Compute the estimated actual endurance limit for SAE 4130 WQT 1300 steel bar with a rectangular cross section of 20.0 mm by 60 mm. It is to be machined and subjected to repeated and reversed bending stress. A reliability of 99% is desired

estimated actual endurance strength = 183.22 MPa

Explanation:

given data

actual endurance limit for SAE 4130 WQT 1300

cross section = 20.0 mm by 60 mm

reliability = 99%

solution

we use here table for get some value for AISI 4130 WQT 1300 steel

Sut = 676 MPa

Sn = 260 MPa

and here

stress factor Cst = 1

and wrought steel Cm = 1

and reliability factor Cr is = 0.81

so here equivalent diameter will be

equivalent diameter = 0.808    ...........1

equivalent diameter = 0. 808  

equivalent diameter = 28 mm

so here size factor will be = 0.87 by the table

so now we can get estimated actual endurance strength will be

actual endurance strength = Sn × Cm × Cst × Cr × Cs ...............2

put here value

actual endurance strength = 260 × 1 × 1 × 0.81 × 0.87

actual endurance strength = 183.22 MPa

angvrswer:

vfg

grfhrtrhr:

j

h

j

jjj

jj

j

j

j

m

j

h

yjujuju

jujuhuyhyt

j

hy

h

gh

g

g

g

g

gg

t

gt

gt

g

g

g

g

g

ef

f

d

dd

d

d

dd

d

d

d

d

d

d

d

d

d

d

d

d

d

d

d

d

d

d

d

d

d

d

d

d

d

d

d

d

d

d

d

d

d

d

d

d

f

s

bv

fb

c

fd

f

bf

bgf

n

g

bgr

gbr

bgr

gtr

bgr

gb

gb

gbgbbg

b

bgg

bbg

bfg

s

dcwf

fdb

b

ggb

bg

b

d

fh

d

e

f

w

fh

cd

cr

r

h

f

ww

a

v

f

vf

tr

rfe

rr

g

gg

e

go

d

d

c

r

rv

ng

gtg

gegte

g

gf

gf

g

gff

gf

gf

g

g

g

f

ds

wd

dfg

h

gfdsax

cvfbgnh

jmhngf

dsaazxscvb

nmhgb

fvdcsxaz

zxcv

bghn

fd

gb

h

answer:

true

explanation: