Quality and Technical Supervision Bureaus of all provinces, autonomous regions, and municipalities directly under the Central Government:
On April 18, 2007, a particularly serious accident occurred in Qinghe Special Steel Co., Ltd. in Tieling City, Liaoning Province, which caused the death of 32 workers at the scene. In accordance with the requirements of the "Notice on Carrying out Special Equipment Hidden Hazard Investigation and Special Remediation Actions for Lifting Machinery" (National Quality Inspection Special Letter  No. 355) issued by the General Administration, work arrangements have been made in various places. According to preliminary information, more than 2,000 non-metallurgical cranes used in the metallurgical industry have been found in Liaoning and Jiangsu alone. In order to ensure the safe use of this type of equipment, combined with the production and operation of the enterprise, after research, the notice on the renovation of metallurgical hoisting machinery is as follows:
1. Non-metallurgical hoisting machinery in use for lifting molten metal rectification requirements
(1) For those who have used general-purpose bridge cranes to lift molten metal, they should be replaced with casting cranes that meet the requirements of JB/T7688.15-1999 "Technical Conditions for Metallurgical Cranes, Casting Cranes". If the unit that does not have the conditions to replace the casting crane due to factors such as plant and foundation, in addition to meeting the regulations and standards of general bridge cranes, the original crane must be modified and meet the following basic technical requirements:
1. Use metallurgical hoisting special motors. When the ambient temperature exceeds 40℃, use H-class insulated motors;
2. Two sets of independent brakes (dual brakes) are installed;
3. A lifting weight limiter must be installed;
4. Equipped with different types of double limiter (double limiter) for the ascending limit position of different forms (generally the combined use of heavy hammer type and rotary type), and should control different circuit breakers, cranes with a lifting height greater than 20m, and The lower limit position limiter should be installed as needed;
5. Use thyristor stator voltage regulation, eddy current brake, energy consumption brake, thyristor power supply, DC unit power supply and speed regulation, and other hoisting mechanisms that may cause overspeed due to speed regulation and general-purpose lifting mechanisms for lifting molten metal above 20t The bridge crane must have overspeed protection;
6. The lifting mechanism should have a positive and negative contactor failure protection function to prevent the motor from losing power while the brake is still energized and causing a stall;
7. The protection level of all electrical equipment should meet the requirements of relevant standards;
8. For hoisting machinery that has been working in a high temperature environment for a long time, protective measures must be taken for its electronic control equipment;
9. Select the wire rope suitable for high temperature occasions, and have sufficient safety factor;
10. Cast iron pulleys are not allowed;
11. If the original crane's working level is lower than A6 (excluding A6), it should be used at a reduced load. The reduction should be based on the actual working conditions, but the specified lifting weight after the load reduction shall not exceed 80% of the original rated lifting weight.
(2) For all types of hoisting machinery that have a rated lifting capacity greater than 10t and use electric hoist as the lifting mechanism, it is not allowed to lift molten metal.
(3) For all types of hoisting machinery with rated lifting capacity less than or equal to 10t and electric hoist as the lifting mechanism to lift molten metal, the original crane must be replaced or modified and meet the requirements of the following basic technical conditions:
1. Ordinary electric hoist shall not be used as lifting mechanism;
2. With supporting brake and safety brake;
3. Different types of lifting double limiters (cranes with a lifting height greater than 20m should also be equipped with lower limit position limiters);
4. With lifting weight limiter;
5. Electric hoist with high temperature insulation protection function;
6. It has a sufficient safety factor for lifting molten metal working conditions, and the working level must reach M5 (including M5) or higher;
7. Select the wire rope suitable for high temperature occasions, and have sufficient safety factor;
8. As far as possible, use remote control and other operating methods far away from the heat source, otherwise a safe passage for the operator must be set up.
(4) The above-mentioned crane transformation must be carried out by a unit with the qualification of transformation permit, and the transformation must be carried out informing procedures. The transformed crane must be supervised by a qualified inspection and testing agency in accordance with the "Lifting Machinery Supervision and Inspection Rules" and the requirements of this article. It can be put into use according to regulations only after passing the inspection.
(5) The transformation work of lifting and transporting molten metal cranes should be completed before June 30, 2008. The user unit should immediately formulate a replacement plan or transformation plan and implement it quickly, otherwise it should stop using it. During the implementation of the transformation, the user unit shall monitor the use and must take effective measures to ensure the safe operation of the equipment.
(6) The periodic inspection period for lifting molten metal cranes has been shortened from 2 years to 1 year.
2. New factory installation of crane requirements for lifting molten metal
New factory-installed cranes for lifting molten metal refer to the lifting machinery for lifting molten metal that has been shipped and installed from the date of publication of this article, excluding the lifting machinery for lifting molten metal that has been overhauled, modified, or moved.
(1) The requirements for newly installed cranes for lifting molten metal are as follows:
1. Cranes with a rated lifting capacity greater than or equal to 75t must be used for casting cranes that meet the requirements of JB/T7688.15-1999 "Technical Conditions for Metallurgical Cranes, Casting Cranes".
2. For cranes with a rated lifting capacity of less than 75t, a general-purpose bridge crane with a working class of A7 (including A7) or higher should be selected, but its configuration and other requirements must meet the 11 basic requirements of the modified crane in the first (1) above Technical conditions and corresponding requirements.
3. A crane that uses an electric hoist as a lifting mechanism to lift molten metal can only be used in working conditions with a rated lifting capacity less than or equal to 10t, and its configuration and other requirements must meet the basic requirements of the above-mentioned first (3) after transformation Technical conditions and corresponding requirements, among which the working level of electric hoist is required to be raised from M5 (including M5) or higher to M6 (including M6) or higher.
(2) Cranes for lifting molten non-metallic materials (the temperature is lower than the molten metal) and for lifting hot solid metals can be appropriately relaxed according to the degree of danger in the workplace, or can be handled in accordance with the above requirements.
Local quality and technical supervision bureaus should take effective measures as soon as possible to do a good job in the renovation of non-metallurgical cranes used in the metallurgical industry to prevent the recurrence of similar accidents. If you have any problems in your work, please report to the Special Equipment Safety Supervision Bureau of the General Administration in time.