Chains are used for lifting and handling applications in workshops, mining, shipyards, steel, cement and other industries. Chains are also used in manufacturing of material handling equipments like chain pulley blocks, ratchet lever hoists, etc. Information about short link chains is given in this article.
Chains of various grades (strengths) are made from carbon steel and alloy steel for different applications. There are two types of chains, calibrated and non-calibrated. Calibrated (accurate) chains are made for pocketed wheel or sprockets. Accurate links are essential for their correct movement over pockets and sprockets to ensure longer life to reduce their maintenance cost.
Information on chains made as per Imperial Standards and Indian standards is as under.
Chains made as per Imperial Specifications
Imperial short link chains are made as per ASTM specifications A413 / A413M, A391 / A391M and A973 / A973M. These specifications do not cover chains for sprocket applications. For dimensional requirements, mechanical testing requirements and material's composition please refer the specifications.
ASTM A413 / 413M
This specification covers carbon steel chain for applications like railroad cars, construction, industrial uses, load binding, and general purposes other than overhead lifting. It covers three classes of carbon steel chains as under.
Grade 30 – Proof coil chain
Grade 43 – High test chain and
Grade 70 – Transport chain.
The Grade designation is 1/10 of the minimum breaking strength in newtons divided by two times the nominal cross-sectional area of the chain in square millimetres.
ASTM A391 / 391M
This specification covers Grade 80 heat-treated alloy steel chain for applications such as slings, lifting assemblies, and load binding. These chains are heat treated which includes quenching and tempering.
The Grade designation is 1/10 of the minimum breaking strength in newtons divided by two times the nominal cross-sectional area of the chain in square millimetres.
Example:
Minimum breaking strength of 10 mm diameter Grade 80 chain can be calculated as under.
10 times the grade designation in Newtons = 80 x 10 = 800 Newtons
Strength for two times of nominal cross section of 1.0 mm2 = 800 x 2 = 1600 Newtons / mm2
Cross section area (πd2 / 4) of 10 mm diameter chain = (3.14 x 10 x 10) / 4 = 78.5 mm2
So minimum breaking strength = 1600 x 78.5 = 125600 Newtons
In other units, the strength is,
125600 x 0.102 = 12811.2 Kgf (as 1 Newton = 0.102 Kgf)
125600 x 0.225 = 28260 lbf (as 1 Newton = 0.225 lbf)
As rated loads for alloy steel chain shall be based on a minimum design factor of 4, rated load for 10 mm chain (Design Factor = 4) will be,
12811.2 / 4 = 3202.8 Kgf (say 3200 Kgf) and
28260 / 4 = 7065 lbf (say 7100 lbf).
Based on above, rated loads (Design Factor = 4) for various sizes are as under
| Nominal Chain Size | Rated Load | ||
|---|---|---|---|
| inch | mm | lb | Kg |
| 9/32 | 7 | 3500 | 1570 |
| 3/8 | 10 | 7100 | 3200 |
| 1/2 | 13 | 12000 | 5400 |
| 5/8 | 16 | 18100 | 8200 |
| 3/4 | 20 | 28300 | 12800 |
| 7/8 | 22 | 34200 | 15500 |
| 1 | 26 | 47700 | 21600 |
| 1 1/4 | 32 | 72300 | 32800 |
ASTM A973 / 973M
This specification covers Grade 100 heat-treated alloy steel chain for such applications as slings, lifting assemblies, and load binding. These chains are heat treated which includes quenching and tempering. This specification is a performance standard for Grade 100 chain used between −20 and 400°F (−29 and 205°C). The chain manufacturer should be contacted for their use at temperatures outside this range.
The Grade designation is 1/10 of the minimum breaking strength in newtons divided by two times the nominal cross-sectional area of the chain in square millimetres.
Chains made as per Indian Specifications
For information on short link chains please refer following Indian Standards.
IS 5616: Short link chain for lifting purposes general conditions of acceptance.
This standard covers general requirements for lifting chain. These electrically welded round steel short link chains are fully heat-treated and tested for use on cranes, in chain slings and for general lifting purposes (non-calibrated) or in pulley blocks (calibrated). Requirements special to chains of a particular type (calibrated, non-calibrated) or of specific materials (carbon steel, alloy steel, etc) are covered in individual standards on chains.
IS 8324: Code of practice for safe use and maintenance on non-calibrated round steel link lifting chains and chain slings.
The standard gives guidance for the selection, use, inspection, testing, maintenance and repair of non-calibrated round steel short link chains and chain slings.
IS 2429, Part 1: Specification for Round Steel Short Link Chains (Electric Butt Welded), Grade L(3) Part 1 Non-Calibrated Load Chain for Lifting Purposes.
This standard (Part 1) covers the requirements for lifting chains, Grade L(3), non-calibrated for lifting purposes. These are electric resistance or flash butt welded round steel short link chains fully tested and heat treated, and complying with the general conditions of acceptance of IS 5616-1982. The sizes from 6 to 45 mm are covered in this standard. Arc welded chains are not covered in this specification.
IS 3109, Part I: Specification for short link chain, Grade M (4) – Part I: Non-calibrated load chain for lifting purposes.
IS 6217: Specification for Short Link Chain, Grade S (6), Non-calibrated for Lifting Purposes
This standard covers the requirements for lifting chains, Grade S (6) non-calibrated, for use on cranes, in chain slings and for general lighting
IS 6296: Specification for short link chain Grade S(6) calibrated for pulley blocks and other lifting appliances.
This standard prescribes the requirements for Grade S (6) accurately calibrated lifting chains, for use as load chains in pulley blocks and other lifting appliances. These are electrically welded round steel short link chains, fully heat-treated and tested and comply with the general conditions of acceptance of IS 5616 : 1982. The sizes from 5 to 36 mm are covered in this standard.
IS 6215: Specification for short link chain, Grade T (8) non-calibrated for lifting purposes.
This standard covers the requirements for lifting chains, Grade T (8) non-calibrated for use on cranes, in chain slings and for lifting purposes. These are electrically welded round steel short link chains, fully heat-treated and tested and comply with the general conditions of acceptance of IS 5616-1982. The sizes from 5 to 45 mm are covered in this standard.
IS 6216: Short link chain, Grade T (8) calibrated for pulley block and other lifting appliances.
This standard prescribes the requirements for lifting chains, Grade T (8), accurately calibrated for use as load chains in pulley blocks and other lifting appliances. These are electrically welded round steel short link chains, fully heat-treated and tested and comply with the general conditions of acceptance of IS 5616 : 1982. The sizes from 5 to 20 mm are covered in this standard.
Dimensions and mechanical properties of Grade T (8) / Grade 80 alloy steel chain as per IS 6215 and IS 6216 are as under.
| Nominal Size d (mm) |
Pitch P (mm) Calibrated |
Out Side Width W (mm) | Minimum Breaking Force (KN) |
Safe Working Load Limit (Tonnes) |
Approximate Weight Kg/m |
|
|---|---|---|---|---|---|---|
| Non-calibrated (Max.) |
Calibrated | |||||
| 8 | 24 / # 23 | 28 | 26 / # 26.5 | 80.6 | 2.0 | 1.4 |
| 9 | 27 | 32 | 30 | 102.0 | 2.5 | 1.7 |
| 10 | 30 | 35 | 33 | 126.0 | 3.2 | 2.2 |
| 12 | 30 / # 33.18 | 42 | 39 / # 39.5 | 182.0 | 4.6 | 3.2 |
| 14 | 42 | 49 | 46 | 248.0 | 6.3 | 4.2 |
| 16 | 48 | 56 | 52 | 322.0 | 8.0 | 5.7 |
| 18 | 54 | 63 | 59 | 408.0 | 10.0 | 7.3 |
| 20 | 60 | 70 | 65 | 504.0 | 12.5 | 9.0 |
| 22 | - | 77 | - | 620.0 | 16.0 | 10.9 |
| 25 | - | 88 | - | 786.0 | 20.0 | 13.4 |
| 28 | - | 98 | - | 986.0 | 25.0 | 17.6 |
| 32 | - | 112 | - | 1288.0 | 32.0 | 23.0 |
| 36 | - | 126 | - | 1630.0 | 40.0 | 29.0 |
# Equipment Manufacturer’s Specification.
Notes:
Safe Working Load is based on Design Factor (Factor of Safety) = 4
Proof testing is done at 2 time of S.W.L.
