CAST IRONSAdvantages and disadvantages of cast irons (in comparison with steels):Advantages :good castability (low Tm, good fluidility)good machinability (graphite cast irons)antivibration properties low stress concentrationsensibilityDisadvantages :high brittleness non machinable (white cast iron, chilled cast iron)cold brittleness (KV = 7 14 J, 40/+23C)

Cast iron structure impactorsChemical composition (C, Si, Mn) Si graphite cast irons , Mn white cast ironCooling ratevjaht white cast iron, chilled cast iron vjaht grey cast iron ModificationMg, Ts, Ca spheroidal graphite cast ironAlloyingMn wear resistanceSi corrosion resistanceCr high-temperature strengthNi corrosion resistance, with Cr, Si wear resistance

CAST IRONS

Structure diagrams of cast irons

Chemical composition and cooling rateChemical composition (C and Si%)CAST IRONS

Classification and properties of cast irons (1)Mechanical properties of main graphite cast irons

CAST IRONS

Types of cast ironsRm, N/mm2HBA, %Lamellar graphite (grey) c.i.Spheroidal graphite c.i.Mallable (nest graphite) c.i.100450

3501000

300800190275

140360

100320 0

222

121,5

Classification and properties of cast irons (2)CAST IRONS

Heat treatment of cast irons (1)Hardness of metallic ground mass ferrite 100160 HB pearlite 180220 HB sorbite 220300 HB bainite 300320 HB martensite 380600 HBGrey cast iron heat treatment

CAST IRONS

Heat treatment Metallic groundmass in. fin.HardnessHardening 850950 CTemperingP+F, P M, Tr, S M, Tr Mnool Trnool SnoolHB 500

Increase of plasticity and toughnessDecrease of hardening stresses

Heat treatment of cast irons (2)Heat treatment of spheroidal graphite/ malleable cast iron

CAST IRONS

Heat treatmentTkar, CHeat treatment, HRCHardening

Isothermal hardening

Tempering900

850880

150170380400530550600650In dependent of structure 2060300 C 45350 C 35400 C 305259384526302227

Designation system of cast irons (EN)Designation and materials No. (1)Grey cast iron EN-GJL L lamellar GSpheroidal graphite c.i. EN-GJS S spheroidal GMalleable cast iron EN-GJM M malleable (temper G)whiteEN-GJMWblack EN-GJMB Grey cast iron (EN1561) Rm basedHB based

CAST IRONS

Designation and materials No. (2)Spheroidal graphite cast iron (EN1563) Rm ja A basedHB based

Malleable cast iron (EN1562)Rm ja A based White Black

CAST IRONS

DesignationMaterial NoDesignationMaterial NoEN-GJMW-350-4 ........... -550-4EN-JM1010 .............. -JM1050EN-GJMB-300-6 ............. -800-1EN-JM1110 ............. -JM1200

CAST IRONSBainitic cast iron (EN 1564)Designation Material No ApplicationEN-GJS-800-8EN-JS 1100 Highly stressed parts; wheel hubs, EN-GJS-1400- EN-JS gear rings, ADI castings (austempered ductile cast iron)Vermicular graphite c.i. (ISO 16112)ISO 16112/JV/300 Automotive parts gear housings ISO 16112/JV/500 Wear resistant cast iron (EN 12513)EN-GJN-HV350 EN-GJN-2019 Dressing rolls dredging shovels impellers for pumps

Cast steelsCast steel for general application (EN 10293)

1) Cast steel for pressure vessels (for high and low temperatures steam turbines, super heated steam armatures, also corrosion resistant)CAST IRONS

DesignationMaterial No.Condi-tionRm,N/mm2Rp,N/mm2A, %KV, JGE2001.0420Norm380-5302002527GE3001.0558Norm600-7503001527G17Mn51.1131Q + T450-6002402470G28Mn61.1165Norm520-6702601827GXCrNi121)1.4107-5403551845GX23CrMoV12-11.4931-740-8805401527

Thank You for attention!priit.kulu@ttu.ee