Engineers specifying ductile iron castings for high-strength applications frequently turn to QT450-10 for its exceptional combination of mechanical strength, ductility, and cost-effectiveness. This comprehensive guide examines QT450-10 material properties, international QT450 equivalent grades, and the unique characteristics of QT450 material that make it indispensable for demanding industrial components. Understanding these specifications enables optimal design decisions and reliable performance across automotive, machinery, and construction applications.
Industry professionals value QT450-10 for several compelling advantages:
- Minimum 450 MPa tensile strength delivers robust load-bearing capacity for high-stress applications
- 10% minimum elongation provides ductility preventing catastrophic brittle failure under impact
- Superior strength-to-weight ratio reduces component mass while maintaining structural integrity
- Excellent machinability enables efficient manufacturing with conventional tooling
- Nodular graphite structure combines strength with toughness for dynamic loading conditions
- Cost-effective alternative to steel forgings offering 20-30% weight savings with comparable performance
Engineers who understand QT450 material properties, chemical composition requirements, and QT450 equivalent standards can optimize component design for reliability, manufacturability, and economic competitiveness.
Key Takeaways
- QT450-10 delivers minimum 450 MPa (65 ksi) tensile strength with 10% elongation for high-strength ductile applications
- QT450-10 material properties include 310 MPa minimum yield strength, hardness 160-210 HB, and nodular graphite microstructure
- International QT450 equivalent grades include EN-GJS-450-10 (Europe), FCD450 (Japan), ASTM A536 Grade 65-45-12 (USA), and GGG-40 (Germany)
- The QT450 material features spheroidal graphite providing excellent impact resistance and fatigue strength
- Applications include automotive crankshafts, suspension components, heavy machinery parts, and wind turbine components
- Selecting experienced ductile iron casting foundries ensures consistent QT450-10 quality and mechanical properties
What Is QT450-10?
QT450-10 is a high-strength ductile iron grade conforming to GB/T 1348 with minimum 450 MPa tensile strength and 10% elongation, featuring spheroidal graphite microstructure that delivers exceptional strength combined with ductility for demanding engineering applications.
Material Classification
QT450-10 follows the Chinese national standard GB/T 1348 for ductile iron castings. The designation “QT” represents ductile iron (Qiu Mo Zhu Tie in Chinese), “450” indicates minimum tensile strength of 450 megapascals, and “10” specifies minimum elongation percentage. This standardized nomenclature ensures clear communication across the manufacturing supply chain.
The QT series encompasses various grades including QT400-18, QT450-10, QT500-7, QT600-3, and QT700-2, with QT450-10 positioned as a balanced grade offering high strength while maintaining useful ductility. This classification addresses applications requiring substantial load-bearing capacity without the brittleness associated with higher-strength grades.
Microstructure Characteristics
The superior performance of QT450-10 stems from its carefully controlled spheroidal graphite microstructure. Unlike gray iron containing flake graphite, ductile iron contains graphite in nodular (spherical) form distributed throughout a ferritic-pearlitic metallic matrix. These graphite nodules eliminate the stress concentration effects of graphite flakes, dramatically improving tensile strength and ductility.
The metallic matrix in QT450-10 material consists predominantly of pearlitic structure (60-80%) with ferritic components (20-40%), providing the balanced mechanical properties required for high-strength applications. This matrix composition differentiates QT450-10 from lower-strength grades like QT400-18 which contain higher ferrite content for enhanced elongation.
| Microstructure Component | Typical Content | Contribution to QT450-10 Properties |
|---|---|---|
| Spheroidal Graphite | 10-15% by volume | Excellent ductility, machinability, impact resistance |
| Pearlite | 60-80% | High strength, wear resistance, hardness |
| Ferrite | 20-40% | Ductility, toughness, machinability |
| Nodule Count | 100-300 nodules/mm² | Property uniformity, consistent performance |
The spheroidal graphite acts as a ductile phase that accommodates stress without creating crack initiation sites. The predominantly pearlitic matrix delivers reliable 450 MPa tensile strength while maintaining 10% minimum elongation for impact resistance and fatigue performance.
QT450-10 Chemical Composition
QT450-10 chemical composition includes 3.5-4.0% carbon, 2.2-2.9% silicon, 0.3-0.6% manganese, with magnesium treatment (0.02-0.06% residual) ensuring spheroidal graphite formation for 450 MPa strength with balanced ductility.
Understanding QT450-10 chemical composition provides essential insight into material properties and casting behavior. Each element serves specific purposes in achieving the ferritic-pearlitic microstructure with spheroidal graphite required for reliable performance.
Primary Alloying Elements
Carbon (C): 3.5-4.0%
Carbon content determines graphite quantity and influences matrix structure in QT450-10 material. This controlled range enables excellent casting fluidity while providing sufficient carbon for spheroidal graphite formation after magnesium treatment. The carbon level affects the ferrite-to-pearlite ratio, with moderate carbon content supporting predominantly pearlitic matrix structure delivering 450 MPa tensile strength.
The carbon equivalent (CE = %C + %Si/3) typically ranges from 4.3 to 4.6 for optimal QT450-10 properties. Foundries monitor carbon precisely during melting to ensure consistent nodular graphite formation and mechanical performance. Proper carbon control prevents carbide formation that would compromise ductility.
Silicon (Si): 2.2-2.9%
Silicon acts as a ferrite promoter and graphitizing element in ductile iron. The silicon range in QT450-10 composition balances graphitization with matrix structure control. Controlled silicon content (2.2-2.9%) promotes appropriate ferrite formation while maintaining adequate pearlite for strength requirements.
Silicon improves casting fluidity and reduces shrinkage tendencies during solidification. The silicon level directly influences final microstructure, affecting both mechanical properties and heat treatment response. Controlled silicon maintains the ferritic-pearlitic balance characteristic of QT450-10 material.
Manganese (Mn): 0.3-0.6%
Manganese contributes to pearlite formation and strength enhancement in QT450-10 composition. The controlled manganese addition provides adequate strength without excessive carbide formation that would reduce ductility. Moderate manganese content (0.3-0.6%) balances strength requirements with ductility maintenance.
Manganese also neutralizes sulfur by forming manganese sulfide inclusions, essential for successful magnesium treatment during ductile iron production. The controlled addition maintains proper nodular graphite formation while supporting the pearlitic matrix.
Magnesium (Mg): 0.02-0.06% (residual)
Magnesium treatment represents the defining characteristic of ductile iron production. Adding magnesium (typically 0.4-0.7% in ladle) to molten iron neutralizes sulfur and modifies graphite formation from flakes to spheroids. Residual magnesium of 0.02-0.06% in final castings confirms successful treatment, enabling the nodular graphite structure essential for QT450-10 material properties.
The spheroidizing treatment transforms gray iron into ductile iron, dramatically improving tensile strength from approximately 250 MPa to 450 MPa while increasing elongation from 0% to 10%. This metallurgical innovation makes ductile iron suitable for high-strength applications previously requiring steel.
Impurity Control
Phosphorus (P): <0.08%
Phosphorus creates brittleness by forming iron phosphide at grain boundaries in ductile iron. The strict phosphorus limit prevents embrittlement that would compromise impact resistance and ductility. Phosphorus control is more critical in ductile iron than gray iron due to higher mechanical property requirements.
Raw material selection controls phosphorus input, with high-purity pig iron and steel scrap ensuring specification compliance. Foundries producing QT450-10 carefully manage phosphorus levels to maintain 10% minimum elongation requirements.
Sulfur (S): <0.02%
Sulfur control is critical in ductile iron production as sulfur interferes with magnesium treatment. The strict sulfur limit (<0.02%) ensures efficient magnesium utilization and consistent nodular graphite formation. Excess sulfur consumes magnesium, preventing spheroidization and resulting in unacceptable graphite morphology.
Desulfurization treatments reduce sulfur content before magnesium addition. The low sulfur specification ensures reliable QT450-10 material properties with consistent nodular graphite structure throughout castings.
| Element | QT450-10 Range | Function |
|---|---|---|
| Carbon (C) | 3.5-4.0% | Graphite formation, casting fluidity |
| Silicon (Si) | 2.2-2.9% | Ferrite promotion, graphitization |
| Manganese (Mn) | 0.3-0.6% | Pearlite formation, strength |
| Magnesium (Mg) | 0.02-0.06% (residual) | Spheroidal graphite formation |
| Phosphorus (P) | <0.08% | Controlled for brittleness prevention |
| Sulfur (S) | <0.02% | Controlled for nodularization |
QT450-10 Material Properties
QT450-10 material properties include minimum 450 MPa (65 ksi) tensile strength, 310 MPa minimum yield strength, 10% minimum elongation, and hardness 160-210 HB, delivering high load-bearing capacity with excellent ductility for dynamic loading applications.
The mechanical and physical properties of QT450-10 determine suitability for high-strength applications requiring impact resistance. Comprehensive understanding enables accurate design calculations and appropriate component specification.
Tensile Properties
Tensile Strength (Rm): ≥450 MPa / 65 ksi (typical 450-500 MPa)
Tensile strength represents the primary specification for QT450-10 material. The minimum value of 450 MPa provides substantial load-bearing capability for demanding engineering applications. Typical production material achieves 450-500 MPa when foundries maintain rigorous process control and optimize the pearlitic-ferritic microstructure.
Tensile strength depends primarily on matrix structure, nodule count, and casting section thickness. The ferritic-pearlitic matrix (60-80% pearlite) provides reliable strength suitable for high-stress applications. Testing procedures follow GB/T 1348 standards using separately cast test bars ensuring consistent evaluation conditions.
Yield Strength (Rp0.2): ≥310 MPa / 45 ksi
Yield strength indicates the stress level where permanent deformation begins. QT450-10 material provides minimum yield strength of 310 MPa, approximately 70% of tensile strength. This yield-to-tensile ratio enables efficient load-bearing design with appropriate safety factors.
The predominantly pearlitic matrix delivers higher yield strength compared to ferritic grades, reducing permanent deformation under service loads. Engineers specify yield strength for design calculations involving cyclic loading and fatigue applications.
Elongation (A): ≥10%
Elongation measures ductility, indicating the material’s ability to deform plastically before fracture. QT450-10 provides minimum 10% elongation, sufficient ductility to prevent catastrophic brittle failure under impact or overload conditions. This ductility distinguishes ductile iron from gray iron (0% elongation) and enables applications requiring damage tolerance.
The 10% elongation results from the spheroidal graphite structure eliminating stress concentrations present in flake graphite. The ferritic component in the matrix contributes additional ductility while maintaining adequate strength. Typical production material achieves 10-15% elongation depending on section thickness and matrix structure.
Hardness Characteristics
Brinell Hardness: 160-210 HB (typical 170-200 HB)
Hardness measurements provide rapid verification of QT450-10 material properties and matrix structure. The Brinell hardness range reflects the ferritic-pearlitic microstructure with values of 170-200 HB indicating optimally controlled material. Lower hardness (<160 HB) suggests excessive ferrite reducing strength, while higher hardness (>210 HB) indicates excessive pearlite potentially compromising ductility.
The moderate hardness range provides adequate wear resistance for general applications while maintaining reasonable machinability. Components operating in moderate abrasive conditions benefit from this balance between strength and workability.
| Property | QT450-10 Value | Test Standard |
|---|---|---|
| Tensile Strength (Rm) | ≥450 MPa / 65 ksi | GB/T 1348 |
| Yield Strength (Rp0.2) | ≥310 MPa / 45 ksi | GB/T 1348 |
| Elongation (A) | ≥10% | GB/T 1348 |
| Brinell Hardness (HB) | 160-210 HB | GB/T 1348 |
| Impact Strength | 12-20 J (Charpy, unnotched) | GB/T 1348 |
Physical Properties
Density: 7.1-7.3 g/cm³ / 0.257-0.264 lb/in³
QT450-10 density remains consistent across composition variations, enabling accurate weight calculations during design. Ductile iron density approximates steel (7.85 g/cm³) while offering approximately 10% weight savings for equivalent volumes, reducing inertial loads in rotating components.
Modulus of Elasticity: 169-175 GPa / 24.5-25.4 million psi
The elastic modulus of QT450-10 material is significantly higher than gray iron (97-117 GPa) but slightly lower than steel (200-210 GPa). This characteristic affects deflection calculations, with ductile iron components showing approximately 15-20% greater deflection than equivalent steel parts under identical loading.
Thermal Properties
Thermal Conductivity: 28-32 W/(m·K)
QT450-10 demonstrates good thermal conductivity, though lower than gray iron (46-52 W/m·K) due to spheroidal graphite structure. The thermal conductivity remains adequate for most applications requiring moderate heat dissipation. The nodular graphite provides less efficient heat transfer pathways compared to interconnected flake graphite in gray iron.
Coefficient of Thermal Expansion: 10.5-12.0 × 10⁻⁶/K
The thermal expansion coefficient closely matches carbon steel values, minimizing thermal stress when assembling QT450-10 components with steel parts. This compatibility prevents loosening or binding across temperature ranges encountered in automotive and machinery applications.
Performance Characteristics
Impact Resistance
QT450-10 exhibits good impact resistance due to spheroidal graphite structure and matrix ductility. Unnotched Charpy impact values typically range from 12-20 joules, substantially higher than gray iron (2-4 joules) though lower than structural steel (40-100 joules). This impact resistance prevents catastrophic failure under shock loading conditions.
Fatigue Strength
The fatigue limit of QT450-10 material typically reaches 195-220 MPa (approximately 45-50% of tensile strength), suitable for components subjected to cyclic loading. The nodular graphite structure prevents crack initiation from stress concentrations, while the pearlitic matrix resists crack propagation. Applications include crankshafts, connecting rods, and suspension components experiencing millions of load cycles.
Machinability
QT450-10 demonstrates good machinability with cutting speeds 20-30% faster than comparable-strength steels. The spheroidal graphite acts as chip breakers producing short, manageable chips. Tool life typically extends 50-100% compared to machining equivalent-strength steel, reducing manufacturing costs through decreased tool replacement frequency.
Surface finishes of 1.6-3.2 μm Ra are readily achievable using conventional machining practices. The moderate hardness (160-210 HB) enables efficient drilling, milling, and turning operations without excessive tool wear or work hardening.
QT450 Equivalent Grades
The QT450 equivalent includes EN-GJS-450-10 (European), FCD450 (Japanese per JIS G 5502), ASTM A536 Grade 65-45-12 (American), and GGG-40 (German) standards, representing balanced high-strength ductile iron grades across international specifications.
Understanding international equivalent grades enables global sourcing and ensures design compatibility across markets. The QT450 equivalent system facilitates international procurement and technical communication.
American Standard
ASTM A536 Grade 65-45-12
The American equivalent for QT450 is ASTM A536 Grade 65-45-12, where “65” indicates minimum tensile strength in ksi (thousand pounds per square inch), “45” represents minimum yield strength in ksi, and “12” specifies minimum elongation percentage. This grade provides comparable mechanical properties to QT450-10 with slightly higher elongation requirements.
ASTM A536 Grade 65-45-12 specifications:
- Tensile strength minimum: 448 MPa (65 ksi)
- Yield strength minimum: 310 MPa (45 ksi)
- Elongation minimum: 12%
- Typical hardness: 140-210 HB
- Ferritic-pearlitic matrix
ASTM A536 Grade 65-45-12 provides the closest match to QT450-10 among American standards, with nearly identical tensile and yield strength requirements. The slightly higher elongation requirement (12% vs 10%) reflects American preference for enhanced ductility in structural applications.
European Standard
EN-GJS-450-10 (EN 1563)
The European designation for QT450 equivalent is EN-GJS-450-10, where “GJS” indicates spheroidal graphite iron and “450-10” represents minimum tensile strength in MPa and elongation percentage. This standard harmonized earlier national standards across European Union member states.
EN-GJS-450-10 specifications:
- Tensile strength minimum: 450 MPa (65 ksi)
- Yield strength minimum: 310 MPa (45 ksi)
- Elongation minimum: 10%
- Ferritic-pearlitic matrix
- Applications: automotive, machinery components
EN-GJS-450-10 provides exact equivalence to QT450-10 with identical tensile strength and elongation requirements, making it the most direct international equivalent for European applications.
German Standard
GGG-40 (DIN 1693)
German standard DIN 1693 designates equivalent material as GGG-40, where “GGG” represents spheroidal graphite cast iron (Gusseisen mit Kugelgraphit) and “40” indicates minimum tensile strength in kgf/mm² (approximately 392 MPa). German automotive and machinery manufacturers extensively utilize GGG-40 for crankshafts, suspension arms, and heavy machinery components.
GGG-40 specifications:
- Tensile strength minimum: 400 MPa (58 ksi)
- Yield strength minimum: 250 MPa (36 ksi)
- Elongation minimum: 18%
- Ferritic matrix structure
Note that GGG-40 has slightly lower tensile requirements but significantly higher elongation compared to QT450-10, reflecting German engineering preference for maximum ductility in safety-critical applications.
Japanese Standard
FCD450 (JIS G 5502)
Japanese Industrial Standard JIS G 5502 classifies equivalent material as FCD450. The “FCD” designation represents ductile cast iron (Ferrite Ductile Cast iron) while “450” indicates minimum tensile strength in MPa. Japanese automotive manufacturers utilize FCD450 for critical components requiring high strength with ductility.
FCD450 specifications:
- Tensile strength minimum: 450 MPa (65 ksi)
- Yield strength minimum: 310 MPa (45 ksi)
- Elongation minimum: 10%
- Ferritic-pearlitic matrix
- Hardness: 140-210 HB
FCD450 provides exact equivalence to QT450-10 with identical tensile strength and elongation requirements, making it the direct Japanese equivalent for Asian manufacturing applications.
International Equivalent Comparison
| Standard | Designation | Tensile (Min) | Yield (Min) | Elongation (Min) | Primary Matrix |
|---|---|---|---|---|---|
| Chinese (GB/T 1348) | QT450-10 | 450 MPa (65 ksi) | 310 MPa (45 ksi) | 10% | Ferritic-Pearlitic |
| American (ASTM A536) | 65-45-12 | 448 MPa (65 ksi) | 310 MPa (45 ksi) | 12% | Ferritic-Pearlitic |
| European (EN 1563) | EN-GJS-450-10 | 450 MPa (65 ksi) | 310 MPa (45 ksi) | 10% | Ferritic-Pearlitic |
| Japanese (JIS G 5502) | FCD450 | 450 MPa (65 ksi) | 310 MPa (45 ksi) | 10% | Ferritic-Pearlitic |
| German (DIN 1693) | GGG-40 | 400 MPa (58 ksi) | 250 MPa (36 ksi) | 18% | Ferritic |
When specifying QT450 equivalent grades internationally, engineers should verify mechanical property alignment and matrix structure. FCD450 (Japan) and EN-GJS-450-10 (Europe) provide the closest equivalence with identical strength and elongation specifications. ASTM A536 Grade 65-45-12 offers comparable performance for North American applications.
Primary Applications of QT450 Material
QT450 applications include automotive crankshafts, suspension components, steering knuckles, heavy machinery parts, wind turbine components, mining equipment, and construction machinery requiring high strength combined with impact resistance for reliable service under dynamic loading.
The unique combination of 450 MPa tensile strength, 10% elongation, excellent machinability, and superior strength-to-weight ratio makes QT450 material suitable for demanding applications where gray iron lacks adequate ductility and steel forgings prove economically uncompetitive.
Automotive Components
Crankshafts and Connecting Rods
Automotive manufacturers utilize QT450-10 for crankshafts in diesel engines and high-performance gasoline engines requiring fatigue strength under cyclic bending and torsional loads. The 450 MPa tensile strength withstands combustion pressures while 10% elongation provides damage tolerance preventing catastrophic failure from overload conditions.
The excellent fatigue limit (195-220 MPa) enables millions of load cycles throughout vehicle service life. Production economies from good machinability (20-30% faster than steel) and 10% weight savings compared to forged steel crankshafts reduce manufacturing costs for high-volume automotive production.
Suspension Components
Steering knuckles, control arms, and suspension brackets employ QT450 material for structural components requiring impact resistance with fatigue strength. The spheroidal graphite structure withstands road shock loads while the pearlitic matrix provides adequate stiffness for suspension geometry control.
The material’s ductility prevents brittle fracture from impact with road hazards, improving vehicle safety. Cost-effective casting processes enable complex geometries uneconomical with forged steel alternatives.
Heavy Machinery and Construction Equipment
Excavator and Loader Components
Construction equipment manufacturers specify QT450-10 for boom supports, bucket teeth adapters, and structural brackets subjected to impact loading and abrasive wear. The 450 MPa tensile strength supports heavy lifting loads while adequate hardness (160-210 HB) provides moderate wear resistance in abrasive soil conditions.
The material withstands shock loads from digging operations without brittle failure. Large casting capability enables one-piece structural components reducing assembly complexity and potential failure points.
Mining Equipment
Crusher housings, conveyor components, and structural supports in mining applications utilize QT450 material for impact resistance combined with adequate wear properties. The spheroidal graphite structure absorbs impact energy from ore processing while the pearlitic matrix provides surface hardness for moderate abrasion resistance.
Production efficiency from casting complex geometries reduces component costs for capital-intensive mining equipment. The 10% weight savings compared to steel reduces shipping costs for large structural components.
Wind Energy Components
Wind Turbine Hubs and Structural Components
Wind turbine manufacturers employ QT450-10 for rotor hubs, main frame components, and structural brackets requiring high strength-to-weight ratio with fatigue resistance. The 450 MPa tensile strength supports blade loads while excellent fatigue properties withstand millions of stress cycles throughout 20-25 year service life.
The casting process enables large, complex geometries essential for turbine hub designs. Material ductility prevents crack propagation from manufacturing defects or service-induced damage, improving reliability for critical renewable energy infrastructure.
Industrial Machinery
Gears and Power Transmission Components
Industrial gearboxes specify QT450 material for large gears, gear housings, and torque-transmitting components in moderate-duty applications. The adequate hardness (160-210 HB) combined with good machinability enables economical gear tooth cutting while the 450 MPa strength supports transmitted torque loads.
The superior damping capacity compared to steel (though less than gray iron) reduces gear noise transmission. Manufacturing economy from casting complex housing geometries with integrated mounting features reduces assembly costs for industrial equipment.
Selecting a Ductile Iron Casting Foundry
Selecting a ductile iron casting foundry for QT450-10 production requires evaluating metallurgical expertise in magnesium treatment and nodular iron control, comprehensive quality systems with mechanical testing capability, and demonstrated experience manufacturing components meeting GB/T 1348 specifications.
Component quality depends critically on foundry expertise in ductile iron production and process control capabilities. Engineers should assess technical competence when selecting manufacturing partners for QT450-10 applications.
Technical Capability Requirements
Ductile Iron Expertise
Foundries specializing in ductile iron production demonstrate deep understanding of QT450-10 chemical composition control, magnesium treatment practices, and ferritic-pearlitic microstructure development. They maintain metallurgical laboratories equipped for spectroscopic analysis, metallographic examination with image analysis for nodule count verification, and comprehensive mechanical testing including tensile, hardness, and impact testing.
Experienced metallurgists oversee magnesium treatment operations and address quality concerns specific to nodular iron grades. The foundry should provide detailed certifications including chemical composition with residual magnesium verification, tensile test results from separately cast test bars, hardness measurements, and metallographic examination confirming nodule count (100-300 nodules/mm²) and nodularity percentage (>80%).
Quality System Certification
Professional foundries maintain ISO 9001:2015 quality management certification demonstrating systematic process control. Advanced facilities pursue IATF 16949:2016 certification for automotive component production, ensuring rigorous quality standards meeting automotive OEM requirements. Certification provides independent verification of quality management supporting consistent QT450-10 material properties.
Production Capability Assessment
Engineers should request sample castings demonstrating capability producing components meeting QT450-10 specification. Examine samples for surface quality, dimensional accuracy, and absence of casting defects such as shrinkage porosity, gas porosity, or sand inclusions that would compromise mechanical properties.
Review material certificates confirming mechanical properties meet requirements: tensile strength ≥450 MPa, yield strength ≥310 MPa, elongation ≥10%, and hardness 160-210 HB. Metallographic examination should verify nodular graphite morphology (nodularity >80%, nodule count 100-300/mm²) with ferritic-pearlitic matrix structure (60-80% pearlite).
Request dimensional inspection reports demonstrating capability meeting geometric tolerances essential for component assembly and function. Evaluate casting surface finish quality appropriate for intended application, with consideration for machining stock requirements.
For engineers seeking a reliable ductile iron casting foundry with proven expertise in QT450-10 production, SHENRGONG delivers specialized capabilities in nodular iron manufacturing with comprehensive metallurgical control, advanced magnesium treatment technology, and rigorous quality assurance systems ensuring consistent material properties for automotive, machinery, and construction applications.
Conclusion
QT450-10 represents an excellent engineering material choice for high-strength applications requiring ductility and impact resistance. The ferritic-pearlitic microstructure with spheroidal graphite created through precise composition control and optimized magnesium treatment provides reliable 450 MPa tensile strength with 10% elongation, enabling applications previously limited to steel forgings.
Understanding QT450-10 material properties, chemical composition requirements, and QT450 equivalent grades enables engineers to optimize component design while controlling manufacturing costs. The material’s superior strength-to-weight ratio, good machinability, and excellent fatigue resistance make it particularly suitable for automotive crankshafts, heavy machinery components, and wind turbine structural parts.
Success depends on partnering with experienced ductile iron casting foundries maintaining rigorous metallurgical control over magnesium treatment, comprehensive mechanical testing programs, and quality systems ensuring consistent QT450-10 properties throughout production volumes.
Frequently Asked Questions (FAQ)
What is QT450-10 used for?
QT450-10 is used for automotive crankshafts, suspension components, heavy machinery parts, wind turbine hubs, mining equipment, and construction machinery requiring 450 MPa tensile strength with 10% elongation for impact resistance and fatigue performance under dynamic loading.
What are QT450-10 material properties?
QT450-10 material properties include minimum 450 MPa tensile strength, 310 MPa minimum yield strength, 10% minimum elongation, hardness 160-210 HB, and ferritic-pearlitic matrix with spheroidal graphite providing excellent strength-ductility balance for high-stress applications.
What is QT450-10 chemical composition?
QT450-10 chemical composition includes 3.5-4.0% carbon, 2.2-2.9% silicon, 0.3-0.6% manganese, with 0.02-0.06% residual magnesium from spheroidizing treatment, controlled phosphorus below 0.08%, and sulfur below 0.02% ensuring consistent nodular graphite formation.
What are QT450 equivalent grades internationally?
QT450 equivalent grades include FCD450 (Japan per JIS G 5502), EN-GJS-450-10 (Europe per EN 1563), ASTM A536 Grade 65-45-12 (USA), and GGG-40 (Germany per DIN 1693), all providing comparable tensile strength (400-450 MPa) with good ductility and ferritic-pearlitic matrix structure.
Why is QT450-10 better than gray iron?
QT450-10 provides 450 MPa tensile strength with 10% elongation compared to gray iron’s 250 MPa with 0% elongation, offering substantially higher strength, impact resistance, and fatigue life through spheroidal graphite structure eliminating stress concentrations from flake graphite.
