MIL-HDBK-5H 1 December 1998

Transcription

1 75 is an Al-Zn-Mg-Cu-Zr alloy developed to have a combination of high strength, high resistance to stress-corrosion cracking, and good fracture toughness, particularly in thick sections. The use of zirconium in lieu of chromium provides a low sensitivity to quench, which results in high strengths in thick sections. Plate, hand, and die forgings in the T74 temper have static strengths about equivalent to those of corresponding products of 779 in the T6 tempers and toughness levels equal to or higher than other conventional high-strength alloys. The properties of extrusions should be based upon the thickness at the time of quenching prior to machining. Selection of the mechanical properties based upon its final machined thickness may be unconservative; therefore, the thickness at the time of quenching to achieve properties is an important factor in the selection of the proper thickness column. For extrusions having sections with various thicknesses, consideration should be given to the properties as a function of thickness. Plate in the T7451 temper has stress-corrosion resistance higher than 775-T7651, and hand and die forgings in the T7452 and T74 tempers, respectively, have stress-corrosion resistance similar to 7175-T74 forgings. The T73 temper provides the highest resistance to stress corrosion for this alloy. The T76 temper provides for good exfoliation resistance and higher stress-corrosion resistance than T6 tempers of 775 and The T74 temper provides stress-corrosion and strength characteristics intermediate to those of T76 and T73. Refer to Section for further comments regarding the resistance of the alloy to stresscorrosion cracking. Refer to Section for comments regarding the weldability of this alloy. Material specifications for 75 are shown in Table (a). Room-temperature properties are shown in Table (b 1 ) through (e 3 ). Specification AMS 5 AMS 418 AMS 417 AMS 4333 AMS 43 AMS 4341 AMS 4342 AMS 421 MIL-A Bare plate Hand forging Die forging Die forging Extruded shape Extruded shape Extruded shape Bare plate Forging Form The temper index for 75 is as follows: Section Temper T7351 and T73511 T74, T7451, and T7452 (formerly T736, T73651, T73652) T7651 and T

2 Figures (a) through (d) present stress-strain and tangent-modulus curves for extrusions. Fatigue data are presented in Figures (a) and (b). Elevated-temperature curves for T7451 plate are presented in Figure Figures (a) through (j) present stress-strain and tangent-modulus curves for various products and tempers. Fatigue data are presented in Figures (a) through (i). Fatigue-crack-propagation data for T7451 plate are presented in Figures (a) through (c). Figures (a) through (f) present stress-strain and tangent-modulus curves for extruded shapes. Fatigue data are presented in Figure (a) and (b). 3-37

3 Specification.. AMS 5 Form.. Plate Temper T7451 Thickness, in Basis.. A B A B A B A B A B A B Mechanical Properties: F tu, ksi: L LT. ST.. F ty, ksi: L LT. ST.. F cy, ksi: L LT. ST.. F su, ksi F brua, ksi: (e/d = 1.5). (e/d = 2.). F brya, ksi: (e/d = 1.5). (e/d = 2.). e, percent (S-basis): L LT. ST.. E, 1 3 ksi. E c, 1 3 ksi G, 1 3 ksi µ. Physical Properties:, lb/in. 3. C, Btu/(lb)(F).. K, Btu/[(hr)(ft 2 )(F)/ft], 1-6 in./in./f. 74 b 74 b b b b 73 b 68 b b a See Table Bearing values are dry pin values per Section b S-basis values. See Table (b 2 ) for rounded T 99 values b 62 b (at 212F) 91 (at 77F) 12.8 (68 to 212F) 71 b 71 b b b b

4 ! " # $ % & '( Thickness, in... Mechanical Properties: F tu, ksi: L. LT.. ST F ty, ksi: L. LT.. ST

5 Specification AMS 421 Form Plate Temper. T7651 Thickness, in Basis S A B A B A B S Mechanical Properties: F tu, ksi: L. LT.. ST F ty, ksi: L. LT.. ST F cy, ksi: L. LT.. ST F su, ksi. F brua, ksi: (e/d = 1.5).. (e/d = 2.).. F brya, ksi: (e/d = 1.5).. (e/d = 2.).. e, percent (S-basis): L. LT.. ST b b E, 1 3 ksi.. E c, 1 3 ksi. G, 1 3 ksi. µ.. Physical Properties:, lb/in. 3.. C, Btu/(lb)(F) K, Btu/[(hr)(ft 2 )(F)/ft], 1-6 in./in./f (at 212F) 89 (at 77F) 12.8 (68 to 212F) a See Table Bearing values are dry pin values per Section b S-basis values since T 99 values could not be determined. 3-31

6 ) Specification.. AMS 417 and MIL-A Form.. Die forging Temper T74 a Thickness b, in Basis.. S S S S Mechanical Properties: F tu, ksi: L T c.. F ty, ksi: L T c.. F cy, ksi: L ST.. F su, ksi F brud, ksi: (e/d = 1.5). (e/d = 2.). F bryd, ksi: (e/d = 1.5). (e/d = 2.). e, percent: L T c.. E, 1 3 ksi. E c, 1 3 ksi G, 1 3 ksi µ. Physical Properties:, lb/in. 3. C, Btu/(lb)(F).. K, Btu/[(hr)(ft 2 )(F)/ft], 1-6 in./in./f (at 212F) 91 (at 77F) 12.8 (68 to 212F) a Design values were based upon data obtained from testing T74 die forgings, heat treated by suppliers and supplied in T74 temper. b Thickness at the time of heat treatment. When die forgings are machined before heat treatment, the mechanical properties are applicable provided the as-forged thickness is not greater than twice the thickness at the time of heat treatment. c T indicates any grain direction not within ±15 of being parallel to the forging flow lines. F cy (T) values are based upon short transverse (ST) test data. d Bearing values are dry pin values per Section

7 )*+ Specification.. AMS 4333 Form.. Die forging Temper T7452 Thickness a, in Basis.. S S Mechanical Properties: F tu, ksi: L T a.. F ty, ksi: L T a.. F cy, ksi: L ST.. F su, ksi F brub, ksi: (e/d = 1.5). (e/d = 2.). F bryb, ksi: (e/d = 1.5). (e/d = 2.). e, percent: L T a.. E, 1 3 ksi. E c, 1 3 ksi G, 1 3 ksi µ. Physical Properties:, lb/in. 3. C, Btu/(lb)(F).. K, Btu/[(hr)(ft 2 )(F)/ft].., 1-6 in./in./f (at 212F) 91 (at 77F) 12.8 (68 to 212F) a T indicates any grain direction within ±15 of being perpendicular to the forging flow lines. F cy (T) values are based upon short transverse (ST) test data. b Bearing values are dry pin values per Section

8 , ) Specification AMS 418 and MIL-A Form Hand Forging Temper. T7452 Thickness, in Basis S S S S S A B S Mechanical Properties: F tu, ksi: L. LT.. ST F ty, ksi: L. LT.. ST F cy, ksi: L. LT.. ST F su, ksi. F brua, ksi: (e/d = 1.5).. (e/d = 2.).. F brya, ksi: (e/d = 1.5).. (e/d = 2.).. e, percent (S-basis): L. LT.. ST E, 1 3 ksi.. E c, 1 3 ksi. G, 1 3 ksi. µ.. Physical Properties:, lb/in. 3.. C, Btu/(lb)(F) K, Btu/[(hr)(ft 2 )(F)/ft], 1-6 in./in./f (at 212F) 91 (at 77F) 12.8 (68 to 212F) a Bearing values are dry pin values per Section b S-basis values. The rounded T 99 values for F ty (LT) = 56 ksi and F ty (ST) = 52 ksi b 51 b

9 -. Specification.. AMS 4341 Form.. Extrusion Temper T73511 Cross-Sectional Area, in Thickness or Diameter, b in Basis.. S S S S S Mechanical Properties: F tu, ksi: L LT. F ty, ksi: L LT. F cy, ksi: L LT. F su, ksi F brua, ksi: (e/d = 1.5). (e/d = 2.). F brya, ksi: (e/d = 1.5). (e/d = 2.) e, percent: L E, 1 3 ksi. E c, 1 3 ksi G, 1 3 ksi µ. Physical Properties:, lb/in. 3. C, Btu/(lb)(F).. K, Btu/[(hr)(ft 2 )(F)/ft].., 1-6 in./in./f (at 212F) 93 (at 77F) 12.8 (68 to 212F) a Bearing values are dry pin values per Section b The mechanical properties are to be based upon the thickness at the time of quench

10 -. Specification.. AMS 4342 Form.. Extrusion b Temper T74511 Cross-Sectional Area, in Thickness or Diameter, c in Basis.. S S S S S Mechanical Properties: F tu, ksi: L LT. F ty, ksi: L LT. F cy, ksi: L LT. F su, ksi F brua, ksi: (e/d = 1.5). (e/d = 2.). F brya, ksi: (e/d = 1.5). (e/d = 2.) e, percent: L E, 1 3 ksi. E c, 1 3 ksi G, 1 3 ksi µ. Physical Properties:, lb/in. 3. C, Btu/(lb)(F).. K, Btu/[(hr)(ft 2 )(F)/ft].., 1-6 in./in./f a Bearing values are dry pin values per Section b Excluding tubing. c The mechanical properties are to be based upon the thickness at the time of quench (at 212F) 93 (at 77F) 12.8 (68 to 212F)

11 -. Specification. AMS 43 Form. Extrusion Temper.. T Thickness, b in Basis. A B S S S S S Mechanical Properties: F tu, ksi: L.. LT F ty, ksi: L.. LT F cy, ksi: L.. LT F su, ksi.. F brua, ksi: (e/d = 1.5) (e/d = 2.) F brya, ksi: (e/d = 1.5) (e/d = 2.) e, percent (S-basis): L E, 1 3 ksi E c, 1 3 ksi.. G, 1 3 ksi.. µ Physical Properties:, lb/in. 3 C, Btu/(lb)(F). K, Btu/[(hr)(ft 2 )(F)/ft]., 1-6 in./in./f (at 212F) 89 (at 77F) 12.8 (68 to 212F) a Bearing values are dry pin values per Section b The mechanical properties are to be based upon the thickness at the time of quench

12 Long Transverse n (L-tension) = 25 n (LT-tension) = 21 2 TYPICAL Thickness: in. Cross-sectional area: 32 in. in Strain,.1 in./in. ) (/ & & (1. 2 n (L-tension) = 22 n (LT-tension) = 19 n (ST-tension) = 14 TYPICAL Long Transverse Short Transverse Thickness: = in. Cross-sectional area: 43 in Strain,.1 in./in. ) (/ & & (

13 Long Transverse 2 n (L-comp.) = 39 n (LT-comp.) = 38 TYPICA Thickness in. Cross-sectional area: 32 in Strain,.1 in./in. Compressive Tangent Modulus, 1 3 ksi ) (/ & & & (1. Short Transverse Long Transverse 2 n (L-comp.) = 29 n (LT-comp.) = 33 n(st-comp.) = 23 Short Transverse TYPICAL Thickness = in. Cross-sectional area: 43 in Strain,.1 in./in. Compressive Tangent Modulus, 1 3 ksi ) (/ & & & (

14 ) (2 3& %45 & (1. 6 Correlative Information for Figure (a) Product Form: Extruded shape,.5 to 5.-inch thick Properties: TUS, ksi TYS, ksi Temp.,F RT Specimen Details: Unnotched.3-inch diameter Surface Condition: Not specified References: (b) and (b) Test Parameters: Loading - Axial Frequency - cpm Temperature - RT Environment - Air No. of Heats/Lots: Not specified Equivalent Stress Equation: Log N f = log (S eq -16) S eq = S max (1-R).55 Standard Error of Estimate =.516 Standard Deviation in Life = 1.1 R 2 = 78% Sample Size = 128 [Caution: The equivalent stress model may provide unrealistic life predictions for stress ratios beyond those represented above.] 3-319

15 ) (2 3& % & (1. 6 Correlative Information for Figure (b) Product Form: Extruded shape,.5 to 5. inch thick Properties: TUS, ksi TYS, ksi Temp.,F RT Specimen Details: Circumferentially notched, K t = inch gross diameter.253-inch net diameter.13-inch root radius, r flank angle, Surface Condition: Not specified References: (b) and (b) Test Parameters: Loading - Axial Frequency - cpm Temperature - RT Environment - Air No. of Heats/Lots: Not specified Equivalent Stress Equation: Log N f = log (S eq -5.) S eq = S max (1-R).56 Standard Error of Estimate =.268 Standard Deviation in Life =.733 R 2 = 87% Sample Size = 13 [Caution: The equivalent stress model may provide unrealistic life predictions for stress ratios beyond those represented above.] 3-32

16 6WUHQJWK DW WHPSHUDWXUH ([SRVXUH XS WR KU ) W\ 3HUFHQWDJH RI 5RRP 7HPSHUDWXUH 6WUHQJWK ) WX 7HPSHUDWXUH ƒ) ) 9( - ) ) & '( 3-321

17 Long Transverse Short Transverse 2 n (L-tension) = 19 n (LT-tension) = 13 n (ST-tension) = 1 TYPICAL Thickness =.5-4. in Strain,.1 in./in. ) 9/ & & '( Long Transverse Short Transverse 2 n (L-comp.) = 19 n (LT-comp.) = 22 n(st-comp.) = 16 TYPICAL Thickness =.5-4. in Strain,.1 in./in. Compressive Tangent Modulus, 1 3 ksi ) 9/ & & & '( 3-322

18 Long Transverse Short Transverse n (L-tension) = 14 n (LT-tension) = 14 n (ST-tension) = TYPICAL Thickness 7. in Strain,.1 in./in. ) 9/ & & '9 Long Transverse Short Transverse Long Transverse Short Transverse 2 n (L-comp.) = 15 n (LT-comp.) = 18 n(st-comp.) = 2 TYPICAL Thickness 7. in Strain,.1 in./in. Compressive Tangent Modulus, 1 3 ksi ) 9/ & & & '

19 2 Short Transverse n (L-tension) = 27 n (ST-tension) = 24 TYPICAL Thickness 3. in Strain,.1 in./in. ) 9/ & & ' Short Transverse 2 n (L-comp.) = 44 n (ST-comp.) = 32 TYPICAL Thickness 3. in Strain,.1 in./in. Compressive Tangent Modulus, 1 3 ksi ) 9/ & & & ' 3-324

20 n (L-tension) = 19 n (LT-tension) = 26 Long Transverse 2 TYPICAL Thickness 1.75 in Strain,.1 in./in. ) 9/ & & '((. Long Transverse 2 Long Transverse n (L-comp.) = 19 n (LT-comp.) = 23 TYPICAL Thickness 1.75 in Strain,.1 in./in. Compressive Tangent Modulus, 1 3 ksi ) 9/ & & & '((

21 2 n (L-tension) = 11 n (ST-tension) = 7.3 TYPICAL Thickness 6. in. Short Transverse Strain,.1 in./in. ) 9/ & & '9 Short Transverse 2 n (L-comp.) = 12 n (ST-comp.) = 18 TYPICAL Thickness 6. in Strain,.1 in./in. Compressive Tangent Modulus, 1 3 ksi ) 9/: & & & '

22 ) 92 3& %45 & '( 6 Correlative Information for Figure (a) Product Form: Plate, 1.-inch thick Properties: TUS, ksi TYS, ksi Temp.,F RT Specimen Details: Unnotched.3-inch diameter Surface Condition: Not specified References: (b) and (b) Test Parameters: Loading - Axial Frequency - cpm Temperature - RT Environment - Air No. of Heats/Lots: 1 Equivalent Stress Equation: Log N f = log (S eq -15.5) S eq = S max (1-R). Standard Error of Estimate =.49 Standard Deviation in Life =.942 R 2 = 73% Sample Size = 35 [Caution: The equivalent stress model may provide unrealistic life predictions for stress ratios beyond those represented above.] 3-327

23 ) 92 3& %45 & '( 6 Correlative Information for Figure (b) Product Form: Plate, 1. to 6. inches thick Properties: TUS, ksi TYS, ksi Temp.,F RT Specimen Details: Unnotched.25- and.3-inch diameter Surface Condition: Not specified References: (b), (b) and (e) Test Parameters: Loading - Axial Frequency - cpm and unspecified Temperature - RT Environment - Air No. of Heats/Lots: 15 Equivalent Stress Equation: Log N f = log (S eq -1) S eq = S max (1-R).59 Standard Error of Estimate =.57 Standard Deviation in Life =.794 R 2 = 59% Sample Size = 85 [Caution: The equivalent stress model may provide unrealistic life predictions for stress ratios beyond those represented above.] 3-328

24 ) 92 3& % & '( 6 Correlative Information for Figure (c) Product Form: Plate, 1. to 6.-inches thick Properties: TUS, ksi TYS, ksi Temp.,F RT Specimen Details: Circumferentially notched, K t = and.373-inch gross diameter.253-inch net diameter.13-inch notch-tip radius, r flank angle, Surface Condition: Not specified References: (b) and (b) and (c) Test Parameters: Loading - Axial Frequency - cpm and unspecified Temperature - RT Environment - Air No. of Heats/Lots: 11 Equivalent Stress Equation: Log N f = log (S eq ) S eq = S max (1-R). Standard Error of Estimate =.248 Standard Deviation in Life =.728 R 2 = 88% Sample Size = 79 [Caution: The equivalent stress model may provide unrealistic life predictions for stress ratios beyond those represented above.] 3-329

25 ) 92 3& % /6 & '(1. 6 Correlative Information for Figure (d) Product Form: Extruded shape,.5 to 5.-inch thick Properties: TUS, ksi TYS, ksi Temp.,F RT Specimen Details: Notched, center hole, K t = inch diameter.25-inch thick 1.-inch wide Surface Condition: Not specified Reference: (a) Test Parameters: Loading - Axial Frequency - Not specified Temperature - RT Environment - Air No. of Heats/Lots: 6 Equivalent Stress Equation: Log N f = log (S eq -1) S eq = S max (1-R).3 Standard Error of Estimate =.243 Standard Deviation in Life =.724 R 2 = 89% Sample Size = 34 [Caution: The equivalent stress model may provide unrealistic life predictions for stress ratios beyond those represented above.] 3-33

26 ) 92 3& %45 & '9 6 Correlative Information for Figure (e) Product Form: Hand forgings, 2. to 8.-inch thick Properties: TUS, ksi TYS, ksi Temp.,F RT Specimen Details: Unnotched.3-inch diameter Surface Condition: Not specified References: (b) and (b) Test Parameters: Loading - Axial Frequency - cpm Temperature - RT Environment - Air No. of Heats/Lots: 1 Equivalent Stress Equation: Log N f = log (S eq -3) S eq = S max (1-R). Standard Error of Estimate =. Standard Deviation in Life =.982 R 2 = 83% Sample Size = 25 [Caution: The equivalent stress model may provide unrealistic life predictions for stress ratios beyond those represented above.] 3-331

27 ) 92 3& %45 & '9 6 Correlative Information for Figure (f) Product Form: Hand forgings, 2. to 8.-inch thick Properties: TUS, ksi TYS, ksi Temp.,F RT Specimen Details: Unnotched.3-inch diameter Surface Condition: Not specified References: (b) and (b) Test Parameters: Loading - Axial Frequency - cpm and unspecified Temperature - RT Environment - Air No. of Heats/Lots: 1 Equivalent Stress Equation: Log N f = log (S eq -21) S eq = S max (1-R).57 Standard Error of Estimate =. Standard Deviation in Life =.3 R 2 = 75% Sample Size = 55 [Caution: The equivalent stress model may provide unrealistic life predictions for stress ratios beyond those represented above.] 3-332

28 ) 92 3& % & ' Correlative Information for Figure (g) Product Form: Hand forgings, 2. to 8.-inch thick Properties: TUS, ksi TYS, ksi Temp.,F RT Specimen Details: Circumferentially notched, K t = inch gross diameter.253-inch net diameter.13-inch root radius, r flank angle, Surface Condition: Not specified References: (b) and (b) Test Parameters: Loading - Axial Frequency - cpm Temperature - RT Environment - Air No. of Heats/Lots: 1 Equivalent Stress Equation: Log N f = log (S eq -5) S eq = S max (1-R).68 Standard Error of Estimate =.37 Standard Deviation in Life =.735 R 2 = 83% Sample Size = [Caution: The equivalent stress model may provide unrealistic life predictions for stress ratios beyond those represented above.] 3-333

29 ) 92 3& %45 & ' 6 Correlative Information for Figure (h) Product Form: Die forging Properties: TUS, ksi TYS, ksi Temp.,F RT Specimen Details: Unnotched.3-inch diameter Surface Condition: Not specified References: (b) and (b) Test Parameters: Loading - Axial Frequency - cpm Temperature - RT Environment - Air No. of Heats/Lots: 4 Equivalent Stress Equation: Log N f = log (S max ) Standard Error of Estimate =.381 Standard Deviation in Life =.82 R 2 = 78% Sample Size = 2 [Caution: The equivalent stress model may provide unrealistic life predictions for stress ratios beyond those represented above.] 3-334

30 ) 92 3& % & ' 6 Correlative Information for Figure (i) Product Form: Die forging Properties: TUS, ksi TYS, ksi Temp.,F RT Specimen Details: Circumferentially notched, K t = and.35-inch gross diameter.253- or.222-inch net diameter.13- or.12-inch root radius, r flank angle, Surface Condition: Not specified References: (b), (b), and (b) Test Parameters: Loading - Axial Frequency -, 1 cpm Temperature - RT Environment - Air No. of Heats/Lots: 6 Equivalent Stress Equation: Log N f = log (S eq ) S eq = S max (1-R).629 Standard Error of Estimate =.56 Standard Deviation in Life =.896 R 2 = 68% Sample Size = 73 [Caution: The equivalent stress model may provide unrealistic life predictions for stress ratios beyond those represented above.] 3-335

31 ) 9; )&<& (&&< & '( =! 9;> Specimen Thickness: inch Environment: Lab air (~5% humidity) and Specimen Width: inches humid air (% humidity) Specimen Type: C(T) Temperature: RT Stress Ratio, R:.1 Frequency, f: 1-2 Hz 3-336

32 ) 9; )&<& (& /&&< & '( =! 9;> Specimen Thickness: inch Environment: Dry air (< 1% humidity) Specimen Width: 3.5 inches Temperature: RT Specimen Type: C(T) Frequency, f: 18.3 Hz Stress Ratio, R:

33 ) 9; )&<& (& /&&< & '( =! 9;> Specimen Thickness: inch Environment: Humid air (>9% humidity) Specimen Width: 3.5 inches Temperature: RT Specimen Type: C(T) Frequency, f: 18.3 Hz Stress Ratio, R:

34 Long Transverse n (L-tension) = 25 n (LT-tension) = 2 2 TYPICAL Thickness: in. Cross-sectional area: 32 in Strain,.1 in./in. ) / & & /(1. Long Transverse Short Transverse 2 n (L-tension) = 28 n (LT-tension) = 13 n (ST-tension) = 13 TYPICAL Thickness: in. Cross-sectional area: 43 in Strain,.1 in./in. ) / & & /(

35 Long Transverse 2 n (L-comp.) = 27 n (LT-comp.) = 33 TYPICAL Thickness in. Cross-sectional area: 32 in Strain,.1 in./in. Compressive Tangent Modulus, 1 3 ksi ) / & & & /(1. Short Transverse Long Transverse 2 n (L-comp.) = 22 n (LT-comp.) = 27 n(st-comp.) = 22 TYPICAL Thickness = in. Cross-sectional area: 43 in Strain,.1 in./in. Compressive Tangent Modulus, 1 3 ksi ) / & & & /(1. 3-3

36 Long Transverse 2 n (L-tension) = 19 n (LT-tension) = 14 TYPICAL Thickness 2. in Strain,.1 in./in. ) / & & /( Long Transverse 2 n (L-comp.) = 18 n (LT-comp.) = Strain,.1 in./in. Compressive Tangent Modulus, 1 3 ksi TYPICAL Thickness 2. in. ) / & & & /(

37 ) 2 3& %45 & /(1. 6 Correlative Information for Figure (a) Product Form: Extruded shape,.55.-inch thick Properties: TUS, ksi TYS, ksi Temp.,F RT Specimen Details: Unnotched.3-inch diameter Surface Condition: Not specified References: (b), (b), and (b) Test Parameters: Loading - Axial Frequency - cpm Temperature - RT Environment - Air No. of Heats/Lots: 1 Equivalent Stress Equation: Log N f = log (S eq -12) S eq = S max (1-R).61 Standard Error of Estimate =.493 Standard Deviation in Life = 1.1 R 2 = 76% Sample Size = 161 [Caution: The equivalent stress model may provide unrealistic life predictions for stress ratios beyond those represented above.] 3-342

38 ) 2 3& % & /(1. 6 Correlative Information for Figure (b) Product Form: Extruded shape,.5 to 5.-inch thick Properties: TUS, ksi TYS, ksi Temp.,F RT Specimen Details: Circumferentially notched, K t = inch gross diameter.253-inch net diameter.13-inch root radius, r flank angle, Surface Condition: Not specified References: (b), (a), and (b) Test Parameters: Loading - Axial Frequency - cpm Temperature - RT Environment - Air No. of Heats/Lots: 1 Equivalent Stress Equation: Log N f = log (S eq -5) S eq = S max (1-R).57 Standard Error of Estimate =.414 Standard Deviation in Life =.778 R 2 = 72% Sample Size = 179 [Caution: The equivalent stress model may provide unrealistic life predictions for stress ratios beyond those represented above.] 3-343