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Dimensional changes in workpiece heat treatment

April 19, 2024

Different organizations have different volumes. The specific volume table of common organizations is as follows:

 

Organization wc (%) Specific volume at room temperature/(cm³/g)
Austenite
0—2
0.1212+0.0033(c%)
Martensite
0—2
0.1271+0.0025(c%)
Ferrite
0—0.02
0.1271
Cementite
6.7+-0.2
0.130+-0.001
∈ - carbides
8.5+-0.7
0.140+-0.002
Graphite
100
0.451
Ferrite+cementite
0—2
0.1271+0.0005(c%)
Low carbon martensite+∈ - carbides
0—2
0.1277+0.0015(c%-0.25)
Ferrite+∈ - carbides
0—2
0.1271+0.0015(c%)

 

The volume deformation caused by the volume difference caused by phase transformation during the heating and cooling process of the workpiece during heat treatment.

 

Dimensional changes caused by structural transformation of carbon steel:

 

Organizational transformation Volume change (%) Size change (%)
Spherical pearlite ->austenite
- 4.64+2.21(wc)
- 0.015+0.0074(wc)
Austenite ->martensite
4.64 – 0.53 (wc)
- 0.0155+0.0018(wc)
Spherical pearlite ->martensite
1.68 (wc)
0.0056(wc%)
Austenite ->lower bainite
4.64 – 1.43 (wc)
0.0156 – 0.0048(wc)
Spherical pearlite ->lower bainite
0.78 (wc)
0.0026(wc)
Austenite ->ferrite ->cementite
4.64 – 2.21(wc)
0.0155 – 0.0074(wc)
Spherical pearlite ->ferrite ->cementite
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