leaf chain that is properly lubricated and chain that has not been lubricated well that shows a rusty plate and will fail prematurelyIt is common for forklift truck chain users to assume that they have lubricated their leaf chain adequately but nevertheless friction corrosion, turned pins, metallic friction, stiff joints, noisy operation and pitting still occur. This is always the case whenever the applied lubricant adheres only to the exterior of the leaf chain and does not completely penetrate down to the leaf chain joints. This situation occurs whenever the lubrication product is not capable of flowing between the leaf chain linkplates and pins. Forklift truck chain users must ensure that lubrication is applied to the leaf chain when it is in a slack condition to enable this problem to be avoided.

The life of an adequately lubricated forklift truck chain is estimated to be 60 times longer than that of a dry running leaf chain.  Even temporary dry running will shorten leaf chain life considerably.  Picking the correct lubricant for forklift truck leaf chain can make a big difference, most chain lubricants are designed for transmission or motorcycle applications, whereas the loading and operations of leaf chain requires a lubricant with totally different properties.

Leaf Chain Graph

The graph shows the results of a test which simulates the work a leaf chain would do when fitted on a forklift truck mast. These leaf chains were loaded to near their maximum working load and repeatedly raised and lowered. In this test we took 3 identical lengths of FB leaf chain and applied 3 different types of oil to them.  At 40,000 cycles, the difference between the best performing leaf chain and the worst was an amazing 3.8 times.  At this point the A sample seized and would no longer articulate. The two other leaf chains continued for a further 40,000 cycles, double the amount compared to oil A.

Another important factor to consider is keeping the leaf chains constantly lubricated; Forklift truck chains that work outdoors or in environments where they are regularly washed or within cold stores, where leaf chains are subjected to condensation, the user needs to pick oil that will stay in place.  Under these circumstances it is unlikely that operators will re-oil their forklift chains regularly enough to achieve the leaf chain’s optimum life.

We applied the same lubricants as above onto 3 further identical samples of leaf chain, rinsed them with water for one minute before putting them through a comprehensive salt spray test, where a hot salt water mist is blown over the leaf chain at regular intervals. The purpose of rinsing the leaf chain with water beforehand is to simulate normal usage where a forklift truck chain is used in outdoor applications or cold stores. This accelerated corrosion test enables us to assess the corrosion resistance of the leaf chain without having to leave it outside for years or months on end.

 

Oil A
after 40 Hours In
salt spray test
Oil B
after 40 Hours In
salt spray test
Oil C
after 15 Hours In
salt spray test
leaf chain lubricated with oil A after 40 hours in a salt spray test lasts longer when properly lubricated Fork lift chain lubricated with oil B after 40 hours in a salt spray test should be kept clean and well lubricated to save money why lift truck chain lubricated with oil C after 40 hours in a salt spray test lasts longer when properly lubricated

 

You can see that the leaf chain lubricated with oil C performed well in the wear test but did not perform at all well in this corrosion test. This is a result of its viscosity being lower, which helps the oil to penetrate between the pin and plates, but regrettably makes it easily removed by washing.  Meaning that for forklift truck chain working outside or in cold stores it would not stay in place long enough to perform its main function of lubricating the forklift truck leaf chain.  Oil B, however, remains in situ longer on the leaf chain and therefore offers the best mix of wear and corrosion resistance.

Lots of forklift chains get encased in dirt and dust stopping any oil flowing to the important load bearing regions of leaf chain between articulating linkplates and pins. It is vitally important that all leaf chains should be kept free of dirt and debris in order to overcome this situation. Should leaf chains not be kept free of dirt or debris then it will not matter what type, or how much lubrication is used, as it will not flow to the critical contact areas of the leaf chain where it can have the most benefit.  You can find information on cleaning forklift truck leaf chain in the leaf chain cleaning section of the website.