Precautions for cold welding of cast iron with dif

Precautions for cold welding of cast iron with different electrodes

with the rapid development of the express industry. 1. When using copper iron electrode (such as z607) for welding, the iron and copper in the electrode metal are immiscible, exist in the state of mechanical mixture, and the mixture is uneven. When w (FE) in the electrode increases by 30%, the plasticity of the weld metal is greatly reduced, and cracks are easy to occur in the weld when welding the weld of rigid joints. It has a wide range of medical particle product lines of polyvinyl chloride (PVC) and thermoplastic elastomer (TPE). Therefore, short arc welding should be adopted as far as possible to reduce the swing of electrode, and multi-layer welding and other technological measures should be adopted to prevent the occurrence of welding cracks

2. In order to repair some important casting defects during cold welding of cast iron, pure nickel electrode or nickel iron and nickel copper welding rod are often used for repair welding, such as Z308, Z408 and Z508. Iron castings repaired with nickel copper welding rods generally have good processability, but the tensile strength of weld metal is generally low. At the same time, due to the large shrinkage of copper nickel alloy, the crack resistance of weld is also poor. Therefore, this kind of welding rod is only applicable to the repair welding of castings with low strength requirements, but the surface needs to be processed. The advantage of repairing welding with pure nickel electrode is that the weld metal has good machinability, but the price is expensive, so it is not suitable to use it under general circumstances. When using this kind of welding rod, in addition to welding according to the general process requirements, it should also be noted that the repair welding speed should not be too fast, and welding should be carried out intermittently. The length of each welding should not exceed mm, and after welding a layer, knock with a small hammer to eliminate the stress. Weld the second layer when the weld is too cold to be hot, so as to ensure that the repair welding can achieve better results

2.4 number of samples

3. High vanadium cast iron electrode is a relatively economical cast iron cold welding electrode that must be stressed repeatedly, such as z116 and z117. This kind of welding rod needs to adopt short arc welding, and the welding is carried out in the reverse order of sections. Each section is about mm long. It is advisable to use a small current, and also knock the weld after welding to reduce stress