I believe this is a portion of an "expander pin" which is used on heavy machinery where hydraulic cylinders or other linkages are hooked together. Take a front end loader, for example. The cylinders and linkages that rotate the bucket are subject to wear as the bucket is used-- it can be thousands of times per day and over the course of years, the pins become worn, as well as the holes the pins pivot in (also called pin bosses). The normal way to fix these wear points is to replace the pin, and if the pin bosses have a hardened wear liner pressed in, the wear liners are replaced. This can get costly in both the price of replacement parts but also in labor and sometimes most importantly, the downtime that the machine has to experience to replace all these parts. There have been many solutions proposed to reduce the cost and downtime resulting from this wear and this pin you are looking at is a portion of one manufacturers solution. It is missing two tapered sleeves that go over each end of the pin that engage the pin bosses and the two bolts that hold those sleeves in place. One of the links shows a 30 second animation of how they go together. Some expanders use bolts, others have a threaded end that is part of the central pin. Obviously, they come in all sizes to fit a wide range of industrial equipment.

I believe this is a portion of an "expander pin" which is used on heavy machinery where hydraulic cylinders or other linkages are hooked together. Take a front end loader, for example. The cylinders and linkages that rotate the bucket are subject to wear as the bucket is used-- it can be thousands of times per day and over the course of years, the pins become worn, as well as the holes the pins pivot in (also called pin bosses). The normal way to fix these wear points is to replace the pin, and if the pin bosses have a hardened wear liner pressed in, the wear liners are replaced. This can get costly in both the price of replacement parts but also in labor and sometimes most importantly, the downtime that the machine has to experience to replace all these parts. There have been many solutions proposed to reduce the cost and downtime resulting from this wear and this pin you are looking at is a portion of one manufacturers solution. It is missing two tapered sleeves that go over each end of the pin that engage the pin bosses and the two bolts that hold those sleeves in place. One of the links shows a 30 second animation of how they go together. Some expanders use bolts, others have a threaded end that is part of the central pin. Obviously, they come in all sizes to fit a wide range of industrial equipment.

References:

https://www.youtube.com/watch?v=VDwY12esRC4

https://www.nord-lock.com/expander-system/solution/