<span title="Crankshaft...........help........?">Crankshaft...........help...</span>

Question

what are the materials used to manufacture crankshaft???

what are the properties of crankshaft???like fatigue strength...

thanks for the help

Answer 1

The range of crankshaft materials runs as follows: billet steel, steel forgings, cast steel, nodular iron, malleable steel or (in some cases) cast iron.

Answer 2

*Essentially, the range of crankshaft materials runs as follows: billet steel, steel forgings, cast steel, nodular iron, malleable steel or (in some cases) cast iron. If we were to produce one crankshaft design and reproduce it in all these materials, the order of strength would approximately follow this same list. While cast cranks are typically less expensive than forgings, they can be produced in shapes not available with forgings. But dollar for dollar, forged cranks tend to be the better method of manufacture, certainly with respect to high output durability.

Often a subject of discussion and frequently believed to be critical in the design, modification and service life of a crankshaft, is how fillet radii are configured. If we were to perform a stress analysis test that included all other design features and conditions of a given crankshaft, fillet radii could be considered the most critical factor in overall design and/or modification procedure. There is belief among crankshaft manufacturers that the use of fillets of non-constant radius—sometimes called “non-circular” contours—is preferred over those of constant radius. Worst case, this is an area worth discussing with your engine builder or crankshaft manufacturer of choice.

*Crankshafts can be forged from a steel bar or cast in ductile iron.

-Today more and more manufacturers tend to favor the use of forged crankshafts due to their lighter weight, more compact dimensions and better inherent dampening.

-With forged crankshafts, &quot;vanadium microalloyed steels &quot; are mostly used as these steels can be air cooled after forging reaching high strengths without additional heat treatment, with exception to the surface hardening of the bearing surfaces.

-The low alloy content also makes the material cheaper than high alloy steels.

-Carbon steels are also used, but these require additional heat treatment to reach the desired properties.

-Cast iron crankshafts are today mostly found in cheaper production engines where the loads are lower.

-Some engines also use cast iron crankshafts for low output versions while the more expensive high output version use forged steel.

-Crankshafts can also be machined out of a billet, often using a bar of high quality vacuum remelted steel. Even though the fiber flow (local inhomogeneities of the material&#039;s chemical composition generated during casting) doesn’t following the shape of the crankshaft (which is undesirable), this is usually not a problem since higher quality steel which normally are difficult to forge can be used.