This standard is based on the standard preparation and revision work plan of the National Pressure Vessel Standardization Technical Committee, unified by the National Pressure Vessel Standardization Technical Committee Manufacturing Subcommittee and Design Subcommittee, and revised by the Hefei General Machinery Research Institute.

　　1 Revision principle

　　Since the implementation of JB/T4736-1995 "Reinforcement Ring" on December 20, 1995, it has played a positive role in improving the design and manufacturing quality of pressure vessel reinforcement rings. With the implementation of the 1999 version of "Pressure Vessel Safety Technical Supervision Regulations" and GB 150-1998 "Steel Pressure Vessels" and other regulations and standards, the relevant provisions of the original JB/T 4736-1995 are no longer compatible with the above new version of the standard; At the same time, the National Pressure Vessel Standardization Technical Committee and the standard-setting units have successively received opinions and suggestions from some design and manufacturing units on JB/T 4736-1995, some of which are beneficial to the improvement of the standard.

　　2 The welding joint structure of the reinforcing ring connected to the shell and the connecting pipe

　　The 1995 version of the standard provides five types of welded joint structures connecting the reinforcing ring to the shell and the nozzle. In the implementation process, the design and manufacturing units generally reflect that the number of these structures is small and cannot meet the requirements of use. When this standard was revised, it was revised and supplemented with reference to HG20583-1998 "Regulations for Structural Design of Steel Chemical Containers".

　　3 Welding process of reinforcing ring

　　Regarding the welding process requirements of the reinforcing ring, the revised 5.7 stipulates that "the welding of the reinforcing ring, the bright body, and the connecting pipe shall be welded using a welding process qualified by JB 4708-2000". The modification of the original standard is based on the following two reasons:

　　(1) Some containers and reinforcing ring materials are different from those of the shell and pipes, and there are problems with welding of dissimilar steels;

　　(2) The welding position of the container shell is usually automatic welding, and the welding of the reinforcing ring, the shell and the pipe joint is manual welding.

　　Therefore, the welding of the reinforcing ring, the bright body, and the nozzle is required to use the same electrode and welding process as the shell welding, which has certain limitations and needs to be modified accordingly.

　　4 The splicing problem of the reinforcement circle

　　Part of the pressure vessel reinforced with a reinforcement ring needs to be welded before the reinforcement ring is installed due to design or manufacturing process reasons

　　Pipe flange, at this time, the entire reinforcement ring cannot be installed. This revision of the standard has added provisions that allow the use of radial splicing for reinforcing rings, which completely solves this problem structurally.

　　5 Flaw detection of splicing weld of reinforcing ring

　　The reinforcement ring allows the use of splicing structure, which brings about welding quality control problems accordingly. The splicing weld of the reinforcing ring is

　　The weakest link of the strong ring, due to the influence of the structure, the splicing weld of the reinforcing ring can generally only be single-sided welding. At the same time, due to the installation of the connecting flange, the welder's operation is subject to certain restrictions, and welding defects are easily generated (especially the part near the connecting pipe in the splicing weld). The ultrasonic inspection requirements for the splicing weld are necessary to ensure the welding quality.