Method for improving flaw detection qualification rate of Q345C steel plate with specification of 14-30 mm

A technology of pass rate and steel plate, applied in the direction of manufacturing converters, etc., can solve the problems of waste of raw materials, low pass rate of flaw detection, and high production cost.

Active Publication Date: 2021-06-22
NANYANG HANYE SPECIAL STEEL CO LTD
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Problems solved by technology

[0005] Both of the above two Q345C steel plates can meet the requirements of use, but the pass rate of flaw detection is low, the production cost is high, and the waste of raw materials is caused

Method used

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  • Method for improving flaw detection qualification rate of Q345C steel plate with specification of 14-30 mm
  • Method for improving flaw detection qualification rate of Q345C steel plate with specification of 14-30 mm
  • Method for improving flaw detection qualification rate of Q345C steel plate with specification of 14-30 mm

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Embodiment

[0027]A method for improving the qualified rate of flaw detection of 14-30mm Q345C steel plate, comprising Q345C steel plate and the production method of said Q345C steel plate; the chemical composition (unit, wt%) of said Q345C steel plate is: C: 0.15-0.18, Si: 0.20~0.40, Mn: 1.25~1.35, P: ≤0.025, S: ≤0.005, Ti: 0.015~0.025, Als: 0.015~0.030, others are Fe and residual elements.

[0028] The production method of described Q345C steel plate comprises the following steps: hot metal KR desulfurization, converter smelting, LF refining, continuous casting, billet sending and rolling;

[0029] Hot metal KR desulfurization: shallow desulfurization is adopted according to the S content of molten iron to ensure that the sulfur content of molten iron in converter smelting after desulfurization is ≤0.010%;

[0030] Converter smelting: C content at the end of the converter tapping ≥ 0.06%, to prevent over-oxidation of molten steel; tapping temperature ≥ 1650 ° C, to ensure that the tempe...

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Abstract

The invention provides a method for improving the flaw detection qualification rate of a Q345C steel plate with the specification of 14-30 mm, belongs to the technical field of medium-thickness steel plate production, and comprises a Q345C steel plate and a production method of the Q345C steel plate. The Q345C steel plate comprises the following chemical components of (unit, wt%) 0.15wt% to 0.18wt% of C, 0.20wt% to 0.40wt% of Si, 1.25wt% to 1.35wt% of Mn, P less than or equal to 0.025wt%, S less than or equal to 0.005wt%, 0.015wt% to 0.025wt% of Ti, 0.015wt% to 0.030wt% of Als and the balance Fe and residual elements. According to the method, in the production, the Q345C process technology is strictly controlled, the sulfur content and the manganese content of a finished product are strictly controlled; on the premise that the surface temperature of a casting blank is higher than the third brittleness temperature interval of steel by 900 DEG C or above when the casting blank is straightened, when the secondary cooling water temperature is lower than or equal to 35 DEG C, the secondary cooling specific water flow is controlled to be 0.42 L / kg, and when the secondary cooling water temperature is higher than 35 DEG C, the secondary cooling specific water flow is controlled to be 0.48 L / kg; and the casting blank is rolled after being cut and slowly cooled. Through the implementation of the method, the flaw detection qualification rate of the rolled Q345C steel plate with the specification of 14-30 mm is increased to 99.80% from 98.40%, and the qualification rate is increased.

Description

technical field [0001] The invention relates to the technical field of production of medium-thick steel plates, in particular to a method for improving the qualified rate of flaw detection of Q345C steel plates with a specification of 14 to 30 mm. Background technique [0002] With the development of the economy, the demand for steel products in all walks of life is increasing day by day, and the requirements are getting higher and higher. Q345C is a low-alloy high-strength steel with good comprehensive mechanical properties and process properties, and is widely used in engineering fields such as steel structures and wind towers. Domestically produced steel sheets of this specification are mainly designed with C, Mn and other elements in the composition design, of which the C content is about 0.11-0.17wt%, and the Mn content is about 1.30-1.60wt%. The qualified rate of flaw detection of Q345C steel plate has not been broken through, especially the qualified rate of flaw det...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C33/04C22C38/02C22C38/04C22C38/06C22C38/14C21C1/02C21C5/28C21C7/06C21C7/064C21C7/072
CPCC22C33/04C22C38/02C22C38/04C22C38/06C22C38/14C21C1/02C21C5/28C21C7/06C21C7/072C21C7/064
Inventor 康文举许少普赵迪冯晓光朱先兴袁高俭任义杨春李嘎子白艺波王勇
Owner NANYANG HANYE SPECIAL STEEL CO LTD
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