4140 steel is a low alloy steel commonly used in structural members and mechanical components. It is composed of Chromium, Manganese, Carbon, Silicon, Molybdenum, Sulfur and Phosphorus submerged in a matrix of Iron.
Introduction
Listed below are several curves detailing the stress-strain relationship and permissible stress as a function of cycles for 4140 steel. Each of the plots provided are captioned with information pertaining to the testing conditions at the time of measurement. The data show experiments performed at varying strain rates, temperatures, load types, cycles, specimen dimensions, heat treatments, hardnesses, and ambient conditions. Consequently, the reader is directed to read the figure captions for context on the specifications of the tests. Each caption terminates with a clickable, bracketed number that redirects the reader to the source from which the information was obtained.
Stress-strain data
Listed below are the many testing conditions for the plots shown on Figures 1-10.
- Steel treatments: hot-rolled, quenched-and-tempered, normalized, austenitized, and hot-worked.
- Test type: tension, compression, torsion, cyclic compression and cyclic tension.
- Strain rates (1/s): 0.0083, 0.03, 0.04, 0.05, 0.06, 0.1, 0.5, and 5.0.
- Temperatures (deg. C): room, 900, and 1000.
Figure 1: True stress-strain and engineering stress-strain curves for AISI 4140 hot-rolled steel.
[1]
Figure 2: Representative flow stress curves obtained from hot torsion and compression test of AISI 4140 steel under various strain rates at 900 degrees Celsius.
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Figure 3: Representative flow stress curves obtained from hot torsion and compression test of AISI 4140 steel under various strain rates at 1000 degrees Celsius.
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Figure 4: Monotonic stress-strain curve and cyclic stress-strain curve at half the number of cycles to failure of quenched-and-tempered AISI 4140 steel at nearly the same strain rates.
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Figure 5: Monotonic stress-strain curve and cyclic stress-strain curve at half the number of cycles to failure of normalized AISI 4140 steel at nearly the same strain rates.
[3]
Figure 6: 4140 chromium-molybdenum alloy steel bar, monotonic and cyclic true stress-strain curves. Heat treatment: austenitized 999 deg. C (1830 deg. F), 1 h, oil quenched. Gage section size = 5.08 mm diam x 7.62 mm long (0.2 in. diam x 0.3 in. long). Strain rate = 0.5/min. Test condition: MT, monotonic tension; MC, monotonic compression; CT, cyclic tension; CC, cyclic compression. Composition: Fe-0.4C-1Cr-0.2Mo.
[4]
Figure 7: 4140 chromium-molybdenum alloy steel bar, monotonic and cyclic true stress-strain curves. Heat treatment: austenitized 999 deg. C (1830 deg. F), 1 h, oil quenched, tempered 199 deg. C (390 deg. F), 1 h, water quenched. Gage section size = 5.08 mm diam x 7.62 mm long (0.2 in. diam x 0.3 in. long). Strain rate = 0.5/min. Test condition: MT, monotonic tension; MC, monotonic compression; CT, cyclic tension; CC, cyclic compression. Composition: Fe-0.4C-1Cr-0.2Mo.
[4]
Figure 8: 4140 chromium-molybdenum alloy steel bar, monotonic and cyclic true stress-strain curves. Heat treatment: austenitized 999 deg. C (1830 deg. F), 1 h, oil quenched, tempered 399 deg. C (750 deg. F), 1 h, water quenched. Gage section size = 5.08 mm diam x 7.62 mm long (0.2 in. diam x 0.3 in. long). Strain rate = 0.5/min. Test condition: MT, monotonic tension; MC, monotonic compression; CT, cyclic tension; CC, cyclic compression. Composition: Fe-0.4C-1Cr-0.2Mo.
[4]
Figure 9: 4140 chromium-molybdenum alloy steel bar, monotonic and cyclic true stress-strain curves. Heat treatment: austenitized 999 deg. C (1830 deg. F), 1 h, oil quenched, tempered 649 deg. C (1200 deg. F), 1 h, water quenched. Gage section size = 5.08 mm diam x 7.62 mm long (0.2 in. diam x 0.3 in. long). Strain rate = 0.5/min. Test condition: MC, monotonic compression; CT, cyclic tension; CC, cyclic compression. Composition: Fe-0.4C-1Cr-0.2Mo.
[4]
Figure 10: 4140 chromium-molybdenum alloy steel bar, true compressive stress-strain curve. Specimens taken from hot-worked 57.15 mm (2.25 in.) diam bar, test specimen 20 mm x 40 mm long, normalized and annealed. After compression of about 40%, specimens remachined to 14 mm diam x 21 mm long. The discontinuity of results was typical. True yield stress at 0.2% offset = 813 MPa (118 ksi); strain-hardening exponent n = 0.145. Composition: FE-0.39C-1.00Cr-0.82Mn-0.26Si-0.21Mo-0.025S-0.012P.
[4] Fatigue-life curves
Listed below are the different testing conditions for the plots shown on Figures 11-18.
- Steel treatments: quenched-and-tempered, shot-peened, ground, deep-rolled, and as-received.
- Rockwell Scale C Hardness: 20, 28, 37, 44, and 52.
- Temperatures (deg. C): room and 340.
Figures 13-18 show fatigue-life curves for 4140 steel exposed to different ambient conditions. These include dry air, 93% moist air, dissolved oxygen in 3 % NaCl, and 93% moist argon.
Figure 11: S-N curves (failure probability, P = 50%) for quenched and tempered AISI 4140 (450 deg C, or 840 deg. F, for 2h). Samples shot-peened at different temperatures are compared with the ground condition.
[3]
Figure 12: A comparison of the effects of deep rolling 4140 at a high temperature (HT) of 340 deg. C followed by fatigue testing at room temperature (RT) with the corresponding room temperature deep rolled and baseline (as received) fatigue data. The numbers in parentheses indicate multiple runout tests at the same imposed stress amplitude.
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Figure 13: Effect of moisture in air and of dissolved oxygen in 3 % NaCl on fatigue life of 4140 steel having a Rockwell hardness (Rc) of 20 at 25 deg. C. Arrows mean no failure.
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Figure 14: Fatigue life of 4140 steel having a Rockwell hardness (Rc) of 28, in moist and dry air, 25 deg. C.
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Figure 15: Fatigue life of 4140 steel having a Rockwell hardness (Rc) of 37, in moist and dry air, and in aerated 3% NaCl, 25 deg. C.
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Figure 16: Fatigue life of 4140 steel having a Rockwell hardness (Rc) of 44, in moist and dry air, and in aerated 3% NaCl, 25 deg. C.
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Figure 17: Fatigue life of 4140 steel having a Rockwell hardness (Rc) of 52, in moist and dry air, and in aerated 3% NaCl, 25 deg. C.
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Figure 18: Effect of moist air and moist argon on fatigue life of 4140 steel having a Rockwell hardness (Rc) of 52 at 25 deg. C.
[6] References
- ↑ Marc André Meyers and Krishan Kumar Chawla. "Mechanical Behavior of Materials."
- ↑ 2.0 2.1 S.I. Kim, Y.Lee, and S.M. Byon. "Study on constitutive relation of AISI 4140 steel subject to large strain at elevated temperatures."
- ↑ 3.0 3.1 3.2 George E. Totten, M. Howes and T. Inoue. "Handbook of Residual Stress and Deformation of Steel."
- ↑ 4.0 4.1 4.2 4.3 4.4 ASM International. "Atlas of Stress-strain Curves."
- ↑ Indian Institute of Metals. "Emerging Challenges for Metals and Materials Engineering and Technology."
- ↑ 6.0 6.1 6.2 6.3 6.4 6.5 H. H. Lee and H. H. Uhlig . "Corrosion fatigue of type 4140 high strength steel."
