JB/T 8108.1-1999 This standard is equivalent to ISO 1834:1980 "General acceptance rules for short link chains for lifting" (second edition). This standard is a revision of JB/T 8108-95 "General acceptance rules for short link chains for lifting". During the revision, only editorial changes were made according to relevant regulations, and the main technical content remained unchanged. This standard is part of the JB/T 8108 "Short link chains for lifting" series of standards. This series of standards includes the following two parts: JB/T 8108.1-1999 General acceptance rules for short link chains for lifting JB/T 8108.2-1999 Short link chains for lifting T(8) grade standard chains for hoists and other lifting equipment This standard specifies the general acceptance rules for round steel short link chains for electric lifting. It includes non-calibrated chains used for cranes, lifting chains and general lifting, as well as calibrated chains for hoists and other lifting equipment. Surface hardened chains are not within the scope of this standard. This standard was first issued on December 24, 1984 as GB 4829-84 and was adjusted to JB/T 8108-95 in April 1996. JB/T 8108.1-1999 General Rules for Acceptance of Short Link Chains for Hoisting JB/T8108.1-1999 Standard Download Decompression Password: www.bzxz.net

JB/T 8108.1---1999
This standard is equivalent to IS(）1834:1980 "General Principles for Acceptance of Short Link Chains for Hoisting" (first edition).
This standard is a revision of JB/T8108-95 "General Principles for Acceptance of Short Link Chains for Hoisting".
This standard differs from IS)1834 only in the referenced standards. The rest of the technical contents are completely the same as IS)1834. This standard is part of the JB/T8108 series of standards "Short link chain for lifting". This series of standards includes the following two parts: JB/T8108.1~1999 Short link chain for lifting
General acceptance rules
Short link chain for lifting
JB/T 8108. 2 --1999
T (8) grade calibration chain for hoists and other lifting equipment This standard replaces JB/T8108-95 from the date of implementation. Appendix A, Appendix B and Appendix C of this standard are all appendices to 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 Rongqing, Hu Weimin, Cui Zhenyuan. 211
JB/T8108.1-1999
ISOForeword
ISO (International Organization for Standardization) is a global organization of national standardization bodies (ISO member bodies). The drafting of international standards is done through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to send representatives to the technical committee. Official and non-official international organizations in liaison with ISO may also take part in this work. Draft international standards adopted by the technical committee should be circulated to the member bodies for voting before being accepted as international standards by the ISO Council.
International Standard 1S) 1834 was drafted by JS0/TC111\Steel round link chain, sprocket, lifting hook and accessories Technical Committee and circulated to member bodies in March 1978.
This International Standard was adopted by the member bodies of the following countries by balloting: Australia
Austria
Canada
Czechslovakia
Ireland
Italy
Triesia
South Africa
Turkey
Yugoslavia
The member bodies of the following countries have expressed their disapproval of the document from a technical point of view: Belgium Germany India
This International Standard cancels and replaces the recommended standard IS0/R1834:1971215, which constitutes a technical revision
0 Introduction
Machinery Industry Standard of the People's Republic of China
Short link chain for lifting purposesGeneral conditions of acceptance-1999
JB/T 8108.1
eq1s0 1834 : 1980
Replaces JB/T8108--95
The chains covered by this standard are classified into several quality grades according to the mechanical properties of the finished product and not simply according to the strength of the material. Each quality grade is indicated by a letter or number in the order L(3), M(4), P(5), S(6), T(8). This also applies to hooks, slings, clips and other accessories. The letters represent the mean stress at the specified minimum breaking force as shown in Table 1. Table 1
Note: 1.(3) and P(5) are not the main grades of chain. Mean stress at the specified minimum breaking force MPa
The stresses in the links are not uniform, especially the maximum stress on the outer curved surface, which is much greater than the mean stress obtained by dividing the load by the total cross-sectional area of ​​the two limbs of the link. It must be noted that the correction of the chain after heat treatment can only be carried out by the original manufacturer or in accordance with the provisions of a specific standard. 1 Scope
This standard specifies the general acceptance criteria for welded round steel short link chains for lifting. It includes non-calibrated chains for cranes, lifting chains and general lifting, as well as calibrated chains for hoists and other lifting equipment. Surface hardened chains are not within the scope of this standard. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards GB/T3159---1992 Hydraulic universal testing machine JJG139-1991 Verification procedures for tension, compression and universal material testing machines Approved by the State Machinery Industry Bureau on June 28, 1999 216
2000-01-01 Implementation
3 Definitions
This standard adopts the following definitions.
JB/T8108.1-1999
3.1 Nominal diameter: the nominal diameter of the steel wire or round steel used to make the chain (d.). 3.2 Actual diameter: the diameter of the chain link material measured (d). 3.3 Chain pitch: the inner length of the chain link (P). 3.4 Proof force: the force (F.) that the entire chain bears after the chain has been processed (see the definition below) in accordance with the provisions of 4.4. 3.5 Breaking force: the maximum tensile force (F.) that the chain can withstand during the static tensile breaking test. 3.6 Ultimate working load (lifting weight): the maximum mass (C,) that the chain is allowed to withstand when suspended vertically under normal conditions of use. 3.7 Total ultimate elongation: the total elongation of the chain at breaking, expressed as a percentage of the measured length. 3.8 Processing: any treatment of the chain after welding. For example, heat treatment, polishing or calibration. 3.9 Chain segment: A specified length of chain from which a test specimen is taken. 4 Dimensions
4.1 Actual diameter
The actual diameter of any section of a finished link is the average of two measurements made at 90° to each other on that section. This actual diameter should correspond to the dimensions of the link and be within the specified tolerances. The welds should be avoided during the measurements. Note: The average diameter can be conveniently obtained in a single measurement using the apparatus recommended in Annex A (Standard Annex). 4.2 Other dimensions of the link
The length and width of a link and the pitch and length of several links of the calibration chain shall conform to the provisions of the particular chain standard.
5 Materials and construction
5.1 Materials
The materials shall conform to the requirements of the particular standard for that grade of chain. These requirements are specified to ensure reliable welding quality and to prevent age-induced brittle strains during straining. In accordance with the above requirements, it is the responsibility of the chain manufacturer to select a steel material so that after appropriate heat treatment, the finished chain has the specified mechanical properties.
The manufacturer shall provide a copy of the steel mill's heat test report upon request. If the user requires a verification analysis of the steel, a section of the chain link after the breaking test shall be selected and a sample shall be taken from a complete cross section. Note: When comparing the verification analysis results of the chain steel with the steel mill's heat test report, tolerances for chemical composition inhomogeneities must be established. 5.2 Manufacturing
5.2.1 Manufacturing Process
Flat or asymmetrical welds (see Figure 1) shall be located in the middle of one or both limbs of the chain link. The dimensional changes in the material due to welding shall not extend on either side of the middle of the chain link limb beyond the value specified in the specific standard for the type of chain. The weld metal shall not be misaligned at any point to produce a depression in the outer contour of the chain link (see Figure 2). 5.2.2 Heat Treatment
Each chain shall be appropriately heat treated before loading verification. 5.2.3 Finishing
5.2.3.1 Flat welded chain
The ridges formed by welding should be removed, and the weld should be smoothed around. 5.2.3.2 Asymmetric welded chain
The ridges formed by welding on the outer surface of the chain link should be removed, and the inner ridges should be retained to form an asymmetric weld with a smooth outer surface 217
JB/T8108.1-1999
d.-Nominal diameter; d--The actual diameter measured at the non-weld: d. The actual diameter measured at the weld (type 1 and type 2) or the weld size perpendicular to the plane of the chain link (type 3); (dimensions on other planes are the same as type 3); - weld influence length on any side of the center of the chain link Figure 1 Weld type
5.3 Surface condition
JB/T 8108.1--1999
Figure 2 Depression at the weld (not allowed)
Unless agreed by the user and the manufacturer, the finished chain should not have any coating. 5.4 Proof force
After heat treatment and processing, the finished chain shall be subjected to the proof force specified for that chain in the specific standard. The testing machine used shall comply with the requirements of Appendix B (Standard Appendix). Care shall be taken that the chain is not twisted when it is placed in the testing machine. After the proof force is removed, it shall be carefully inspected by a competent person and any unsatisfactory links shall be replaced (see 5.5). The chain shall turn freely when the inspector moves it. 5.5 Links inserted during the manufacturing process
Any inserted link shall be treated similarly to the chain to ensure that the quality of each link in the finished chain is consistent. For links inserted after the load proof (see 5.4), the part of the chain affected by this shall be re-verified and tested for proof force. 6 Test requirements
6.1 Conditions for chain testing
The chain shall be tested in the finished condition. The chain shall be clean and free of oil, grease or paint. 6.2 Selection of test specimens
The inspector shall select from each chain segment or part of each chain segment at least one test specimen of the gauge length specified in 6.3.2. The length of the chain segment shall be specified in the standard for each particular chain. If the length of the chain is required to be continuous, the test specimens must be cut into links. Sampling and cutting for the test shall be carried out before heat treatment. After the links are joined, the test specimens shall be wired to the required length of chain and subjected to the same process before tensile verification. When required by the manufacturer, three test specimens may be selected from the full or partial length of the chain to be used as retest specimens when necessary (see 6.4).
If the chain is not required to be continuous, the test specimens shall be selected from the finished chain. Note: If the user requires a chain longer than the normal supply length, this should be stated in his inquiry and order. 6.3 Static tensile test
6.3.1 Testing machine
The testing machine shall comply with the requirements of Appendix B.
6.3.2 Specimens for tensile tests
The specimen shall consist of the number of broken links as specified in Table 2 to form its gauge length. Unless a half-ring or other method is used to connect it to the jaws of the testing machine, two additional links shall be required. These two additional links shall not be taken into account when determining the total elongation. 219
6.3.3 Test procedure
Nominal diameter of chain
>6～17
JB/T8108.1--1999
Minimum number of links within the gauge length of the actual test N7
The tensile test shall be carried out using an automatic recorder and a tension-elongation diagram shall be drawn (see Appendix B). The links shall be clamped so that they can freely load. The clamping device shall be constructed to prevent slippage. The load shall be applied uniformly [e.g. 10N/(mm2/s)] until breakage occurs. The minimum breaking force shall comply with the provisions of the specific standard for this type of chain. 6.3.4 Total ultimate elongation
The total ultimate elongation shall be based on the total elongation at break shown in the tension-elongation diagram (see Figure B1 in Appendix B). It shall be expressed as a percentage of the initial internal length of the specimen after load verification (i.e. the sum of the pitches obtained according to the measured length in Table 2). The minimum value of the total ultimate elongation shall comply with the provisions of the specific standard for this type of chain. 6.4 RetestbzxZ.net
If a specimen fails to meet the test requirements, two more specimens may be selected from the same chain segment for retesting at the manufacturer's request. If both additional specimens meet the requirements, the chain segment is qualified. 7 Inspection
If the user requires the dispatch of a supervisor, the supervisor shall be able to visit the manufacturer at all appropriate times to personally observe the specified tests and check the testing machine and inspection methods. The manufacturer shall provide the supervisor with a copy of the test report during his inspection. The test report shall give all the results of the tests conducted in the presence of the supervisor.
8 Marking
Quality grade marking
At least every 20 links or every 1m link (whichever is shorter) shall be stamped or engraved with a clear mark of the corresponding quality grade. The mark shall be the letter or number of the corresponding quality grade, i.e. 1L (3), M (4), P (5), S (6) or T (8). The size of the mark shall comply with the provisions of Table 3.
When stamping is used, it shall be concave and the indentation shall not be sharp or too deep. Table 3
Nominal diameter of chain
>8～12.5
>12.5～2
8.2 Identification marks
Marking diameter
Such marks shall be clearly stamped or engraved on all end links, idler links or on solid metal plates or tags permanently attached to the end links of the chain. Alternatively, such marks may be printed at the same spacing as the quality grade marks (see 8.1). The marking shall include the name of the chain manufacturer by trade mark or symbol.
8.3 Inspection marking
If the chain meets the requirements of the above tests, the inspector can make obvious marks on the tail rings of all chains from which the test samples are taken, at the position that does not overlap with the weld. 9 Test certificate
JB/T8108.1-.1999
If required, the manufacturer shall provide a test and inspection certificate with each batch of chains supplied. The standard format of the test and inspection certificate is shown in Appendix C (Standard Appendix).
The certificate of conformity shall at least provide the following data:
a) Standard number:
b) Quantity and name;
c) Mark;
d) Nominal chain diameter, mm;
e) Proof force, kN;
f) Breaking tensile force, kN (i.e., proof that the specified minimum breaking tensile force is reached or exceeded);
The total ultimate elongation at break expressed as a percentage (i.e., proof that the specified minimum total ultimate elongation is reached or exceeded). 221
JB/T8108.1--1999
Appendix A
(Appendix to the standard)
Measuring tool for measuring the actual average diameter of chain links
A1 When chain links are made of round steel, the cross section may be slightly flattened at the part where it contacts the die and is squeezed. However, the metal in the flat part is displaced mainly in the direction of the cross-section tangent, so the cross-sectional area and elastic modulus do not change significantly. It has been shown that when measuring such deformed links, the actual average diameter corresponding to the cross-sectional area can be measured in one measurement using a caliper or micrometer with a measuring flat surface at one end and a narrow blade with a 135° V-shaped groove at the other end. A2 Figure A1 shows a caliper gauge suitable for use in the field. If equipped with a set of replaceable flat anvils, this gauge can be used for several specifications of chain.
Pinghard measuring narrow piece
Caliper gauge for 10mm chain Total length 95mm Figure A] Caliper gauge
A3 For more accurate measurements, the flat anvil of the ordinary sub-scale can be replaced with a narrow piece with a 135V-shaped groove. However, in order to allow this pull piece to enter the inside of the chain link, the outer end of the micrometer arch can be cut off, as shown in Figure A2, cut off
Figure A2 Micrometer
A4 When using the above two measuring tools, the narrow piece should be placed on the inside of the chain link. The flat anvil should contact the outer side of the chain link. The measurement direction changes within ±20° with the plane of the chain link without causing a significant difference in the result. A5 There is no risk of misoperation when using these two instruments, because the flat anvil cannot be inserted into the inside of the chain link. A6 Both measuring tools must be calibrated with round steel of known diameter, which ranges from ±10% of the nominal diameter of the chain. 222
JB/T 8108.1
Appendix B
(Appendix to the standard)
Requirements for chain testing machines
B1 The travel of the tensioning mechanism, relative to the length of the chain under test, shall be sufficient to apply the full tensile force without re-clamping. B2 The machine shall be calibrated in accordance with JJG139 and shall meet the 1.0 grade accuracy conditions. B3 In any case, the tolerance of the tensile force of the testing machine shall not exceed ±1.5%; if necessary, the machine shall be inspected and adjusted by competent independent personnel at intervals not exceeding 1 year. B4 The signed certificate of the most recent inspection shall be clearly displayed near the testing machine. B5 For the inspection of the chain after the proof force test, appropriate equipment and suitable lighting shall be available. The testing machine used for the static tensile test described in B65.3 shall be equipped with an automatic recorder to draw the tension-elongation diagram during the test (see 5.3.3 and Figure B1).
Actual breaking force F
Specified
Minimum breaking force Fm
Verification force card
Limit T. Working load C
Maximum total elongation (measured)
Note: The above graph is used to illustrate the terms used; the shape of the curve is schematic and does not refer to any specific grade of chain. Figure B1 Tension-elongation curve
JB/T 8108.1--1999
Appendix C
(Appendix to the standard)
Example of test and inspection certificate
It is hereby guaranteed that all chains supplied below comply with JB/T8108.1-1999. Quantity
The selection and testing of the test specimens, which truly represent all the chains delivered this time, are carried out in accordance with the specified requirements. The actual results are tabulated as follows:
Nominal chain diameter
The chain undergoes the following heat treatment during the manufacturing process: 224
Breaking force of the test specimen
Manufacturer
Manufacturer inspector
and (or)
Date of stamp and (or) user supervisor
Total ultimate elongation
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