Welding design of pressure vessels

Welding procedures for steel pressure vessels: 8 Weld repair 8.1 For the defects that require welding repair, the causes behind them shall be analyzed, improvement measures shall be proposed, a welding procedure qualification shall be carried out in accordance with the standards, and a welding repair procedure shall be developed. 8.2 The number of repairs to the same weld location should not exceed 2 times. 8.3 Before rework, the defects must be completely eliminated; if necessary, surface flaw detection can be used for verification. 8.4 Grooves with uniform width, a smooth surface, and ease of welding should be created in the areas to be rewelded, with a certain slope at both ends. 8.5 If preheating is required, the preheating temperature should be increased appropriately compared to that of the original weld. 8.6 The performance and quality requirements of the repaired weld shall be the same as those of the original weld. 8.7 Containers that require heat treatment must undergo heat treatment again if repair welding is performed on them after heat treatment. 9 Welding Inspection 9.1 Main Aspects of Welding Inspection 9.1.1 Before Welding a, Base Metal, Welding Materials ； b、Welding equipment, instruments, process equipment ； c. Welding grooves, joint assembly, and cleaning ； d. Welder qualifications ； e. Welding procedure documents. 9.1.2 During welding process a, welding procedure parameters ； b. Welding process execution status ； c. Implementation of technical standards ； d. Implementation of the pattern specifications. 9.1.3 After welding a, actual welding records ； b. Weld appearance and dimensions ； c、Post-heating, post-weld heat treatment ； d. Product welding test plates, welding process compliance inspection test plates ； e. Non-destructive testing ； f. Pressure test ； g. Density test.

Take a look at the provisions regarding welding in the Code for Pressure Vessels and GB150; following these specifications and standards is already quite strict

Hehe, the specifications stated in the relevant standards along with the requirements outlined in GB150 are sufficient. Additionally, JB/T4735 \"Steel Welded Atmospheric Pressure Vessels\" might be useful for your reference

For welding design, refer to GB150; for welding procedures, consult JB 4708 and JB 4709

The welding quality must be high; whether this requirement can be considered high or not is debatable, but it is indeed quite high. The preparation of welding procedure documents is one aspect of this process, and everything is carried out in accordance with established regulations. It seems that welders with high technical skills are even more important in this regard

The welding specifications and standards specific to the pressure vessel itself must be followed. Furthermore, enterprises undertaking pressure vessel manufacturing should possess the basic qualifications required for the job.

That’s good. We need to look up more information

Welding pressure vessels is not something that can be done just by deciding to do it; qualifications, software, and hardware are all factors that need to be taken into consideration.

It is recommended to hire a senior welding engineer in charge; this will be beneficial for everyone (make sure not to choose someone who only knows how to talk big but doesn’t do any actual work)

Part I: Use and Management of Welding Procedure Qualification & Preparation of Welding Procedure Specifications
I. Concepts Related to Welding Procedure Qualification
II. Procedures for Welding Procedure Qualification and Its Use Management
III. Factors Affecting Welding Procedure Qualification and the Rules for Their Evaluation
IV. How to Read Welding Procedure Qualification Reports
V. How to Prepare Welding Procedure Specifications

I. Concepts Related to Welding Procedure Qualification
1. Definition and Purpose of Welding Procedure Qualification
2. Eliminating Misconceptions Regarding Welding Procedure Qualification
3. “Welding Performance” vs. “Weldability”
4. “Welding Performance Tests” vs. “Welding Procedure Qualification”
5. “Weld” vs. “Welded Joint”
6. “Welding Procedure Qualification” vs. “Welder Skill Assessments”
7. Basic Conditions for Welding Procedure Qualification
8. Commonly Used Standards for Welding Procedure Qualification:
JB4708–2000 “Welding Procedure Qualification for Steel Pressure Vessels”
GB50236–98 “Code for Construction and Acceptance of Welded Structures for Field Equipment and Industrial Pipelines”, Chapter 4
Ministry of Labor Regulation No. 1996 “Safety Supervision Regulations for Steam Boilers”, Appendix I
JGJ81–2000 “Technical Code for Welding of Building Steel Structures”, Chapter 5
GB128–90 “Code for Construction and Acceptance of Vertical Cylindrical Welded Steel Oil Tanks”, Appendix I
ASME Volume IX “Welding and Brazing”

II. Procedures for Welding Procedure Qualification and Its Use Management
1. Procedures for Welding Procedure Qualification
(1) Initiation of welding procedure qualification
(2) Commissioning of welding procedure qualification
(3) Preparation and approval of the Welding Procedure Instruction (WPI)
(4) Welding of the test plates used for qualification
(5) Inspection of the test plates
If the welding procedure qualification fails, the Welding Procedure Instruction must be revised, and the above procedures must be repeated. (6) Prepare and approve the Welding Procedure Qualification Report (PQR). 2. Use and management of welding procedure qualification documents: (1) Controlled registration of welding procedure qualification documents. (2) Valid versions of welding procedure qualification and version conversion. (3) Prepare a catalog of the valid versions of welding procedure qualification documents on a quarterly basis. (4) Ensure a 100% coverage rate for the welding process evaluations of on-site projects and products. (5) The welding procedure qualification documents, as part of the company’s welding technology resources, are considered important technical confidential documents of the company and should be stored properly. III. Factors in Welding Procedure Qualification and the Rules for Their Evaluation 1. Main factors in welding procedure qualification: Test piece shape, base material type, welding method, welding process parameters, type and parameters of post-weld heat treatment, base material thickness, thickness of the weld metal deposit. IV. How to read a welding procedure qualification report 1. Understanding the role of a welding procedure qualification report: (1) Legitimacy of the welding procedure qualification report; (2) Validity of the welding procedure qualification report; (3) Limitations of the welding procedure qualification report and the welding procedure specification; (4) The welding procedure qualification report is an important quality assurance document that must be signed by the company’s welding engineer in charge and the chief engineer. It is also one of the main bases used by technical supervision agencies and customer representatives to assess the quality assurance capabilities of construction companies. 2. The relationship between the welding procedure qualification report and the welding procedure specification 3. Methods for reading welding procedure qualification reports V. How to prepare a welding procedure specification 1. The role of the welding procedure specification 2. Basic requirements for welding procedure specifications 3. Principles to be followed in preparing welding procedure specifications 3. Instructions for filling out welding procedure specifications Part Two: Thoughts on welding materials... I. Introduction to standards and documents related to engineering welding II. Identification of electrode types and grades III. Storage and use of electrodes IV. Selection of electrodes V. Selection of TIG welding wires VI. Selection of welding materials for nickel-based alloys I. Introduction to commonly used standards in engineering welding (I) Commonly used standards in engineering welding GB50236-98 “Code for Construction and Acceptance of Welding Works of Field Equipment and Industrial Pipelines” JB4708-2000 “Welding Procedure Qualification for Steel Pressure Vessels” JB/T4809-2000 “Welding Procedures for Steel Pressure Vessels” JGJ81-2002 “Technical Regulations for Welding of Building Steel Structures” SH3085-1997 “Technical Requirements for Welding Carbon Steel and Chrome-Molybdenum Steel Tubes in Petrochemical Tubular Heaters” SH/T3523-1999 “Welding Procedures for Chromium-Nickel Austenitic Steels, Ferro-Nickel Alloys, and Nickel Alloys in Petrochemical Applications” SH3524-92 “Construction Technology Standards for On-Site Welding of Steel Tower-Type Vessels in Petrochemical Industries” SH3525-92 “Welding Procedures for Low-Temperature Steels in Petrochemical Industries” SH3526-92 “Welding Procedures for Dissimilar Steels in Petrochemical Industries” SH/T3527-1999 “Welding Procedures for Stainless Steel and Composite Steel in Petrochemical Industries” SHJ520-91 “Technical Regulations for Welding of Chrome-Molybdenum Heat-Resistant Steel Pipes in Petrochemical Projects” SY/T4103-1995 “Welding and Acceptance of Steel Pipes” SY/T4071-93 “Welding Procedures for Downward Pipe Welding” HGJ222-92 “Welding Technology Regulations for Aluminum and Aluminum Alloys” HGJ223-92 “Welding and Brazing Technology Regulations for Copper and Copper Alloys” (II) Standards for commonly used welding materials in engineering welding JB3223-1996 “Quality Management Regulations for Welding Materials”