The electrode custody of the good or bad has a direct impact on the welding quality, in particular, pay special attention to work in the field. Each welder, curators and technical staff should be aware of the electrode storage, custody rules. Electrode and other coatings, in many cases will be destroyed: 1) Transport, handling, use damage; 2) immersed in water or moisture absorption; 3) the oil or other corrosive medium pollution.

Injury: (1) electrode in the general case of damage resistance to the outside world, but can not ignore the the safekeeping bad very vulnerable to damage. The electrode is a ceramic product, he can not impact resistant as steel core, loading and unloading can not throw him. Cartons electrode can not be used can not be linked to handling. Certain models of electrode such as the special drying requirements of basic Welding Rod coatings more than the normal electrode to be handled with care.

Moisture absorption (2): too high moisture in the electrode coating contains very dangerous, because many workers do not understand the electrode is wet welding finished weld surface pores is not necessarily visible with the naked eye, but X-ray inspection showing stomata. When welding rod factory, all of the electrode has a water content, which change according to the model of the electrode, the water content is normal, that is, the formation of pores with a water content of the safety factor, the quality of the weld has no effect. All have to electrodes in the air can absorb moisture and relative humidity of 90%, the welding rod coatings absorb water quickly, ordinary alkaline electrode exposed to a very serious day damp old, even a relative humidity of 70% coating moisture increased. only in the relative humidity of 40% or less, the electrode is long-term storage was not the first impact.

Due to the difference between day and night humidity, the moisture of the air in the morning it is easy to condense into dew, it is easy wet electrode packaging. Electrode stored for a long time, it is easy to damp, so it is best done first storage electrode first.

Under normal circumstances, the electrode from a plastic bag and carton packaging, in order to prevent moisture absorption in the electrode before use, can not be arbitrarily apart, as far as possible be done now with now demolished, there may be remaining after Welding Electrode is then sealed.

Simple identification wet method:

(1) removed from different locations several electrode with two hand thumb and index finger between the electrode support gently shaken, if the electrode is dry hard and brittle, metallic sound, if the electrode is damp, sound blunt. Electrode is often in use for a variety of tests, the sound is different between dry and damp electrode, this can prevent the misuse of damp electrodes.

(2) If the electrode welding using some model of damp found a crack sound and stomatal, then we must consider the electrode whether drying, and then consider other reasons.

(3) with damp electrode welding electrode water content is very high, and even can see the electrode surface water vapor issued, or when electrode welding a most electrode tail cracks exist.

The electrode welding core and drug skin of two parts. The electrode is outside the core of metal welding, coating (drug skin) uniform pressure applied to the welding core carefully. Different Types Of Welding Electrodescore. Ie,Mig Welding Electrodecore metal core, in order to ensure the quality and performance of the weld, butt the content of metal elements in the core there are stringent regulations, especially the content of harmful impurities (such as sulfur, phosphorus, etc.), there should be strict restrictions, better than the parent metal. Welding core composition directly affect the composition and performance of the weld metal, so the harmful elements in the welding core as little as possible.

 Welding of carbon steel and low alloy steel welding core, generally use low-carbon steel core as welding, manganese, silicon, chromium, nickel, and fill up the ingredients (see wire national standard GB1300-77). The one hand, low-carbon and low carbon content steel wire plastic, easier to wire drawing, on the other hand can reduce the reducing gas CO concentration, reduce spatter or porosity can be increased weld metal solidification temperature, beneficial to the overhead position welding. Adding other alloying elements in order to ensure the comprehensive mechanical properties of the weld, welding performance and to remove impurities, but also have a certain effect.

 Other high-alloy steel, aluminum, copper, iron and other metal materials, the composition of the solder core addition to asking the weld metal are similar, the same should also control the content of impurities, according to process requirements often by adding certain alloying elements.

   The electrode is coated with a drug skin for SMAW consumable electrode, which is a medicated skin and welding core composed of two parts. Electrode front-end drug skin around the 45 ° chamfer, in order to facilitate arc. Some bare welding core in the tail, about the electrode length of 1/16, to facilitate the welding clamp hold and conductivity. Electrode diameter Chung actually refers to the solder core diameter) is usually 2,2. 5,3. 2 or 3, 4, 5 or 6mm several specifications, it is common 3. 2, 4, 5 its length "L" is generally between 250 ^ -450 mm.

(1) welding core

Electrode welding in the metal core covered by the medicine bag is known as core. Welded core is generally a certain length and diameter of the wire. When welding, the welding core has two effects: First, the conduction of the welding current, arc energy converted into heat, welding core melting as the formation of the weld filler metal with the liquid base metal fusion.

 Electrode welding, welding core metal part of the whole of the weld metal. Welding core {chemical composition directly affect the quality of the weld. Therefore, as the electrode core wire single potential alone provides for the grade and composition. , Known as the wire for submerged arc welding, electroslag welding, gas shielded arc welding, gas welding fusion welding method for the filler metal. (1) welding of various alloying elements in the core welding

1) carbon (C) Carbon is the major alloying elements in steel, when the increase in carbon content of steel {strength, hardness significantly increased, while the plasticity decreases. In the welding process, the carbon play a certain role in deoxy role in the arc under high temperature and oxygen compounds, to generate carbon monoxide and carbon dioxide gas, arc and pool ambient air excluded, to prevent oxygen in the air, nitrogen harmful gas bath adverse impact of reducing the oxygen and nitrogen content in weld metal. If the carbon content is too high, severe reduction will cause a large splash and stomatal Taking into account the impact of carbon steel hardened crack sensitivity increased, the carbon content is generally of low carbon steel welding core cluster by 0.1%.

2) Manganese (Mn) of manganese in steel is a good alloying agent, with the increase of manganese content, the strength and toughness will be increased. In the welding process, manganese is also a good deoxidizer, can reduce the oxygen content in the weld. Manganese and sulfide co-formation of manganese sulfide float in the slag, thereby reducing the weld hot cracking tendency. General carbon structural steel welding core manganese content of 0.30% 0 55%, welding some special purpose steel wire up to 1.70% 2 10% of its manganese content.

3) Silicon (Si), silicon is also a good alloying agent in steel and adding an appropriate amount of silicon can improve the yield strength, flexibility and acid resistance; if the content is too high, then reduce the ductility and toughness. In the welding process, the silicon also has a good deoxidation capacity with oxygen to form silicon dioxide, but it will improve the viscosity of the slag, easy to promote non-metallic inclusions generated.

 4) Chromium (Cr) Chromium can increase the hardness, wear resistance and corrosion resistance. For low-carbon steel, chromium is an accidental impurity. Metallurgical characteristics of the chromium is subject to rapid oxidation, the formation of refractory oxides of chromium oxide (Cr2O3), thereby increasing the likelihood of weld metal inclusions. Chromium oxide transition to slag make the slag viscosity increased, decreased mobility.

5) Nickel (NO nickel on the toughness of steel has more significant effect, the general low-temperature impact value is higher, the appropriate incorporation of some nickel.

6) sulfur (S) Sulfur is a harmful impurities, with the increase of sulfur content will increase the tendency of hot cracking of welds, welding core sulfur content not greater than 0.04%. In the welding of important structures, the sulfur content not greater than 0.03%.

7) Phosphorus

(2) the classification of welding core

Welding core welding wire in accordance with national standards (GB 1300-77) classification for the welding of special steel wire can be divided into the three types of carbon structural steel, alloy steel, stainless steel.

 (2) drug skin

 Pressure applied to the surface of the coating of the welded core called coating. The electrode coating plays an extremely important role in the welding process. The use of a drug-free skin, light electrode welding in the welding process, the oxygen and nitrogen in the air will be a substantial intrusion of molten metal, oxide and nitride formation of metallic iron and useful elements carbon, silicon, manganese and other various oxides and nitride, and left in the weld, causing the weld slag or cracks. Melt into the molten bath, the gas may cause the weld to produce a large number of pores, these factors can greatly reduce the weld mechanical properties (strength, impact value, etc.), while the weld brittle. In addition to using the optical electrode welding, the arc is very unstable, serious splash, weld forming poor.

 Found in the course of practice outside in the light electrode coated with a layer from a variety of minerals composed of drug skin, make arc stability, weld quality is improved, the electrode is coated electrode. With the continuous development of industrial technology, people created a now widely used in high-quality thick coated electrode.