In the past one or two months, the sales of electric furnace wires in the market have gradually strengthened. When communicating with new customers, I often hear that the electric furnace wires purchased are easy to fuse and the furnace wire breakpoints cause headaches. Whether it is a quality problem or improper use, the root cause is not found and distressed. After communicating with our technicians, we summarized some possible reasons for the melting of the electric furnace wire, for reference only!
The fuse of the electric furnace wire is analyzed from the internal and external factors:
1. The upper area power cord is connected incorrectly, the current increases, the power is too high, and it burns out.
2. The resistance wire is ironed with the muffle tank and melted locally.
3. The surface load of the resistance wire is too large.
4. The purchased resistance wire is a low-quality product. During the normal use of the electric furnace, due to the uneven density of the electric furnace wire, or the long-term fixed local overheating during use, local oxidation is caused, which increases the resistance of this part and brings local voltage drop. And the temperature further rises and enters a vicious circle. At the moment of fusing, the distance between the two ends of the electric furnace wire is close after the fusing, and the conduction effect of the molten electric furnace wire oxide forms an electric arc. At this time, it can instantly generate higher Temperature, melting part of the refractory bricks of the electric hob.
Based on the above situation, our company recommends that the majority of electric furnace manufacturers purchase high-quality electric furnace wire products, which is one of the effective methods to ensure the service life and safety. In addition, the pit furnace is a periodic operation furnace, which is suitable for the heat treatment of rods and long shaft parts. The structure of the pit furnace is: the furnace body is a cylindrical deep well, and the workpiece is vertically loaded into the furnace by a special crane for heating. The fuel used is usually gas and oil. When electricity is used as a heat source, it is called a well-type resistance furnace. Pit furnaces are generally placed below the ground level of the workshop, and some are placed above the ground level, or half of the above and below the ground level. The names of the pit furnace are: forced convection pit furnace, natural convection pit furnace, pit gas carburizing furnace, etc.
The heating body of the pit furnace will become soft, swell, fall, fall over first, and then fuse (melt) after long-term operation. The main solutions to this problem are:
First, in order to prevent the contact between the furnace wires, a spacer should be used.
Can be used to isolate the resistance wire made of high temperature resistant materials such as 95 porcelain to prevent overlapping. In particular, the transition between the brick layer and the layer in the furnace (when building the furnace, there is generally a 50mm gap between the brick and the front and rear walls for the turning and installation of the resistance wire), which should be pre-padded with ceramic chips or furnace wires Put on the porcelain tube (the porcelain tube should be pushed to the top). High-temperature furnaces cannot use diatomaceous earth brick saw slices to be placed in the middle of the furnace wire. Because diatomaceous earth bricks are poor in heat resistance, they can only be used below 900 ℃, and they are easy to dissolve and deteriorate in high-temperature furnaces.
Second, to prevent the furnace wire from softening, collapsing or sagging, so that it has a certain strength at high temperatures
First of all, we must design the structural dimensions of the furnace wire, such as the spiral resistance wire, and pay attention to the diameter of the alloy element, the pitch and the pitch diameter of the spiral. The heating body should be installed close to the furnace lining, and should be placed flat on the bricks, leaving proper space for expansion. The position of the small hook should be appropriate, generally 400 ~ 600mm one, and can be firmly hooked to prevent lying down.
Third, the furnace wire with the tendency of lodging
Check whether the small hook of the stove wire is functioning (the hook for erecting the resistance ribbon must be firmly laid, pressed, plugged, and not loosened), and the stove wire can be softened by gas welding or torch, and then restored to its original shape And size, and put a porcelain tube in the furnace wire (the mandrel can be worn in the porcelain tube), etc. If two porcelain tubes are used at the same time, the ends of the porcelain tubes must be close together.
Fourth, the heating body is fused
Generally, the broken ends can be repaired by welding directly. For the severely collapsed, unable to straighten, and the partial over-burning part is seriously damaged, the method of repairing a section can generally be used, and the whole set does not need to be scrapped due to partial failure.
The above simple analysis of the easy-to-fuse problem of the electric furnace wire of the pit furnace, and how we can better take measures when such a problem occurs. Various technical problems may occur during use. If you need consultation for existing or occurring problems, you can directly contact our company
