Development of X80 Pipeline Steel Matching Welding Rod CHE657GX

【Abstract】This paper discusses a high-strength, high-toughness and low-hydrogen electrode (CH E657G X) specially designed for X80 pipeline steel. The electrode exhibits excellent physical and chemical properties when welding X80 steel, which can fully meet the pipeline. Various performance requirements for engineering welding. At the same time, through the combination of theory and practice, the factors affecting the physical and chemical properties of the electrode, especially the strength and impact toughness, are analyzed.

1 Overview

Pipeline transportation is the most reasonable transportation method for long-distance transportation of oil and natural gas. It has obvious characteristics such as economy, safety, high efficiency, energy saving, uninterrupted, and small damage to the environment. Pipeline transportation has become the fifth largest transportation industry after road, rail, waterway and air transportation. Its overall development trend is long distance, large diameter, high strength and high toughness. At present, X70 steel grade pipeline steel is widely used in pipeline construction at home and abroad, and some long-distance pipeline construction begins to adopt X80 pipeline steel. At present, the cumulative length of the world is only 1750km. However, the total length of the second-line natural gas pipeline project constructed in China is about 4800km, which has made the application of X80 pipeline steel popular, and also put forward new and higher requirements for X80 pipeline steel and supporting welding materials.

In the high-strength welded pipe manufacturing process, the most difficult problem is the reduction of strength and toughness of the weld metal and heat-affected zone. How to control the weld performance is a key issue that needs to be solved in the development and use of high-strength welded pipe. Our company has always followed the pace of market demand, and invested a lot of manpower and material resources in the research and development of welding materials for pipeline steel. Since the late 1980s, we have been researching and developing welding consumables for X60 pipeline steel. Pipeline steel supporting welding material research and development, in 2001, X70 supporting welding material research and development, by 2008 completed a series of research work on X80 pipeline steel supporting welding material research and development. At present, the CHE657GX welding rod of our factory has been put into mass production. After using it by users, it has affirmed its good welding performance and can fully meet the performance requirements of X80 steel pipe welding for the second-line natural gas pipeline project of the West-East Gas Pipeline.

2. X80 pipeline steel and its supporting electrode

(1) Technical requirements of X80 pipeline steel The technical requirements of the second-line project of West-East Gas Pipeline for high-strength pipeline steel, the chemical composition is shown in Table 1, and the mechanical properties are shown in Table 2.

For more information, please refer to the attachment or read the 18th issue of Metalworking (Hot Processing).

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