Reinforcement ring reinforcement refers to the shell around the hole to weld a circle of steel plate, that is, reinforcing ring. Reinforcing ring generally with the wall using overlapping structure, material and the same wall, reinforcement ring size can be determined by reference standards, can also be calculated by the principle of equal area reinforcement. When the thickness of reinforcement ring is more than 8mm, the full penetration structure is used to make the wall bear the same force at the same time, otherwise the reinforcing effect can not be strengthened. In order to facilitate welding, reinforcing ring can be placed on the outer surface of the wall or the inner surface, or internal and external surface symmetrically placed, but in order to facilitate welding, the general reinforcement ring outside the unilateral reinforcement. To check the tightness of the weld, the reinforcing ring has a small threaded hole of M10. Weld tightness test from compressed air. Reinforcing ring is now standardized.
The reinforcing ring has the advantages of simple structure, easy manufacture and wide application. But there is a layer of static air gap between the reinforcing ring and the shell, the heat transfer effect is poor, resulting in two temperature difference and thermal expansion difference is large, easy to cause temperature stress. When the reinforcing ring is welded with the shell, the rigidity becomes larger, the cooling contraction of the diagonal weld is restrained greatly, and cracks are easy to occur in the weld seam. Especially high strength steel hardening, welding crack sensitive, more prone to cracking. Because the reinforcing ring and the shell or the connecting metal do not form a whole, the fatigue resistance is poor. Therefore, the use of reinforcement lap welding structure needs to be limited