41. HSS makes up 59 % of vehicle body mass; 1, 500 MPa yield strength steel makes up 7 %. 42. At that point the bolt has a preload determined by the bolt area and the yield strength of the bolt material. 43. For perfectly brittle materials, yield strength and ultimate strength are the same, because they do not experience detectable plastic deformation. 44. Thus, there is then an inverse relationship between grain size and yield strength , as demonstrated by the Hall Petch equation. 45. However, as the normal force increases, eventually the stresses in the plate's surface will exceed its yield strength . 46. The formed tube is then cooled and can be cold worked to refine the diameters and to achieve the desired yield strengths . 47. The hull is constructed of high tensile steel with a yield strength of S355 N / mm?structural steel grades '. 48. The ferritic structure and alloy additions, such as nitrogen provide yield strengths that are twice that of 300 series stainless steels. 49. In addition, structures are required to be of an acceptable strength, which is related to a material's yield strength . 50. Let a material have a yield strength \ sigma _ Y and a fracture toughness in mode I K _ { IC }.
