Seismic tungsten filament according to its normal and has the characteristics of high seismic named, it is mixed with the tungsten powder potassium, sulfur and prepared from aluminum and other elements. It is the tungsten material has the special properties of a class of products, which not only has high resistance to sag tungsten normal performance, good around the system performance, but also has a high shock and vibration resistance performance.

Tungsten is mainly used in seismic vibration environment lighting systems, for example, various traffic lights, special light bulbs for military purposes, aerospace engine heating wire, etc., which is the largest amount of cars, motorcycles, tractors, aircraft lighting lights.

Another important seismic tungsten is a variety of application areas kinescope cathode heating wire, the annual consumption of at least 600 million meters. As the world's automotive, electronics and other industries, these figures every year extensions. According to statistics, in 1999 the domestic market demand is 214 million meters, at an annual growth rate of 8%, to 2005 domestic demand will reach 31.8 billion meters, its output will be 314 billion yuan in 1999 to 514 in 2005 billion.

However, with the development of society and the advancement of science and technology, but also on the quality of seismic tungsten proposed more stringent requirements. General production process seismic tungsten wire, high temperature work, the seismic performance is not satisfactory, tungsten formability poor wound easily broken when the double helix filament yarn, filament deformation and luminosity is unevenly distributed. Therefore, the optimization of production processes, improve production processes, high temperature performance with good preparation, processing and wire around the excellent performance of the seismic tungsten has important practical significance.


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1 Errors Introduced by Improper Installation

Thermocouples should be mounted too close to the door and the heated places, insertion depth should be at least the diameter of the protective tube 8 to 10 times , and the insertion depth of the installation position does not reflect the true temperature of the furnace . Thermocouple protection tube with intramural interval Unfilled adiabatic material , resulting in overflow hot or cold air furnace , so the thermocouple protection tube and the gap between the furnace wall hole applications such as refractory cement or asbestos insulating material clogging rope to avoid hot and cold air convection and affect the accuracy of temperature measurement . Thermocouple should be installed as far as possible away from strong magnetic fields and strong electric field, thermocouple and power cables should not be wire-bound with a catheter in order to avoid the introduction of interference caused by errors. Thermocouples can not be installed in measured media rarely flows in the region, when measured with a thermocouple tube gas temperature must be going against the flow direction of the thermocouple installation , and full contact with the gas .

2 Error Introduced Insulation Deterioration

Such as thermocouple protection tubes and pull plates excessive dirt or salt residue resulting thermocouple very poor insulation between the wall of the furnace at high temperature is more serious , it will not only cause the loss of thermoelectric power but also the introduction of interference , resulting the error sometimes up on Baidu .

3 the Error Introduced by the Thermal Inertia

As the thermal inertia of the thermocouple indication value of the instrument behind the measured temperature changes , while a fast measurement of this effect is particularly prominent. It should be possible using the hot electrode smaller, smaller diameter thermocouple protection tube . Temperature environment permit, or even take away the protective tube . Because of measurement hysteresis , thermocouple temperature fluctuation of the detected temperature fluctuation amplitude is small amplitude . Measuring lag larger the smaller the amplitude of fluctuation thermocouple , the greater the difference between the actual oven temperature . When a large time constant thermocouple or temperature control , the instrument displays the temperature fluctuation is small though , but the actual oven temperature fluctuations may be significant. To accurately measure the temperature , time constant should be selected thermocouple . The time constant and the heat transfer coefficient is inversely proportional to the diameter of the thermocouple hot end , and the material density is proportional to the specific heat , such as to reduce the time constant , in addition to increasing the heat transfer coefficient , the most effective way is to minimize the size of the hot end . Use, usually good thermal conductivity materials, thin wall, small diameter protection tube . In the more precise temperature measurement, the use of non- bare wire thermocouple protection tube , but the thermocouple easily damaged, should be promptly corrected and replaced.


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Tungsten at a certain temperature and a certain resistance to their sagging under load deformation capacity. Anti-sagging properties of the material is actually a reflection of high temperature creep resistance, which is doped with tungsten is a very important performance indicators.

Tungsten filament incandescent bulbs and a vacuum device, its working temperature is usually above 2000 ℃, so the effect of high temperature and tungsten weight, since the material strength is decreased and the grain boundary sliding and produce sag. To ensure that the shape of the filament at a high temperature and dimensional stability, requires tungsten must have good high temperature sag resistance capability. This capability and the recrystallization temperature of tungsten grains after recrystallization geometry closely related. For doped with potassium, aluminum, silicon, tungsten wire, because of its high recrystallization temperature, and recrystallized to form a large aspect ratio of recrystallized grains, and between the grains was dovetail lap, this structure makes the most of the grain boundary is parallel or nearly parallel axes wire, which significantly improves the ability of the tungsten filament temperature sag resistance.

Tungsten-doped high-temperature sag resistance capacity, mainly by the potassium tungsten bulb size, number, and distribution (dispersion state) is determined, and the dispersion state of the bubble in addition to potassium and potassium in the outside, suitable deformation and heat treatment system is essential, the former is the ability to obtain a prerequisite for sag resistance, and the latter is a necessary condition.

Determination of anti-sag tungsten wire performance in many ways, a common high-temperature creep test method, high flexural droop method (V-shaped test) and so on. Service conditions from the point of view of the filament, sagging test method than the creep test method using tungsten better meet the actual situation. Thus creep test method is gradually being replaced by sagging test for detecting anti-sag tungsten high temperature performance.


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1.1 powder preparation and doping techniques

Preparation of low temperature pre-reduction of suitable phase composition of blue tungsten oxide , and tungsten blue oxide is doped tungsten powder acid , tungsten powder as needed , and control the ratio of rhenium powder .

Doping uniformity is the first element control , to be able to obtain a stable in terms of purity , scale, and the particle size requirements of the three indicators .

The use of advanced hydrogen reduction equipment, as well as doping , pickling, large capacity V-type mixed powder machine , especially for hydrogen production system optimization , for the implementation of powder technology to provide reliable protection .

1.2 sintering and molding processing technology cogging

Using isostatic round billet rolling through vertical melt after blooming , which is tungsten and molybdenum Solton most advanced processing technology , preparation of billet single weight 3 kg , the use of high-power -controlled vertical melt equipment, to stable obtain density , purity and grain size , etc. to meet the requirements of the master index tungsten rhenium billet .

Blooming accommodate large rolling method billet , to achieve quality and efficient, large-scale production of the best processing methods. Solton tungsten and molybdenum technology uses KDCKS three multi-stand rolling mill rolls and master its system technology. At present, most enterprises still use rotary forging billet made ​​to open , but open up technology and equipment, molds, auxiliary facilities and so has shrunk, with advanced rationality.

1.3 swaging and stretching techniques

Multimode string forging more with welding, high frequency continuous annealing , Big Wheel and multimode continuous drawing machine drawing machine applications, using a large compression rate processing, oxidation annealing , using condensate crystal drawing dies , etc., composed this section technical characteristics .

Using a large compression ratio stretched to the protection of tungsten rhenium wire has good high temperature performance with excellent positive significance. Has adopted pass compression rate specification , ¢ 3.7-0.7mm range of 30% -40%, ¢ 0.7-0.2mm range of 18% -28 % . Four to ten die mold sliding multimode drawing machine has been applied .

1.4 Electrochemical Processing Technology

Since sapphire tungsten rhenium alloy wire with multi- supplier status with white silk , so it is necessary to wash separately electrolytic corrosion , galvanic corrosion and electrolytic polishing reducing effect.

1.5 Control Management Technology

Because they have a better grasp of APT and ammonium perrhenate from raw materials to final products, all tungsten rhenium wire process control and management techniques to develop more scientific focus of the process measurement and control standards, and has a full range of advanced testing methods, Solton tungsten and molybdenum Technology is focused on creating ¢ 1.0-0.2mm range crack detection system .

1.6 Equipment Technology : mixer, reduction furnace , vertical melt equipment, rotary swaging machine, wire drawing machine, electrochemical etching equipment, testing equipment and packaging machines.


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