Crankshaft is the most important part of engine, it came to withstand the force of the connecting rod, converted it to the torque, which outputted by the crankshaft and drives other accessories working on the engine. Crankshaft suffered the combined effects from the centrifugal force of the rotating mass, the gas inertia force of periodic variation and reciprocating inertia force, which makes the crankshaft to bend the torsional load effects. Thus it requires the crankshaft to have sufficient strength and rigidity, the surfaces of crankshaft journal should be with good wear resistance, work uniform and good balance.

 

Since it is an action that to convert the linear reciprocating piston motion into rotation, that is connected the piston crankshaft with a rod and bearing, when the piston moves up and down, crankshaft operates, the rod and bearing will be at a circular motion, then the crankshaft begins to spin. Therefore, in the engine, it is necessary to use counterweights to keep the balance of each piston reciprocating motion and connecting rod, and these are usually used as part of the crankshaft. Although lead is very cheap, but its density is lower than tungsten alloy, and has great harms to environment; as for steel, its density is lower than as twice much as tungsten alloy. So compared to other materials, tungsten alloy deserved to be the most suitable crankshaft material due to its a series of excellent performance of high density, small size, high hardness, high wear resistance, high corrosion resistance, high temperature, environmental protection and the strong fighting force,etc.

 

But also because of these series of advantages, so that the tungsten alloy counterweight is often used as aircraft ailerons counterweights, various types of machinery, vessels (including rowers), aerospace aircraft, yachts, spacecraft counterweights and son on. In addition, tungsten alloy counterweights are often used in some other place where needs the small volume but  large weight counterweights.(The pic.is tungsten alloy crankshaft counterweights)