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MT/T 716-2019 PDF in English


MT/T 716-2019 (MT/T716-2019, MTT 716-2019, MTT716-2019)
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MT/T 716-2019: PDF in English (MTT 716-2019)

MT/T 716-2019
MT
NATIONAL COAL INDUSTRY OF THE
PEOPLE’S REPUBLIC OF CHINA
Replacing MT/T 716-2005
Technical delivery requirements of steel wire ropes for coal
mine hoisting
ISSUED ON: DECEMBER 29, 2018
IMPLEMENTED ON: JULY 01, 2019
Issued by: State Coal Mine Safety Supervision Bureau
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Wire rope material ... 6
4 Requirements ... 7
5 Inspection and testing ... 20
6 Inspection rules ... 24
7 Packaging, marking, quality certificates and safety signs ... 26
Annex A (normative) Wire rope twist quality and surface quality ... 27
Technical delivery requirements of steel wire ropes for coal
mine hoisting
1 Scope
This document specifies the requirements for acceptance, pre-hanging inspection,
inspection and testing, inspection rules, packaging, marking, quality certificates and
safety signs, etc. of steel wire ropes for coal mine hoisting.
Steel wire ropes for coal mine hoisting include: shaft hoisting wire ropes, inclined shaft
hoisting wire ropes, hanging hoist wire ropes, inclined wire ropes for transporting
personnel, traction belt conveyor wire ropes and tilted stepless rope winch wire ropes
and wire ropes for overhead passenger installations.
This Standard applies to various round strand wire ropes, special-shaped strand wire
ropes and compacted strand wire ropes for coal mine hoisting.
This Standard does not apply to balancing flat wire ropes and sealed wire ropes.
2 Normative references
The following referenced documents are indispensable for the application of this
document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
GB/T 228.1, Metallic materials -- Tensile testing -- Part 1: Method of test at room
temperature
GB/T 238, Metallic materials -- Wire -- Reverse bend test
GB/T 239.1, Metallic materials -- Wire -- Part 1: Simple torsion test
GB/T 1839, Test method for gravimetric determination of the mass per unit area of
galvanized coatings on steel products
GB/T 2104, Steel wire ropes -- Packing, marking and certificate -- General
requirements
GB/T 8170, Rules of rounding off for numerical values and expression and
judgement of limiting values
GB/T 8358, Steel wire ropes -- Determination of breaking force
GB/T 8706, Steel wire ropes -- Vocabulary, designation and classification
GB/T 8918, Steel wire ropes
GB/T 8919, Wire for steel wire ropes use
GB/T 15030, Sisal wire rope core
GB/T 21965, Steel wire ropes -- Vocabulary for acceptance and defect
AQ 1043, Mining Products Safety Label
YB/T 5343, Steel wire for ropes
YB/T 5359, Compacted strand ropes
NB/SH/T 0387, Wire rope greases
Coal Mine Safety Regulations (Edition 2016)
3 Wire rope material
3.1 Steel wire for rope making
The steel wire used for rope making shall comply with the requirements for important
purpose steel wire in GB/T 8919. Compacted strand wire rope wires shall comply with
the requirements for important purpose steel wires in YB/T 5343.
3.2 Rope core
3.2.1 Fiber core
The fiber core shall comply with the requirements of GB/T 15030 or be made of jute,
synthetic fiber or other fibers that meet the requirements. Unless otherwise required by
the purchaser, the fiber core shall be soaked with lubricating grease with anti-corrosion
and anti-rust properties.
3.2.2 Steel core
The steel core is divided into independent steel wire rope core [IWR, IWRC, IWRC(K)],
compacted strand parallel twisted steel wire rope core [PWRC(K)] and steel wire strand
core (IWS, WSC). For compacted strand steel wire ropes, if the purchaser has no special
requirements, the supplier shall determine whether the steel core is a compacted strand
core.
3.3 Grease
Unless otherwise required by the purchaser, the surface of the wire rope shall be evenly
and continuously coated with anti-rust lubricating grease. When the purchaser requires
the steel wire rope to have friction-increasing performance, the steel wire rope shall be
coated with friction-increasing grease and there shall be no leakage.
The grease and hemp core grease used for steel wire ropes shall comply with NB/SH/T
0387 or other relevant requirements.
4 Requirements
4.1 Basic requirements
4.1.1 Wire ropes shall have mining product safety signs.
4.1.2 Wire ropes shall have quality certificates. Among them, the requirements for steel
wire ropes shall comply with the implementation standards and requirements for safety
signs of mining products.
4.1.3 After the new wire rope arrives, it shall be inspected for performance according
to this Standard and can only be used after passing the test.
4.1.4 Steel wire ropes stored for more than 1 year shall be tested again according to this
Standard before being hung, and can only be used after passing the test.
4.1.5 The safety factor when hanging wire ropes for various purposes (the ratio of the
measured sum of the breaking tension of qualified steel wires to the maximum static
tension it bears) shall comply with the relevant provisions of the "Coal Mine Safety
Regulations".
4.2 Requirements for wire ropes
4.2.1 Diameter
4.2.1.1 Nominal diameter
The nominal diameter shall comply with the requirements of GB/T 8918 and YB/T
5359, otherwise it shall be agreed upon by both parties. The nominal diameter shall be
indicated on the wire rope quality certificate.
4.2.1.2 Diameter deviation and out-of-roundness
Diameter deviation and out-of-roundness are shown in Table 1.
breaking tension of the steel wire and the corresponding conversion factor between the
sum of the minimum breaking tension of the steel wire and the minimum breaking
tension of the steel wire in GB/T 8918 or the product of the conversion factor
corresponding to the sum of the minimum breaking tensile forces in the table of
mechanical property in YB/T 5359.
NOTE: When the typical structure of the wire rope is inconsistent with GB/T 8918 or YB/T 5359,
the minimum total wire breaking tension confirmed by the mining product safety mark shall be
followed.
4.2.7.2.2 Method 2 -- Wire rope breaking tension
The measured breaking force of the wire rope shall not be less than the minimum
breaking force of the wire rope corresponding to the nominal tensile strength of the wire
rope in the mechanical property table of GB/T 8918 or the mechanical property table
of YB/T 5359.
NOTE: When the nominal diameter and nominal tensile strength of the wire rope are inconsistent
with the mechanical properties table of GB/T 8918 or YB/T 5359, the minimum breaking tension
of the wire rope shall be calculated according to the method of GB/T 8918 or YB/T 5359. When the
typical structure of the steel wire rope is inconsistent with GB/T 8918 or YB/T 5359, and the
minimum breaking tension of the steel wire rope confirmed by the mining product safety mark is
greater than the calculated value, the minimum breaking tension of the steel wire rope confirmed by
the mining product safety mark shall be followed.
4.3 Requirements for split steel wire
4.3.1 General
Remove the steel wire from the wire rope specimen. The tensile strength, breaking
tension, repeated bending and torsion of the steel wire are assessed based on the
nominal tensile strength and nominal diameter of the steel wire. Or take steel wires with
the same nominal diameter as a group (the nominal diameter of the steel wire before
twisting for compacted stranded steel wire ropes), and use the nominal tensile strength
in Table 2 below the actual measured average tensile strength value as the nominal
tensile strength of the steel wire. Assess various test results of steel wires.
When the nominal tensile strength of the steel wire is inconsistent with Table 2, use it
as the nominal tensile strength to evaluate the tensile strength of the steel wire. Under
repeated bending and torsion, the nominal tensile strength in Table 2 is used for
assessment.
4.3.2 Diameter
4.3.2.1 Nominal diameter
It shall be noted on the wire rope quality certificate.
Wire rope length measurements are in meters. The accuracy of the measuring tool shall
be no less than ±2.5%.
5.1.3 Measurement of weight
Measure the total weight of the wire rope (including spool, hook and packaging material)
in kg. Subtract the weight of the reel, chain hook and packaging material from the total
weight and divide it by the actual measured length of the wire rope (in hundreds of
meters). The resulting quotient is the actual unit weight of the wire rope, expressed in
kg/100 m.
The total weight of the wire rope shall be measured with a scale.
5.1.4 Appearance inspection
The appearance of the wire rope and its strands shall be inspected by hand and visual
inspection.
5.1.5 Inspection for no looseness
Unwind one end of the wire rope into two symmetrical strands, about two lay lengths.
When the two strands return to their original positions, they shall not spread out on their
own (except for wire ropes with multi-layer strands and four fan-shaped strands). The
steel wire rope determined to be loose during inspection is the steel wire rope with
substandard twisting quality.
5.1.6 Measurement of elongation
The measurement of wire rope elongation shall be agreed between the supplier and the
purchaser.
5.1.7 Determination of the sum of the breaking tensile forces of wires in wire ropes
The sum of the breaking forces of steel wires is the sum of the measured breaking forces
of all steel wires.
5.1.8 Breaking tensile test of wire rope
The breaking tension of the wire rope shall be determined according to the method
specified in GB/T 8358.
5.2 Split wire test
5.2.1 Measurement of diameter
Two diameter values shall be measured on the same section of the steel wire in
perpendicular directions. Then take the average value as the actual measured diameter
of the steel wire.
5.2.6.1.2 Compacted strand wire rope shall meet the following conditions:
a) The number of low-value steel wires shall not exceed the requirements in Table 9;
b) The total number of low-value steel wires allowed for the three tests of steel wire
breaking tension, repeated bending and torsion is calculated based on the ratio of
the total cross-sectional area of the low-value steel wires to the total cross-
sectional area of the test steel wires. Wire ropes used to lift people or to lift people
and materials shall be less than 6%. Wire ropes designed for lifting materials shall
be less than 10%;
c) The number of steel wires whose galvanized layer weight is lower than the
minimum zinc layer weight shall not exceed 5%.
When the same steel wire has multiple low values, only one wire will be counted. When
the number of unqualified steel wires calculated based on the galvanized layer weight
is less than one, one is allowed.
5.2.6.2 Method 2
5.2.6.2.1 Round strand wire ropes and special-shaped strand wire ropes shall meet the
following conditions:
a) The number of unqualified steel wires of any diameter shall not exceed 1;
b) If the number of unqualified steel wires of any one diameter is 2 or more, other
steel wires of that diameter shall be tested for unqualified items one by one. The
number of unqualified steel wires shall not be greater than 4% of the number of
steel wires of the same diameter (rounded to an integer according to GB/T 8170);
c) The number of steel wires whose galvanized layer weight is lower than the
minimum zinc layer weight shall not exceed 5%.
When the same steel wire has multiple failures, only one wire will be counted. When
the number of unqualified steel wires calculated based on the galvanized layer weight
is less than one, one is allowed.
5.2.6.2.2 Compacted strand wire rope shall meet the following conditions:
a) The number of steel wires whose galvanized layer weight is lower than the
minimum zinc layer weight shall not exceed 5%;
b) If one or more test items do not meet the specified requirements, the unqualified
items of the remaining strands of steel wires of the same nominal diameter shall
be retested. The original test results shall be added to the 100% test evaluation
specified in Table 9.
When the same steel wire has multiple low values, only one wire will be counted. When
the number of unqualified steel wires calculated based on the galvanized layer weight
is less than one, one is allowed.
6 Inspection rules
6.1 General
6.1.1 Each wire rope shall undergo acceptance inspection and inspection before hanging.
6.1.2 Acceptance inspection and pre-hanging inspection shall be proposed and sampled
by the user.
6.1.3 Acceptance inspection and pre-hanging inspection shall be carried out by qualified
inspection organizations authorized by the department responsible for supervision and
management of production safety.
6.2 Sampling method and sampling quantity
6.2.1 Method 1
Cut a specimen of sufficient length from the end that has passed the visual inspection.
The number of tests shall be 100% of the total number of test specimens (excluding
galvanized coating tests). Group steel wires of the same nominal diameter. Carry out
various tests according to the provisions of 5.1.7 and 5.2.
The filling steel wires in the strands, the various strand core steel wires and the steel
cores in the steel wire ropes only participate in the test and assessment of the total
breaking tensile force of the steel wires.
The low carbon steel wires, filler wires and patch wires that make up the triangular
strand core are not included in the sample range.
The length of the specimen shall not be less than 1.5 m.
6.2.2 Method 2
Take a specimen of sufficient length from one end of each wire rope. Carry out the
breaking tensile test of the wire rope according to the provisions of 5.1.8.
Take a specimen of sufficient length from one end of each wire rope. Choose any 1
strand of single-layer wire rope. Multi-layer strand steel wire ropes are selected
according to Table 12, and multi-layer strands of compacted strand steel wire ropes are
selected according to Table 13 (except for welding points). Carry out various tests
according to the provisions of 5.2. The steel wires tested do not include filler wires in
strands, various strand core steel wires and steel cores in steel wire ropes.
The length of the specimen shall not be less than 4 m.
Annex A
(normative)
Wire rope twist quality and surface quality
A.1 Twist quality
A.1.1 The strands shall be twisted evenly and tightly.
A.1.2 The size of the strand core wire and strand fiber core shall ensure sufficient
support so that the outer twisted steel wire can be twisted evenly. A relatively uniform
gap is allowed between adjacent steel wires of strand ropes with fiber cores. For strands
made of steel wires of the same diameter and the steel core in the rope, the center wire
and center strand shall be appropriately enlarged.
A.1.3 The wire rope shall be twisted evenly, tightly and not loosely. The intrafemoral
wire shall not be loose. It must not be wavy when unfolded and unloaded.
A.2 Surface quality
The following appearance defects are not allowed on steel wire ropes:
a) Broken wire: the phenomenon of steel wire breakage in the steel wire rope strand;
b) Jump wire: a steel wire in a strand with one or more protrusions forming an arch
or loop;
c) Missing wire: there is a lack of steel wire in the steel wire rope strand;
d) Interlacing of steel wires: one or several steel wires cross on the surface of the
steel wire rope, and the steel wires are not in the specified geometric position;
e) Uneven tightness of strands or wires: protrusions or depressions in the strands or
wires in the rope;
f) Wrong wire connection: there are wire diameter mismatches, wire hooking,
overlapping, and twisting in the strands;
g) Kink in the wire rope: the wire rope cannot return to a straight shape due to
excessive bending or twisting;
h) Surface damage: damage occurs on the surface of the steel wire due to collision,
squeezing, falling, etc.;
i) Exposed hemp core: the rope core is extruded from between the rope strands, the
local hemp core is thickened, the rope diameter becomes larger, or the hemp core
......
 
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.