Possible problems of continuous nitrogen protection brazing furnace

Main features of aluminum brazing furnace


1. From the stirring and spraying of flux, the drying, brazing and cooling of the products are carried out continuously and automatically, which ensures the mass production and saves the cost of Zui to a great extent.


2. All parameters related to brazing quality, such as drying temperature, brazing speed, brazing temperature, heating rate, nitrogen flow and pressure, are automatically controlled to ensure the stability of the product.


3. All key components are purchased globally, which ensures the reliability of aluminum brazing furnace.


4. The muffle chamber in the heating furnace of aluminum brazing furnace is made of imported stainless steel plate (SUS316L), and the thickness of steel plate is 8mm or above.


5. Aluminum brazing furnace adopts advanced automatic temperature control technology, and the temperature control accuracy is ± 1 ℃.


6. The advanced atmosphere protection design of aluminum brazing furnace can ensure that the furnace can work with sufficient N2 protection and the minimum amount of N2.

radiator brazing furnace

Importance of automation of continuous mesh belt brazing furnace


1. The spray main body of mesh belt brazing furnace is circular structure, and the surface is passivated, which not only ensures the beautiful appearance, but also makes the recovery effect of flux better. It can effectively prevent the flux accumulation in the spray room, and the cleaning is also very convenient. The circular structure adopts real high-pressure fan, the pressure can reach 280mbar, and with the special air nozzle, the wind speed can reach 50-200m / s, which can effectively blow off the residual flux on the surface.


2. Spray mixing system contains a lot of humanized design, flux recovery tank is installed with impurity filter, which can filter most of tiexu. The barrel is designed as a deep barrel structure, which can effectively prevent the flux from overflowing due to stirring and affect the appearance. The upper part of the barrel is equipped with Omron liquid level control, which can alarm the lack of liquid.


3. High temperature brazing furnace adopts all fiber structure (all around cotton). After long-term verification and consideration, it has better heat preservation performance, which can save 2-3 hours of heating time and 10-20% of electric energy during long-term operation. The main performance of the furnace is fast response speed, low heat storage capacity, good heat preservation performance and no expansion effect.


4. The main component of aluminum copper brazing furnace is the furnace liner, which is 12m one-time forming, that is, there are only two welding seams on two sides and two V-shaped grooves at the bottom.


5. The slag cleaning chamber is equipped with nitrogen preheating system. Since the slag cleaning chamber has a high temperature, at 500-600 ℃, when it is not used, these high temperatures also need to be discharged out of the room. As a result, the high temperature brazing furnace causes a certain amount of energy loss. Now our Huahui industrial furnace can preheat the nitrogen to 350-400 ℃ through the special process structure of slag cleaning chamber, internal installation of loose belt and nitrogen circulation, which indirectly reduces the energy consumption of brazing furnace due to nitrogen heating.


6. In the energy saving design of high temperature brazing furnace for nitrogen, the loss of nitrogen is mainly at the inlet and outlet. How to ensure the loss of nitrogen is the key to save nitrogen. The conventional design will make nitrogen overflow from both sides of the metal curtain, and the metal curtain will roll after long-term use, which can not achieve the expected effect. At present, our company has inserted metal curtain and high temperature polyester cloth from the top to make the connection between the two sides of the furnace and the metal curtain closer. The metal curtain will curl after long-term use, but we still have high-temperature polyester cloth on the outer layer, which will still block the nitrogen overflow.


7. Automatic electrical control system, program preset manual and automatic two undisturbed switching mode, can accurately record the temperature curve of each zone, at the same time can copy the computer and use Excel analysis. The programmed control of brazing furnace can set the required heating time very conveniently and contribute to the protection of mesh belt brazing furnace. According to the different temperature requirements of different products, it has the function of one key switching process products. The touch screen can monitor the faults of each line, motor, temperature control and frequency converter in real time, timely detect and alarm, and display and store in Chinese.


8. Remote control function, in the case of equipped with network cable, can use computer, mobile phone and other real-time connection with touch screen, can view or remote control, also can be used for remote maintenance. The main parts of brazing furnace can also be viewed on the screen

nitrogen brazing furnace


Prevention of oxidation and decarburization during heating of brazing furnace


In production, we often encounter that the longer the heating time at high temperature, the more serious the surface oxidation and decarburization of the parts. This phenomenon shows the chemical action of heating medium on steel, which seriously affects the quality of parts after treatment. Therefore, it is determined to conduct annealing and normalizing quenching Heating temperature and holding time should not only consider homogenized austenite, but also prevent oxidation and decarburization of workpiece during heating.


Both oxidation and decarburization belong to oxidation diffusion process, but there are differences between them. Oxidation refers to a layer of oxide scale formed by oxidation in iron jade ring in steel. The outer surface of oxide layer is Fe2O3, the middle part is Fe3O4, the junction of metal and oxide layer is FeO, and saturated iron oxide is in the inward side.


In order to prevent oxidative decarbonization, the following methods can be used at present:

radiator flux

In order to prevent oxidation and decarburization, general parts can be heated by salt bath furnace with better deoxidation. When the salt bath furnace can not be used for heating, borax or boric acid can be coated on the surface of parts with heating money. After heating to about 200 ℃, the borax water solution is sprayed on the surface of the parts or the parts are stored with borax water. Good results can be achieved.


2. The effective way to prevent oxidation and decarbonization is to inject protective gas with controllable components to make the furnace in neutral atmosphere, or to pass neutral gas and inert gas into the furnace. The latter two can prevent oxidation, but have decarburization tendency to steel parts.


Preparation before production of aluminum brazing furnace


It is an important part of brazing aluminum and aluminum alloy workpiece to design the workpiece according to the needs and clamp it into shape and fix it. In this design, we should pay attention to the following three points:

radiator brazing furnace

1) The influence of the change of brazing seam width on the tooling accuracy during brazing;


2) The coefficient of linear expansion of aluminum alloy is 1 / 3 larger than that of metal, so the fixture should be flexible;


3) Aluminum alloy is relatively soft when being brazed and heated, and the slender and vertical workpiece must be supported.

The welding gap of aluminum brazing affects the brazing process and the quality of brazing seam. The narrower the gap is, the stronger the capillary effect of flux and filler metal in the joint is; if the gap is too wide, the solder is difficult to flow to the end, and the stress of the joint is uneven.