Vacuum furnace selection

Vacuum furnace selection

A, vacuum heat treatment furnace according to use can be divided into vacuum quenching furnace, vacuum tempering furnace, vacuum annealing furnace, etc.
1, vacuum quenching furnace; Vacuum quenching furnace can be divided into the vacuum oil quenching furnace and vacuum gas quenching furnace.
1, 1, vacuum oil quenching furnace is suitable for steel, spring steel, stainless steel, bearing steel, high temperature alloy steel such as vacuum heat treatment. Its main characteristic is wide applicable materials, hardenability is strong, the cost is low, the quenching oil can be reused. Deficiencies; The deformation relative to a few bigger, workpiece needed after cleaning. Vacuum oil quenching furnace and three from the structure can be divided into double chamber furnace chamber furnace, etc.
1, 2, vacuum high-pressure gas quenching furnace is suitable for high speed steel, stainless steel, die steel and some other better material of vacuum heat treatment of hardenability, characterized by small parts deformation, do not need to wash after heat-treatment. Deficiencies have quenching gases cannot be recycled, the cost is higher. Vacuum high-pressure gas quenching furnace from the structure can be divided into horizontal and vertical two kinds. Horizontal can be divided into single room, double room and 3 rooms, etc. The application of the vertical ring shape, tubular and long rod parts heat treatment. Vacuum high-pressure gas quenching furnace quenching pressure is commonly 2 b a r ~ 10 b r a. According to the needs of the user can select parts is suitable for the pressure of furnace type.
2, vacuum tempering furnace, vacuum tempering furnace can be divided into the single room, double room, and vertical generally USES nickel chrome with highest heating temperature is 800 ℃. Vacuum tempering furnace generally applicable requirements after tempering parts surface light, no oxidation color.
3, vacuum annealing furnace, vacuum annealing furnace can be divided into single rooms, double rooms and vertical. Vacuum annealing furnace according to the parts material can choose the high, moderate and low temperature (high temperature 800 ℃ ~ 1350 ℃, low temperature 800 ℃).

Vacuum brazing for tungsten carbide and cobalt titanium 40Cr steel

Vacuum brazing for tungsten carbide and cobalt titanium 40Cr steel

Cobalt tungsten titanium carbide and carbon steel 40Cr vacuum brazing welded. Vacuum brazing method is suitable for mass production of carbide cutting tools and drilling of carbide drills and the like. 
Once heated to complete multiple blade brazing of carbide cutting tools, we have a higher efficiency of brazing. Most carbide tools welding methods previously embedded in the carbon steel or low alloy steel substrate use is closely related to the use of performance cemented carbide welding process, the welding performance has a direct impact on the use of carbide effect. When vacuum brazing tungsten carbide cobalt titanium, welding residual stress must be minimized. Measures must be taken to reduce the braze welding stress can be taken to reduce brazing temperature, preheat and slow cooling, use plastic good solder, plus compensation pads, and other measures to improve the joint structure. When a large area of hard alloy brazing, regardless of intensity, should take special measures to reduce welding stress and prevent cracks.

Heat Treatment of Temper-able Aluminum alloys

  Heat Treatment of Temper-able Aluminum alloys

Aluminum with its alloys is becoming more and more important in the development of lightweight materials for use in the automotive industry. To meet the strength standards required for this purpose, heat treatment of the materials is often necessary.
Sophisticated process engineering provides for increased strength
For the heat treatment of temperable aluminum alloys Shanghai Gehang provides solutions for the process steps annealing, quenching and aging adapted to the specific requirements.heat traetment vacuum furnace.
Annealing is performed at approx. 535 °C for a period of several hours. Mixed aluminum crystals are formed, in which the alloying constituents such as silicon and magnesium are completely dissolved.
Quenching serves for "freezing" this condition. This prevents the precipitation of the alloying constituents dissolved in the mixed crystal.
The subsequent aging is performed at 140 °C to 200 °C for several hours. In this process, the required strength is achieved due to segregation processes in the crystal.
Rendering processes stable and reproducible
The conceptual and construction design of Shanghai Gehang heat treatment plants is performed with the clear objective of accomplishing stable and reproducible processes. The design of the circulating air flow, the definition of the heating zone length (gas-heated or electrically heated), the conveyor concept as well as the design of the quench will be optimized and adapted to the requirements of the actual products before accomplishing this objective. This ensures an equal starting basis for all the products being manufactured with the objective of leaving the production plant as a "first class" end product.
SIMUWU engineer has both in-depth process knowledge and extensive project experience. As a leading manufacturer of heat-treatment plants, with over 60 customer references, Shanghai Gehang is the partner of choice for manufacturers of aluminum structural components for cars and cylinder heads, engine blocks, transmission parts, other aluminum parts, and wheels.

Vacuum Furnace in Aerospace

Vacuum Furnace in Aerospace

Under the background of developing the big commercial aircraft in China, high quality aluminum alloy, titanium alloy, heat resistant materials of either wrought super alloy or PM alloy, and composites are requested by the structure and the propulsion of aircraft manufacturing in China. High standard heat treatment processes under aerospace specification is substantial to perform these materials on the demand of strength, fatigue, heat resistance and so on.
The materials used to manufacture engine components are lighter, stronger and can tolerate harsher service environments. Unique manufacturing processes that reduce waste and cost are being used to fabricate these components.
The gas turbine engines of today's aircraft are required to run at higher temperatures and with greater efficiency, yet meet the demands for longer time between overhauls and reduced maintenance costs.
While surface treatment have long been employed as key elements of gas turbine engines, new coating materials can withstand higher temperatures, and improve overall operating efficiency. For airframe components including landing gear system, traditional plating is increasingly replaced by environmentally friendly processes.

Several common heat treatment concept

Several common heat treatment concept

Is fire, the steel or steel heated to a critical point AC3 or ACM above the proper temperature to keep a certain time in the air cooling, pearlite organization get heat treatment process; Annealing: hypoeutectoid steel workpiece heated to above AC3 20 to 40 degrees, heat preservation after a period of time, with the slow cooling furnace (or buried in the sand or lime cooling) to 500 degrees Celsius in air cooling heat treatment process; Solid solution heat treatment: keep single-phase zone temperature alloy is heated to high temperature, the excess phase dissolves into solid solution, and then rapidly cooling, to get the supersaturated solid solution heat treatment process; Limitation: alloy after solution heat treatment or cold plastic deformation at room temperature or slightly higher than room temperature keeping, the phenomenon of its performance change with time; Various phase in the alloy solid solution treatment: fully dissolved, solid solution and improve the toughness and corrosion resistance performance, eliminate stress and softening, in order to continue processing molding; Aging treatment: in the precipitation strengthening phase temperature heating and heat preservation, make the strengthening phase precipitates out, hardening, improving strength; Quenching: the steel austenitizing with proper cooling, cooling speed after all or certain parts within the cross section within the scope of martensite and unstable organization structure change of heat treatment process; Heated to a critical point to tempering after quenching workpiece AC1 under proper temperature keeping time, method of cooling, then used to meet the requirements to obtain required by the organization and performance of heat treatment process; Steel carbonitriding: carbonitriding is to steel surface infiltration process of carbon and nitrogen at the same time. Traditionally carbonitriding is also known as cyanide.
Now as a medium temperature gas carbonitriding and low temperature gas carbonitriding (i.e., gas soft nitriding) are more widely application. Medium temperature gas carbonitriding's main purpose is to improve the steel hardness, wear resistance and fatigue strength. Low temperature gas carbonitriding with nitriding is given priority to, its main purpose is to improve the wear resistance and resistance to bite of steel; Conditioning treatment: general practice combining high temperature quenching and tempering heat treatment known as conditioning treatment. Conditioning treatment is widely used in various important structural parts, especially those who work under alternating load of connecting rod, bolts, gears and shaft, etc. Conditioning treatment after get tempered sorbite organization, its mechanical performance than the same hardness of normalizing sorbite for optimal organization. It depends on the high temperature tempering temperature and hardness and tempering stability of steel and the workpiece with the size of section, generally between HB200-350; Brazing: the two kinds of artifacts together with solder heat treatment process.

The solutions to Vacuum induction furnace FAQ

The solutions to Vacuum induction furnace FAQ

 Vacuum induction furnace is an important device vacuum smelting. The key is used for smelting precision alloy, alloy steel, magnetic materials and high-temperature materials. Vacuum induction furnace, there are two: namely, intermittent and semi-continuous capacity of less than 150 kg of the furnace commonly intermittent, two capacities between 150-300 kg can be used, and capacity is more than 500 kg using a semi-continuous.
Staff at the time of using a vacuum induction furnace smelting, often encounter a variety of problems, today's vacuum furnace Ltd. Suzhou Joe on compiled some frequently asked questions, and also organize a number of methods to solve these problems, hope Consumers are able to have a little help, here together to understand under vacuum induction furnace FAQ What now.
1, vacuum induction furnace SPLASH
Vacuum induction furnace smelting such a problem at this time is mainly composed of two reasons: one is melting fast, the charge inside the exhaust gas is not sufficient, or that there is a problem in bridging the melting process, the lower part of the crucible of molten metal temperature is too high, chunks of cold material suddenly fall into the bath inside, this will cause splashing; the other reason is supplemented with the alloy material inside, a relatively high content of the gas, the added excessive speed, high temperature, had a chance to fully deflate it was melted into a liquid, and so are likely to cause splash. So for such a vacuum  furnace smelting problem how to solve it?
Solution: One way is to start from the preparation and loading of raw materials, on the choice of a suitable power supply system, careful operation in the melting time, avoid bridging situations, and supplemented with alloy material time, first bath down to a suitable temperature of molten steel, then slowly added to avoid splashing. Another approach is to take place after the splash, to the appropriate cooling, slow down the reaction, let boil slowly weaken. Have a big splash at the time, you can pass into the argon gas, reduce the degree of vacuum, increase the pressure inside the furnace, molten steel after pressing calm boiling, then continue evacuated.
2, vacuum induction furnace slag circle problems arise
Such problems arise when smelting is caused by two reasons: the crucible smelting long time, taking the process in constant spray of liquid steel, thereby forming a slag circle. Another reason is that the molten steel inside the gas content is relatively high, when rapidly evacuated slag formation lap.
Solution: There are three solutions, the first lap after the slag generated in the prepurge time, by increasing the load volume and front and rear tipping way to put out hot slag circle. Second, has left circle arc slag, can be treated by feeding baskets. Third, for large slag circle, as it has been the crucible of welding relatively solid, so it can be used to break the vacuum of the way, the direct use of fire to clear welding or welding.
3, vacuum induction furnace bridging problems arise
Bridging problems arise when smelting the following main reasons: charge too long; steel containing carbon monoxide in addition, when carbon monoxide board later joined, when the molten solder, which appears bridge; slag ring too large appears bridge.
Solution: There are three solutions: First, use a hammer hanging breaking open; second, tilting crucible with molten steel of the bridge parts hot start; third, to bridge serious, can be taken to break the vacuum processing.

How To Measure Vacuum Furnaces Temperature

How To Measure Vacuum Furnaces Temperature

Heating by direct radiation, the main heating mechanism in vacuum heat treatment furnace, tends to be a slower process than other heating mechanisms such as convection or conduction. As a result, there are times in the heat treating cycle, particularly during heat up, when the load will be at a lower temperature than the furnace hot zone. This is known as temperature lag. Hot zone temperature is controlled and measured through two (or more) thermocouples located close to the heating elements. One thermocouple, the control thermocouple, is connected to the thermal process controller which transmits signals to control the amount of power directed to the furnace elements.
The second thermocouple is known as the overtemperature thermocouple and is connected to the overtemperature safety controller. Both control and overtemperature thermocouples are also connected to the furnace datalogger to provide a permanent record of time and temperature data. These thermocouples ar platinum/rhodium combination known as Type S that retains accuracy under vacuum throughout a range between ambient temperature and 1480ºC (2700ºF). The location of these thermocouples within the hot zone is quite important in maintaining good temperature control and uniformity.
The recommended practice is to use at least three workload thermocouples. One should be buried deep inside the load. The second should be placed at a midpoint between the center and outside of the load. The third can be placed on the surface or outermost limit of the load. Normally, the center of the load will require the longest amount of time to heat to the processing temperature. By monitoring all three workload thermocouples via the datalogger, processing decisions can be made to ensure a sufficient soak of the entire load is achieved. VAC vacuum furnaces can also be programmed with a load guaranteed soak feature where signals from workload thermocouples to the thermal process controller ensure that the load automatically receives the full programmed time at temperature.
Workload thermocouples are usually attached directly to the load and connected to the vacuum furnace datalogger through extension cables. This makes it possible to record the exact time at temperature of the workload. Proper placement of these thermocouples will ensure the load receives the correct time at temperature by making adjustments for any temperature lag.
It's also popular for general heat treating applications. While these thermocouple types are not recommended for repeated use at high temperatures, they are less delicate and much cheaper than Type S and can be supplied in a flexible construction ideally suited for attachment to a variety of load configurations. The locations where workload thermocouples are placed in the load can have a significant effect on temperature indications.