Coated steel sheet with thin aluminum alloy coating and coating method thereof

Abstract

The invention relates to a coated steel sheet with thin aluminum alloy coating and a coating method thereof. The coated steel sheet provided by the invention is used for hot stamping forming, coatingthickness of the coated steel sheet is 5-14 microns, wherein the aluminum alloy coating comprises a FeAlSi inhibiting layer close to a matrix steel sheet and an Al alloy layer at outside thereof, thickness of the FeAlSi inhibiting layer is not greater than 60% of thickness of the coating and is 1.5-6.0 microns, diameter of Kirkendall holes from an interface of the FeAlSi inhibiting layer and the matrix steel to less than 2 microns in the matrix steel is less than 2.5 microns, wherein the number of the Kirkendall holes with the diameter of more than 0.5 microns and less than 2.5 microns is notmore than 15 / 35 microns. The invention also discloses a coating method of applying the thin aluminum alloy coating on the matrix steel sheet for hot stamping forming, and the method can eliminate omission of coating and make a hot stamping forming member obtained from the coated steel sheet have excellent resistance spot welding performance.

Description

technical field

[0001] The present invention relates to a coated steel sheet having a thin aluminum alloy coating layer and a coating method thereof. Background technique

[0002] In recent years, with the increasingly stringent requirements of energy and environmental protection, crash regulations and passive safety of passengers, hot stamping has been increasingly applied to the design and production of automotive components. In order to improve the strength and toughness of hot stamping components of Al-Si coated plates, CN108588612A proposes to obtain hot stamped components by using thin coated plates, wherein the initial coating thickness of coated steel plates before hot stamping is 3-19 μm. However, in the production of thin-coated boards, it is found that the problems of large fluctuation of coating thickness, unstable production and local leakage are prone to occur during the production process.

[0003] In addition, in the process of hot stamping, the coated steel...

Examples

Embodiment 5

[0079] The coating process parameters of Example 5 and Comparative Example 4 are only different in the temperature of the steel plate into the pot, wherein the comparative example 4 has a significantly higher temperature of the steel plate into the pot. Therefore, the more Kirkendall holes and the thicker FeAlSi inhibition layer in Comparative Example 4 are caused by the high temperature of the steel plate into the pot. From this, it can be seen that a high temperature of the steel plate into the pot is not desirable.

[0080] image 3 It is a typical underplating defect photograph of the plated steel sheet of Comparative Example 4. It is evident that in some areas the underplating is severe. This is because compared with Example 5, the higher temperature of the steel plate in Comparative Example 4 accelerated the diffusion, resulting in a thicker FeAlSi inhibitory layer and a thinner corresponding Al alloy layer, so the air-knife purging requirement was high. It is difficu...

technical field

[0001] The present invention relates to a coated steel sheet having a thin aluminum alloy coating layer and a coating method thereof. Background technique

[0002] In recent years, with the increasingly stringent requirements of energy and environmental protection, crash regulations and passive safety of passengers, hot stamping has been increasingly applied to the design and production of automotive components. In order to improve the strength and toughness of hot stamping components of Al-Si coated plates, CN108588612A proposes to obtain hot stamped components by using thin coated plates, wherein the initial coating thickness of coated steel plates before hot stamping is 3-19 μm. However, in the production of thin-coated boards, it is found that the problems of large fluctuation of coating thickness, unstable production and local leakage are prone to occur during the production process.

[0003] In addition, in the process of hot stamping, the coated steel...

Examples

Embodiment 5

[0079] The coating process parameters of Example 5 and Comparative Example 4 are only different in the temperature of the steel plate into the pot, wherein the comparative example 4 has a significantly higher temperature of the steel plate into the pot. Therefore, the more Kirkendall holes and the thicker FeAlSi inhibition layer in Comparative Example 4 are caused by the high temperature of the steel plate into the pot. From this, it can be seen that a high temperature of the steel plate into the pot is not desirable.

[0080] image 3 It is a typical underplating defect photograph of the plated steel sheet of Comparative Example 4. It is evident that in some areas the underplating is severe. This is because compared with Example 5, the higher temperature of the steel plate in Comparative Example 4 accelerated the diffusion, resulting in a thicker FeAlSi inhibitory layer and a thinner corresponding Al alloy layer, so the air-knife purging requirement was high. It is difficu...

Images