Method of manufacturing seamless steel pipe for inhibiting hydrogen resulted abscission layer defect

Abstract

The invention provides a seamless steel pipe manufacturing method for suppressing hydrogen-induced ionosphere defects, including converter smelting, LF furnace refining, square billet continuous casting, continuous rolling pipe billet and steel pipe rolling, which is characterized in that titanium is added after molten steel smelting alloy, and the final titanium content of the steel is controlled at 0.010% to 0.030% of the total. The titanium alloy can be added during the tapping process of the converter, or added in the LF furnace, or can be added for the first time during the tapping process of the converter, and then added again in the LF furnace. On the basis of the existing equipment and technology, the present invention adds seamless steel pipes produced by a simple micro-titanium treatment process, the yield of finished products is significantly improved, the product rejection rate is almost zero, and the operation is simple and the component control precision is high. Compared with the vacuum treatment or slow cooling process, it not only reduces the production process, reduces the cost, but also shortens the production cycle and improves the productivity.

Description

technical field [0001] The invention belongs to a low-alloy steel pipe manufacturing process, in particular to a seamless steel pipe manufacturing method capable of preventing hydrogen-induced ionospheric defects. Background technique [0002] J55 oil well pipe and casing is the most commonly used steel grade oil well pipe in the petroleum industry at present. It must have good mechanical properties and excellent internal and external surface quality to ensure its well-forming quality and long service time after it goes into the well. At present, most of the J55 oil well pipes are produced by medium carbon manganese steel. In the production process, the products are often completely useless due to serious inner surface delamination defects (such as attached figure 1 with 2 Shown), the rejection rate of individual furnace numbers is even as high as more than 40%, which seriously affects the production and quality of oil well pipes. Through inspection and analysis, it is con...

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Problems solved by technology

[0004] In the prior art, there are many technologies for adding titanium to molten steel, such as the publication number CN1664125, titled "Medium Carbon and Alloy Structural Steel Ingot Adding Titanium to Prevent Longitudinal Cracks and Production Technology" and the publication number CN1092470, titled The two patents for "high-temperature recrystallization rolling accelerated cooling of titanium-treated steel plate instead of medium-low temperature controlled rolling process" although both add a certain amount of titanium to the steel, do not solve the defect of rolling delamination caused by high hydrogen in the billet The problem

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