3.3 Connector fixing When the rail is fixed, five workers stand and look at the position away from the joint 1 and use a wooden wedge to fine-tune the joint. In order to avoid the formation of low joints at the weld after welding, the weld is required to be slightly elevated during the solid rail, leaving a certain degree of pre-camber. As shown in Figure 2: use the mutual m square ruler to close the top surface of the rail, and the height of the weld is 1-2mm at the end of the flat ruler. At this time, the height of the weld is 0.5-l. After the joint is welded, the cushion rubber sheet is not placed under the backing plate, so the backing plate 2 should be removed after welding. After adjusting the height and direction of the joint, tighten the fastener nut to prevent displacement during welding. 3.4 Preheating before welding The heating range of oxyacetylene flame is about 150-200mm on both sides of the weld, and the temperature is 250-400 °C, which should be uniform. 3.5 Welding method 3.5. L welding sequence Rail bottom butt welding flat rail single-sided vertical welding double-sided flat forming ten-track multi-layer multi-channel flat welding one rail bottom and pad double-sided angle flat welding. Attention should be paid to three points during welding: First, it is not allowed to clamp iron bars and other things in the welding joints, and should be gradually integrated from the sides of the welded joints. The second is the double-sided welding of the rail waist. After the front surface is welded, the back surface is not welded and the slag is removed by the shoulder shovel, and the steel brush is used for cleaning before welding. Third, the welding of each joint should be completed continuously, the last weld of the rail surface should be flat, and slightly higher than the two rail faces 0.5-l (because it is worse than the rail hardness, easy to wear). 3.5.2 Welding current In order to ensure penetration, a large current intensity is adopted: when the rail bottom and the rail head are flat welded, 200-220A is selected, and the rail waist vertical welding is reduced to 160-180A. The diameter of the electrode is not changed during welding. 3.5.3 Welding speed Short-arc welding is used to reduce the amplitude of the swing, the welding speed is moderate, and the arc pit is filled at the end. The thickness of each layer of weld should not exceed 4mm, the welding direction between the layers should be reversed, and the joints should be staggered from each other. After welding a layer of weld, the surface slag and spatter should be cleaned before welding. Next level. 3.5.4 Renovation welds Each layer of the weld shall be visually inspected and found to be repaired in time for repair and repaired after welding to facilitate the replacement of the fishplate. 3.5.5 Slow cooling after welding It should be slow after welding. Summer heat can allow it to cool naturally, otherwise it should be taken as a asbestos or asbestos ash. 4 effects I stood in May 1998 to weld the gantry crane running rail joints of two cargo lines. The effect is good: First, the joint breaks less: the utilization grade is below A5, so far no break; the utilization grade is A6 Above, there are successive breaks after one year, so far only 5 times (after the weld is broken, it should be cleaned and then repaired); the joint welding of the trolley track is more convenient and reliable, so far there is no break. Basically achieve the desired results. Second, the crane runs smoothly after welding, and the damage of electrical components and lighting fixtures and the loosening of the connecting bolts are greatly reduced, and good economic benefits have been achieved. Previous page Screwdriver Types,Offset Screwdriver,Mobile Screwdriver,Magnetic Screwdriver henan horn tools co.,ltd. , https://www.horn-tool.com
Manual arc welding crane running track (2)