Executive Summary

This comprehensive analysis compares C26000 (ASTM Cartridge Brass) and H68 (Chinese Standard Brass), two of the most widely used single-phase brass alloys globally. While both alloys share similar copper-zinc compositions and single-phase microstructures, their subtle differences in chemistry and processing standards create distinct performance characteristics that influence their suitability for specific applications.

C26000, with its 70% copper content, represents the Western standard for high-performance brass applications, particularly where corrosion resistance and formability are critical. H68, containing 68% copper, has become the most widely used brass grade in China and increasingly in Asian markets, offering excellent plasticity combined with cost-effectiveness.

Understanding the nuanced differences between these alloys is crucial for engineers, procurement specialists, and manufacturers operating in today’s interconnected global supply chains, where material selection impacts both performance and economic outcomes.

1. Introduction and Alloy Background

1.1 Historical Development

C26000 (Cartridge Brass) emerged from military applications during the industrial revolution, originally developed for ammunition manufacturing. Its 70/30 copper-zinc composition became the benchmark for applications requiring superior deep drawing capabilities and atmospheric corrosion resistance. The alloy gained widespread adoption in North American and European markets, becoming synonymous with high-quality brass applications.

H68 was developed within China’s industrial framework as part of the comprehensive GB (Guobiao) standard system. With 68% copper content, it was engineered to provide optimal balance between performance characteristics and material cost, making it particularly suitable for high-volume manufacturing applications. H68 has gained recognition as “the most widely used brass variety” in Chinese industry.

1.2 Current Market Position

Market RegionC26000 UsageH68 UsagePrimary Applications
北米Dominant限定Architecture, marine, electronics
ヨーロッパDominant (as CW508L)EmergingAutomotive, building hardware
中国限定DominantManufacturing, electronics, hardware
Southeast Asia適度GrowingMixed industrial applications
India/South Asia適度GrowingCost-sensitive manufacturing
中東適度限定Infrastructure, marine applications

2. Chemical Composition and Metallurgy

2.1 Detailed Chemical Analysis

要素C26000 (ASTM B36)H68 (GB/T 5231)Difference Impact
68.5 – 71.5%67.0 – 70.0%C26000: +1.5% average
亜鉛(Zn)Balance (28.5-31.5%)Balance (30.0-33.0%)H68: +1.5% average
鉛(Pb)≤ 0.07%≤ 0.05%H68: Tighter control
鉄(Fe)≤ 0.05%≤ 0.10%H68: More permissive
アルミニウム(Al)≤ 0.002%H68: Specified limit
錫(Sn)≤ 0.002%H68: Specified control
Antimony (Sb)≤ 0.005%H68: Trace element control
Arsenic (As)≤ 0.02%C26000: Dezincification control
リン(P)≤ 0.02%≤ 0.002%H68: Stricter limit
シリコン(Si)≤ 0.007%H68: Process control

2.2微細構造特性

財産C26000H68Significance
Phase StructureSingle α-phaseSingle α-phaseBoth excellent formability
Grain Size (ASTM)5-74-6H68: Slightly finer grain
Zinc Equivalent30.5%31.5%H68: Higher equivalent
Phase Stability素晴らしい素晴らしいBoth stable at room temperature
Recrystallization Temp300-400°C310-420°CSimilar processing windows

2.3 Compositional Impact on Properties

C26000 Advantages from Higher Copper:

  • Enhanced electrical conductivity (28% IACS vs 26% IACS)
  • Superior corrosion resistance in atmospheric conditions
  • Better thermal conductivity for heat transfer applications
  • Improved brazing and welding characteristics
  • Enhanced ductility for extreme forming operations

H68 Advantages from Optimized Composition:

  • Improved strength-to-cost ratio
  • Better dimensional stability during processing
  • Enhanced machinability due to refined microstructure
  • Optimized hot working characteristics
  • Reduced material cost while maintaining performance

3. Mechanical Properties Comprehensive Analysis

3.1 Tensile Properties Comparison

状態財産C26000H68単位Performance Difference
Annealed (O)抗張力300-380295-375MPaC26000: +5 MPa average
Yield Strength (0.2%)75-14080-145MPaH68: +5 MPa average
伸長60-6865-70%H68: +3% average
Hardness (HV)60-8555-80HVC26000: +5 HV average
Half Hard (H02)抗張力370-450365-445MPaComparable
降伏強さ170-275175-280MPaH68: +5 MPa average
伸長25-3528-38%H68: +3% average
Hard (H04)抗張力410-540405-535MPaComparable
降伏強さ275-380280-385MPaH68: +5 MPa average
伸長15-2518-28%H68: +3% average

3.2 Fatigue and Endurance Properties

Test ConditionC26000H68単位Application Impact
High Cycle Fatigue (10^7)140-160145-165MPaH68: Better spring applications
Low Cycle Fatigue (10^4)280-320285-325MPaSimilar performance
Rotating Bending120-140125-145MPaH68: Slight advantage
Axial Fatigue100-120105-125MPaH68: Better for rods/bars
Corrosion Fatigue80-10075-95MPaC26000: Better in corrosive environments

3.3 Temperature-Dependent Mechanical Properties

温度財産C26000H68Performance Notes
-40°C抗張力420 MPa415 MPaBoth maintain ductility
耐衝撃性高い高いNo brittle transition
20℃抗張力340 MPa335 MPaReference condition
Modulus110 GPa108 GPaSimilar stiffness
100℃抗張力315 MPa310 MPaGradual reduction
Creep Resistance良い良いSuitable for moderate temp
200℃抗張力280 MPa275 MPaLimited applications
Oxidation適度適度Protective atmosphere recommended
300℃抗張力245 MPa240MPaShort-term exposure only

4. Forming and Manufacturing Characteristics

4.1 Cold Forming Performance

Forming OperationC26000 RatingH68 RatingRelative PerformanceRecommended Applications
Deep DrawingExcellent (5/5)Excellent (5/5)C26000: +5% deeper drawsCartridge cases, cups
SpinningExcellent (5/5)Excellent (4.8/5)C26000: Better thin wallsDecorative components
曲げExcellent (5/5)Excellent (5/5)Equal performanceArchitectural hardware
Stretch FormingExcellent (5/5)Very Good (4.5/5)C26000: Better complex curvesAutomotive panels
Cold HeadingVery Good (4/5)Excellent (5/5)H68: Better surface finishFasteners, rivets
CoiningGood (3.5/5)Very Good (4/5)H68: Better detail definitionPrecision parts
Roll FormingExcellent (5/5)Excellent (5/5)Equal performanceContinuous sections

4.2 Hot Working Characteristics

Process ParameterC26000H68最適な範囲Process Notes
熱間加工温度600-800°C650-820°C650-800°CH68: Wider window
Forging Temperature650~750℃670-780°C670-750°CSimilar optimal range
Rolling Temperature600-750°C620-770°C620-750°CH68: More forgiving
Extrusion Temperature650-800°C670-820°C670-800°CBoth excellent
Hot Forming Rate適度Moderate-FastVariableH68: Faster rates possible
Grain Growth Control良いとても良いCriticalH68: Better control

4.3 Machinability Assessment

Machining OperationC26000 PerformanceH68 PerformanceCutting ParametersTool Life Comparison
旋回Good (3.5/5)Very Good (4/5)Speed: 150-300 m/minH68: 15% longer life
掘削Good (3.5/5)Very Good (4/5)Speed: 80-150 m/minH68: 20% longer life
フライス加工Good (3/5)Good (3.5/5)Speed: 100-200 m/minH68: 10% longer life
ThreadingFair (2.5/5)Good (3.5/5)Speed: 60-120 m/minH68: 25% longer life
表面仕上げRa 1.6-3.2 μmRa 1.2-2.5 μmH68: Superior finish
Chip FormationLong, stringyShorter, betterH68: Easier handling

5. Physical and Thermal Properties

5.1 Fundamental Physical Properties

財産C26000H68単位Application Impact
密度8.538.50g/cm3Weight calculations
融点915-940905-930Processing temperatures
Liquidus940930Casting parameters
Solidus915905熱処理
比熱0.380.38J/g·KThermal calculations
熱膨張20.5×10⁻⁶20.8×10⁻⁶/KDimensional stability
透磁率1.01.0μ/μ₀Non-magnetic applications

5.2 Electrical and Thermal Conductivity

状態財産C26000H68単位Performance Difference
Annealed電気伝導性28% IACS26% IACS%C26000: +7% better
熱伝導率120109W/m・KC26000: +10% better
抵抗率6.2×10⁻⁸6.6×10⁻⁸Ω·mC26000: Lower resistance
Cold Worked電気伝導性25% IACS23% IACS%C26000: +8% better
熱伝導率10898W/m・KC26000: +10% better

5.3 Heat Treatment Response

処理C26000 ResponseH68 ResponseTypical ParametersMicrostructural Changes
応力緩和素晴らしい素晴らしい250-300°C, 1-2hResidual stress reduction
Partial Annealとても良い素晴らしい350-450°C, 1hPartial recrystallization
Full Anneal素晴らしい素晴らしい450-650°C, 2hComplete recrystallization
Grain Size Control良いとても良いControlled coolingH68: Better uniformity
Precipitation適用できない適用できないSingle-phase alloys

6. Corrosion Resistance and Environmental Performance

6.1 Atmospheric Corrosion Performance

Environment TypeC26000 PerformanceH68 PerformanceCorrosion Rate (μm/year)Service Life Estimate
Rural Atmosphere素晴らしいとても良いC26000: 1-2, H68: 2-3C26000: >50 years
Urban Atmosphere素晴らしい良いC26000: 2-5, H68: 4-7C26000: 30-50 years
工業的な雰囲気良いFair-GoodC26000: 5-10, H68: 8-15C26000: 20-30 years
Marine Atmosphereとても良い良いC26000: 8-15, H68: 12-20C26000: 15-25 years
Coastal Severe良い公平C26000: 15-25, H68: 20-30C26000: 10-15 years

6.2 Aqueous Corrosion Resistance

Water TypeC26000 RatingH68 RatingCorrosion MechanismRecommended Applications
Distilled Water素晴らしい素晴らしいMinimal attackLaboratory equipment
Tap Water (Soft)素晴らしいとても良い均一な腐食Plumbing fittings
Tap Water (Hard)とても良い良いScale formationWater meters
海水良いFair-GoodUniform + pitting船舶用ハードウェア
汽水良い公平Selective attackCoastal applications
Acidic Water (pH 4-6)公平公平Accelerated uniformLimited exposure

6.3 Dezincification Susceptibility

試験方法C26000 ResultH68 ResultInterpretationApplication Guidelines
ASTM B858 Method AType 1 (Excellent)Type 2 (Good)Surface layer <200μmC26000: Unrestricted use
ISO 6509-1 (24h, 75°C)Layer <100μmLayer 100-200μmAcceptable performanceBoth suitable with limits
Accelerated (80°C, 168h)Minimal penetrationModerate penetrationRelative performanceH68: Controlled conditions
Field Exposure (5 years)Surface onlySubsurface <0.5mmReal-world validationC26000: Superior long-term

7. Applications and Performance Optimization

7.1 Industry-Specific Application Matrix

産業部門Application CategoryC26000 PreferenceH68 PreferenceSelection Rationale
ArchitectureExterior hardware★★★★★★★★Weather resistance critical
Interior fittings★★★★★★★★★Cost-performance optimization
Decorative elements★★★★★★★★★Appearance and durability
自動車熱交換器★★★★★★★★Thermal performance vs cost
Fuel system components★★★★★★★★Corrosion resistance essential
Interior trim★★★★★★★★Cost-sensitive application
エレクトロニクスコネクタ★★★★★★★★Conductivity and reliability
ヒートシンク★★★★★★★★Cost-effective thermal management
Precision components★★★★★★★★★Machinability advantage
マリンDeck hardware★★★★★★★Seawater exposure
Interior fittings★★★★★★★★Controlled environment
楽器Professional grade★★★★★★★★Acoustic properties
Student instruments★★★★★★★★コストに関する考慮事項

7.2 Forming Application Guidelines

アプリケーションタイプ推奨グレードCritical PropertiesDesign Considerations
Deep Drawn ShellsC26000 preferredUltimate elongationWall thickness uniformity
Complex StampingsC26000 preferredStrain hardeningProgressive die design
Precision FastenersH68 preferred被削性Thread quality critical
Spring ComponentsH68 preferred耐疲労性Stress concentration control
熱交換器チューブH68 preferredThermal conductivity/costWall thickness optimization
Decorative HardwareC26000 preferred表面品質Finishing considerations

7.3 Manufacturing Process Optimization

Process CategoryC26000 OptimizationH68 OptimizationKey Parameters
冷間圧延Lower reduction/passHigher reduction possibleWork hardening control
Annealing CyclesStandard parametersShorter cycles possibleEnergy efficiency
Surface FinishingStandard processingReduced finishing requiredQuality consistency
Joining OperationsExcellent weldability良好な溶接性Heat input control
品質管理Standard protocolsEnhanced machinability testingProcess monitoring

8. Economic Analysis and Supply Chain Considerations

8.1 Comprehensive Cost Comparison

Cost ComponentC26000 ImpactH68 ImpactTypical DifferenceEconomic Driver
Raw MaterialHigher Cu contentLower Cu contentH68: 8-12% lowerCopper price premium
処理Standard ratesImproved efficiencyH68: 5-10% lowerMachinability advantage
品質管理標準Reduced inspectionH68: 2-5% lowerBetter surface finish
在庫Global availabilityRegional variationVariableSupply chain maturity
Transportation標準標準中性Density similar
Total ManufacturingBaselineReducedH68: 6-15% lowerCombined effect

8.2 Regional Market Dynamics

地域C26000 Market ShareH68 Market ShareTrend DirectionKey Factors
北米85%5%安定したEstablished standards
ヨーロッパ80%10%Slow H68 growthCost pressures
中国15%70%H68 dominanceDomestic preference
Southeast Asia40%35%H68 growingManufacturing migration
インド30%40%H68 growingCost sensitivity
Latin America60%20%Mixed trendsApplication dependent

8.3 Supply Chain Risk Assessment

Risk FactorC26000 Risk LevelH68 Risk LevelMitigation Strategies
Raw Material Supply低い適度Diversified sourcing
Price Volatility適度適度Long-term contracts
Quality Consistency低い適度Supplier qualification
Lead Time Variability低い適度Safety stock management
Geographic Concentration低い高いRegional diversification
Trade Regulations低い適度Compliance monitoring

9. Standards and Quality Specifications

9.1 International Standards Comparison

Standard BodyC26000 DesignationH68 Equivalent主な違いRegional Adoption
ASTM (USA)C26000No direct equivalentComposition toleranceAmericas
EN (Europe)CW508LNo direct equivalentEnvironmental testing欧州連合
JIS (Japan)C2600C2680 (similar)Processing requirementsJapan, SE Asia
GB (China)No equivalentH68Trace element controlChina, Asia
IS (India)1945 Grade 1Similar to H68Local adaptationsインド
ABNT (Brazil)NBR equivalent限定Regional modificationsBrazil

9.2 Quality Control Specifications

Test ParameterC26000 SpecificationH68 Specification試験方法頻度
化学組成ASTM B36 limitsGB/T 5231 limitsICP-OES analysisEvery heat
Tensile PropertiesASTM B36GB/T 228.1Universal testingPer lot
Grain SizeASTM E112GB/T 6394MetallographicSelected lots
表面品質Visual/dimensionalGB/T 8888Inspection100%
耐食性ASTM B858GB/T 10119Accelerated testing資格
Dimensional ToleranceASTM B36GB/T 4423Precision measurementStatistical

9.3 Certification and Traceability

Requirement TypeC26000 StandardH68 StandardドキュメンテーションCompliance Level
材料認証Mill test certificateFactory certificateChemical/mechanical必須
プロセス制御Statistical processQuality manualProcess parametersRecommended
TraceabilityHeat numberBatch trackingProduction records必須
Third-Party Testingオプション多くの場合必要Independent labsVariable
環境RoHS complianceSimilar requirementsRegulatory docs必須

10. Advanced Technical Considerations

10.1 Microstructural Analysis

Microstructural FeatureC26000H68Significance
Grain StructureEquiaxed α-grainsEquiaxed α-grainsSimilar formability
Average Grain Size50-100 μm45-90 μmH68: Slightly finer
Grain Boundary CharacterClean boundariesClean boundaries良好な延性
Phase DistributionUniform α-phaseUniform α-phaseHomogeneous properties
Inclusion Content低いVery lowH68: Better cleanliness
Texture Development適度適度Similar anisotropy

10.2 Stress Corrosion Cracking Susceptibility

環境C26000 SusceptibilityH68 SusceptibilityCritical Stress LevelPrevention Methods
Ammonia Solutions高い高い30-50% yield strengthStress relief, inhibitors
Mercury Exposure高い高いVery low levelsComplete avoidance
Nitrate Solutions適度適度50-70% yield strengthControlled pH
Steam Environments低い低い80-90% yield strengthCondensate removal
Sulfur Compounds適度適度40-60% yield strengthProtective coatings

10.3 Fatigue Performance Analysis

Loading ConditionC26000 PerformanceH68 PerformanceDesign Implications
High Cycle (>10^6)140-160 MPa145-165 MPaH68: Better for springs
Low Cycle (<10^4)280-320 MPa285-325 MPaSimilar performance
Thermal Fatigue良い良いTemperature cycling OK
Fretting Fatigue適度良いH68: Better surface
Corrosion Fatigue良い公平C26000: Better in corrosive

11. Emerging Applications and Future Trends

11.1 Advanced Manufacturing Technologies

TechnologyC26000 SuitabilityH68 SuitabilityDevelopment Status
添加剤の製造Research stageResearch stageLimited commercial use
Micro-machining良い素晴らしいH68: Better surface finish
Laser Processing良い良いSimilar thermal response
Precision Forming素晴らしいとても良いC26000: Complex shapes
Hybrid ProcessesDevelopingDevelopingBoth show promise

11.2 Sustainability Considerations

Sustainability FactorC26000 ImpactH68 ImpactIndustry Response
リサイクル性素晴らしい素晴らしいBoth 100% recyclable
エネルギー効率標準Improved processingH68: Lower energy
Carbon FootprintHigher Cu impactReduced Cu impactH68: 8-12% lower
Lifecycle AssessmentWell establishedImprovingBoth sustainable
Circular EconomyEstablished loopsDevelopingRegional differences

11.3 Market Evolution Drivers

Technology Trends:

  • Miniaturization favoring H68’s machinability
  • Cost pressures in manufacturing driving H68 adoption
  • Quality requirements supporting C26000 in critical applications

Regulatory Influences:

  • Environmental regulations affecting material choice
  • Trade policies influencing regional preferences
  • Standards harmonization efforts

Supply Chain Evolution:

  • Regional manufacturing preferences
  • Localization trends affecting material selection
  • Quality system harmonization

12. Selection Guidelines and Decision Framework

12.1 Application-Based Selection Matrix

Selection CriteriaWeight FactorC26000 ScoreH68 ScoreWeighted Impact
Corrosion Environment
Atmospheric exposure20%97C26000: +0.4
Water contact15%87C26000: +0.15
Chemical compatibility10%87C26000: +0.1
Manufacturing Requirements
Formability needs15%98C26000: +0.15
Machining requirements10%79H68: +0.2
Surface finish5%79H68: +0.1
経済的要因
Material cost15%69H68: +0.45
Processing cost10%79H68: +0.2

12.2 Decision Tree Methodology

Step 1: Environment Assessment

  • Marine/coastal → C26000 preferred
  • Indoor/controlled → H68 acceptable
  • Industrial atmosphere → C26000 recommended

Step 2: Manufacturing Process

  • Deep drawing required → C26000 preferred
  • High-volume machining → H68 preferred
  • Complex forming → C26000 recommended

Step 3: Economic Evaluation

  • Premium performance justified → C26000
  • Cost optimization critical → H68
  • Balanced requirements → Either suitable

Step 4: Supply Chain Factors

  • Global sourcing → C26000 (wider availability)
  • Regional sourcing → Depends on location
  • Long-term reliability → C26000 preferred

12.3 Implementation Recommendations

For C26000 Selection:

  1. Specify ASTM B36 or equivalent EN standard
  2. Require corrosion testing for critical applications
  3. Implement forming process optimization
  4. Plan for premium material cost
  5. Ensure global supply chain capability

For H68 Selection:

  1. Specify GB/T 5231 or establish equivalent
  2. Implement enhanced quality control procedures
  3. Optimize machining parameters for cost savings
  4. Develop regional supply relationships
  5. Consider total cost of ownership benefits

13. Conclusion and Strategic Recommendations

13.1 Comparative Assessment Summary

Both C26000 and H68 represent excellent choices within the single-phase brass family, with their selection dependent on specific application requirements and operational constraints:

C26000 Strengths:

  • Superior corrosion resistance for demanding environments
  • Excellent deep drawing and forming capabilities
  • Established global supply chains and standards
  • Proven long-term performance record
  • Better electrical and thermal conductivity

H68 Strengths:

  • Excellent plasticity with cost optimization
  • Superior machinability and surface finish
  • Improved fatigue performance
  • Better strength-to-cost ratio
  • Enhanced manufacturing efficiency

13.2 Strategic Selection Guidelines

Choose C26000 for:

  • Marine and coastal applications
  • Architectural hardware with weather exposure
  • High-end decorative applications
  • Applications requiring maximum corrosion resistance
  • Complex deep-drawn components
  • Global supply chain requirements

Choose H68 for:

  • High-volume manufacturing applications
  • Cost-sensitive markets
  • Precision machined components
  • Indoor controlled environments
  • Spring and fatigue-loaded applications
  • Regional Asian supply chains

13.3 Future Outlook

The market positions of both alloys will likely evolve based on:

Technological Factors:

  • Advanced manufacturing favoring H68’s machinability
  • Environmental requirements supporting both alloys’ sustainability
  • Miniaturization trends benefiting precision capabilities

Economic Drivers:

  • Copper price volatility affecting C26000 economics
  • Manufacturing cost pressures favoring H68
  • Quality requirements maintaining C26000 demand

Regional Developments:

  • Asian market growth supporting H68 expansion
  • Western market maturity maintaining C26000 dominance
  • Emerging markets showing mixed preferences

13.4 Final Recommendations

For Engineers and Designers:

  1. Conduct application-specific performance testing
  2. Consider total lifecycle costs, not just material price
  3. Evaluate supply chain requirements early in design
  4. Maintain flexibility for material substitution
  5. Stay informed on regional standards evolution

For Procurement Professionals:

  1. Develop qualified supplier networks for both alloys
  2. Implement risk management for supply continuity
  3. Monitor copper market trends affecting pricing
  4. Build relationships with regional suppliers
  5. Maintain material traceability systems

For Manufacturing Organizations:

  1. Optimize processes for selected alloy characteristics
  2. Train personnel on alloy-specific handling requirements
  3. Implement appropriate quality control measures
  4. Consider regional manufacturing strategies
  5. Develop sustainability metrics for material selection

This comprehensive analysis provides the technical foundation for informed decision-making between C26000 and H68 brass alloys. While both alloys offer excellent performance within their optimal application ranges, understanding their nuanced differences enables optimization of performance, cost, and reliability in specific applications.

The choice between these alloys ultimately depends on balancing performance requirements, economic constraints, and supply chain considerations within the context of specific applications and operating environments. Both alloys will continue to play important roles in the global brass market, with their relative importance varying by region and application sector.