Engineering Steel Chain

FIGURE 1-19 Typical engineering steel chains with rollers. 

The early engineering steel chains were taken directly from cast pintle chains. They were designed with the same pitches and similar dimensions as cast chains so that the steel chains would fit identical sprockets. This meant that higher strength steel chains could be substituted for cast chains when necessary without having to change sprockets. 

Most engineering steel chains were developed to operate dependably in the most demanding conditions. Many classes of engineering steel chains are covered by the ASME B29 sraies of standards, and those standard chains are often available from manufacturers stocks. Howcvct, an important part of the engineering steel chain market is special chains for unique installations or to meet unusual designs needs. 

It is only in the past few decades that certain raigineering steel chains have been standardized so that recognized standards could be issued. The first engineering steel chains to be covered by an ANSI standard were heavy-duty offset sidebar power transmission roller chains (ASME B29.10). That was soon followed by standards covering steel bushed roUa-less chains (ASME B29.12) and 

FIGURE 1-20 Bushed rollerless engineering steel chain. 

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Engineering steel chain drives are especially suited for heavy-duty apphcations.The normally offset sidebar chain (Fig. 5.87) can handle speeds up to 1000 ft/min (305 m/min) and power... 

TABLE 5.20 Engineering Steel-Chain Size and Strength... 

There are many general types of engineering steel chains, and some of those covered in this book are shown in Figure 1-19 to Figure 1-22. Those with steel rollers are perhaps the most widely used on both drives and conveyors. The bushed, rollCTless style meets the needs of many conveyor and bucket elevator applications. Welded steel versions of the basic cast chains are now quite popular, and a simple bar-link type is used for slow-moving conveyors and tension hnkages. Each of these types is illustrated and described in detail in a subsequait chapter. 

FIGURE 1-22 Bar-link, or block and bar, style engineering steel chains. 

FIGURE 1-31 Typical link plate for roller chain and sidebar for engineering steel chain. 

On the other hand, a sidebar in an engineering steel chain is likely to be placed in a conveyor miming in a wet and dirty environment. The sidebar is subjected to relatively few cycles at high loads, but is subjected to a lot of moisture and dirt. Engineering steel chains more often have to be replaced because of corrosion and abrasive wear. 

In ehapter 1, the evolution of the chain industry was ouflined from the first cast chains to flat-top chains. This book outlines four major kinds of chain from an industry standpoint roller chains, silent chains, engineering steel chains, and flat-top chains. 

FIGURE 2-4 Engineering steel chain with large carrier rollers. 

Rollerless chain is similar in appearance to chain with rollers, and is used for applications where rollers are not required. Most rolleriess chains are engineering steel chains. There are other types of chain that do not have rollers, because rollers would obviously not be appropriate. Examples are bar-link, silent, and flat-top chains, which were shown in Figures 1-22, 1-25, and 1-28. 

Roller chains and engineering steel chains are used in all types of applications. Silent chain is essentially for drive applications, although a few conveying applications exist. Hat-top chain is intended only for conveying. 

Engineering steel chains are made of fabricated and machined steel. They are designed for a wide variety of uses and operating conditions. Because of their broad range of uses, there are many types available and many ways to classify them. Engineering steel chains have been in existence for more than a century. But manufacturers identify similar types of engineering steel chains by widely differing terms. The same apphes to the component parts of this class of chains. 

In recent decades, a concerted effort has been made by the American Chain Association to standardize the terminology and hmit dimensions for this class of chains. We now have ASME standards for many styles of engineering steel chains. 

Generally speaking, the types of engineering steel chains as classified under ANSI standards fall into the following categories or types ... 

Many other types of engineering steel chains exist, although most of them are not the subjects of published standards. Special-purpose chains for handling materials, such as double-flex conveyor chains, welded rooftop and flat-top chains, steel detachable chains, and steel fabricated chains with plastic bushed rollers for use where lubrication is unacceptable, are only a few of the products available. All of these may be found in manufacturers catalogs. 

Since engineering steel chains are used in such a wide variety of applications, many different attachments are available. Figure 2-30 illustrates some of the more common attachments available for engineering steel chains for use in conveying and elevating. These attachments are better suited... 

FIGURE 2-29 Other types of engineering steel chains. 

Eingineering steel chain has all of the advantages of roller chain listed above, except that engineering steel chain drives tend to be somewhat noisiCT than roller chain drives. That is because of the additional clearances built into engineering steel chains and the pitch-line clearance usually provided in sprockets for engineering steel chain drives. However,... 

Engineering steel chains can span extrranely long gaps between shafts. 

Engineering steel chains can absorb very large shock loads because of their toughness... 

Engineering steel chains can run in very dirty conditions without soious damage. That is because the added clearance built into these chains provides ready egress of dirt and debris. 

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 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. 

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. 

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. 

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