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 Posted: Thu 18:23, 30 Dec 2010 Post subject: air jordan shoes cheap Surfacing in the mold repai |
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Welding repair of the mold
In general,[link widoczny dla zalogowanych], surfacing only to the former can not warm or slightly warm. Therefore, higher productivity, the workpiece deformation is small,[link widoczny dla zalogowanych], very suitable for on-site mold repair. Manual arc welding using DCRP when the general approach, deposition efficiency, surfacing layer of good quality and low dilution rate. 5 Application for mold welding, the welding defect is prone to cracking and peeling, to prevent the occurrence of such phenomena, it generally takes to preheat and post weld heat, preheat should be about 450 ~ C, no less than 45min; electrode is required in the drying temperature of 250-350 ~ C melting 1 ~ 2h. Will be preheated welding weldment removed from the oven and immediately welding, after welding into the furnace heat of not less than 30min, and then removed, air-cooled, with the hammer before welding to eliminate stress, which prevents cracking and stripping. Liaoning Yellow car (Group) Co., Ltd production of passenger cars,[link widoczny dla zalogowanych], the second split beam mode, external dimensions of 930mmx190mm, material for the 10Ti, material thickness 6mm, the mold tool steel inserts for the T8, blade shape surface. After a period of use, appears in the middle section of the die edge chipping 30mmx6mmx5mm (see Figure 1),[link widoczny dla zalogowanych], in front of the punch has a cutting edge chipping. According to traditional repair methods, to carry out the second operation, now adopted \No. 4, No. 9, 53 with the total edge welding repair, achieved very good results. 5.1 die welding preparation (1) clean-up to be welded parts, welded parts with a grinding wheel grinding will be treated as shown in Figure 2. Fig 2 grinding before welding shape (2) parts to be welded near the oil spill clean-up, oil can be used oxyacetylene severe heat removal. (3) selection of TDC58 electrode, in the 250 ~ C drying chamber drying lh, really electrode diameter of 3.2mm. (4) use reverse DC welder, welding current is 90A, the arc length (short arc) 5mm; welding speed 120mm/min; layer temperature 150cC. 5.2 Operating points (1) electrode swing is not too wide. (2) Do not close the stress concentration at the arc,[link widoczny dla zalogowanych], to close when the arcs must be filled to prevent crater cracks. (3) and then when pressure arc crater 20 ~ 30mm. (4) welding blade should be appropriate to ensure that post-weld grinding. 5I3 treatment after welding (1) air-cooled blade after grinding to make the edge sharp. (2) ensure that with the gap. (3) to check for defects. Punch can also be used to repair the same way. 6 Conclusion welding process is suitable for small quantities of large and complex molds and parts of the mold repair process, reduce costs and extend die life. Eventually have to re-create the mold parts to replace damaged place. Air pressure gas quenching heat treatment heat treatment plant in Taizhou Da Xing (Zhejiang Taizhou 318050) Wu Shiqiang factors affect the die life of course a lot, but with reasonable heat treatment is very important. I plant a high-pressure gas quenching vacuum heat treatment to obtain good results, especially mold. After treatment, the mold-free oxidation and decarbonization, the deformation is small, very clean bright surface. Mold has a higher than normal heat treatment strength, wear resistance, toughness and fatigue strength, service life 2-3 times. Vacuum high pressure gas quenching principle: the workpiece into a certain vacuum in the pumping of the furnace, the atmosphere conditions in the vacuum after the heating and insulation, high-pressure inert gas filled, hardened by high-power cooling fan. Has the following characteristics: (1) no oxidation and decarbonization. Have been drawn into the vacuum furnace oxidation and decarbonization little gas to prevent oxidation, decarbonization, has protective effects. Furnace is very low partial pressure of oxygen, surface oxides at high temperature decomposes: 2FeO-+2 Fe + O. At the same time, also volatile oils and break down into water, hydrogen and carbon dioxide and other gases. Generated by the vacuum pump away the gas. There are metal smelting absorption, due to the cooling too quickly, stay in the gas within the metal. And melt into the metal under normal pressure of the gas at high temperature under vacuum to escape from the metal surface. One obvious effect of hydrogen degassing, which strength and toughness are improved remarkably. (2) small deformation of the workpiece. Vacuum heating mainly by radiation due to achieve, so the heating is slow. Warming the surface and center temperature difference is small, the resulting thermal stress is also small. High-pressure gas quenching, the gas is relatively modest cooling medium, cooling rate can be inflated to the pressure and fan speed control, the resulting thermal stress and structural stress is relatively small, to prevent cracking and reduce the deformation of the workpiece. While also achieving grade quenching. (3) using graphite products, higher temperature than conventional furnaces, up to 1300 ~ C. Easy to operate, pollution-free, clean, with modern high quality and low heat requirements. Vacuum high pressure gas quenching is one of the advanced treatment methods, with the mold material on the ever-increasing demands, will be an inevitable development trend of the mold heat treatment.
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