Manufacturing method of steel ingot for gas cylinder

Abstract

The invention belongs to the technical field of manufacturing of steel ingots and discloses a manufacturing method of a steel ingot for a gas cylinder. The manufacturing method of the steel ingot for the gas cylinder comprises the following steps of: raw material purporting, converter smelting, alloy addition, LF (Low Frequency) steel ladle refining, vacuum degreasing treatment, casting as well as electroslag re-melting, wherein the raw material contains not less than 4wt% of C, not more than 0.015wt% of P and blast furnace molten iron with a temperature being not lower than 1200 DEG C; in a converter smelting stage, content of P is lowered by P-removing pretreatment; the LF steel ladle refining adopts an aluminum-free deoxidation process; after the electroslag re-melting and the secondary refining are carried out onto the steel ingot obtained by primary refining and casting so that S and impurities in the steel are lowered. According to the manufacturing method disclosed by the invention, the quantity of harmful elements and impurities in the steel ingot are controlled by twice refining, so that a purpose of controlling components and structure of the steel ingot is reached, the steel ingot for the gas cylinder with excellent strength and toughness is finally obtained, and therefore, working pressure and safety of the steel ingot for the gas cylinder are improved.

Description

technical field [0001] The invention belongs to the technical field of manufacturing steel ingots, and in particular relates to a method for manufacturing steel ingots for gas cylinders. Background technique [0002] Domestic gas cylinder production started in the 1960s, with 35 steel and 45 steel; DZ40 steel was generally used in the 1970s; by the early 1980s, steel pipes for manganese steel gas cylinders had been mass-produced, and the representative steel grades were 40Mn2, 42Mn2, 40Mn2V etc., a small amount of 30CrMoA, 35CrMoA, 30CrMnSiA and other steel pipes are used to manufacture gas cylinders. From the mid-1980s to the mid-1990s, with the establishment and revision of national gas cylinder standards and the expansion of the scope of use of gas cylinders, the C content in manganese steel gas cylinders was lowered twice in order to improve low-temperature impact toughness and integrate with international standards as soon as possible. , and finally dropped from ≤0.44%...

AI Technical Summary

Problems solved by technology

As the working pressure increases, the original gas cylinder steel cannot be used due to insufficient strength, and the increase in strength means the decrease in toughness and plasticity, and at the same time reduces the safety of gas cylinders, so the steel for gas cylinders with excellent strength and toughness can be obtained appear crucial

Domestic smelting and research on steel for gas cylinders above 25MPa is still in its infancy. The main problem is that the control of steel components for gas cylinders and the stability of inclusion content and shape control in steel ingots are poor, resulting in large dispersion of strength and toughness of materials.

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