its simple composition means fewer steps than high-alloy steels. Here’s the process:
Primary Production: Making Raw ST35 Steel
- Blast furnace process: Melts iron ore with coke and limestone to produce pig iron (the base material for ST35).
- Basic oxygen steelmaking (BOS): Blows pure oxygen into pig iron to adjust carbon content (to 0.14–0.22%) and remove impurities like sulfur.
- Electric arc furnace (AEP): Melts scrap steel (used for smaller batches of ST35—more flexible for custom orders).
Secondary Production: Shaping ST35 into Usable Forms
- Hot rolling: Heats ST35 to 1100–1250°C, then rolls it into poutres, colonnes, assiettes, ou barres (most common method—boosts strength and ductility).
- Cold rolling: Rolls ST35 at room temperature for parts that need a smooth surface (par ex., automotive body components or small pièces de moteur—improves precision but reduces ductility slightly).
Traitement thermique: Optimizing ST35’s Performance
- Normalizing: Heats ST35 to 850–900°C, then cools in air (refines grain structure—enhances résistance à la traction pour bridge girders ou bâtis de machines).
- Recuit: Heats to 700–750°C, then cools slowly (softens the steel—improves usinabilité for cutting custom pièces de convoyeur ou composants de suspension).
Fabrication: Turning ST35 into Finished Products
- Coupe: Utilisations oxy-fuel cutting (thick ST35 plates for building columns), coupage au plasma (medium-thickness sheets for barriers), ou découpe laser (thin parts for supports de moteur).
- Pliage: Uses press brakes or rolling machines (easy to shape into curved beams ou vehicle frame rails—thanks to ST35’s high formabilité).
- Soudage: Joins parts with arc welding (on-site construction), Soudage MIG (high-volume parts like conveyor frames), ou Soudage TIG (precision parts like composants du moteur).
- Assemblée: Puts together fabricated parts (par ex., attaching poutres à colonnes) using bolts or welding.
4. Études de cas: ST35 Structural Steel in Action
These real-world examples show how ST35 solves problems and saves money for businesses.
Étude de cas 1: 12-Story Office Building (Allemagne)
- Défi: Need an affordable steel for beams and columns that’s easy to weld on-site.
- Solution: Used ST35—its soudabilité let workers join parts without expensive pre-heating, et formabilité allowed custom beam shapes for the building’s unique design.
- Résultats: Construction finished 3 weeks early; material costs were 25% lower than using high-strength steel. The building’s structure remains stable after 10 années.
Étude de cas 2: Highway Guardrails (Thaïlande)
- Défi: Need a low-cost steel for 50 km of guardrails that can withstand rain and mild humidity.
- Solution: Used ST35 with a powder-coat finish—its abordabilité fit the budget, and the coating boosted résistance à la corrosion.
- Résultats: Guardrails cost $15/linear meter (contre. $20 pour l'acier inoxydable) et n'a montré aucune rouille après 8 années. Les coûts de maintenance ont diminué 40%.
Étude de cas 3: Conveyor Frames (NOUS. Manufacturing Plant)
- Défi: Need a steel for conveyor frames that’s easy to cut and lasts under daily use.
- Solution: Used ST35—its usinabilité let the plant cut custom parts in-house, et résistance à la fatigue handled 12-hour daily operation.
- Résultats: Conveyor frames lasted 8 années (contre. 5 ans pour l'aluminium); in-house machining saved $5,000/year in outsourcing costs.
5. ST35 Structural Steel vs. Autres matériaux
How does ST35 stack up against alternatives? This table helps you choose the right material for your project:
| Matériel | Limite d'élasticité (MPa) | Coût (par kg) | Avantage clé | Idéal pour |
|---|---|---|---|---|
| ST35 Structural Steel | ~235 | $1.20–$1.80 | Force équilibrée, formabilité, et le coût | Mid-rise buildings, conveyor frames, guardrails |
| Aluminium (6061-T6) | 276 | $3.00–$4.00 | Léger, better corrosion resistance | Aircraft parts, lightweight vehicle components |
| Acier inoxydable (304) | 205 | $4.00–$5.00 | Excellente résistance à la corrosion | Coastal infrastructure, food-processing equipment |
| Fonte | ~200 (compressif) | $1.50–$2.00 | High compressive strength | Manhole covers, low-impact machinery bases |
| Béton | 40 (compressif) | $0.10–$0.20 | Ultra-low cost, high compressive strength | Building foundations, low-rise walls |
Key Takeaways
- Coût par rapport. Performance: ST35 is cheaper than aluminum or stainless steel while offering better tensile strength than cast iron or concrete.
- Workability: ST35 is easier to weld and form than stainless steel or cast iron—saves time on fabrication.
- Valeur: It’s the best choice for mid-load projects where you don’t need ultra-high strength but want reliability (par ex., small office buildings, systèmes de convoyeurs).
6. Yigu Technology’s Perspective on ST35 Structural Steel
Chez Yigu Technologie, we see ST35 as a “workhorse material” for mid-scale projects. Its biggest strength isn’t just its technical properties—it’s its ability to balanceabordabilité, formabilité, etfiabilité—solving the “cost vs. performance” problem many clients face. We recommend pairing ST35 with galvanizing for outdoor use (commeponts routiers) and usingnormalizing heat treatment for parts needing extra strength (e.g.,bâtis de machines). For projects that don’t require Grade 50 ou 80 acier, ST35 is the smart, choix rentable.
FAQ About ST35 Structural Steel
1. Can ST35 be used outdoors?
Yes—but it needs protection. ST35 has lowrésistance à la corrosion, so add a coating likehot-dip galvanizing, peinture époxy, or zinc spray. We’ve supplied galvanized ST35 forhighway guardrails etsmall piers—they lasted 10+ years in rainy or humid climates.
2. Is ST35 strong enough for building columns?
Absolutely—for mid-rise buildings (5–15 stories). ST35’syield strength (~235 MPa) etrésistance à la traction (335–435 MPa) easily support floor loads and wind forces in these structures. Pour les bâtiments plus hauts (20+ histoires), we recommend higher-strength steel like Grade 50.
3. How does ST35 compare to Grade 50 acier?
ST35 is cheaper and more formable, but Grade 50 is stronger. ST35 costs ~30% less and is easier to weld/form—ideal for mid-load projects (par ex., conveyor frames). Grade 50 has a higheryield strength (~345 MPa)—better for tall buildings or heavy machinery.