This standard specifies the technical requirements, test methods and judgment rules for the periodic test of steel wire ropes used for important purposes in coal mines during suspension and use. This standard applies to round and special-shaped wire ropes and flat wire ropes (hereinafter referred to as ropes) used for important purposes in coal mines. This standard does not apply to surface contact wire ropes and sealed wire ropes. MT 717-1997 Performance determination method and judgment rules for steel wire ropes used for important purposes in coal mines MT717-1997 Standard download decompression password: www.bzxz.net

MT717-1997
Wire rope is an important part of the safety of coal mine hoisting and transportation. This standard is formulated to strengthen the management of the main use of wire ropes in coal mines (including wire ropes before and during use) and ensure the safe production of coal mines. This standard is proposed by the Material Technology and Education Department of the Ministry of Coal Industry. This standard is under the jurisdiction of the Coal Mine Safety Standardization Technical Committee of the Ministry of Coal Industry. The drafting unit of this standard: Fushun Branch of the China Coal Research Institute. The main drafters of this standard: Li Banjuan and Yang Yungong. This standard is entrusted to the Ministry of Coal Industry Coal Mine Safety Standardization Technical Committee Hoisting and Transportation Safety Technology and Equipment Branch for interpretation. 761
Coal Industry Standard of the People's Republic of China
Performance of steel wire ropes for in use mine koisting
Testing method and decision rule of wire ropesfor in use mine koisting
MT 7171997
This standard specifies the technical requirements, test methods and decision rules for the suspension and use period test of steel wire ropes for in use mine koisting. This standard applies to round and special-shaped stranded steel wire ropes and flat steel wire ropes (hereinafter referred to as ropes) for important use in coal mines. This standard does not apply to surface contact steel wire ropes and sealed steel wire ropes. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through the use of the reference number 1 in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and the parties using this standard should explore the possibility of using the latest version of the following standards. GB/T228-87 Metal tensile test method
GB/T238-84 Metal wire repeated bending test methodMT716—1997 Technical conditions for acceptance of steel wire ropes for important purposes in coal mines Coal safety regulations 1992 Ministry of Energy of the People's Republic of China 3 Technical requirements before hanging of new wire ropes
3.1 After the arrival of new wire ropes, they must be inspected according to MT716 for acceptance and can only be used or put into reserve after passing the inspection. 3.2 Ropes with a storage period of more than 1 year must be inspected again according to MT716 before hanging and can only be used after passing the inspection. 3.3 The safety factor of ropes for various purposes when hanging (the ratio of the total breaking tension of qualified steel wires to the maximum static tension they withstand) must comply with the relevant provisions of the "Coal Mine Safety Regulations". 3.4 The toughness index (number of repeated bending and twisting) of new ropes must meet the following requirements: a) For ropes used for lifting personnel or lifting personnel and materials, the toughness index of the smooth rope shall not be lower than the requirements of the smooth rope and Class B galvanized rope in MT716; the galvanized rope shall not be lower than the requirements of Class AB in MT716; b) For ropes used for lifting materials, the toughness index of the smooth rope shall not be lower than the requirements of the smooth rope and Class B galvanized rope in MT716, and the galvanized rope shall not be lower than the requirements of Class A in MT716.
4 Technical requirements for periodic inspection of ropes in use
4.1 Cycle:
4.1.1 Ropes used for lifting personnel or lifting personnel and materials shall be inspected once every 6 months from the time of suspension; ropes used for hanging hoisting platforms shall be inspected once every 12 months.
4.1.2 Ropes used for lifting materials shall be inspected for the first time one year after the suspension, and then every 6 months. Approved by the Ministry of Coal Industry of the People's Republic of China on December 30, 1997762
Implementation on July 1, 1998
MT7171997
4.2 Only two tests, namely, breaking tensile force and repeated bending test, shall be carried out for periodic inspection. 4.2.1 The breaking tensile force of steel wires of the same nominal diameter shall be not less than 90% of the average breaking tensile force of the steel wires in the group. 4.2.2 For smooth ropes used for lifting personnel or lifting personnel and materials, the repeated bending times of steel wires shall not be less than 90% of the allowable bending times of new ropes; for AB type galvanized ropes used for lifting personnel or lifting personnel and materials, the repeated bending times of steel wires shall not be less than 85% of the allowable bending times of new ropes; for smooth and galvanized ropes used for lifting materials, the repeated bending times of steel wires shall not be less than 80% of the allowable bending times of new ropes. The results of the above percentage calculations shall be rounded to integers (as shown in Table 1). 763
MT 717 -- 1997
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4.2.3 The nominal tensile strength and nominal diameter of the steel wire shall be based on the values ​​determined during the acceptance inspection of the new rope. Note
1 When there is no original data of the new rope, the single average tensile strength corresponding to the flat spot breaking tension of the steel wire with the same nominal diameter shall be based on the nominal tensile strength grade in the MT716 standard as the nominal tensile strength of the steel wire of the same nominal diameter. 2 When the user does not provide the nominal diameter of the steel wire, the actual measured diameter can be used for calculation and assessment. 4.3 The ratio of the cross-sectional area of ​​the unqualified steel wire to the total cross-sectional area of ​​the steel wire (low-carbon steel wire with triangular strand core, excluding filling wire and shuttle wire) must be less than 25%.
4.4 The safety factor of the rope in use must meet the following requirements after regular inspection: a) When it is specially used for lifting personnel, it must not be less than 7.
b) When it is used for lifting personnel and materials, it must not be less than 7 when lifting personnel and not less than 6 when lifting materials. c) When it is specially used for lifting materials and hanging plates, it must not be less than 5. 5 Test method
5.1 Ropes that have been stored for more than 1 year after passing the rubber test shall be inspected again before hanging according to the method specified in MT716. 5.2 Regular test method for in-use ropes:
5.2.1 Cut a sample of sufficient length, disassemble it completely, and group the steel wires of the same nominal diameter into a group, and conduct repeated bending tests on the steel wires by a tensile machine.
The filling steel wire, center wire, special-shaped core steel wire, and steel core of the rope in the round strand only participate in the test and assessment of the total breaking tensile force of the steel wire. The low-carbon steel wire, filling wire, and correction wire in the triangular strand core are generally not included in the sample range. 5.2.2 The breaking tensile test of the steel wire shall be carried out in accordance with the method specified in GB/T228. The distance between the jaws shall not be less than 100mm. 5.2.3 The reverse bending test of the steel wire shall be carried out in accordance with the method specified in GB/T238. 5.2.4·In the case where the user does not provide the nominal diameter of the steel wire, the steel wire diameter shall be measured. The measurement shall be carried out according to the method in 5.2.1 of MT 716 on the part without wear and corrosion, and the nominal diameter of the steel wire shall be determined by comparing with relevant data (standards or product samples). 5.2.5 If broken wires are found during the debonding, the broken wires shall not be subjected to the breaking tensile force and repeated bending tests, and shall be noted in the inspection record. The influence of broken wires shall be eliminated when calculating the average tensile strength of the steel wire. 6 Judgment rules
6.1 New ropes that have passed the acceptance inspection or the inspection before hanging shall be used only if their toughness index and safety factor during hanging meet the requirements of 3.3.3.4.
6.2 Judgment of regular test knots for ropes in use:
6.2.1 Judgment of unqualified steel wires:
a) Steel wires whose breaking tensile force does not meet the requirements of 4.2.1 are unqualified steel wires, 6) Steel wires whose repeated bending times do not meet the requirements of 2.2 are unqualified steel wires, and c) Steel wires with broken wires in the sample are unqualified steel wires. Note: If a wire has multiple items that do not meet the requirements, it will be counted as one. 6.2.2 If the number of unqualified wires exceeds the requirements of 4.3, the wire rope must be replaced. 6.2.3 If the safety factor does not meet the requirements of 4.4, the wire rope must be replaced.
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