Engineering Steel Chain Design Considerations

Many different types of engineering steel chains are used in a wide variety of apphcations. Most engineering steel chains are used in conveyors, bucket elevators, and tension linkages. Only a few are used in drives. Space does not permit a discussion of all the different types of engineCTing steel chains mentioned in chapter 2. Only straight sidebar chains, with and without rollers, for conveyors and bucket elevators, and offset sidebar chains for drives will be discussed. Welded steel chains and block and bar chains are beyond the scope of this chapt.  

The straight sidebar conveyor chains discussed here arc steel bushed roUerless chains and steel roller conveyor chains. The main design considerations for these chains are most tensile loads, several types of wear, lubrication, and environment. 

The main design considerations for an engineering steel chain to be used on a drive are very similar to those for a roller chain. These include the various tensile loads, certain types of wear, roller and bushing impact, and galling. 

The dimensions of offset sidebar drive chains are grairaally proportional to the pitch. For example, roller diameters are approximately one-half the pitch and pin diameters are approximately one-forth of the pitch. Other dimensions are only very roughly proportional to the pitch. In contrast, the dimensions of engineering steel conveyor chains are not proportional to the pitch. 

An engineering steel chain in a conveyor or drive may be snbjected to all of the tensile loads that were described earher. However, the tensile loads from centrifugal force, chordal action, and vibration are not very hkely to be a major factor. Thns, engineering steel chain mnst have certain tensile strength properties to withstand the wide range of tensile loads that may be imposed on it. The major strength properties that an engineering steel chain must have are discussed below. 

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Yield strraigth is an important consideration in designing engineering steel chains. For many raigineering steel chains, the jdeld strength is about 40% to 60% of the MUTS. 

Fatigue strength in the finite-life range is a very important consideration in designing engineering steel chains. Loads sometimes exceed the fatigue Unfit in some heavily loaded conveyors and drives. 

The fatigue Unfit usually is not a critical consideration in designing engineering steel chains. This is because most engineering steel chains accrae cycles very slowly and these chains are expected to wear out before fatigue can cause the chains to fail. 

Wear is probably the most important consideration in designing an engineering steel chain. Joint wear, roller and bushing wear, and sidebar and track wear are the greatest concerns for conveyor chains. Joint wear and roller and sprocket wear are the major concerns for drive chains. 

Only design considerations for standard engineering steel chains were covered earlier. Engineering steel chain manufactmers also make many special chains to work in very hostile conditions. 

This section reviews the general considerations for the design of roller, silent, engineering steel, and flat-top chains. The considerations differ as the functions of each type of chain differ. The specific design considerations for each class of chain will be covaed later. 

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