1. A quality verification method for a structural steel plate for a wind power tower is characterized by comprising the following steps:

1) and (3) carrying out mechanical property inspection and fracture macroscopic analysis on the structural steel plate for the wind power tower:

2) carrying out non-metal inclusion inspection on the structural steel plate for the wind power tower;

3) and (4) carrying out microscopic structure analysis on the structural steel plate for the wind power tower.

2. The quality verification method of the structural steel plate for the wind power tower according to claim 1, wherein the specific operation process of the step 1) is as follows:

11) cutting 2 plate-shaped tensile standard samples from a structural steel plate for the wind power tower along the transverse direction, and performing a room temperature tensile test;

12) cutting 3V-shaped impact samples from a structural steel plate for the wind power tower along the longitudinal direction, selecting test temperature according to the quality grade of the steel plate, and performing impact test on the V-shaped impact samples at corresponding temperature;

13) cutting 2 bending samples from a structural steel plate for the wind power tower along the transverse direction, and performing a 180-degree bending test on the bending samples;

14) the method comprises the steps of obtaining yield strength, tensile strength, elongation after fracture, impact absorption energy and bending test results, carrying out macroscopic observation on the tensile fracture and the impact fracture, confirming whether the fracture has a separation crack phenomenon, and confirming whether the outer surface has cracks.

3. The quality verification method of the structural steel plate for the wind power tower according to claim 1, wherein the specific operation of the step 2) is as follows:

and (3) longitudinally cutting out a full-thickness sample from the structural steel plate for the wind power tower to be detected, grinding, polishing, cleaning and blow-drying, observing nonmetal impurities under a metallographic microscope, analyzing the overall distribution state and category of the nonmetal impurities, and grading the nonmetal impurities to judge whether the layering defect caused by the impurities exists.

4. The method for verifying the quality of the structural steel plate for the wind power tower according to claim 1, wherein the specific operation of step 3) is:

longitudinally cutting out a full-thickness sample from a structural steel plate for the wind power tower to be detected, grinding, polishing, cleaning and drying, corroding by nitric acid and alcohol with the mass percentage concentration of 4%, analyzing a matrix microstructure under a metallographic microscope, and observing whether segregation and layering defects exist in the central position; and when the bainite content is less than or equal to 30%, performing banded structure rating according to the banded structure evaluation map in the steel, determining the position of a bainite band, and when the bainite content is more than 30%, forming segregation, and indicating the segregation position.

5. The method for verifying the quality of the structural steel plate for the wind power tower according to claim 1, wherein the structural steel plate for the wind power tower comprises C, Si, Mn, P, S, Cr, Ni, Cu, N, and Fe, wherein the mass percentage of C, Si, Mn, P, S, Cr, Ni, Cu, and N is (0-0.24%), (0-0.55%), (0-1.60%), (0-0.035%), (0-0.30%), (0-0.40%), and (0-0.012%), respectively.

6. The quality verification method of the structural steel plate for the wind power tower according to claim 1, wherein the structural steel plate for the wind power tower is a hot rolled steel slab.

7. The method for verifying the quality of the structural steel plate for the wind power tower according to claim 1, wherein the thickness of the structural steel plate for the wind power tower is less than 20mm, and the width of the structural steel plate is 600mm or more.

8. The method for verifying the quality of the structural steel plate for a wind power tower according to claim 1, wherein the metallographic structure in the structural steel plate for a wind power tower includes ferrite and pearlite.

Background

With the vigorous popularization of renewable pollution-free high-energy clean energy in China, the wind power generation industry is continuously developed, and the demand of structural steel plates for wind power towers is increasing day by day. Through a large number of tests before the installation of the wind power tower, the problems of layering, high content of non-metallic inclusions, segregation and the like of the steel plate are found. These problems have been found to be common. The analysis of the tower barrel tilting and bending cases shows that in the actual service process, the steel plate of the tower barrel is subjected to bearing pressure and can generate certain fatigue stress, so that the service performance of the steel plate can be influenced by the banded structure, segregation and the like; meanwhile, a large amount of inclusions of manganese sulfide and aluminum oxide can affect the continuity of the matrix and generate the layering defect. In the existing standard, the examination contents such as microscopic structure, segregation and non-metallic inclusion are not used as indexes for quality verification, and the standard has one-sidedness. The aim of accurately evaluating the quality of the steel plate cannot be achieved according to the standard, the application of the actual wind power tower is adversely affected, and serious potential safety hazards are buried, so that serious economic loss is caused; at present, a structural steel plate quality verification system for the wind power tower with a comprehensive system is not formed. Aiming at the above proposed method for verifying the quality of the structural steel plate for the wind power tower, the quality of the steel plate is strictly controlled, and the service performance is ensured.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a quality verification method of a structural steel plate for a wind power tower, which can verify the quality of the structural steel plate for the wind power tower.

In order to achieve the purpose, the quality verification method of the structural steel plate for the wind power tower comprises the following steps of:

1) and (3) carrying out mechanical property inspection and fracture macroscopic analysis on the structural steel plate for the wind power tower:

2) carrying out non-metal inclusion inspection on the structural steel plate for the wind power tower;

3) and (4) carrying out microscopic structure analysis on the structural steel plate for the wind power tower.

The specific operation process of the step 1) is as follows:

11) cutting 2 plate-shaped tensile standard samples from a structural steel plate for the wind power tower along the transverse direction, and performing a room temperature tensile test;

12) cutting 3V-shaped impact samples from a structural steel plate for the wind power tower along the longitudinal direction, selecting test temperature according to the quality grade of the steel plate, and performing corresponding temperature impact test on the V-shaped impact samples;

13) cutting 2 bending standard samples from a structural steel plate for the wind power tower along the transverse direction, and performing a 180-degree bending test on the bending standard samples;

14) the method comprises the steps of obtaining yield strength, tensile strength, elongation after fracture, impact absorption energy and bending test results, carrying out macroscopic observation on the tensile fracture and the impact fracture, confirming whether the fracture has a separation crack phenomenon, and confirming whether the outer surface has cracks.

The specific operation of the step 2) is as follows:

and (3) longitudinally cutting out a full-thickness sample from the structural steel plate for the wind power tower to be detected, grinding, polishing, cleaning and blow-drying, observing nonmetal impurities under a metallographic microscope, analyzing the overall distribution state and category of the nonmetal impurities, and grading the nonmetal impurities to judge whether the layering defect caused by the impurities exists.

The specific operation of the step 3) is as follows:

longitudinally cutting out a full-thickness sample from a structural steel plate for the wind power tower to be detected, grinding, polishing, cleaning and drying, corroding by nitric acid and alcohol with the mass percentage concentration of 4%, analyzing a matrix microstructure under a metallographic microscope, and observing whether segregation and layering defects exist in the central position; and when the bainite content is less than or equal to 30%, performing banded structure rating according to the banded structure evaluation map in the steel, determining the position of a bainite band, and when the bainite content is more than 30%, forming segregation, and indicating the segregation position.

The structural steel plate for the wind power tower comprises C, Si, Mn, P, S, Cr, Ni, Cu, N and Fe, wherein the mass percent of C, Si, Mn, P, S, Cr, Ni, Cu and N are respectively (0-0.24%), (0-0.55%), (0-1.60%), (0-0.035%), (0-0.30%), (0-0.40%) and (0-0.012%).

The structural steel plate for the wind power tower is continuous casting hot rolled steel.

The thickness of the structural steel plate for the wind power tower is less than 20mm, and the width of the structural steel plate is more than or equal to 600 mm.

The metallographic structure of the structural steel plate for the wind power tower comprises ferrite and pearlite.

The invention has the following beneficial effects:

the quality verification method of the structural steel plate for the wind power tower performs mechanical property inspection and fracture macroscopic analysis, non-metal inclusion inspection and microscopic structure analysis on the structural steel plate for the wind power tower during specific operation so as to verify the quality of the structural steel plate for the wind power tower, avoid quality problems and adverse results caused by the structural steel plate in actual operation, make up for one-sidedness which is only dependent on chemical components and mechanical property verification indexes, realize accurate assessment of the overall quality of the structural steel plate for the wind power tower, and ensure service performance.

Drawings

FIG. 1 is a photomicrograph of a tensile fracture from example one;

FIG. 2 is a photograph of non-metallic inclusions in the first example;

FIG. 3 is a photograph of a ribbon-like structure according to a first embodiment;

FIG. 4 is a photograph of the microstructure of the matrix in the first example;

FIG. 5 is a photomicrograph of a tensile fracture from example two;

FIG. 6 is a photograph of non-metallic inclusions from example two;

FIG. 7 is a photograph of a ribbon-like structure of example two;

FIG. 8 is a photograph of the microstructure of the matrix in example two.

Detailed Description

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments, and are not intended to limit the scope of the present disclosure. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present disclosure. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

There is shown in the drawings a schematic block diagram of a disclosed embodiment in accordance with the invention. The figures are not drawn to scale, wherein certain details are exaggerated and possibly omitted for clarity of presentation. The shapes of various regions, layers and their relative sizes and positional relationships shown in the drawings are merely exemplary, and deviations may occur in practice due to manufacturing tolerances or technical limitations, and a person skilled in the art may additionally design regions/layers having different shapes, sizes, relative positions, according to actual needs.

The quality verification method of the structural steel plate for the wind power tower comprises the following steps of:

1) and (3) carrying out mechanical property inspection and fracture macroscopic analysis on the structural steel plate for the wind power tower:

the specific operation process of the step 1) is as follows:

11) cutting 2 plate-shaped tensile standard samples from a structural steel plate for the wind power tower along the transverse direction, and performing a room temperature tensile test;

12) cutting 3V-shaped impact samples from a structural steel plate for the wind power tower along the longitudinal direction, selecting test temperature according to the quality grade of the steel plate, and performing corresponding temperature impact test on the V-shaped impact samples;

13) cutting 2 bending standard samples from a structural steel plate for the wind power tower along the transverse direction, and performing a 180-degree bending test on the bending standard samples;

14) the method comprises the steps of obtaining yield strength, tensile strength, elongation after fracture, impact absorption energy and bending test results, carrying out macroscopic observation on the tensile fracture and the impact fracture, confirming whether the fracture has a separation crack phenomenon, and confirming whether the outer surface has cracks.

2) Carrying out non-metal inclusion inspection on the structural steel plate for the wind power tower;

the specific operation of the step 2) is as follows:

the method comprises the steps of longitudinally cutting out a full-thickness sample from a structural steel plate for the wind power tower, grinding, polishing, cleaning and drying, observing nonmetal inclusions under a metallographic microscope, analyzing the overall distribution state and category of the nonmetal inclusions, and grading the nonmetal inclusions to judge whether the layering defect caused by the inclusions exists or not.

3) And (4) carrying out microscopic structure analysis on the structural steel plate for the wind power tower.

The specific operation of the step 3) is as follows:

longitudinally cutting out a full-thickness sample from a structural steel plate for the wind power tower to be detected, grinding, polishing, cleaning and drying, corroding by nitric acid and alcohol with the mass percentage concentration of 4%, analyzing a matrix microstructure under a metallographic microscope, and observing whether segregation and layering defects exist in the central position; and when the bainite content is less than or equal to 30%, performing banded structure rating according to the banded structure evaluation map in the steel, determining the position of a bainite band, and when the bainite content is more than 30%, forming segregation, and indicating the segregation position.

The structural steel plate for the wind power tower comprises C, Si, Mn, P, S, Cr, Ni, Cu, N and Fe, wherein the mass percent of C, Si, Mn, P, S, Cr, Ni, Cu and N are respectively (0-0.24%), (0-0.55%), (0-1.60%), (0-0.035%), (0-0.30%), (0-0.40%) and (0-0.012%).

The structural steel plate for the wind power tower is continuous casting hot rolled steel.

The thickness of the structural steel plate for the wind power tower is less than 20mm, and the width of the structural steel plate is more than or equal to 600 mm.

The metallographic structure of the structural steel plate for the wind power tower comprises ferrite and pearlite.

Example one

The structural steel plate for the wind power tower in the embodiment is continuous casting hot rolled steel Q355D, and comprises the chemical components of (C: 0.14), Si:0.23, Mn:1.48, P:0.014, S:0.004, Cr:0.046, Ni:0.030, Cu:0.011 and N: 0.004).

The specific operation process of the invention is as follows:

1) mechanical property inspection and fracture macroscopic analysis

Cutting 2 plate-shaped tensile standard samples of a steel plate (with the thickness of 17.3mm) to be detected along the transverse direction (vertical to the rolling direction), and performing a room-temperature tensile test; cutting 3V-shaped impact samples along the longitudinal direction (rolling direction), wherein the size of each V-shaped impact sample is 10 multiplied by 55mm, and performing a low-temperature impact test at the temperature of-20 ℃; the steel sheet was subjected to 180 ° bending test (D ═ 3a) by taking 2 full-thickness bending test pieces (standard test pieces) in the transverse direction.

The mechanical property test result is as follows: the upper yield strength is 397MPa (not less than 345MPa), the tensile strength is 534MPa (470-630MPa), the elongation is 21 percent (not less than 20 percent), the low-temperature impact value at 20 ℃ is 108J (not less than 34J), and the separation and rupture length at the tensile fracture is 5 mm.

2) Examination of non-metallic inclusions

The method comprises the steps of cutting a full-thickness sample of a steel plate (with the thickness of 17.3mm) to be detected along the longitudinal direction (rolling direction), carrying out nonmetal inclusion observation under a metallographic microscope after grinding, polishing, cleaning and blow-drying, analyzing the overall distribution state and category of nonmetal inclusions, carrying out nonmetal inclusion rating by using a microscope software system, and mainly observing the central position to determine whether the layering defect caused by the inclusions exists.

The non-metallic inclusion test results are: inclusions of A type (sulfide) and D type (spherical oxide) exist in the center of the steel sheet, and the grades are A type: fine line 2.5 grade; and D type: fine grade 0.5; no delamination defects were found.

3) Microstructural analysis

Cutting a full-thickness sample of a steel plate (with the thickness of 17.3mm) to be detected along the longitudinal direction (rolling direction), grinding, polishing, cleaning and blow-drying, corroding by 4% nitric acid and alcohol, and analyzing a matrix microstructure under a metallographic microscope, wherein the matrix structure is ferrite, pearlite and bainite, the bainite is intensively distributed at the central position, the content is 15%, a bainite strip is formed in the center of the steel plate, and the bainite strip is internally provided with elongated sulfide nonmetal impurities; the banded structure rating was (5B, central bainite band, 15%).

Example two

The structural steel plate for the wind power tower in the embodiment is continuous casting hot rolled steel Q355D, and comprises the chemical components of (C: 0.14), Si:0.23, Mn:1.48, P:0.014, S:0.004, Cr:0.046, Ni:0.030, Cu:0.011 and N: 0.004).

The specific operation process of this embodiment is as follows:

1) mechanical property inspection and fracture macroscopic analysis

Cutting 2 plate-shaped tensile samples (standard samples) of a steel plate (with the thickness of 14.3mm) to be detected along the transverse direction (vertical to the rolling direction), and performing a room-temperature tensile test; cutting 3V-shaped impact samples along the longitudinal direction (rolling direction), wherein the size of each V-shaped impact sample is 10 multiplied by 55mm, and performing a low-temperature impact test at the temperature of-20 ℃; the steel sheet was subjected to 180 ° bending test (D2 a) by cutting 2 full-thickness bending test pieces (standard test pieces) in the transverse direction.

The mechanical property test result is as follows: the upper yield strength is 363MPa (not less than 355MPa), the tensile strength is 518MPa (470-630MPa), the elongation is 27.5 percent (not less than 20 percent), the low-temperature impact value at 20 ℃ is 83.3J (not less than 34J), the tensile fracture has slight separation phenomenon, and the fracture length is 2 mm.

2) Examination of non-metallic inclusions

The method comprises the steps of cutting a full-thickness sample of a steel plate (with the thickness of 14.3mm) to be detected along the longitudinal direction (rolling direction), carrying out nonmetal inclusion observation under a metallographic microscope after grinding, polishing, cleaning and blow-drying, analyzing the overall distribution state and category of nonmetal inclusions, carrying out nonmetal inclusion rating by using a microscope software system, and mainly observing the central position to determine whether the layering defect caused by the inclusions exists.

The non-metallic inclusion test results are: inclusions of type a (sulfide), type B (alumina) and type D (spherical oxide) are present in the center of the steel sheet, and the grades are type a: fine grade 0.5; b type: coarse grade 2.0, fine grade 4.0; and D type: fine line 1.5 grade; wherein, alumina is included as brittle phase, and no delamination defect is found.

3) Microscopic structure analysis:

cutting a full-thickness sample of a steel plate (with the thickness of 14.3mm) to be detected along the longitudinal direction (rolling direction), grinding, polishing, cleaning and blow-drying, corroding by 4 percent nitric acid alcohol, and analyzing a matrix microstructure under a metallographic microscope, wherein the matrix structure is ferrite and pearlite; the banded structure grade was (5B, pearlitic band).