Welding method is usually selected in accordance with the following principles, the selected welding method must be able to ensure the welding quality, to meet the technical requirements of product design; at the same time can improve welding productivity, reduce manufacturing costs and improve labor conditions.

The selection of welding rod must be in order to ensure the safety of the welding structure, reliable use of the premise, according to the chemical composition of the welded material, mechanical properties, plate thickness and joint form, welding structure characteristics, the state of force, the structure of the use of the conditions of the weld performance requirements, welding construction conditions and technical and economic benefits of a comprehensive examination, targeted selection of welding rods, welding test is also required when necessary.

Weldability, refers to homogeneous or heterogeneous materials in the manufacturing process conditions, can be welded to form a complete joint, and to meet the expected use of the ability of the material, design, process and service environment for the four major factors affecting weldability.

The development of precision casting industry is more and more fast, and the use of precision castings is more and more. Therefore, the problems which we consider in the process of precision casting are much more.

To improve the quality of precision castings, to provide users with more reliable product application ability, in order to increase the productivity of the actual push, let it reflect on the nature of the performance advantage in the market competition, effectively promote the full expansion of all aspects of its application advantages of strength.