To ensure the welding quality of the pressure pipeline valve's surfacing welding, qualification of welding procedure should be carried out before welding. The purpose of the evaluation is to evaluate whether the company can weld welded joints that meet the requirements of the corresponding specifications and technical conditions. However, for surfacing welding, including corrosion-resistant surfacing welding and wear-resistant surfacing welding, there are different features for requirements for evaluating surfacing welding procedure.
In the petroleum, chemical, metallurgical and energy industries, a valve is one of the most widely used fluid control devices. As an important part of the pipeline system, there are many types of valves with many specifications, and their functions are also different. The manufacturing process of the valve will directly affect the safe operation of the pipeline device, and the surfacing welding of the valve’s sealing surface is one of the key processes in the entire manufacturing process. The valve sealing surface's surfacing welding is to weld metals with a certain thickness on the base metal of the valve's sealing position to meet the performance of the valve, such as wear resistance and corrosion resistance. Therefore, the surfacing welding of valve manufacturing is divided into corrosion-resistant surfacing welding and wear-resistant surfacing welding. Welding procedure documents need to be compiled for surfacing welding, and the most important welding procedure document is the Welding Procedure Specification (hereinafter referred to as WPS). At present, there are many qualification standards and specifications for welding procedure related to pressure piping and component manufacturing in China, mainly are NB/T 47014-2011 Qualification of Welding Procedure for Pressure Equipment, GB 50236-2011 Requirements for Engineering Construction and Acceptance for Field Equipment Industrial Pipe Welding, GB 50369-2014 Requirements for Engineering Construction and Acceptance for Long-distance Oil and Gas Pipelines, SY/T 0452-2012 Welding Procedures for Petroleum and Natural Gas Metal Pipelines, SY/T 4103-2006 Welding and acceptance of Steel Pipelines, GB/T 31032-2014 Welding of the Steel Pipe and Its Acceptance, DL/T 868-2014 Regulations of Qualification of Welding Procedure and GB/T 22652-2019 Procedure Qualification of Surface Welding of the Valve Seal.
The process evaluation standards for surfacing welding of valve sealing surfaces at home and abroad generally include EN 15614-7-2016 of the European Union, ASME IX of the United States, and NB/T 47014-2011 and GB/T 22652-2019 of China. Some differences between NB/T 47014-2011 and GB/T 22652-2019 in China from the aspects of sample preparation, inspection and testing requirements and assessment are analyzed based on the purpose of surfacing welding to assist in the successful realization of procedure qualification of the surfacing welding process and the successful completion of the contract orders.
Purposes and general requirements of procedure qualification of surfacing
NB/T 47014-2011 and GB/T 22652-2019 both specify the general process of process qualification in the general requirements. The purpose of process qualification is to verify whether the welding process formulated by the welding company is correct, and to evaluate whether the welding meets the relevant requirements of the surfacing layer. However, the requirements of the two standards are different for the welders of the process qualification. See Table 1. The standards both emphasize hiring skilled welders, while GB/T 22652-2019 clarifies adopting the company's equipment. In addition, GB/T 22652-2019 includes corrosion-resistant surfacing and wear-resistant surfacing, while N B/T 47014-2011 only requires corrosion-resistant surfacing.
Table 1 A comparison of general requirements of NB/T 47014-2011 and GB/T 22652-2019
In the petroleum, chemical, metallurgical and energy industries, a valve is one of the most widely used fluid control devices. As an important part of the pipeline system, there are many types of valves with many specifications, and their functions are also different. The manufacturing process of the valve will directly affect the safe operation of the pipeline device, and the surfacing welding of the valve’s sealing surface is one of the key processes in the entire manufacturing process. The valve sealing surface's surfacing welding is to weld metals with a certain thickness on the base metal of the valve's sealing position to meet the performance of the valve, such as wear resistance and corrosion resistance. Therefore, the surfacing welding of valve manufacturing is divided into corrosion-resistant surfacing welding and wear-resistant surfacing welding. Welding procedure documents need to be compiled for surfacing welding, and the most important welding procedure document is the Welding Procedure Specification (hereinafter referred to as WPS). At present, there are many qualification standards and specifications for welding procedure related to pressure piping and component manufacturing in China, mainly are NB/T 47014-2011 Qualification of Welding Procedure for Pressure Equipment, GB 50236-2011 Requirements for Engineering Construction and Acceptance for Field Equipment Industrial Pipe Welding, GB 50369-2014 Requirements for Engineering Construction and Acceptance for Long-distance Oil and Gas Pipelines, SY/T 0452-2012 Welding Procedures for Petroleum and Natural Gas Metal Pipelines, SY/T 4103-2006 Welding and acceptance of Steel Pipelines, GB/T 31032-2014 Welding of the Steel Pipe and Its Acceptance, DL/T 868-2014 Regulations of Qualification of Welding Procedure and GB/T 22652-2019 Procedure Qualification of Surface Welding of the Valve Seal.
The process evaluation standards for surfacing welding of valve sealing surfaces at home and abroad generally include EN 15614-7-2016 of the European Union, ASME IX of the United States, and NB/T 47014-2011 and GB/T 22652-2019 of China. Some differences between NB/T 47014-2011 and GB/T 22652-2019 in China from the aspects of sample preparation, inspection and testing requirements and assessment are analyzed based on the purpose of surfacing welding to assist in the successful realization of procedure qualification of the surfacing welding process and the successful completion of the contract orders.
Purposes and general requirements of procedure qualification of surfacing
NB/T 47014-2011 and GB/T 22652-2019 both specify the general process of process qualification in the general requirements. The purpose of process qualification is to verify whether the welding process formulated by the welding company is correct, and to evaluate whether the welding meets the relevant requirements of the surfacing layer. However, the requirements of the two standards are different for the welders of the process qualification. See Table 1. The standards both emphasize hiring skilled welders, while GB/T 22652-2019 clarifies adopting the company's equipment. In addition, GB/T 22652-2019 includes corrosion-resistant surfacing and wear-resistant surfacing, while N B/T 47014-2011 only requires corrosion-resistant surfacing.
Table 1 A comparison of general requirements of NB/T 47014-2011 and GB/T 22652-2019
| Projects | NB/T 47014—2011 | GB/T 22652—2019 |
| Purposes | To verify the correctness of the welding procedure for the proposed weldment | To verify the correctness of the welding procedure for the proposed weldment |
| Types of surfacing | Corrosion-resistant surfacing | Corrosion-resistant surfacing and wear-resistant surfacing |
| Requirements for welder | Performed by the skilled welding staff in the company | The procedure evaluation of the surfacing welding should be carried out in the company, and the welding should be performed by skilled personnel using the equipment from the company. |
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