CN103014530A - Method for improving impact performance of D-level ship plate - Google Patents

Abstract

The invention provides a method for improving the impact property of a D-level ship plate, which adopts a mode of optimizing chemical components and a rolling process, wherein the content of C is controlled to be 0.14wt%, the thickness of a steel plate is more than or equal to 7.0mm and less than or equal to 19.9mm, and the content of Mn is controlled to be 0.90 wt%; the thickness of the steel plate is more than or equal to 20mm and less than or equal to 40mm, and the Mn content is controlled to be 0.95 wt%; and meanwhile, according to different thicknesses of the steel plates, selecting a secondary initial rolling target temperature, a final rolling target temperature and a two-stage total reduction ratio correspondingly. The impact value of the D-level ship plate produced by the method is more than 100MPa, the performance qualified rate reaches 98.6%, the performance qualified rate is improved by 38.6% compared with the performance qualified rate before the method is implemented, and the process control capability is more than 1.0, so that the steel modification loss is reduced by 500 yuan/ton, the economic benefit of an enterprise is improved, the contract execution rate is ensured, and the credibility of the enterprise is improved.

Description

A kind of method that improves D level deck of boat impact property

Technical field

The invention belongs to technical field of ferrous metallurgy, relate in particular to a kind of method of the D of raising level deck of boat impact property.

Background technology

According to standard-required, the chemical composition of D level ship steel generally is controlled at: C≤0.2%, Si≤0.35%, Mn≤0.6%, P≤0.030%, S≤0.030%, Cr≤0.2%, Ni≤0.3%, Cu≤0.3%, Mo≤0.08%, Als0.015-0.045%.Because the needs that use, the D level deck of boat is very strict for the requirement of the requirement of performance especially impact property, therefore for a long time, the problem that D level deck of boat impact property does not conform to fails to solve always, that qualification rate only can reach about 60%, not only directly affected the quality index of steel plate and the economic benefit of enterprise, and lumber recovery and contract execution rate have been caused very big impact.

Summary of the invention

The object of the invention is to for the problems referred to above, a kind of preferred technical scheme is provided, thereby increase substantially D level deck of boat properties percent of pass and lumber recovery, the method for suretyship contract implementation rate.

For this reason, the solution taked of the present invention is:

A kind of method that improves D level deck of boat impact property is characterized in that, takes the preferred mode of chemical composition and rolling technology, and concrete grammar is:

(1), strictly control C, the Mn content of steel:

C content is controlled at 0.14wt%;

According to steel plate thickness control Mn content: steel plate thickness 〉=7.0mm～≤ 19.9mm, Mn content is controlled at 0.90wt%; Steel plate thickness 〉=20mm～≤ 40mm, Mn content is controlled at 0.95wt%;

(2), different according to steel plate thickness, correspondence is chosen secondary open rolling target temperature, finish to gauge target temperature and two-stage total reduction:

Steel plate thickness 〉=7.0mm～≤ 27.9mm, secondary open rolling target temperature is 880 ℃, 820 ℃ of finish to gauge target temperatures, two-stage total reduction are 63%;

Steel plate thickness 〉=28mm～≤ 40mm, secondary open rolling target temperature is 870 ℃, 800 ℃ of finish to gauge target temperatures, two-stage total reduction are 60%.

Beneficial effect of the present invention is:

The D level deck of boat impact value that the inventive method is produced is all more than 100MPa, properties percent of pass reaches 98.6%, improve 38.6% than implementing before the present invention, and the process control ability is greater than 1.0, not only reduced and changed 500 yuan/tons of steel losses, improve the business economic income, and guaranteed the contract execution rate, improved the goodwill degree.

Embodiment

Below, the present invention will be further described in conjunction with the embodiments.

Embodiment 1:

Finished steel plate thickness is 15mm.

1, chemical composition wt% is: C0.14%, and Si≤0.35%, Mn0.90%, P≤0.030%, S≤0.030%, Cr≤0.2%, Ni≤0.3%, Cu≤0.3%, Mo≤0.08%, Als0.015-0.045%, remaining is Fe and trace impurity.

2, the rolling technology system of determining according to steel plate thickness is:

Secondary open rolling target temperature is 880 ℃, and 820 ℃ of finish to gauge target temperatures, two-stage total reduction are 63%.

Remaining is common process.

Embodiment 2:

Finished steel plate thickness is 35mm.

1, chemical composition wt% is: C0.14%, and Si≤0.35%, Mn0.95%, P≤0.030%, S≤0.030%, Cr≤0.2%, Ni≤0.3%, Cu≤0.3%, Mo≤0.08%, Als0.015-0.045%, remaining is Fe and trace impurity.

2, the rolling technology system of determining according to steel plate thickness is:

Secondary open rolling target temperature is 870 ℃, and 800 ℃ of finish to gauge target temperatures, two-stage total reduction are 60%.

Remaining is common process.

Claims (1)

1. a method that improves D level deck of boat impact property is characterized in that, takes the preferred mode of chemical composition and rolling technology, and concrete grammar is:

(1), strictly control C, the Mn content of steel:

C content is controlled at 0.14wt%;

According to steel plate thickness control Mn content: steel plate thickness 〉=7.0mm～≤ 19.9mm, Mn content is controlled at 0.90wt%; Steel plate thickness 〉=20mm～≤ 40mm, Mn content is controlled at 0.95wt%;

(2), different according to steel plate thickness, correspondence is chosen secondary open rolling target temperature, finish to gauge target temperature and two-stage total reduction:

Steel plate thickness 〉=7.0mm～≤ 27.9mm, secondary open rolling target temperature is 880 ℃, 820 ℃ of finish to gauge target temperatures, two-stage total reduction are 63%;

Steel plate thickness 〉=28mm～≤ 40mm, secondary open rolling target temperature is 870 ℃, 800 ℃ of finish to gauge target temperatures, two-stage total reduction are 60%.