Abstract
The writer has related in this paper to the characteristics of crankshaft steels for aero-engines used in the past and present, and fundamental essential ideas in designing a crankshaft with a view to select the most suitable steel for it.
The fact has also been pointed out that the results obtained from ordinary tensile tests and fatigue tests are not alwrays applicable to the practical strength calculation in design, but it is a most important fact to consider upon the stress-concentration and consequent intercrystalline changes of properties.
Simple relation between static strength and fatigue strength being found out by introducing a new idea of "Cohesion Strength" (die Trennfestigkeit), the writer has established a formula which satisfies the actual cases. The result has been applied for aero-engine crankshaft as an example in purpose of studying it more concretely.
Necessary conditions and advices in selecting crankshaft steels for aero-engines have also been referred to as a conclusion.
