Editing Crankshaft (section)

==Construction==
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=== Forged crankshafts ===
[[File:IPH Kurbelwelle.jpg|thumb|upright=0.8|Forged crankshaft]]

Crankshafts can be created from a steel bar using [[Forging#Roll forging|roll forging]]. Today, manufacturers tend to favour the use of forged crankshafts due to their lighter weight, more compact dimensions and better inherent damping.<ref>{{Cite web |title=Cast vs Forged Crankshaft |url=https://www.dropforging.net/cast-vs-forged-crankshaft.html |access-date=2024-07-31 |website=www.dropforging.net}}</ref> With forged crankshafts, [[Vanadium#Applications|vanadium]] micro-alloyed steels are mainly used as these steels can be air-cooled after reaching high strengths without additional heat treatment, except for the surface hardening of the bearing surfaces. The low alloy content also makes the material cheaper than high-alloy steels. Carbon steels also require additional heat treatment to reach the desired properties.

=== Cast crankshafts ===
Another construction method is to [[casting (metalworking)|cast]] the crankshaft from ductile iron. [[Cast iron]] crankshafts are today mostly found in cheaper production engines where the loads are lower.

=== Machined crankshafts ===
Crankshafts can also be [[Machining|machined]] from [[Billet (manufacturing)|billet]], often a bar of high quality [[Vacuum arc remelting|vacuum remelted steel]]. Though the fiber flow (local inhomogeneities of the material's chemical composition generated during casting) does not follow the shape of the crankshaft (which is undesirable), this is usually not a problem since higher quality steels, which normally are difficult to forge, can be used. Per unit, these crankshafts tend to be expensive due to the large amount of material that must be removed with lathes and milling machines, the high material cost, and the additional heat treatment required. However, since no expensive tooling is needed, this production method allows small production runs without high up-front costs.