CHAIN INTRODUCTION
Chain is a reliable machine element that transmits power to drive machinery or equipment via sprockets.
There are many types of chains for different purposes, but they are primarily used for power transmission and conveyance. The basic chain components are:
Link Plate: Link plates act as the main tension members when load is applied. Link plates must have excellent strength and resistance to fatigue.
Roller: Rollers act as shock absorbing members to protect other components when chain engages with sprockets teeth. Rollers must have high toughness and surface hardness.
Bushing: Bushings act as the bearing members along with pins. Bushings must have high wear-resistance as well as strength and toughness.
Pin: Pins act as the bearing members to receive shearing and bending force when load is applied. Pins must have high strength, toughness and wear-resistance.
Ultimate Tensile Strength (UTS)
UTS is the load required to break the chain. It is also called breaking load. UTS or breaking load is not the allowable working load.
Elongation
During the start-up period, there is usually an initial elongation. An initial elongation of less than 0.5% is generally considered reasonable and acceptable. After the start-up period the chain should stop to elongate until towards the end of its service life when the bearing components start to wear out.
The maximum allowable wear elongation is about 3% for most industrial applications. It is recommended that when the elongation reaches 1.5% the chain should be checked carefully, and when the elongation is more than 3% the chain should be replaced.
Wear elongation happens because material is removed from pin and bushing. Therefore, the quality of pin and bushing is very important to the service life of the chain. At TYC we use the best materials, and the materials are processed with tightly-controlled heat-treatment process to ensure their hardness and strength.
Pre-loading
Preloading is done as a final alignment of various chain components. Also preloading helps to eliminate the initial elongation, and this can increase the service life of the chain. Upon using a chain it is recommended that you check with the supplier if the chain has been properly pre-loaded during production. TYC chains are made with high precision, and are pre-loaded to minimize the possible initial elongation.
Technical Aspects of Using a Chain
Horsepower Rating
Corrosion Resistance
Installation and Maintenance
Lubrication
Factors to Consider When Selecting a Chain
Machine to be driven
Load classification
Source of power
kW or horse-power to be transmitted
Diameter and RPM of driving shaft
Diameter and RPM of driven shaft
Center distance between shafts
Service factors
Chain size and number of teeth
Chain length (number of links)
Method of Lubrication