The quality of welding rod storage has a direct impact on the quality of welding, especially in the field work to pay attention. Each welders, custodians and technicians should know rod storage, custody rules. Electrodes and other coatings, in many cases will be destroyed: 1) the transport, handling, use damage; 2) was immersed in water or moisture absorption; 3) by oil pollution or other corrosive media. 1) Damage: Although the Welding Electrode Manufacturer in general has a destructive power against the outside world, but can not ignore the poor because it is vulnerable to damage custody. Electrode is a ceramic product, he did not like the steel core and impact resistance, so the loading and unloading can not throw him. Electrode with carton packaging can not be used can not be linked to transport. Some models, such as special drying requirements of the welding electrode coatings alkaline than normal electrodes have to be handled with care.
2) moisture absorption: In the welding rod coatings contain very dangerous when the water is too high, because many workers do not understand the electrode is wet, when finished welding the weld surface is not necessarily visible with the naked eye holes, but by X-ray examination on vent to display. When the electrode factory, all the electrodes have a water content, which changes according to the model of electrode, the water content is normal, that is, the formation of pores with a water content of the safety factor has no effect on the weld quality. All electrodes were able to absorb moisture in the air, the relative humidity of 90%, the welding rod coatings absorb water quickly, ordinary alkaline wet welding rod sticking out one day old is very serious, even when the relative humidity of 70% of the coating also increases the water faster, only in the relative humidity of 40% or less, the electrode was not the first long-term storage effects.
As the great difference between day and night humidity, moisture in the air condenses into dew the morning is easy, very easy to wet electrode packaging. Electrodes can easily be stored when wet longer, so it is best done before the first use of storage of the electrode.
In general, welding by the plastic and carton packaging, in order to prevent moisture absorption, the Nickel Welding Electrodes before use and can not open, try to be done now with the current split, if possible, the remaining electrode after welding and then sealed.
Simple way to identify the damp: (1) Remove from several different locations with two hands with the rod of the rod between the thumb and index finger gently shake the support, if the electrode is dried to produce hard and brittle, metallic sound, if the electrodes wet , the sound made blunt. Electrode is often used for various tests, dry and wet over the sound is different between the electrodes, which can prevent the misuse of damp electrodes. (2) If a model with wet welding electrodes voice cracks and holes are found, then we must consider whether the dry electrode, and then consider other causes. (3) wet welding electrodes welding if the water content is very high, even given that water vapor to the surface of electrodes, or electrode welding when half, we found that the phenomenon of electrode tail cracks exist.
By drawing on the raw materials and drawing lines, and cut into a certain shape and size. Note to select the appropriate connector type, when the workpiece thick, the joints must also be processed into the shape of the groove.
(2) the choice of welding specifications
Arc welding electrode specification, mainly the type of welding current and electrode diameter size choice. According to the welding electrode workpiece material selection grade, as the welding speed and arc length, usually by Welding Electrode grades and according to the location of the weld where the space in the welding process appropriate adjustments.
(1) electrode diameter
To improve productivity, thick electrode diameter is usually used, but generally not more than 6mm. Workpiece thickness of 4 mm below the butt welding, generally equal to the workpiece with a diameter less than the thickness of the electrode. Refer to Table 4.1. Large thickness of the workpiece during welding, the general groove joints should, play in the bottom of welding, soldering, can be 2.5 ~ 4mm diameter electrode, the layers can be used after 5 ~ 6 mm diameter rod. Vertical welding, the electrode diameter of not more than 5 mm; Yang welding should not exceed 4 mm.
The size of the welding current is determined primarily on the basis of electrode diameter. Welding current is too small, low productivity, welding, arc of instability, and may not weld through the workpiece. Welding current is too large, it will cause serious molten metal splash, and even burn the workpiece. For welding general steel work piece, electrode diameter 3-6mm, the following empirical formula obtained by the welding current reference value:
I = (30-55) d
I - Welding current (A);
d - electrode diameter (mm);
In addition, the current size of the selection, with every joint type and Nickel Alloy Welding Electrodes position in space and other factors. Vertical welding, horizontal welding welding welding current level should be reduced more than 10 - 15%; overhead position welding is reduced by 15 - 20%.
3. Weld layers
Weld layers depending on the thickness of the weldment. In thick multi-layer welding is generally used. More weld layers, will help improve the ductility of weld metal toughness. Requires high quality welds on each layer thickness preferably not more than 4 ~ 5mm. Figure 4-8 shows the multi-layer welding of the weld, the welding sequence number in accordance with the plans for welding.
4 the spatial location of the weld
Based on the location of the weld in space is different from a flat welding, vertical welding, horizontal welding and overhead position welding of four, as shown in Figure 4-11. Flat welding easy to operate, working conditions, high productivity, easy to weld quality assurance, so arranged as far as possible on the flat seam welding position. Vertical welding, horizontal welding and overhead position welding, due to gravity, is the molten metal to drip down the difficulties caused by welding, therefore, should be avoided.