I have a query regarding Maximum allowable stress values , S , (From Table 1A) and Design stress intensity, Sm , (From Table 2A).
For A106 Gr B (-20 to 100)---- Design stress intensity= 20.0 Ksi
For A106 Gr B (-20 to 100)---- Maximum allowable stress values , S = 17.1 Ksi
My doubt is why...