Thixoforming : Semi-solid Metal Processing

Temperature (ºC)
1550
1500
1450
1400
1350
1300
1250
1200
1150
1100
1050
1000
L+α
α
+
γ
L+γ
γ+M 7C 3
0 1 2 3 4 5 6 7 8
C (mass%)
L
L+γ
+M7C3 L+M 7 C 3
γ+M7C3 +M7C3 L+C
L+C+M 7 C 3
+M
L+ 7C3 +M3C L+M3C Figure 3.39 Thermo-Calc calculated pseudo-binary phase
diagram in equilibrium for the system Fe–Cr–W–C–Mn–Si with
11.5% Cr, 0.7% W, 0.3% Mn and 0.25% Si.
20
0.10 200
18
Cr 0.09 150
16
0.08 100
14
0.07
50
12
10
8
C
0.06
0.05
0.04
0
-50
RT
6
0.03
-100
4
0.02 -150
2
0.01 -200
(a)
0
900 1000 1100 1200 1300 1400 1500
Temperature (ºC)
-250
1000 1100 1200 1300 1400
(b) Equilibrium temperature (ºC)
Figure 3.40 Thermodynamic calculations for the carbon and
chromium contents within austenite under equilibrium
conditions (a) and from this calculated Ms temperatures as a
function of the annealing temperature using the empirical
equation Ms ¼ 635 – 475[mass% C(g)]
(b) [64].
17[mass% Cr(g)]
w C (γ), .10 -3
90j 3 Material Aspects of Steel Thixoforming
w Cr (γ)
Ms (ºC)