Foreword
Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
JB/T 7688 consists of the following seven parts under the general title Specifications for metallurgy cranes:
——Part 1: General requirements;
——Part 2: Scrap charging cranes;
——Part 3: Forge cranes;
——Part 4: Slab handling cranes;
——Part 5: Ladle cranes;
——Part 6: Quenching cranes;
——Part 7: Claw cranes.
This is Part 5 of JB/T 7688.
This part is developed in accordance with the rules given in GB/T 1.1-2009.
This document replaces JB/T 7688.15-1999 Specification for ladle cranes, and the following main technical changes have been made with respect to JB/T 7688.15-1999:
——The scope of application of the previous edition is modified and extended to cranes for lifting molten metal (see Clause 1 hereof).
——The contents of "Normative references" in the previous edition are modified (see Clause 2 hereof).
——The definition of rated capacity in subclause 3.2.1 of the previous edition is modified (see 4.3.1 hereof).
——The description of the auxiliary hoisting mechanisms in 3.2.2 of the previous edition is modified (see 4.3.3 hereof).
——The contents of 3.3.2.1 and 3.3.2.2 in the previous edition are modified (see 4.4.1.1.1 and 4.4.1.1.6 hereof).
——The contents in 3.3.3 of the previous edition are modified (see 4.4.1.3 hereof).
——The requirements of steel wire rope of the main hoisting mechanism in 3.2.3 of the previous edition are modified (see 4.5.4 hereof).
——The contents in 3.5.2 of the previous edition is modified (see 4.5.6 hereof).
——The contents of 3.3.1, 3.4.1, 3.5.3, 3.5.4 and Clause 7 in the previous edition are deleted.
——The following contents are added:
a) Requirements for welded forks (see 4.4.1.2 hereof);
b) Requirements for forged hooks (see 4.4.1.4 hereof);
c) Steel wire ropes with wire cores or wire strands (see 4.4.2.1 hereof);
d) Requirements upon the tail of steel wire rope is fixed with steel wire rope clamps (see 4.4.2.2 hereof);
e) Requirements upon the tail of steel wire rope is fixed with a wedge joint (see 4.4.2.3 hereof);
f) Requirements for the installation of two independent brakes on the drive shaft of the transmission chain of the main hoisting mechanism (see 4.5.1 hereof);
g) Safety measures to be taken in the transmission chain of the main hoisting mechanism (see 4.5.2 hereof);
h) Requirements upon the compensating pulley shall not be used in the steel wire rope winding system of the main hoisting mechanism (see 4.5.5 hereof);
i) Requirements for the installation of lifting capacity limiters on the main and auxiliary hoisting mechanisms (see 4.5.7 hereof);
j) Provisions for the prevention of electrical failures (see 4.5.8 to 4.5.13 hereof);
k) Requirements to be met upon electric hoist may be used as the hoisting mechanism if the rated capacity is not greater than 16t (see 4.5.14 hereof);
l) Safety brake test (see 5.6 hereof).
This part was proposed by the China Machinery Industry Federation.
This part is under the jurisdiction of the National Technical Committee on Hoisting Machinery of Standardization Administration of China (SAC/TC 227).
The previous editions of this part are as follows:
——JB/T 6129-1992;
——JB/T 7688.15-1999.
Specifications for metallurgy cranes—
Part 5: Ladle cranes
1 Scope
This part of JB/T 7688 specifies the technical requirements, test methods, and inspection rules for ladle cranes (hereinafter referred to as cranes).
This part is applicable to cranes for lifting molten metal.
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 (including any amendments) applies.
GB/T 1591-2008 High strength low alloy structural steels
GB/T 2970-2004 Method for ultrasonic testing of thicker steel plates
GB/T 3811-2008 Design rules for cranes
GB/T 5973 Cuneiform connector for use with steel wire ropes
GB/T 5976-2006 Wire rope grips
GB/T 6974.1 Cranes - Vocabulary - Part 1: General
GB/T 6974.5 Cranes - Vocabulary - Part 5: Bridge and gantry cranes
GB 8918 Steel wire ropes for important purposes
GB/T 10051.1 to 10051.15-2010 Lifting hooks
GB 12602 Lifting appliances - Safety devices against overloading
GB/T 19418-2003 Arc-welded joints in steel - Guidance on quality levels for imperfections
GB/T 20303.5 Cranes - Cabins and control stations - Part 5: Overhead travelling and portal bridge cranes
JB/T 6061 Non-destructive testing - Magnetic particle testing of welds
JB/T 6406 Electro-hydraulic drum brakes
JB/T 7020 Electro-hydraulic disc brakes
JB/T 7688.1-2008 Specifications for metallurgy cranes - Part 1: General requirements
JB/T 9008 (all parts) Electric wire rope hoists
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 6974.1 and GB/T 6974.5 apply.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Technical requirements
4.1 Basic requirements
4.2 Environmental conditions
4.3 Lifting capacity
4.4 Main parts and components
4.5 Safety
5 Test methods
5.1 Visual inspection
5.2 Static load test
5.3 Static rigidity test
5.4 Rated load test
5.5 Dynamic load test
5.6 Safety brake test
5.7 Electrical braking deceleration test of the hoisting mechanism
5.8 Noise test
5.9 Detection of vertical and horizontal deviation of crane wheels
6 Inspection rules
7 Marking, packaging, transportation and storage
