1. The rods should be stored in dry warehouse with sound ventilation. The rods must be stored on the supporter in different types and batch numbers more than 0.3m away from the wall; It is better to keep a certain temperature and moisture in the warehouse for the low hydrogen rods. It’s suggested that the 60% to avoid the deterioration due to dampness. It is required to store highly efficient iron powder rod, ultrahigh strength rods, heat resistant rod, stainless steel rods, low temperature steel rods and aluminum allow rods, to avoid rust of the iron powder in the flux coat and the flux coat falling down due to moisture, which will damage the welding seam performance.
2. The improper and long storage will result in damp rods. All rods including acid and alkali types are required to dry before using. After the baking, the processing performance test is required to make. The rod can be used continuously in case of no flux coat falling down in pieces and no increasing air pores. The performance test should be made according to rod products, using conditions, performance requirement and dampness level, if necessary.
3. The baking of the rods is different in requirements for different types. Generally, the non-damped acid rods can be used without baking for structural steel rods. In case of baking, such rods containing cellulose are only required to be baked for 0.5-1 hour at the temperature of 70-80˚C; others are required to be baked for 0.5-1 hour at the temperature of 100-150˚C; the low hydrogen rods are required to be baked for 1-2 hours at the temperature of 300-400˚C. The explanations will be made on particular baking requirements in the manual. It is better to bake the rods in the baking oven and it’s forbidden to make rapid heating with the gas welding torch or spray torch.
4. It is required to learn the characteristics of the rod, processing requirements and proper current before the welding. The process performance test may be made to observe arc stability, restarting, de-slagging, spatter, and slag flow ability, seam shape penetration level, melting speed and deposition efficiency and all-position welding performance. The items of X-ray photograph, anti-cracking test, dynamic performance test and anti-corrosion test will be made, if necessary. The trial welding will be made to make overall learning on various performances of the rods, to improve the welding quality.
1. The rods must be stored in dry warehouse with sound ventilation;
2. The rods must be stored in different patches above from the ground and more than 0.3m from the wall.
3. It’s better to store the rods for important engineering, especially the low hydrogen rods into the special warehouse, where a certain temperature and moisture should be kept. It is suggested to keep relative moisture less than 60%.
1. Know and match mechanical properties. For mild steel, generally E60XX or E70XX electrodes match base metal. For low alloy steel, select electrodes that match base metal properties.
2. Know and match composition. For mild steel, any E60XX or E70XX electrode is satisfactory. For low ally steel, select electrode that most closely matches base metal composition.
3. Match electrode to welding position encountered.
4. Match power supply available. Some electrodes are designed for direct current (DC), some are for alternating current (AC) and some can be s=used with either AC or DC. Observe current polarity.
5. Select for penetration characteristics – digging, medium, or light. For no beveling of tight fit-up, use digging. For thin material or wide root opening, use light or soft arc.
6 .To avoid weld cracking on thick and heavy material of complicated design, select electrode with maximum ductility. Low hydrogen processes or electrodes are recommended.
7. Determine service conditions, low temperature, high temperature, shock loading, and match base metal composition, ductility and impact resistance. Use low hydrogen process. Also, check welding procedure or specification for electrode.
8. Production Efficiency and Job Conditions For high deposition and most efficient production under flat position requirements, select high iron powder types or large diameter wires. For other conditions, you may need to experiment with various electrodes and sizes.
The correct choice of electrode size involves consideration of a variety of factors, such as the type, position, and preparation of the joint, the ability of the electrode to carry high current values without injury to the weld metal or loss of deposition efficiency, the mass of work metal and its ability to maintain its original properties after welding, the characteristics of the assembly with reference to effect of stresses set up by heat application, the practicability of heat treatment before and/or after welding, the specific requirements as to welding quality and the cost of achieving the desired results.
If current on equipment is too high or too low, you are certain to be disappointed in your weld. If too high, the electrode melts too fast and your molten pool is large and irregular. If too low, there is not enough heat to melt the base metal and your molten pool will be too small, then pile up and look irregular.
If the arc is too long or voltage too high, the metal melts off the electrode in large globules which wobble from side to side as the arc wavers, giving a wide, spattered and irregular bead with poor fusion between original metal and deposited metal. If the arc is too short, or voltage too low, there is not enough heat to melt the base metal properly and the electrode quite often sticks to the work, giving a high, uneven bead, having irregular ripples with poor fusion.
When your speed is too fat your pool does not last long enough, impurities and gas are locked in. The bead is narrow and ripples pointed. When speed is too slow the metal piles up, the bead is high and wide, with a rather straight ripple.
The electrode angle is of particular importance is fillet welding and deep groove welding. Generally speaking, when making a fillet weld, the electrode should be held so that it bisects the angle between the plates and is perpendicular to the line of weld. If undercut occurs in the vertical member, lower the angle of the arc and direct the arc toward the vertical member.
