Platinum metal metallurgical physical properties make it a spot weldability is poor

Platinum metal metallurgical physical properties make it a spot weldability is poor, platinum products at home and abroad to connect far more riveting process . Developed by the authors of this " single- cycle pulse key projection welding foil new technology" , as well as to achieve the two layers of platinum foil product no cushion welded directly in the trial production of some products can be indicated in the application . Introduced the new technology is the main process characteristics and   molybdenum alloys   mechanism . Product launch tube projection welding weld head surface topography x50 bump bonding design, direct spot platinum foil electrode and the workpiece surface will produce serious bonding process which destroys the normal spot . Domestic and international studies show that bonding is difficult to achieve with products direct spot one important reason . After use of  molybdenum screws  , the current can be in the dyeing of the bump and the internal heat increases the distance between the electrode surface , the temperature gradient along the thickness direction is easily formed . Meanwhile, the projection welding electrode end face than the large multi- spot welding , a significant increase of the contact area of ​​the electrode and the workpiece , reducing the welding electrode and the workpiece surface the heating intensity , which are effective in reducing the sticking of the electrode . Further , since the projection welding can reduce the energy input ( reduced welding current ) , reducing grain products grew , the key to improve the welding heat brittleness .

Projection welding spot is tungsten carbide plate larger than the electrode face significantly

Phase material weldability is poor, therefore , domestic rice Chuan Liu products connections using riveting process . To this end , the development of a single- cycle pulse of platinum foil projection welding of new technology, the two layers as well as the non- cushion foil product key is welded directly . After the lamp is designed with raised bumps , bumps at the current can be concentrated on the internal heat source and increases the distance between the electrode surfaces , easy to form a  tungsten carbide plate  in the thickness direction . Meanwhile, the projection welding electrode end face larger than the spot welding , a significant increase of the contact area of ​​the electrode and the workpiece , reducing the welding  sandblasted tungsten target  and the surface of the heating strength , effectively reduce the sticking of the electrode . Further , since the projection welding heat input can be reduced ( reduced welding current ) , reducing grain products grown , heat welding of the aluminum to improve brittleness . Designed bumps and tested in practice , the choice is less detailed projections play an important part of the benefits . The choice of the shape of the bumps on the suppression of the bump foil tears , generally spherical shape. Spherical bumps having a high strength welded joints , and conical -shaped bumps can remove the residual stress concentration at the bottom and the maximum circumference of the cracks , at the same time , the crush bumps process also easy to produce and move along splash.

Molybdenum copper material commonly used conventional powder metallurgy sintering infiltration was prepared

Molybdenum Copper is composed of two immiscible fake metal alloy, molybdenum, copper material density is low, and tungsten-copper material deformation processing more easily, these features make the material in the material requiring high quality aerospace, Portable equipment has good application prospects. For sealing molybdenum copper, its expansion coefficient difference with ceramic larger sealing surface near the greater the stress, the more likely porcelain burst. Therefore, to obtain a hermetic seal, sealing metal and ceramic must have close to the thermal  tungsten carbide ball  and a certain degree of plasticity. Mo-Cu materials generally used conventional method of powder metallurgy sintering  tungsten balls  immiscible as Mo and Cu, it is difficult to obtain fully dense Mo-Cu materials, raw materials present in the sealing gap affects the airtightness and thermal expansion properties. Mechanical alloying is a high energy ball milling machine by rotating or vibrating the powder to medium strong impact, grinding and mixing, the powder is crushed into nano-sized particles to obtain a uniform distribution of Mo-Cu composite powders. Preparing a sintered composite network-like structure, to improve the density and improve the sealing properties of materials.

Department of foil rolling mill tungsten electrode work roll surface and aluminum foil rolls printed

Department of foil rolling mill work roll surface and aluminum foil rolls printed surface causes lateral stripe test in order to clear foil rolling mill work rolls lateral surface of the formation process of the action roller printing, foil rolling mill for the production control process part of every action performed were tested demonstrated. Push the new work roll support rollers and a new, check the hydraulic system, the calibration rolling baseline. 60T pressure with a continuous three  tungsten electrode  against the calibration operation, out of work rolls checking roller printing. With 120T pressure  copper molybdenum  pressed against the calibration operation three times, out of work rolls checking roller printing. 60T 250m/min speed with pressure and heat roller, every 5 minutes, for 2 times, draw roller Check roller printing. 120T pressure and speed of 350m/min with hot roll, every 5 minutes, for 2 times, draw roller Check roller printing. Open Gap State slow-roll five consecutive times, out of work rolls checking roller printing.

Transparent quartz glass softening temperature, thermal shock resistance, is the best source of strong light material

Transparent quartz glass softening temperature, thermal shock resistance, strong light source material is the best, most high-intensity discharge lamps are quartz glass as the arc  tungsten carbide ball  material. However, due to the expansion coefficient of quartz glass is low (room temperature to 1000 ℃, α = 5.5 × 10-7 / K) and the sealing temperature (2000 ~ 2200 ℃), so find similar coefficient of thermal expansion match with the refractory metal sealing. However, quartz glass with the blade-like molybdenum foil (temperature α = 5.3 × 10-6 / K) to be well sealed non-matching, the molybdenum  molybdenum foil  inner tube plays a dual role. In the 1960s and 1980s, China's major will be 0.55 mm thick sheet of pure molybdenum foil cut to a width of 2 ~ 4 mm, length 100 ~ 150 mm narrow-band, and then into a bladed electrolytic corrosion sealing material. Disadvantage is that the process is unstable quality, consistency is poor, low productivity, material loss, a more continuous operation can not adapt.

Molybdenum is added to the rare earth oxide , molybdenum greatly improved performance

Molybdenum is added to the rare earth oxide , molybdenum greatly improved performance . In recent years , increasing attention molybdenum application industry 's attention. Molybdenum is mainly used in high-precision electronic warfare and narrowband satellite communications , tubes , electric light and other fields. In the electronics industry , vacuum electronic devices are a large vacuum and gas -based electron (ion ) produce a variety of effects , amplified , converted signal is active devices,  tungsten balls  , launch tubes , microwave tubes, camera tubes , display tubes, vacuum optoelectronic devices, vacuum switch tube , X-ray tubes, new lighting , and gas lasers. Molybdenum narrow strip , foil , light industry mainly for sealing quartz glass , electric vacuum tubes, traveling wave tubes ,  tungsten electrode  lamps , high pressure mercury lamp , high pressure sodium , metal halide lamps , television lamp . Vacuum , gas-tight sealing of pipe materials have been using pure molybdenum foil , molybdenum rod . In such a tight molybdenum foil tube , vacuum production process, when the temperature reaches the softening temperature of the quartz glass 1800 ℃ , the pure molybdenum foil recrystallization , the plastic drop rapidly showed severe recrystallization brittleness clip tight seal during the molybdenum disc rupture great possibility. Rare molybdenum at 1800 ℃ when its plasticity and creep properties are good, molybdenum disc rupture phenomenon does not occur .

Molybdenum and molybdenum alloy metal temperature resistant materials, high strength can maintain a high

Molybdenum and molybdenum alloy metallic high temperature materials, the high temperature to maintain a high strength, but also has a high thermal conductivity and low thermal expansion coefficient, good thermal shock resistance, electrical conductivity and wear resistance, is widely used in aerospace field, including spacecraft solar  tungsten electrode  sheet molybdenum foil. However, molybdenum is relatively poor weldability and high temperature strongly oxidized, the oxide film is no protective effect, so the surface to be plated molybdenum modification. As the silver brazing with good  tungsten carbide inserts , usually silver plating surface of the molybdenum to improve the weldability and to reduce or prevent the oxidation of molybdenum. However, there is often a natural molybdenum oxide surface, the coating will interfere with adsorption, coupled between the molybdenum and silver alloy (solid solution) is difficult, therefore, molybdenum, silver plating surface is difficult, often plated directly adhered strong, coating quality is poor. Difficulties molybdenum plating solution approach is generally used in the pre-plating or strike plating layer deposited on the first surface of a thin metal (such as chromium, nickel, gold, rhodium, platinum, etc.), and then continue through the high temperature heat treatment plating process more cumbersome.

Extensive use of powder metallurgy production methods to produce molybdenum disk products

Molybdenum is a high temperature material, is widely used in modern industry, but its price is higher, in order to reduce costs, and now widely produced by powder metallurgy method to produce molybdenum products, molybdenum crucible is one of them, this article  sandblasted tungsten target  the molybdenum combination of repression crucible mold design. Parts and die design features molybdenum crucible shape and size. Which is  copper molybdenum  by wall parts and a lower tapered tube composed of two parts, and the tube wall thickness ratio of the height close to the manual pressing is not easy to ensure uniform density compacts, and prone to cracking. After repeated in the production process adjustment, find the following ideal combination of manual mold design.