This standard specifies the requirements for Class T lifting chains. These lifting chains are precisely calibrated and are used as load-bearing chains for hoists and similar equipment. The chains are made of short links welded from round steel and are fully heat treated and tested to comply with the provisions of JB/T 8108.1. The chain size range covered by this standard is 4 to 20 mm. Appendix A (Appendix to the standard) gives a temporary additional size range of 6 to 19 mm. JB/T 8108.2-1999 Short link chains for lifting Class T(8) calibrated chains for hoists and other lifting equipment JB/T8108.2-1999 Standard download decompression password: www.bzxz.net

JB/T 8108.21999
This standard is equivalent to ISO3077:1984 "Short link chain for lifting-T (8) grade calibration chain for hoists and other lifting equipment" (second edition).
This standard is a revision of JB/T8109
T (8) grade calibration chain for hoists and other lifting equipment"--95 "Short link chain for lifting".
This standard differs from IS03077 only in the following two places: according to my country's standard system and composition, appropriate adjustments have been made in the referenced standards; the material of the chain is made of 20Mn2 alloy structural steel wire according to my country's steel varieties and many years of domestic manufacturing experience. This standard is part of the JB/T8108 series of standards "Short link chain for lifting", which includes the following two parts: General acceptance rules
JB/T8108.1--1999
Short link chain for lifting
JB/T8108.21999 Short link chain for lifting
T(8) grade calibration chain for hoists and other lifting equipment This standard replaces JB/T810995 from the date of implementation. Appendix A of this standard is the appendix of the standard.
This standard is proposed and managed by the National Technical Committee for Standardization of Lifting Machinery. The responsible drafting unit of this standard: Hangzhou Wulin Machinery Factory. The main drafters of this standard: Chen Shaorong and Cui Zhenyuan. 225
JB/T 8108.2-1999
ISOForeword
ISO (International Organization for Standardization) is a global organization of national standards bodies (IS member bodies). The drafting of international standards is mainly completed through IS technical committees. Each member body interested in a subject for which a technical committee has been established has the right to send representatives to participate in the technical committee. Some official and non-official international organizations in contact with ISO may also participate in this work.
Draft International Standards adopted by the technical committees are circulated to the member bodies for voting before being accepted as international standards by the ISO Council.
International Standard ISO 3077 was prepared by ISO/TC 111\Steel round-link chains, sprockets, lifting hooks and accessories\Technical Committee The first edition of this standard (1ISO 3077:1980) was adopted by the member bodies of the following countries: Australia
Austria
Belgium
Canada
Czechoslovakia
Italy
Democratic People's Republic of Korea
Mexico
Republic of South Africa
Spain
Turkey
Yugoslavia
The following countries The member bodies of the following countries have expressed their disapproval of the document from a technical point of view: France Japan Netherlands
This second edition revokes and replaces 1S)3077:1980, including amendment 1 sent to member bodies in May 1983. It has been voted on by the member bodies of the following countries: Australia
Austria
Belgium
Canada
Romania
Republic of South Africa
Yugoslavia
The member bodies of the following countries have expressed their disapproval of the document from a technical point of view: Germany India
1 Scope
Machinery Industry Standards of the People's Republic of China
Short link chains for hoists and other
Lifting equipment, class T(8) calibrated chains
Short link chain for lifting purposes -Grade T(8)calibrated,for chain hoists and other lifting appliancesJB/T 8108.2-1999
eqv IsO 3077:1984
Replaces JB/T810995
This standard specifies the requirements for Grade T lifting chains. These lifting chains are accurately calibrated and are used as load-bearing chains for hoists and similar equipment. The chains are made of short links welded from round steel and are fully heat treated and tested to comply with the provisions of JB/T8108.1. The chain sizes covered by this standard range from 4 to 20 mm. Appendix A (Annex to the standard) gives a temporary additional size range of 6 to 19 mm.
2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard by reference in this standard. The versions shown are valid at the time of publication of this standard. All standards are subject to revision and parties using this standard should investigate the possibility of using the latest versions of the following standards. JB/T8108.1-1999 General Rules for Acceptance of Short Link Chains for Hoisting YB/T5148--1993 Method for Determining Average Particle Size of Metal Products YB/T5211-1993 Steel Wire for Round Link Chains for Chain Hoists 3 Definitions
This standard adopts the following definitions, and the definitions in JB/T8108.1 apply to this standard. 4 Dimensions
4.1 Nominal Diameter (See Definitions in Chapter 3 of JB/T8108.1--1999) The nominal diameter of the chain shall conform to the dimensions listed in the first column of Table 2, i.e. the nominal diameter d of the round steel or steel wire used to manufacture the chain. Note: It is important to control the dimensions of the materials used to manufacture the chain. However, this standard refers to finished chains, and it must be assumed that the inspectors may not have the opportunity to investigate the provisions of the raw material dimensions. Therefore, the manufacturer must ensure that the dimensions of the raw materials are within the allowable tolerance range. 4.2 Actual diameter (see JB/T8108.1 for the definition and measurement method of actual diameter) 4.2.1 Diameter tolerance
When the actual diameter is less than 18mm, the tolerance of the diameter of any section of the finished chain link except the weld should be less than 2%~-6% of the nominal diameter.
When the actual diameter is greater than or equal to 18mm, the tolerance of the diameter of any section of the finished chain link except the weld should not exceed 5%~~-5% of the nominal diameter.
4.2.2 Tolerance at weld
The actual diameter d at the weld shall not be less than the actual diameter d adjacent to the weld in any section, and the tolerance at the weld shall not be greater than the following values ​​(see Figure 1 and Table 2):
Approved by the State Machinery Industry Bureau on June 28, 1999 and implemented on January 1, 20000
JB/T 8108.2 -1999
Type 1: 8% of the nominal diameter in any direction; Type 3: 8% of the nominal diameter in the direction perpendicular to the plane of the chain link. 17% for other planes. 4.2.3 Welding influence length
The welding influence length e. on any side of the center of the chain link shall not exceed 0.6 times the nominal diameter. 4.3 Length and width
The length and width dimensions of the chain link shall comply with the provisions of Table 2 and Figure 2. 4.3.1 Nominal dimensions
The preferred nominal dimensions are as follows:
The pitch P (inner length of the chain link) is 3 times the nominal diameter d of the chain. The outer width W is 3.25 times the nominal diameter of the chain. When the chain is to be used with sprockets of different sizes, its pitch and outer width should be clearly specified during negotiation and ordering. 4.3.2 Tolerance
4.3.2.1 Outer width (measured on the finished chain) The actual outer width at the non-weld seam should be within the range of formula (1): Actual outer width = W
4.3.2.2 Length (measured on the finished chain) ()
When the load does not exceed half of the specified chain proof force, the relative error between the inner length of a chain link or the sum of the inner lengths Z of N chain links measured from the load-bearing surface to the load-bearing surface of the chain and the nominal length N should not exceed the tolerance value expressed in percentage in formula (2), and is shown in Table 1.
X100(%)=
+(1.6/N+0.33)
Table 1 Example
Nominal diameter d
Number of chain links N
Difference (positive value)
（2）
dNominal diameter of the chain:
dActual diameter measured at the non-weld joint;
JB/T 8108.2
d--actual diameter measured at the weld (type 1 welded chain) or the dimension at the weld perpendicular to the plane of the chain link (type 3 welded chain): G--dimensions on other planes (type 3 welded chain); length of weld influence on any side of the chain link center All chain link types:
When d<18mm, d=dt
When d≥18mm, d=da
Welding tolerance:
Type I: du=di,
Type 3: dw=dyndn
G=dg
Figure 1 Chain link types and welding tolerances
JB/T 8108.2
Jiang: All dimensions are based on the nominal diameter d of the chain. Given: Pitch (inner length) is preferably 3dh
: 1999
The preferred value of the outer width W (non-weld) is 3.25dh: The minimum permissible value of the inner width W is 1.25d. (non-weld) or the minimum size that can prevent the chain from kinking; length 1 (see 4.3.2.2)
Figure 2 Chain and chain size
Table 2T (8) grade calibration chain size (code see Figure 1 and Figure 2) 4
Nominal true diameter" Diameter tolerance
Maximum tolerance at weld (see Figure 1)
Type 1 and Type 3
(dw--d)
Preferred pitch!
(Inner length)
Single link
Pitch tolerance
(Positive value)
Preferred outer width
Outer width tolerance at non-weld
(Positive value)
(o.075d.)
5 Materials and manufacturing
5.1 Material
JB/T 8108.2
Steel must be smelted by open hearth, electric furnace or oxygen top-blown converter. Finished steel provided to chain manufacturers, when inspecting and analyzing round steel, steel wire or finished chain links, should meet the following requirements: The steel must be killed steel, with good weldability and cold bending properties, and contain sufficient alloy elements to ensure the mechanical properties of the chain after appropriate heat treatment.
The chain shall be made of 20Mn2 steel with mechanical properties not lower than those in YB/T5211. The grain size of the steel shall be determined in accordance with YB/T5148 and shall reach austenite grain size of 5 or above. The steel shall be selected according to the above requirements so that the finished chain after the corresponding heat treatment can meet the mechanical properties specified in this standard. 5.2 Heat treatment
All chains shall be quenched and tempered before being subjected to the test force inspection during the manufacturing process. 5.3 Test force during the manufacturing process
Chains that have been heat treated during the manufacturing process shall be able to withstand the test force during the manufacturing process specified in the fifth column of Table 4 or Table A2, and the value is 60% of the minimum breaking force.
5.4 Verification force during acceptance
The verification force listed in the second column of Table 1 or the second column of Table A2 shall only be used during acceptance tests and inspections. The test force (see 5.3) during the manufacturing process of this level of chain has met the requirements for the verification force during acceptance specified in 5.4 of JB/T8108.1-~~1999. 6 Test requirements
6.1 Mechanical properties and test force
The mechanical properties shall comply with the provisions of Table 3. Table 4 and Table A2 specify the test forces for chains of various sizes. Table 3 Mechanical properties
Mechanical properties
Average stress under the specified minimum breaking force 2Fmmnin/(di)Average stress under the verification force 2F./(yuand)Ratio of the verification force to the specified minimum breaking forceMinimum value of the specified total ultimate elongation
Average stress at the ultimate working load
800MPa
400MPa
200MPa
The stress in the table is the average stress obtained by dividing the force by the total cross-sectional area on both sides of the chain link. In fact, stress is not evenly distributed, especially the maximum internal stress at the outer arc surface of the foot chain is much larger than the average stress. The selected working load shall not exceed the limit working load specified in the fourth column of Table 4 or the fourth column of Table A2 in any case. Table 4T(8) Test requirements for grade calibration chain
Nominal diameter d.
Verification force F during acceptance
Minimum breaking force ra
Limit working load ()
Test force during manufacturing
Nominal diameter d,
6.2 Sample selection
Verification force F during acceptance.
JB/T8108.2-1999
Table 4 (end)
Minimum breaking force Fmm
Limit working load Cp
The sample should be selected according to the provisions of JB/T8108.1, and the inspector should take samples from 200m or shorter chains. 6.3 Static tensile test
6.3.1 Testing machine and test method
The testing machine and test method shall comply with the provisions of JB/T8108.1. 6.3.2 Tensile test
The breaking force shall not be less than the provisions in the third column of Table 4 or the third column of Table A2. 6.3.3 Total ultimate elongation
According to the provisions of JB/T8108.1, and the total ultimate elongation shall not be less than 10%. 7 Inspection
7.1 Inspection items
The inspection items shall comply with the provisions of JB/T8108.1. 7.2 Acceptance
The acceptance procedure shall comply with the provisions of JB/T8108.1. 8 Marking
8.1 Quality marking
The quality mark of the chain is T or 8 and shall comply with the provisions of JB/T8108.1. 8.2 Identification mark
Identification mark shall comply with the provisions of JB/T8108.1. 8.3 Inspection mark
Inspection mark shall comply with the provisions of JB/T8108.1. 9 Test certificate
Test force during manufacturing
If required, the manufacturer shall provide a certificate of conformity for each batch of chain supplied by the manufacturer, including the test and inspection contents specified in JB/T8108.1. The format of the certificate of conformity is shown in Appendix C10 General acceptance rules in JB/T8108.1--1999
The chain must fully comply with the technical requirements of JB/T8108.1 and this standard. 232
JB/T 8108.2--1999
Appendix A
(Appendix to the standard)
T(8) grade calibration chain temporary additional dimensions and test requirements A1 The temporary additional dimensions listed in Table AI and the test requirements listed in Table A2 are used as transitional measures for selecting chains. Table A1 Dimensions (codes see Figures 1 and 2)
Nominal diameter
True diameter tolerance
Maximum tolerance at weld (see Figure 1)
Type 1 and Type 3
Preferred pitch P
(inner length)
(3dh)
Single chain link
Pitch tolerance
(positive value)
Preferred outer width
(3.25dn)
Outer width tolerance at non-weld joint (positive value)
(0.075d.)
Nominal diameter d.
Verification force F during acceptance.
JB/T 8108.2-1999
Table A2 Test requirements
Minimum breaking force Fm
Ultimate working load C
Test force during manufacturing process4 Verification force for acceptance
The verification force listed in the second column of Table 1 or the second column of Table A2 is only used during acceptance test and inspection. The test force (see 5.3) during the manufacturing process of this level of chain has met the requirements for the verification force for acceptance specified in 5.4 of JB/T8108.1-~~1999. 6 Test requirements
6.1 Mechanical properties and test force
The mechanical properties shall comply with the provisions of Table 3. Table 4 and Table A2 specify the test force for chains of various sizes. Table 3 Mechanical properties
Mechanical properties
Average stress under specified minimum breaking force 2Fmmnin/(di)Average stress under proof force 2F./(yuand)Ratio of proof force to specified minimum breaking forceMinimum value of specified total ultimate elongation
Average stress at ultimate working load
800MPa
400MPa
200MPa
The stress in the table is the average stress obtained by dividing the force by the total cross-sectional area on both sides of the chain link. In fact, stress is not evenly distributed, especially the maximum internal stress at the outer arc surface of the foot chain is much larger than the average stress. The selected working load shall not exceed the limit working load specified in the fourth column of Table 4 or the fourth column of Table A2 in any case. Table 4T(8) Test requirements for grade calibration chain
Nominal diameter d.
Verification force F during acceptance
Minimum breaking force ra
Limit working load ()
Test force during manufacturing
Nominal diameter d,
6.2 Sample selection
Verification force F during acceptance.
JB/T8108.2-1999
Table 4 (end)
Minimum breaking force Fmm
Limit working load Cp
The sample should be selected according to the provisions of JB/T8108.1, and the inspector should take samples from 200m or shorter chains. 6.3 Static tensile test
6.3.1 Testing machine and test method
The testing machine and test method shall comply with the provisions of JB/T8108.1. 6.3.2 Tensile test
The breaking force shall not be less than the provisions in the third column of Table 4 or the third column of Table A2. 6.3.3 Total ultimate elongation
According to the provisions of JB/T8108.1, and the total ultimate elongation shall not be less than 10%. 7 Inspection
7.1 Inspection items
The inspection items shall comply with the provisions of JB/T8108.1. 7.2 Acceptance
The acceptance procedure shall comply with the provisions of JB/T8108.1. 8 Marking
8.1 Quality marking
The quality mark of the chain is T or 8 and shall comply with the provisions of JB/T8108.1. 8.2 Identification mark
Identification mark shall comply with the provisions of JB/T8108.1. 8.3 Inspection mark
Inspection mark shall comply with the provisions of JB/T8108.1. 9 Test certificate
Test force during manufacturing
If required, the manufacturer shall provide a certificate of conformity for each batch of chain supplied by the manufacturer, including the test and inspection contents specified in JB/T8108.1. The format of the certificate of conformity is shown in Appendix C10 General acceptance rules in JB/T8108.1--1999
The chain must fully comply with the technical requirements of JB/T8108.1 and this standard. 232
JB/T 8108.2--1999
Appendix A
(Appendix to the standard)
T(8) grade calibration chain temporary additional dimensions and test requirements A1 The temporary additional dimensions listed in Table AI and the test requirements listed in Table A2 are used as transitional measures for selecting chains. Table A1 Dimensions (codes see Figures 1 and 2)
Nominal diameter
True diameter tolerance
Maximum tolerance at weld (see Figure 1)
Type 1 and Type 3
Preferred pitch P
(inner length)
(3dh)
Single chain link
Pitch tolerance
(positive value)
Preferred outer width
(3.25dn)
Outer width tolerance at non-weld joint (positive value)
(0.075d.)
Nominal diameter d.
Verification force F during acceptance.
JB/T 8108.2-1999
Table A2 Test requirements
Minimum breaking force Fm
Ultimate working load C
Test force during manufacturing process4 Verification force for acceptance
The verification force listed in the second column of Table 1 or the second column of Table A2 is only used during acceptance test and inspection. The test force (see 5.3) during the manufacturing process of this level of chain has met the requirements for the verification force for acceptance specified in 5.4 of JB/T8108.1-~~1999. 6 Test requirements
6.1 Mechanical properties and test force
The mechanical properties shall comply with the provisions of Table 3. Table 4 and Table A2 specify the test force for chains of various sizes. Table 3 Mechanical properties
Mechanical properties
Average stress under specified minimum breaking force 2Fmmnin/(di)Average stress under proof force 2F./(yuand)Ratio of proof force to specified minimum breaking forceMinimum value of specified total ultimate elongation
Average stress at ultimate working load
800MPa
400MPa
200MPa
The stress in the table is the average stress obtained by dividing the force by the total cross-sectional area on both sides of the chain link. In fact, stress is not evenly distributed, especially the maximum internal stress at the outer arc surface of the foot chain is much larger than the average stress. The selected working load shall not exceed the limit working load specified in the fourth column of Table 4 or the fourth column of Table A2 in any case. Table 4T(8) Test requirements for grade calibration chain
Nominal diameter d.
Verification force F during acceptance
Minimum breaking force ra
Limit working load ()
Test force during manufacturing
Nominal diameter d,
6.2 Sample selection
Verification force F during acceptance.
JB/T8108.2-1999
Table 4 (end)
Minimum breaking force Fmm
Limit working load Cp
The sample should be selected according to the provisions of JB/T8108.1, and the inspector should take samples from 200m or shorter chains. 6.3 Static tensile test
6.3.1 Testing machine and test method
The testing machine and test method shall comply with the provisions of JB/T8108.1. 6.3.2 Tensile test
The breaking force shall not be less than the provisions in the third column of Table 4 or the third column of Table A2. 6.3.3 Total ultimate elongation
According to the provisions of JB/T8108.1, and the total ultimate elongation shall not be less than 10%. 7 Inspection
7.1 Inspection items
The inspection items shall comply with the provisions of JB/T8108.1. 7.2 Acceptance
The acceptance procedure shall comply with the provisions of JB/T8108.1. 8 Marking
8.1 Quality marking
The quality mark of the chain is T or 8 and shall comply with the provisions of JB/T8108.1. 8.2 Identification mark
Identification mark shall comply with the provisions of JB/T8108.1. 8.3 Inspection mark
Inspection mark shall comply with the provisions of JB/T8108.1. 9 Test certificate
Test force during manufacturing
If required, the manufacturer shall provide a certificate of conformity for each batch of chain supplied by the manufacturer, including the test and inspection contents specified in JB/T8108.1. The format of the certificate of conformity is shown in Appendix C10 General acceptance rules in JB/T8108.1--1999
The chain must fully comply with the technical requirements of JB/T8108.1 and this standard. 232
JB/T 8108.2--1999
Appendix A
(Appendix to the standard)
T(8) grade calibration chain temporary additional dimensions and test requirements A1 The temporary additional dimensions listed in Table AI and the test requirements listed in Table A2 are used as transitional measures for selecting chains. Table A1 Dimensions (codes see Figures 1 and 2)
Nominal diameter
True diameter tolerance
Maximum tolerance at weld (see Figure 1)
Type 1 and Type 3bzxZ.net
Preferred pitch P
(inner length)
(3dh)
Single chain link
Pitch tolerance
(positive value)
Preferred outer width
(3.25dn)
Outer width tolerance at non-weld joint (positive value)
(0.075d.)
Nominal diameter d.
Verification force F during acceptance.
JB/T 8108.2-1999
Table A2 Test requirements
Minimum breaking force Fm
Ultimate working load C
Test force during manufacturing process
Verification force F during acceptance.
JB/T 8108.2-1999
Table A2 Test requirements
Minimum breaking force Fm
Ultimate working load C
Test force during manufacturing
Verification force F during acceptance.
JB/T 8108.2-1999
Table A2 Test requirements
Minimum breaking force Fm
Ultimate working load C
Test force during manufacturing
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