JB/T 7688.1-2008 PDF English
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Specifications for metallurgy cranes - Part 1: General requirements
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JB/T 7688.1-2008: Specifications for metallurgy cranes - Part 1: General requirements---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/JBT7688.1-2008
JB
MECHANICAL INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 53.020.20
J 80
Filing No.: 24654-2008
Replacing JB/T 7688.1-1995
Specifications for metallurgy cranes - Part 1: General
requirements
ISSUED ON: JUNE 04, 2008
IMPLEMENTED ON: NOVEMBER 01, 2008
Issued by: National Development and Reform Commission of PRC
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Technical requirements ... 8
3.1 Environmental conditions ... 8
3.2 Use performance ... 9
3.3 Materials of important metal structural parts ... 10
3.4 Welding ... 10
3.5 High-strength bolted connections ... 11
3.6 Main components ... 11
3.7 Assembly ... 14
3.8 Electrical equipment ... 17
3.9 Safety and hygiene ... 22
3.10 Painting ... 24
3.11 Lubrication ... 25
4 Test method ... 25
4.1 Visual inspection ... 25
4.2 Static load test ... 25
4.3 Static stiffness test ... 26
4.4 Rated load test ... 26
4.5 Dynamic load test ... 26
4.6 Electric brake deceleration test of hoisting mechanism ... 27
4.7 Noise test ... 27
4.8 Vertical and horizontal deflection detection of bridge and crane wheels ... 27
5 Inspection rules ... 28
5.1 Inspection classification ... 28
5.2 Exit-factory inspection ... 28
5.3 Type test ... 29
6 Sign, packaging, transportation, storage ... 30
6.1 Sign ... 30
6.2 Packaging, transport, storage ... 30
Appendix A (Normative) Detection method of braking distance of hoisting mechanism
... 32
Appendix B (Normative) Detection method for horizontal and vertical deflection of
wheel axes of bridge and trolley ... 34
Specifications for metallurgy cranes - Part 1: General
requirements
1 Scope
This Part of JB/T 7688 specifies the general technical requirements, test methods,
inspection rules for metallurgical cranes (hereinafter referred to as cranes).
This Part is mainly applicable to special-purpose cranes for metal smelting, rolling,
thermal processing enterprises, including ladle cranes, bin cranes, slab handling cranes,
claw cranes, forging cranes, quenching cranes. Other similar metallurgical cranes may
also refer to this standard.
2 Normative references
The terms in the following documents become the terms of this Part through the
reference of this Part of JB/T 7688. For dated reference documents, all subsequent
amendments (excluding errata content) or revisions do not apply to this Part; however,
parties who reach an agreement based on this Part are encouraged to study if the latest
versions of these documents are applicable. For undated references, the latest edition of
the referenced document applies.
GB/T 146.1 Standard gauge railway rolling stock gauge
GB/T 699 Quality carbon structural steels
GB/T 700 Carbon structural steels (GB/T 700-2006, ISO 630:1995, NEQ)
GB 755 Rotating electrical machines - Rating and performance (GB 755-2000, idt
IEC 60034-l:1996)
GB/T 985 Basic forms and sizes of weld grooves for gas welding, manual welding
and gas- shielded welding
GB/T 986 Basic forms and sizes of weld grooves for submerged arc weld
GB/T 1228 High strength bolts with large hexagon head for steel structures (GB/T
1228-2006, ISO 7412:1984, NEQ)
GB/T 1229 High strength large hexagon nuts for steel structures (GB/T 1229-2006,
ISO 4775:1984, NEQ)
GB/T 10051 (all parts) Lifting hooks
GB/T 10183-2005 Cranes - Overhead travelling cranes and portal bridge cranes -
Tolerances for cranes manufacture and tracks laying (ISO 8306:1985, MOD)
GB/T 11352 Carbon steel castings for general engineering purposes (GB/T 11352-
1989, neq ISO 3755:1975)
GB/T 13306 Plates
GB/T 13384 General specifications for packing of mechanical and electrical product
GB/T 14405-1993 General bridge crane
GB 15052-1994 Lifting appliances - Dangerous positions and signs
GB/T 19418 Arc-welded joints in steel - Guidance on quality levels for
imperfections (GB/T 19418-2003, ISO 5817:1992, IDT)
GB/T 20303.5 Cranes - Cabins - Part 5: Overhead travelling and portal bridge cranes
(GB/T 20303.5-2006, ISO 8566-5:1992, IDT)
JB/T 3241 SWP universal coupling with spider and split bearing eye
JB/T 4315 Crane electric control equipment
JB/T 5513 SWC type whole fork cross spindle universal coupling
JB/T 6392 Rail wheels for crane
JB/T 6406 Electro-hydraulic drum brakes
JB/T 7009 Spherical roller coupling for drum
JB/T 7017 Hydraulic buffer for cranes
JB/T 7019 Test methods for fiber cement products
JB/T 7020 Testing method of insulating glass
JB/T 7687.l ~ JB/T 7687.4 Lifting hook accessories
JB/T 7944 Sampling procedures for inspection by attributes of coiled helical springs
JB/T 8110.1 Spring buffer for crane
JB/T 8854.l Curved-tooth coupling GCLD
JB/T 8854.2 Curved-tooth coupling GIICL, GIICLZ
JB/T 8854.3 Curved tooth coupling GICL, GICLZ
JB/T 8905.1 Three-point support gearboxes for cranes
JB/T 8905.2 Foot mounted gearboxes for cranes
JB/T 9005 Casting sheaves for cranes
JB/T 9006 Drums for cranes
JB/T 10104 YZ Range of three-phase induction motors for crane and metallurgical
application - Technical specifications
JB/T 10105 YZR Range of three-phase slip-ring rotor induction motors for crane
and metallurgical application technical specifications
JB/T 10559 Non-destructive testing of lifting appliances - Ultrasonic testing of steel
welds
JB/T 10833 The polyurethane buffer for cranes
3 Technical requirements
3.1 Environmental conditions
3.1.1 The power supply of the crane is generally three-phase AC, which has a frequency
of 50 Hz (60 Hz). The voltage is 380 V. For large metallurgical cranes, if the single-
mechanism driving motor's capacity exceeds 400 kW, OR if the total motor capacity
exceeds 500 kW during use, it is recommended to use a three-phase AC, 50 Hz, 3000
V power supply. Under normal working conditions, the voltage fluctuation of the power
supply system, at the access point of the crane feeder, shall not exceed ±10% of the
rated value.
If there are special requirements for the power supply, it can be determined by
negotiation between the supplier and the buyer, according to the needs of the user.
3.1.2 When the altitude of the place, where the crane is installed and used exceeds 1000
m, the capacity of the motor shall be checked, according to the provisions of GB 755.
3.1.3 The working environment temperature and humidity of the crane shall meet the
following requirements:
a) The working environment temperature of the crane is generally -10 °C ~ +50 °C;
b) The relative humidity does not exceed 50%, at a temperature of +40 °C.
accuracy requirements: ;
- For cranes requiring high positioning accuracy: .
Note: The realization of the positioning accuracy requirements depends on the complementary
matching of different speed control system grades and different static rigidity indicators, whilst
the acceptable positioning accuracy refers to the positioning accuracy between low and medium.
3.2.6 During the static load test, the crane shall be able to withstand a test load of 1.25
times the rated working load. After the test, carry out a visual inspection. There is no
crack, permanent deformation, peeling of paint, no loosening at the joints.
3.2.7 During the dynamic load test, the crane shall be able to withstand a test load of
1.1 times the rated working load. During the test, it shall work normally; the safety
devices such as brakes shall operate sensitively and reliably. After the test, a visual
inspection shall be carried out. There shall be free from cracks and permanent
deformation, peeling paint, loosening or damaged joints.
3.2.8 Drive the trolley to the end of the span, to check that the main girder has camber,
which shall not be less than 0.7S/1000.
3.3 Materials of important metal structural parts
3.3.1 The material of the important metal structural parts of the crane shall comply with
the requirements of "Structural member steel" in GB/T 3811.
Note: The important metal structural parts refer to: main girder, auxiliary girder, trolley frame,
lifting beam, hook side plate, piece hook, suspension fork, balance lever, wheel frame, etc.
3.3.2 The electrodes, wires, fluxes used for welding components shall be compatible
with the materials of the parts to be welded.
3.3.3 The materials of important metal structural parts shall be de-rusted by surface
spray (shot) blasting before welding; it shall reach Sa2 1/2 level specified in GB/T 8923;
other components shall reach Sa2 level or St2 level.
3.4 Welding
3.4.1 The form and size of the welding bevel shall comply with the provisions of GB/T
985 and GB/T 986; if there are special requirements, it shall be indicated on the drawing.
3.4.2 The defective quality of the welds of the main structural parts shall meet the
requirements of medium (C) level in defect quality of GB/T 19418.
3.6.2 Pulleys
Rolled pulleys are recommended. When cast pulleys are used, they shall comply with
the provisions of JB/T 9005.
3.6.3 Reels
3.6.3.1 When a cast reel is used, its performance shall not be lower than that specified
in JB/T 9006.
3.6.3.2 When welding reels are used, steel grades with suitable impact toughness shall
be selected, according to different ambient temperatures; their material properties shall
not be lower than Q235-B steel in GB/T 700.
The reel shall be annealed as a whole, after welding is completed.
Steel pipe or welded reels rolled from steel plates are recommended.
3.6.3.3 The deviation of reel diameter shall not be greater than h11.
3.6.3.4 When double lifting points and double reels are used, the diameter tolerance of
the reels shall not be greater than h9.
3.6.3.5 It is recommended to use the special coupling for the reel in JB/T 7009.
3.6.4 Couplings
3.6.4.1 It is recommended to use the drum-shaped gear coupling, which is specified in
JB/T 8854.1 ~ JB/T 8854.3.
3.6.4.2 Universal couplings shall meet or have performance not lower than those
specified in JB/T 3241 and JB/T 5513.
3.6.4.3 The friction discs in the friction limit torque coupling shall be evenly contacted;
the contact area shall not be less than 75%. All friction surfaces shall be well lubricated.
The adjustment spring for limit torque shall be easy to install and adjust.
3.6.4.4 When the column pin limit moment coupling is used, the diameter of the safety
shear pin is determined, according to the limit shear moment. Safety shear pins shall be
easy to install and replace.
3.6.5 Brake
3.6.5.1 The JB/T 6406 electro-hydraulic drum brakes or JB/T 7020 electro-hydraulic
disc brakes are used; disc brakes are recommended for hoisting mechanisms.
3.6.5.2 The material properties of the steel brake wheel shall not be lower than the
No.45 steel specified in GB/T 699 or the ZG310-570 steel, which is specified in GB
is within ±15 mm and the vertical amplitude of the bridge is within the range of ±20
mm.
3.8.3 Installation of electrical equipment
3.8.3.1 The electrical equipment shall be installed securely. During the working process
of the main engine, there shall be no horizontal movement or vertical jump, as relative
to the main engine. For vertically installed control panels and cabinets, the
perpendicularity shall not exceed 12‰. The highest vibration condition of the installed
parts is 5 Hz ~ 13 Hz; the displacement is 1.5 mm. When it reaches 13 Hz ~ 150 Hz,
the vibration acceleration does not exceed 10 m/s2.
3.8.3.2 The degree of protection of electrical equipment, which is installed in the
electrical room, may be IP00, BUT it shall have appropriate protective measures, such
as protective railings and protective nets.
3.8.3.3 Resistors of four boxes or less can be stacked directly. When there are more than
four boxes, the number of stacked boxes can be increased, under the condition of
ensuring stable heat dissipation and temperature rise; however, reinforcement measures
shall be considered and the distance between boxes shall not be less than 80 mm. If the
spacing is too small, the capacity usage shall be reduced or other corresponding
measures shall be taken.
3.8.3.4 After the resistor is installed, there shall be sufficient ventilation and heat
dissipation measures.
3.8.3.5 The electrical equipment, which is installed in each part of the crane, shall be
easily and safely maintained. There shall be a channel of more than 500 mm, in front
of the electrical equipment on the walking platform and in the electrical room. A
channel of not less than 400 mm shall be reserved, in the back of the electrical
equipment for maintenance or wiring.
3.8.3.6 For cranes used indoors, the electrical equipment installed on the bridge frame
shall have no exposed live parts; the minimum degree of protection shall not be lower
than IP10 in GB/T 4208. If the electrical equipment is installed in an outdoor unshielded
place, the degree of protection of the enclosure shall not be lower than IP33.
3.8.3.7 The minimum distance -- BETWEEN the exposed live parts of the bridge and
trolley feeders on the crane AND the metal structure -- shall be greater than 30 mm.
When the crane may cause relative shaking during operation, the distance shall be
greater than the maximum shaking plus 30 mm.
3.8.3.8 In places with strong heat radiation, protective measures shall be taken for
electrical equipment.
3.8.3.9 For cranes used in a dusty environment, the control panel shall be centrally
placed in a heat-insulated and dust-proof electrical room.
3.8.4 Conductors and their laying
3.8.4.1 Cranes shall use copper core, multi-strand, sheathed insulated wires.
3.8.4.2 Cranes shall use multi-strand single-core conductors, which have a cross-
sectional area of not less than 1.5 mm2, OR multi-strand multi-core conductors, which
have a cross-sectional area of 1 mm2. The cross-sections of connecting wires, such as
electronic devices, hydraulic servo mechanisms, sensing elements, are determined as
required.
3.8.4.3 The wires on the crane shall be laid in wire slots or metal pipes. Where wire
slots or metal pipes are inconvenient to lay OR have relative movement, they can be
laid through metal hoses. Cables are allowed to be laid directly, BUT protective
measures shall be taken, in places with mechanical damage, high temperature radiation,
chemical corrosion, oil corrosion.
3.8.4.4 The wires of different institutions, different voltage types, voltage levels shall
be separated as much as possible, when passing through the pipes. The lighting wires
should be laid separately.
3.8.4.5 Single-core conductors (or cables), which have an AC current carrying current
of more than 25 A, are not allowed to pass through metal pipes alone.
3.8.4.6 For cables that are fixedly laid, the bending radius shall not be less than 5 times
the outer diameter of the cable. The laying of mobile cables shall comply with the
provisions in GB/T 3811.
3.8.4.7 Rainproof measures shall be taken, for the wire inlet and outlet holes, wire slots,
wire pipe inlet and outlet openings of cranes, driver's cabs, electrical rooms and
electrical equipment used outdoors. There shall be no water accumulation in the wire
slots.
3.8.4.8 Cables for transmitting low voltage and low power shall not use the same multi-
core cable as power cables or cables of different voltage levels; shielded cables shall be
used, if necessary.
3.8.4.9 Where the wire passes through the steel pipe or metal hole, there shall be
protective measures to prevent the wire from being worn out.
3.8.4.10 The two ends of the conductors shall be cold-pressed copper terminals; the
connection between the conductors and the terminals shall be pressed tightly, by special
cold-press pliers.
3.8.4.11 Both ends of the conductor shall have permanent identification marks, which
are consistent with the circuit diagram or wiring diagram.
3.8.4.12 All conductors are not allowed to have intermediate joints. Lighting wires
3.9 Safety and hygiene
3.9.1 The working support brake, which is adopted by the crane, shall be normally
closed. The brake safety factor shall not be less than the provisions in GB/T 3811. The
brake shall be sensitive and reliable.
The operating mechanism needs to stop accurately. If there are special requirements,
such as emergency stop, it should use a normally open brake, which is operated
manually.
3.9.2 The safety protection device of the crane shall be set, according to the provisions
of GB 6067.
3.9.3 The hoisting mechanism of the crane shall be equipped with a hoisting height
limiter. When the pick-up device rises to the limit position, which is specified in the
design drawing, it shall be able to automatically cut off the power supply of the motor.
In the case of special needs, a second-level lifting height limiter can be installed, OR
other measures can be taken to prevent the overrun accident.
When there is a lower limit position requirement, a lowering limiter shall also be set.
In addition to automatically cutting off the power supply of the motor, the number of
winding turns of the wire rope on the drum shall be at least two, regardless of the
number of fixed wire rope turns.
3.9.4 The crane shall be equipped with a travel limit device, a track clearing plate, a
buffer; a stop device shall be installed at the end of the trolley track, the stop head shall
be welded firmly.
3.9.5 When two or more cranes are running on the same track, they must be equipped
with anti-collision devices.
3.9.6 The safety and hygiene requirements of the crane driver's cab shall comply with
the provisions in GB/T 20303.5.
3.9.7 The distance -- between the crane pick-up device and the cab -- shall not be less
than 0.4 m.
3.9.8 The part of the crane, that is directly exposed to high temperature radiation, shall
be equipped with heat insulation boards or heat insulation walls.
3.9.9 The rotating parts of the crane, that are exposed and may cause injury (such as
open gears, transmission shafts and couplings, etc.), shall be provided with safety
protection covers.
3.9.10 The crane shall be provided with a platform, which leads to each transmission
system, electrical equipment and maintenance. Refer to the provisions of "Aisle and
platform" in GB/T 3811, for requirements on the height, width and load bearing of the
aisle and platform. Safe, reliable, convenient inclined ladders (when the layout is not
difficult) or straight ladders and step ladders shall be set up, between passages for
maintenance and debugging at different levels.
The railings set on the crane shall comply with the provisions of "railings" in GB/T
3811.
3.9.11 The end fixed section of the wire rope winding system of the hoisting mechanism
shall be arranged in a place, that is convenient for installation and maintenance (it shall
be on the platform of the trolley frame as much as possible). The end of the wire rope
shall be fixed during installation. When reaching the lowest lifting height, the number
of fixed wire rope turns shall be kept at least two.
3.9.12 The boarding place of the crane shall be equipped with a signal, to communicate
with the driver's cab. If the distance between the driver's cab and the ground is greater
than 20 m, a communication device should be installed to communicate with the ground.
3.9.13 An inspection room or an inspection platform shall be set up on one side of the
conductive slide line. When the height of the slide line is greater than the crane track
surface OR the position of the hook is too close to the slide line due to the limit position,
a protective stop shall be installed at the slide line. When the driver's cab and the
conductive slide line are on the same side, the contact section of the slide line collector
shall be provided with a protective net.
3.9.14 The door entering the driver's cab and the door leading to the bridge frame shall
be equipped with an electrical interlock protection device. When any door is opened,
except for the hoisting mechanism, other mechanisms of the crane shall stop working.
3.9.15 The crane shall be equipped with pressure loss protection and zero position
protection. Set up an emergency power off switch, at the driver's convenience.
3.9.16 An isolating switch or other measures should be installed at the inlet of the crane;
a main circuit breaker shall be installed for short-circuit protection.
3.9.17 When the speed control system adopts energy consumption brake and eddy
current brake hoisting mechanism, the loss of excitation protection device shall be
installed.
3.9.18 For important hoisting mechanisms and unbalanced luffing mechanisms that
may cause danger due to over-speeding of loads, an overspeed protection switch shall
be provided. The setting value of the overspeed switch depends on the performance of
the control system and the rated descending speed, which is usually 1.25 ~ 1.4 times of
the rated descending speed.
3.9.19 Each mechanism shall be provided with an overcurrent protection device
separately (except the mechanism driven by cage motor).
color, without defects such as roughness, unevenness, holiday, wrong paint, wrinkles,
pinholes, severe sagging.
3.11 Lubrication
3.11.1 The type of lubricating system shall be determined according to the location of
the crane mechanism, the number of lubricating points, the demand for lubricating oil.
Generally, centralized lubricating can be used. Electric lubrication shall be used for
systems which have many lubrication points and long distances. The lubricating points
of each mechanism shall be located, where maintenance personnel can easily maintain.
3.11.2 Steel wire ropes shall be well lubricated with grease.
4 Test method
Crane tests shall follow the specifications and procedures, which are specified in GB/T
5905.
4.1 Visual inspection
Visual inspection shall include whether the specifications and status of all important
parts meet the requirements: such as mechanisms, electrical equipment, safety devices,
controllers, indicating devices, instruments, lighting and signaling systems, metal
structures of cranes and their connections, ladders, passages, driver's cab and all
protective devices, hooks or other pick-up devices and their connectors, wire ropes and
their fixings, pulley blocks and their axial fixings.
When checking, open covers that shall be opened, during normal maintenance and
inspection (such as axle box covers, limit switch covers). During the visual inspection,
it shall also be checked that the required and reviewed certificates are provided.
4.2 Static load test
The load of the test shall be gradually increased, until it is lifted to 100 mm ~ 200 mm
above the ground; the suspension time shall not be less than 10 minutes.
The test load of the crane is 1.25P (where P is the rated working load).
After unloading, check the bridge frame. If no cracks, permanent deformation, peeling
paint or damage affecting the performance and safety of the crane is found, meanwhile
no looseness or damage occurs at the joints, the test is passed.
......
Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al.
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