Figure 1.
Schematic illustrations of (a) the overall process flow for manufacturing a drive shaft, and (b) a detailed flowchart for fabricating preform (unit: mm).
Figure 1.
Schematic illustrations of (a) the overall process flow for manufacturing a drive shaft, and (b) a detailed flowchart for fabricating preform (unit: mm).
Figure 2.
(a) Time–temperature history of spheroidizing and annealing, and (b) heat-treated and phosphophyllite-coated AISI 1035 medium carbon steel workpiece.
Figure 2.
(a) Time–temperature history of spheroidizing and annealing, and (b) heat-treated and phosphophyllite-coated AISI 1035 medium carbon steel workpiece.
Figure 3.
Microstructures of raw material: (a) OM image (×1000); (b) SEM image (×1000); (c) SEM image (×3000).
Figure 3.
Microstructures of raw material: (a) OM image (×1000); (b) SEM image (×1000); (c) SEM image (×3000).
Figure 4.
Microstructures of spheroidized and annealed specimen: (a) OM image (×1000); (b) SEM image (×1000); (c) SEM image in section I (×3000); (d) SEM image in section II (×3000).
Figure 4.
Microstructures of spheroidized and annealed specimen: (a) OM image (×1000); (b) SEM image (×1000); (c) SEM image in section I (×3000); (d) SEM image in section II (×3000).
Figure 5.
Stress-strain curves extracted by uniaxial compression tests: (a) compressive stress-strain curves of raw and spheroidized-annealed specimens; (b) compressive true stress-strain curve of spheroidized and annealed specimen.
Figure 5.
Stress-strain curves extracted by uniaxial compression tests: (a) compressive stress-strain curves of raw and spheroidized-annealed specimens; (b) compressive true stress-strain curve of spheroidized and annealed specimen.
Figure 6.
Comparison of flow stress curves using experimental data from uniaxial compression tests: (a) true plastic stress-strain curves using various flow stress models; (b) true plastic stress-strain curves between Voce model and experimental data.
Figure 6.
Comparison of flow stress curves using experimental data from uniaxial compression tests: (a) true plastic stress-strain curves using various flow stress models; (b) true plastic stress-strain curves between Voce model and experimental data.
Figure 7.
(a) FE simulation flow of cold forward extrusion for shaping preform, and (b) discretized mesh structure of initial billet with one-sixteenth planar symmetric condition.
Figure 7.
(a) FE simulation flow of cold forward extrusion for shaping preform, and (b) discretized mesh structure of initial billet with one-sixteenth planar symmetric condition.
Figure 8.
Deformation history during forward extrusion and ejection in the case where plastic material model was applied.
Figure 8.
Deformation history during forward extrusion and ejection in the case where plastic material model was applied.
Figure 9.
Numerical simulation results in the case where plastic material model was applied: (a) effective stress distribution; (b) plastic deformation damage distribution; (c) distribution of residual stress and plastic deformation damage after preform ejection.
Figure 9.
Numerical simulation results in the case where plastic material model was applied: (a) effective stress distribution; (b) plastic deformation damage distribution; (c) distribution of residual stress and plastic deformation damage after preform ejection.
Figure 10.
Deformation history during forward extrusion and ejection in the case where elasto-plastic material model was applied.
Figure 10.
Deformation history during forward extrusion and ejection in the case where elasto-plastic material model was applied.
Figure 11.
Numerical simulation results in the case where elasto-plastic material model was applied: (a) effective stress distribution; (b) plastic deformation damage distribution; (c) distribution of residual stress and plastic deformation damage after preform ejection.
Figure 11.
Numerical simulation results in the case where elasto-plastic material model was applied: (a) effective stress distribution; (b) plastic deformation damage distribution; (c) distribution of residual stress and plastic deformation damage after preform ejection.
Figure 12.
Forging load prediction required for forward extrusion and ejection.
Figure 12.
Forging load prediction required for forward extrusion and ejection.
Figure 13.
Initial workpiece, spheroidizing-annealing heat-treated specimen, and phosphophyllite-coated initial billet.
Figure 13.
Initial workpiece, spheroidizing-annealing heat-treated specimen, and phosphophyllite-coated initial billet.
Figure 14.
Fabricated preform and metal flow: (a) outer diameter of cold forward-extruded preform (unit: mm) and (b) metal flow on longitudinal cross-section.
Figure 14.
Fabricated preform and metal flow: (a) outer diameter of cold forward-extruded preform (unit: mm) and (b) metal flow on longitudinal cross-section.
Figure 15.
Dimension variation (unit: mm): (a) target layout vs. plastic FE simulation, and (b) target layout vs. elasto-plastic FE simulation.
Figure 15.
Dimension variation (unit: mm): (a) target layout vs. plastic FE simulation, and (b) target layout vs. elasto-plastic FE simulation.
Figure 16.
Comparison of dimensional suitability between fabricated and numerically simulated preforms (unit: mm).
Figure 16.
Comparison of dimensional suitability between fabricated and numerically simulated preforms (unit: mm).
Figure 17.
Vickers micro-hardness distribution of preform fabricated by cold forward extrusion: (a) detailed grid structures for measuring micro-hardness; (b) comparison of Vickers micro-hardness distribution between ductile damage and residual stress.
Figure 17.
Vickers micro-hardness distribution of preform fabricated by cold forward extrusion: (a) detailed grid structures for measuring micro-hardness; (b) comparison of Vickers micro-hardness distribution between ductile damage and residual stress.
Figure 18.
EBSD IQ map and IPF map, and KAM map, of raw and spheroidized-annealed specimen.
Figure 18.
EBSD IQ map and IPF map, and KAM map, of raw and spheroidized-annealed specimen.
Figure 19.
Measuring sections for EBSD analysis of cold forward-extruded preform.
Figure 19.
Measuring sections for EBSD analysis of cold forward-extruded preform.
Figure 20.
EBSD IQ map and IPF map, and KAM map: (a) on central core regions; (b) on near outer surface regions.
Figure 20.
EBSD IQ map and IPF map, and KAM map: (a) on central core regions; (b) on near outer surface regions.
Table 1.
Chemical composition of AISI 1035 medium carbon steel material as received [unit: wt%].
Table 1.
Chemical composition of AISI 1035 medium carbon steel material as received [unit: wt%].
C | Mn | Si | P | S | Fe |
---|
0.350 | 0.800 | 0.275 | 0.003 | 0.005 | Bal. |
Table 2.
Grain size of raw and heat-treated AISI 1035 specimens.
Table 2.
Grain size of raw and heat-treated AISI 1035 specimens.
| Min. | Max. | Average |
---|
Raw Material | 7.27 µm | 11.42 µm | 8.84 µm |
Spheroidized-Annealed Material | 6.67 µm | 12.31 µm | 9.36 µm |
Table 3.
Mechanical properties obtained by uniaxial compressive tests of AISI 1035 specimens.
Table 3.
Mechanical properties obtained by uniaxial compressive tests of AISI 1035 specimens.
Properties | Raw Material | Heat-Treated Material |
---|
Engineering | True | Engineering | True |
---|
Young’s Modulus (GPa) | 196 | 196 | 196 | 196 |
Poisson’s Ratio | 0.29 | 0.29 | 0.29 | 0.29 |
Yield Strength (MPa) | 362.32 | 342.53 | 299.20 | 289.65 |
Ultimate Strength (MPa) | | 723.99 | | 638.30 |
Table 4.
Prediction and comparison on true stress-strain curve using various flow stress models.
Table 4.
Prediction and comparison on true stress-strain curve using various flow stress models.
Flow Stress Model | Formulation | Fitted Equation |
---|
Hollomon | | (MPa) | | (MPa) |
Swift | | (MPa) | | (MPa) |
Ludwik | | (MPa) | | (MPa) |
Voce | | (MPa) | | (MPa) |
[Note] | | : the material constants |
| : the initial stress and strain |
| : the work-hardening coefficients |
Table 5.
Summary of dimensional compatibility of preform obtained through forward extrusion and ejection operations (unit: mm).
Table 5.
Summary of dimensional compatibility of preform obtained through forward extrusion and ejection operations (unit: mm).
Properties | Target | Plastic | Elasto-Plastic | Experiment |
---|
Extrusion | Ejection | Extrusion | Ejection |
---|
Whole Length | (134.15) | 136.73 | 136.65 | 135.53 | 135.62 | 135.38 |
Upper Head Diameter | Ø51.0 | Ø50.99 | Ø50.99 | Ø50.99 | Ø51.05 | Ø51.04 |
Lower Head Diameter | Ø50.6 | Ø50.59 | Ø50.59 | Ø50.59 | Ø50.65 | Ø50.64 |
Shaft Diameter | Ø37.0 | Ø36.67 | Ø36.71 | Ø36.80 | Ø36.83 | Ø36.58 |
Extruded Shaft Length | 34.5 ± 1.0 | 34.52 | 34.52 | 34.42 | 34.42 | 34.35 |
Table 6.
Measured Vickers micro-hardness before and after spheroidizing-annealing of AISI 1035 workpiece material (unit: HV25).
Table 6.
Measured Vickers micro-hardness before and after spheroidizing-annealing of AISI 1035 workpiece material (unit: HV25).
| Measured Point | Raw | Heat-Treated |
1 | 178.2 | 136.2 |
2 | 170.3 | 137.8 |
3 | 171.1 | 137.7 |
4 | 188.1 | 135.0 |
5 | 168.2 | 134.6 |
6 | 172.8 | 138.2 |
7 | 178.1 | 139.9 |
8 | 172.1 | 136.0 |
9 | 174.4 | 142.8 |
Average | 174.8 | 136.8 |