Safety technical measures for the hottest casting

Safety technical measures for casting operation

as there are far more industrial accidents in the casting workshop than in other workshops, safety technical measures need to be taken from many aspects

(I) process requirements

1. Process layout

should comprehensively consider the layout of process equipment and production process according to the production process level, equipment characteristics, plant site and plant conditions, combined with dust-proof and anti-virus technology. The molding and core making sections with less pollution should be arranged on the leeward side of the minimum frequency wind direction in the non heating season in the centralized heating area, and the heating area in the non centralized what is new material should be located on the leeward side of the minimum frequency wind direction in the whole year. Sand treatment, cleaning and other sections should be separated from other parts by light materials or solid walls and other facilities; The sand treatment and cleaning sections of large foundry workshops can be arranged in separate workshops. Modeling, sanding and passed the TS16949 quality system certification in the automotive industry in 2017. It is appropriate to fix the working station or site for the processes such as sanding, grinding, cutting and welding repair, so as to facilitate the adoption of dust prevention measures. When arranging process equipment and work flow, necessary conditions shall be provided for the reasonable arrangement of dust removal system

2. Process equipment

all finalized casting equipment that produces dust pollution (such as sand mixer, sand screen, belt conveyor, etc.). The manufacturer shall be equipped with a closed cover, and non-standard equipment shall be equipped with dust-proof facilities during design. Molding sand preparation and sand treatment should be sealed and mechanized. The belt conveyor conveying bulk dry materials shall be equipped with a closed cover. For sand mixing, it is not suitable to use crawler tipper feeder and external quantifier with large dust, and it is better to use closed sand mixer with weighing device. The weighing, feeding and feeding of furnace charge preparation shall adopt mechanized devices

3. process method

when adopting new processes and materials, new pollution should be prevented. Fluorite should not be added in cupola smelting. The structure, fuel and combustion method of various heating furnaces should be improved to reduce smoke pollution. The recycled hot sand shall be cooled and deashing treated

4. process operation

under the possible conditions of the process, wet operation should be adopted. For occasions with poor operating conditions such as sanding, grinding and cutting, remote control and isolation operation of manipulator should be adopted

(1) charge preparation. Furnace charge preparation includes metal blocks (cast iron blocks, scrap iron, etc.), coke and various auxiliary materials. In the preparation process, the most prone to accidents is the crushing of metal blocks

(2) melting equipment. The melting equipment used in machine manufacturing plants are mainly cupola (iron melting) and electric arc furnace (steel making)

the smelting process of cupola is: coke, pig iron, waste steel and limestone are added from the charging port on the top of the furnace, the high-temperature furnace gas rises and the metal furnace charge drops. With the combustion of bottom coke, the metal furnace charge is preheated and melted and the molten iron is overheated, and the composition of molten iron changes under the action of furnace gas, slag and coke. Therefore, its safety technology is mainly considered from the aspects of charging, blowing, melting, slag and iron tapping, furnace tapping and furnace repair

(3) pouring operation. The pouring operation generally includes three processes: baking, pouring and cooling. Before pouring, check whether the ladle meets the requirements. Whether the lifting mechanism, tilting mechanism, self-locking mechanism and Shandong innovation group choose the relatively more difficult road frame is intact, flexible and reliable; The molten iron in the ladle shall not be too full, which shall not exceed 80% of the volume, so as to avoid spilling and hurting people} during pouring, all tools in contact with metal solution, such as slag raking rods, tongs, etc., shall be preheated to prevent splashing in contact with cold tools

(4) sand preparation. Dust pollution is an unsafe factor in sand mixing operation; Nails, iron sheets, casting fins and other sundries are punctured; When the sand mixer is running, the operator reaches for the sand sample or tries to shovel out the molding sand, resulting in being injured or dragged into the sand mixer

(5) molding and core making operations. The process of making sand mold is called molding, and the process of making sand core is called core making. The commonly used molding equipment in production includes compaction, compaction, shock compression, etc., and the commonly used core making equipment includes core extruding machine, core shooting machine, etc. Many molding machines and core making machines use compressed air as the power source. In order to ensure safety and prevent equipment accidents or personal injuries, corresponding safety devices, such as limit devices, interlocking devices and safety devices, should be set in the structure, air circuit system and operation

(6) sand removal operation. After the casting is cooled to a certain temperature, the process of taking it out of the sand mold and removing the core sand and core bone from the inner cavity of the casting is called sand falling. Sometimes, in order to improve productivity, if the casting is taken out too early, it is easy to cause scalding accidents because it has not yet fully solidified

(II) building requirements

the casting workshop should be arranged in the building group of high-temperature workshop and power workshop, and built on the wind side of other production buildings in the plant that do not release harmful substances this year

the main direction of the plant should be north-south. The plane layout of the plant shall be comprehensively considered with the requirements of building, structure and dust prevention on the premise of meeting the output and process flow. There should be a certain green belt around the casting workshop

in addition to local ventilation devices, the casting workshop should also use skylights for ventilation or set roof ventilators. The melting and pouring area and the sand falling and cleaning area shall be provided with windbreak windows. For side spans with bridge crane equipment, window sashes that can be opened and closed should be set at appropriate height

(III) dust removal

1. Furnace

(1) steelmaking electric arc furnace. Smoke exhaust should adopt smoke exhaust outside the furnace, smoke exhaust inside the furnace, and combined smoke exhaust inside and outside the furnace. The design parameters of ventilation and dust removal system shall be considered according to the maximum flue gas volume during smelting and oxidation period. The flue gas purification equipment of electric arc furnace should adopt dry-type high-efficiency dust collector

(2) cupola. Mechanical smoke exhaust purification equipment should be used for the smoke exhaust purification of cupola, including high-efficiency cyclone dust collector, particle layer dust collector and electric dust collector. When the dust emission concentration is mg/m3, it is best to use natural ventilation and sprinkler devices for smoke extraction and purification

2. Crushing and milling equipment

the upper part of jaw crusher is directly fed. When the drop is less than LM, it can only be used as a closed cover without ventilation. No matter whether the upper part has exhaust or not, when the lower drop is greater than or equal to LM, the lower part should be set with exhaust sealing cover. The rotating drum of the ball mill shall be set in a fully enclosed cover