Graphite on the effect of vacuum heat treatment

Graphite on the effect of vacuum heat treatment

Graphite in the vacuum furnace application role in the development of growing, not only simplify the design and manufacture of vacuum furnace, but also greatly reduces the metal consumption, save the cost. Both economy and technology have very significant!
Using graphite as heater in vacuum resistance furnace displays in: the advantages of graphite with excellent properties can meet the various requirements of vacuum resistance furnace heating elements; Processing is convenient, can according to need to be processed into rod, tube, plate and so on to adapt the demand of all kinds of vacuum resistance furnace heating elements; Simple structure, easy installation and disassembly, more convenient than other metal heating element; Cheap, cheap.
Graphite as a kind of very good energy conservation and environmental protection material, with the development of modern science and technology and industry, continue to broaden its application domain, not only the mechanical industrial vacuum heat treatment furnace equipment, more become an important raw material in the field of high-tech new compound material, and show a more and more important role in national economy.

Aluminum alloy heat treatment technology

Aluminum alloy heat treatment technology

1, the principle of the aluminum alloy heat treatment
Aluminum alloy casting heat treatment is to choose a certain heat treatment specification, control the heating rate rises to a corresponding temperature cooling, heat preservation time to must speed to change its alloy, its main purpose is to improve the alloy's mechanical properties, enhance the corrosion resistance, can improve the processing, get the size stability.
2, the characteristics of the aluminum alloy heat treatment
As is known to all, for carbon steel, immediate access to the high hardness after quenching, and the plastic is very low. But for aluminum alloy and otherwise, the aluminum alloy after quenching, higher strength and hardness is not immediately, as for the plastic instead of down, instead of rose. But this kind of alloy after quenching, placed a period of time (e.g., after 4 ~ 6 days and nights), strength and hardness will be significantly increased, and the plastic is significantly reduced. The strength and hardness of aluminum alloy after quenching grow along with the time and improve the phenomenon, referred to as aging. Aging can occur at room temperature, according to the natural aging, can also be higher than the room temperature at some stage in the temperature range (100 ~ 200 ℃), called artificial aging.

Three sworn brothers of the vacuum heat treatment furnace

Three sworn brothers of the vacuum heat treatment furnace

"Three sworn brothers of the vacuum heat treatment furnace
The classification of the vacuum heat treatment furnace many confusion, today for you in detail about the vacuum heat treatment furnace, the three major points to according to use can be divided into the vacuum quenching furnace, vacuum tempering furnace, vacuum annealing furnace "three brothers".
1, vacuum quenching furnace; Vacuum quenching furnace can be divided into the vacuum oil quenching furnace and vacuum gas quenching furnace.
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 data size, strong hardenability, low capital and quenching oil can be repeated use. Deficiencies; The deformation relative to a few bigger, workpiece follow-up needs cleaning. Vacuum oil quenching furnace and three from the layout can be divided into double chamber furnace chamber furnace, etc.
Vacuum high-pressure gas quenching furnace is suitable for high speed steel, stainless steel, steel and so on some vacuum heat treatment of hardenability better data, characterized by small parts deformation, don't need cleaning after heat-treatment. Deficiencies have quenching gases Can't take back, capital is higher. Vacuum high-pressure gas quenching furnace from the layout 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. High vacuum pneumatic quenching furnace quenching pressure is usually 2 b a r ~ 10 b r a. According to the needs of users can select parts suitable for pressure of furnace type.
2, vacuum tempering furnace, vacuum tempering furnace can be divided into the single room, double room, and vertical usually choose nickel chromium with highest heating temperature is 800 ℃. Vacuum tempering furnace usually applicable requirements after tempering parts appearance of light, no oxidation color.
3, vacuum annealing furnace, vacuum annealing furnace can be divided into single rooms, double rooms and vertical. Vacuum annealing furnace can be selected in high temperature, low temperature, according to the parts data (in the high temperature of 800 ℃ ~ 1350 ℃, low temperature 800 ℃).

The process of heat treatment

The process of heat treatment

Heat treatment process generally includes three heating, heat preservation, cooling process, sometimes only two heating and cooling process. The process to connect to each other, completely.
Heating is one of the important process of heat treatment. Heating of metal heat treatment method are many, the first is to use charcoal and coal as a heat source, in the application of liquid and gas fuel. The application of electric heating is easy to control, and no environmental pollution. The heat source can be used to direct heating, but can be by molten salt or metal, and floating particles with indirect heating.
Metal heating workpiece when it is exposed to the air, often occur oxidation and decarburization (that is, the surface carbon content lower) steel parts, the performance on the surface of the parts after heat treatment have a bad effect. Thus metals usually should be in a controlled atmosphere or protective atmosphere, molten salt and a vacuum heating, coating or packing method to protect the heating is also available.
The heating temperature is one of the important process parameters of heat treatment process, selection and control of heating temperature, is a major problem to ensure the quality of heat treatment. Heating temperature is processed and varies the purpose of the metal material and heat treatment, but is usually heated to above phase transition temperature, in order to obtain high temperature. Another change will take time, so when the heating temperature of metal surface is achieved, still must in the temperature keeping time, make internal and external temperature, the microstructure change completely, this paragraph of time is called the heat preservation time. Heating with high energy density and surface heat treatment and heating speed, generally there is no heat preservation time, and the chemical heat treatment of heat preservation time tend to be long. Cooling is indispensable in the process of heat treatment process steps, cooling method for craft different and different, main is to control the cooling rate. General annealing cooling speed of the slowest, normalizing the cooling speed faster, quenching cooling speed is faster. But also with different steel grade have different requirements, such as empty hard steel can be hardened by normalizing the same cooling rate.

Introduction to the vacuum furnace automatic control system

Introduction to the vacuum furnace automatic control system

Brazing process of the necessary equipment, its performance fit and unfit quality directly affect the brazing quality of the products. Vacuum furnace system is mainly composed of vacuum system and heating system and related control equipment. Vacuum system by the mechanical pump, diffusion pump, the main valve, bypass valve and high vacuum flapper valve, etc. Mechanical pump for coarse vacuum device and its power is the three-phase ac motor, high vacuum oil diffusion pump for high vacuum device, with the help of a former level of mechanical pump and the role of oil diffusion pump and electric heating extraction of the high vacuum degree requirements, all through the contactor control. Heating system is composed of heating power and heating element, heating power magnetic voltage regulator, using dc excitation power supply for non-contact smooth stepless voltage regulation of load the dc excitation power supply controlled by power governor, governor using temperature control and power! Free toe thermocouples detect the temperature of the current value and the difference between the set value, the PID arithmetic, dc signal output, control magnetic voltage regulator of magnetic saturation voltage, and then according to the set temperature control curve of temperature controller to realize the heating current and temperature automatic control. Vacuum protection automatic control system of the control goal is: 1 manual pump can qigong can realize automatic; Instrument shows vacuum degree, and the manual or automatic control in accordance with the requirements of the vacuum brazing process of related work steps; Temperature by using temperature controller and thermocouple and a trigger to realize automatic computer program control and manual control, digital display, automatic recording, overtemperature and water, automatic alarm, high in the greenhouse and chamber of vacuum cooling.

Nitrogen - vacuum heat treatment the important auxiliary facilities

Nitrogen - vacuum heat treatment the important auxiliary facilities

Nitrogen, sounds like a "loner" word, in fact, it is widely used in national economy and life, especially in the casting industry, nitrogen is often used to deal with the vacuum heat treatment furnace and recycled purging, prevent the formation of metal surface oxidation and reduce the dross.
When steel in the vacuum furnace heated, if high vacuum degree, the volatilization of the alloying elements in order to prevent the workpiece material, need to recharge the right amount of nitrogen in the furnace, to trace the pressure of the gas from the oven.
In the process of vacuum heating oil quenching vacuum quenching, sometimes to ensure or improve the cooling ability of quench oil, before the workpiece cooling, the comparison of vacuum heat treatment is both at home and abroad are adopting advanced heat treatment method, in the vacuum heat treatment, often without the use of nitrogen.
When steel in the vacuum furnace heated, if high vacuum degree, the volatilization of the alloying elements in order to prevent the workpiece material, need to recharge the right amount of nitrogen in the furnace, to trace the pressure of the gas from the oven.
In the process of vacuum heating oil quenching vacuum quenching, sometimes to ensure or improve the cooling ability of quench oil, before the workpiece cooling, to back plenty enough nitrogen in vacuum furnace. In high pressure gas quenching, need to quickly to the vacuum furnace in filling the above an atmosphere of nitrogen. Used in the steel bending steel pipe bender) vacuum tempering, the need to recharge after vacuum nitrogen to achieve uniform heating furnace protection gas circulation, and realize the fast cooling after tempering.
Overall vacuum heat treatment furnace using the chemical stability of nitrogen, the inert nature, at the time of heat treatment, back filling nitrogen, to adjust the vacuum furnace, prevent the volatilization of metal elements; When quenching, recharge nitrogen, achieve the goal of improve the cooling capacity.

The vacuum furnace and intermediate frequency electric furnace heat treatment techniques

The vacuum furnace and intermediate frequency electric furnace heat treatment techniques

Vacuum furnace and intermediate frequency electric stove had a very good development prospect in the field of hot working, used in heating, rolling, forging, bending and heat treatment (quenching), the welding process of induction heating. The vacuum furnace and intermediate frequency electric furnace heat treatment techniques?
1. Vacuum furnace processing of titanium alloy, unfavorable use nitrogen as cooling gas, because titanium and nitrogen reaction at high temperature, forming the golden titanium nitride.
2. The vacuum furnace active connection parts are all made of type O rubber ring sealing connection, this part is cooled.
3. The workpiece quenching under a vacuum, vacuum quenching oil should be used, the oil has a lower saturated vapor pressure.
4. Vacuum furnace maintenance should be in the condition of vacuum or pure nitrogen inflator, avoid inspiratory when not in use at ordinary times, moisture absorption.
5. The domestic vacuum furnace pressure increase rate should be no greater than 1.33 Pa/h, some enterprises abroad standard Pa 0.67 / h
6. Vacuum heating is given priority to with radiation, should keep distance between artifacts in the oven.
7. In the process of heating workpiece and furnace material will be deflated, resulting in a vacuum.
8. Vacuum tempering, vacuum annealing, vacuum heating of vacuum solid solution treatment and aging temperature generally the same as the conventional heating temperature when processing.
9. Vacuum tempering furnace should have fast cooling device. Cooling water pressure should be greater than 0.2 Mpa, the flow should be adjustable.
10. The cooling gas: steel generally USES ninety-nine point nine nine five percent purity of nitrogen, nitrogen or argon gas, high temperature alloy with ninety-nine point nine nine nine percent of titanium alloy with ninety-nine point nine nine five percent argon gas.
11. Temperature: after into the workpiece, the general first drainage to Pa 6.67 can heat up when heated.

What is a vacuum heat treatment furnace?

What is a vacuum heat treatment furnace?

Two professional vacuum heat treatment of vacuum technology and heat treatment technology that combines an integrated, refers to the whole and part of heat treatment process in a vacuum. Our country could be divided into low, medium and high vacuum and high vacuum. At present most of the vacuum heat treatment furnace work vacuum degree in 1.33 ~ 1.33 x 10 ˉ & sup3; Pa.
Vacuum heat treatment can achieve almost all heat treatment process, such as quenching, annealing, tempering, carburizing, nitriding, during the quenching process can realize gas quenching, quenching oil, water nitrate quenching, quenching, etc., can also be vacuum brazing, sintering and surface treatment, etc. Vacuum heat treatment furnace thermal efficiency is high, which can realize the rapid heating and cooling, which can realize no oxidation and decarburization, carburizing, can remove phosphorus crumbs on the surface of the workpiece, and has the effect such as degreasing degassing, so as to achieve the surface brightness purification effect. Generally speaking, the processed workpiece in the heating furnace is slow, and internal temperature difference is small, the thermal stress is small, so little deformation. Product qualified rate is high. Can reduce costs, have degassing effect, so as to improve the mechanical properties of the work and life. Good working environment, safety operation, no pollution and no pollution. Be processed workpiece no hydrogen embrittlement risk, to prevent surface of the titanium and refractory metal shell hydrogen embrittlement, stability and repeatability of vacuum heat treatment process. A series of advantages, the development of vacuum heat treatment equipment and technology is more and more attention and applied more and more widely.