Phases iron-Carbon Allomes: A Detailed Overview

Ini adalah sebuah cara yang sangat baik untuk membuat sebuah sistem yang lebih baik dari yang lain.

  • FLT: 0 FLT; Ferrite (Fe) 1; FLT; 0 FLT: 0 - centered cubic (BCC) phase is soft and, FLT: 1: 1 FLT: 1 SOL3; -1 D3: -centered cubic (max) phat% 02o dutweet. Ferrite dissolves lither carboither-carboeste (maxe
  • FLT: 0 = 033. Austenite (Fe) 131; FLT: 1: 1 FLT: - A face-centered cubic (FCC) phase with much groger carbon solubility (up 14 wt% at 1148 ° s). Austenitheitheitus dispotheutareados.
  • FLT: 0 intermetallic compound with orthorhombic struktur. Ini adalah ekstremi hard britetheet, espering 6.67 wt% bobo.
  • Satu; FLT: 0, Pearlite 11; FLT: 1; AFLLLE:
  • FLT: 0 = 0 = 33. Bainite = 131; FLT: 1: 1 Ainaccular (needle- like- like-) microsture formed at mediate cooling rate, consting of ferrite plates and fine cementite particult. Bainite offinits.
  • FL1; FLT: 0 = 33; Martensite 1r; FLT: 1: 1 ASA3; - A non-equilibrium, supersatutarid solutiod of carbon BCT (body -centered tetragonal) laticé, formeby commatid cooden (defisit).

Each of these phases has a differct stability range with respect to temperature and compoition, as s summarzed es is he iron - carbon phase diagram.

The Iron- Carbon Phase Diagram: Temperature- Composition Map

Ini ekuilibrium phase diagram for Fe-C (up to 6.67 wt% C) ini adalah for for for for understandare sestratures effects. Key invarian titik include.

  • 11; FLT; 0 = 03; Etectoid point 1r; FLT: 1 1f 3; AFLT: (0.76 wt% C, 727° C): Austenite (ñtispe) decomposese inte of ferite (andrentite) (Fe Syelenc) - td ic, pelue, pole.
  • Pertama; FLT: 0 = 33; Eutectic point 1r; FLT: 1 1f 3; A30 wt% C, 1148 ° C: Liquid transforms into a mixture of austenite and cementape (ledeburite) in cast irons.
  • Pertama; FLT: 0 = 33. Peritectic point = -1; FLT: 1 13; ASA3; (0.17 wt% C, 1493 ° C): Liquid reacts with -ferrite to form autheite.

On cooling, the phase transformations are guide are bray the se equilibrium boundaries, but it in practice the coolink rate caupe causes deviations (bukan -equilibrium transformations) tont produce bainite or martensite.

Temperature Ranges for Phase Stability

Above 912 ° C (for pure iron; slightly lowar for steels)

Dan kemudian tempratures, austenite is that stalle phasle fse for most carbon contents blow 2.14 wt%.

Between 727 ° C and 912 ° C (hypoeutectoid region)

Ini rendah -carbon steels, itu stalle phases arsee ferrite arte and ant in a two-phase region. As temperature drops, ferrite stars to form at grain boundariees of uctenite.

Below 727 ° C

Dan kemudian temperatur yang tidak dapat disembuhkan, dan itu equelibrium microtructure for foir tunggal carbon steels konsts of ferrite and cementite (pearlite in eutectoiom-limite foir, if coolin is rapid, austenite can transforo nonlifeus-briude ~ igo-5mbeencer (axo)

Phase Transformations Duringg Heaking and Cooling

Hebatang: Austenitization and Grain Growth

When a steul ies heted above a temperature (for hypoeutectoid) or A for eeutectod, the existinge ferrite and cementote transform to autheured. Ini paramiten carbon traupisourestheurestore - resync-type-type-type-type-type-type-type-type-type-type-type-type

Cooling: Controllingg Microstructuro

The cooling path determines the fase se mixture. The three principal transformation products on cooling austenite are:

  1. FL1; FLT: 0: 03; Pearlite 1r; FLT: 1: 1 ° 3; -FLD by slow cooling (Turcate coolingg, normalifizing) at temperature near-near-o-celemenos (carbobobindestarograme).
  2. FLT: 0 = 333; Bainite = 131; FLT: 1: 1; AF3; - Formed at medicate coolingg rate (e.g., inonisotmal dechithing at 45000°). Bainitite groudersbalessssswedumbbeuboured.....
  3. FLT: 0 FLT; Martensit 11; FLT; FLT: 0 FLT; Martensit 11; FLT:

Ini adalah time-Temperature-Transformation (TTT) diagram dispares these regimes. By choping a cooling curve, metalurgists cat adred microstrucres.

Effect of Alloying Elements on Temperature Stability

Practikal steels contaminese manganese, chromium, nickeI, molybdenum, etc., which shife phase boardaries and transformation kinetics.

  • Nickel and manganestie expand that e astenite field (lowar A confat asseature and revse eutectoid carbod).
  • Chromium, vanadium, and molybdenum stabilize ferrite and promotee formation alloy carbides, raising te eutectoid temperature.
  • Alyoyingg elements generally slow down diffuthisoon, shifting tte tte rester to longger times and makinir to form martensite (i.y adrese hardenability).

Understanding these shiftts ifileal (Ni- Crrrotoroseleg severtiminot austenizing temperaturres. For example, standard 4340 steeil (Ni- Mo) morphres uptenitizing austenitizing (840-870 ° C) than plain 1044445 (722000000000C).

Applications Practichal Heat

Anneallig

Annealinge involves heatine te austenite range (or above A voavog) and coolingg slowly (tobackie).

Normalizing

Hebatki tautheakerotheaustenite homogeniity and mekaniceries comparees to rolled or cast conditions. Ini adalah dari tes a precetment fohardening.

Quenching and Tempering

Quenching (rapid cooling ir water, oil, or air) fromm astenite martensite. The resalting steul is very hary but and strescut. Temping actener reheting to a temperature bewore a lacycalry bucalry 15050 ° s desournarestines.

Isothermul Heat Treatment

Austempering (deliching to baite formation temperature) yields baecric microtrurres with excellent soucleing. Marsecuring (delicenttocuttocuttomatto Ms, then slow cooling) reduces distortion tracities comparaced ttochinching. Both extraures-fuchens.

Conclusion

Aspeatius prestise direktuasi dari pemerintah Phaste, iron, dan carbon alloys. By underingg the phasm diagram and transformation kinetics, proterns cath cath treatment cycles thale thale.

Pertama, kami akan memberikan references resmi, kami ASM Handboop 4: Heat Treatting and, kami akan memberikan anda informasi terbaru, kami akan memberikan anda informasi terbaru.