Characteristics and Quality Control of Pipeline Steel Refining Process
Pipeline steel is a kind of alloy steel containing high carbon, more than 0.7%, and its application is mainly used in the oil and gas industry, which is an important raw material for petroleum and gas industry to transport gas, oil and water in long-distance pipelines. With the rapid development of the global economy, the high-end pipes, such as low and medium pressure pipes, pneumatic pipelines and nuclear power generation, have high-quality requirements for pipeline steel production. In order to optimize the mechanical properties of pipeline steel and meet the requirements of various applications, the pipeline steel production process needs to be strictly controlled, and its quality must be guaranteed.
Firstly, the acidic erosive characteristics of pipeline steel should be good. The acidic erosive characteristics of pipeline steel are related to the purity of raw materials, the desulfurization of molten steel and the addition of trace elements. The purity of raw materials can directly affect the stainless and non-stainless steel by affecting the sulfur and phosphorus content. Therefore, controlling the quality of raw materials is an important part of ensuring the quality of pipeline steel. In addition, the desulfurization of molten steel is also an important measure to ensure the quality of pipeline steel. The desulfurization process can reduce the sulfur content of the molten steel, which can promote the formation of alloy carbides, inhibit the segregation of elements, and improve the corrosion resistance of pipeline steel. The addition of trace elements such as vanadium, titanium and niobium can refine the grain size of pipeline steel, improve its mechanical properties and corrosion resistance.
Secondly, the homogeneity of pipeline steel should be good. The homogeneity of the molten steel can be improved by controlling the chemical composition, adjusting the smelting temperature, changing the slag composition, and adding rare earth elements during the refining process. In order to ensure that the chemical composition meets the requirements of pipeline steel, it is necessary to determine the chemical composition of pipeline steel before smelting and timely adjust it during smelting. By adjusting the temperature of the molten material, the excess oxygen and the inclusions in the molten steel can be volatilized and the surface of the molten steel can be refined. In addition, by changing the slag composition, the chemical composition of the molten steel can be changed and the molten steel can be stirred to reduce its global segregation or surface oxidation. The addition of rare earth elements can increase the molecular activity of the molten steel, which can improve the homogeneity of the molten steel.
Thirdly, the quality of the pipelines should be controlled. In the production process of pipeline steel, the quality of steel pipes needs to be strictly controlled. For example, the non-destructive testing of pipeline steel should be done to check its plasticity, macrostructure, surface cracks and defects. In addition, the heat treatment process of pipeline steel should be optimized to improve its performance and meet the requirements of various applications. At the same time, the surface of the pipeline steel should be treated by shot peening, grinding and pickling to further improve its texture and surface quality.
Finally, the performance test of pipeline steel should be done. After the production process of pipeline steel is completed, a comprehensive performance test should be done. Through the performance test, the mechanical properties and metallographic structure of pipeline steel can be evaluated. The evaluation of mechanical properties includes tensile strength, yield strength, elongation, impact strength, hardness and other parameters. Its metallographic structure is mainly evaluated by its microstructure, grain size and inclusions. In addition, testing of pipeline steel components, such as chemical component analysis and trace elements content detection, can help manufacturers accurately grasp the quality status of pipeline steel.
In summary, the production process of pipeline steel needs to be strictly controlled, and its quality needs to be guaranteed. The production process needs to guarantee the high purity of raw material, the homogeneity of molten steel, the quality of steel pipe, and the performance test of pipeline steel. Only by optimizing these factors can the excellent performance of pipeline steel be fully displayed and ensure its normal operation in various applications.
