TourTour MAXIMUM TENSILE LOADING
 Metric thread : -
 Initial tensile stress : σt = xRp0.2 
 
ISO 724 pitch P mm
ISO 724 pitch diameter d2 mm
ISO 724 root diameter d3 mm
ISO 724 tensile stress area At =π/4 d02 ; d0=(d2+d3)/2 mm2
 ultimate tensile strength Rm  MPa
 yield strength Rp0.2 MPa
 tensile stress σt = σ't x Rp0.2 MPa
 Tensile load Fi kN
1) Ultimate tensile stress of 8.8 grade is 800 MPa, the Yield strength is 0.8·800=640 MPa. An initial tensile stress of 800 MPa is selected by taking=1/0.8=1.25Rp0.2
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