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Factors affecting pump valve process

There are many solidification methods for castings. During the solidification process of castings, their cross-section is generally divided into three zones: 1- Solid phase zone 2- Solidification zone 3- Liquid phase zone. The width of the solidification zone has a significant impact on the solidification process, and the solidification mode is divided accordingly. Firstly, intermediate solidification: The solidification of most alloys falls between layer by layer solidification and paste solidification. Secondly, layer by layer solidification: Pure metals and eutectic alloys do not have a solidification zone during the solidification process. The liquid and solid phases on the cross-section are clearly separated by a boundary. As the temperature decreases, the solid phase layer continuously increases and the liquid phase layer continuously decreases, reaching the center. Thirdly, paste solidification: The alloy has a wide range of crystallization temperatures. During a certain period of solidification, there is no solid layer on the surface of the casting, and the solidification zone runs through the entire cross-section, first becoming paste and then solidifying. According to relevant experts, the factors affecting the solidification mode of castings can be summarized as follows: firstly, the temperature gradient of the castings. When the temperature range of alloy crystallization is constant, the width of the solidification zone depends on the temperature gradient of the inner and outer layers of the casting. The smaller the temperature gradient, the wider the solidification zone. (Large temperature difference between inside and outside, fast cooling, narrow solidification zone). Secondly, the crystallization temperature range of the alloy. Small range: The solidification zone is narrow and tends to solidify layer by layer. For example, sand casting, layer by layer solidification of low carbon steel, and paste solidification of high carbon steel. Casting defect repair agent is a two-component, adhesive like, room temperature cured polymer resin adhesive, polymer metal composite cold welding repair material with metal and alloy as strengthening fillers. It has high bonding strength with metals and can basically preserve color consistency, with characteristics of wear resistance, corrosion resistance, and aging resistance. The cured material has high strength, no shrinkage, and can be subjected to various mechanical processing. It has excellent properties such as wear resistance, oil resistance, waterproofing, and resistance to various chemical corrosion, and can withstand high temperatures of 120 ℃.

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Pump and Valve Operating Procedures

1) Before starting work, check whether the furnace body, furnace door, trailer, wire rope pulley, blower and other equipment are normal, and whether there are any unsafe factors such as collapse, breakage, and cracking. If any, it should be handled properly before opening the furnace. When using electric furnace annealing, the oxide skin and metal on or near the resistance wire should be carefully cleaned. 2) When setting fire, carefully check for explosives in the coal. During the shutdown process, the coal seam must not be thickened too much to prevent gas explosions. Coal slag should be disposed of at any time and should not be piled up. 3) Before loading and unloading, check if there are any obstacles on the track groove, and if tools such as hooks and chains are reliable. 4) When loading and unloading large castings or thin-walled workpieces, they must be leveled and placed steadily. Appropriate gaps should be left between adjacent areas, and the loading height should not exceed the specified limit. 5) Before being discharged from the furnace, the refractory bricks and refractory mud on the furnace door should be cleaned, and the pulling mechanism should be checked for usability. Rest or stacking of items around the furnace is prohibited. 7) When the temperature of the working object is above 400 ℃, it is prohibited to use chains or steel wire ropes for lifting (or take insulation measures) to avoid fracture after annealing. When using a crane to lift work objects, it is necessary to follow the safety operating procedures for crane and hook workers. 8) When using the gas furnace, the gas ignition sequence shall be followed: first blow out the residual gas in the furnace with compressed air, close the compressed air valve, light the ignition rod, slightly open the gas nozzle valve, and adjust the compressed gas and gas flow after burning the nozzle to make it fully burned. During a ceasefire, the order is reversed and it is strictly prohibited to reverse the order. 9) When baking with an oil stove, the ignition sequence is: first close the air valve, ignite the ignition rod, slightly open the throttle, after ignition, adjust the air valve and throttle to fully burn, and prohibit "air pressure oil". 10) When using a coal powder fuel furnace, it is prohibited to burn the furnace when the blower is faulty or the pipeline has cracks. 11) To repair an electric furnace, the main switch must be cut off, a warning sign stating "Maintenance is required, no closing is allowed" must be hung, or someone must be assigned to supervise.

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