A prediction model for crack arrest toughness temperature correlation index of shipbuilding high-strength steel thick plate based on chemical composition and its establishment method and application

Abstract

The present invention relates to the technical field of testing the fracture resistance of metal materials, and provides a prediction model of the temperature correlation index of crack arrest toughness of a shipboard high-strength steel thick plate based on chemical composition, and a method for establishing the model and application thereof. The method for establishing the temperature correlation index prediction model comprises the following steps: S1. Analysis of main influencing factors. The crack arrest steel for the shipboard high-strength steel thick plate is ferritic steel. The short-range obstacle in the dislocation sliding process is mainly the penta-force. The carbon equivalent (C eq ) characterizes the effect of substitutional solid solution elements on lattice resistance, and the oxygen equivalent (O eq ) characterizes the effect of interstitial solid solution elements on lattice resistance; S2. The temperature correlation index prediction model is established, and the correlation model of chemical composition and temperature correlation index T0 is obtained based on the effect of substitutional solid solution elements and interstitial solid solution elements on lattice resistance. The present invention clarifies the main influencing factors of the crack arrest toughness temperature correlation index T0, and provides strong support for the evaluation and research and development technology of crack arrest performance of high-strength thick plates for ships.

Description

Technical Field

[0001] The present invention relates to the technical field of testing the fracture resistance of metal materials, and in particular to a prediction model for a temperature correlation index of crack arrest toughness of a shipboard high-strength steel thick plate based on chemical composition, and an establishment method and application thereof. Background Art

[0002] Crack arrest performance is a core application performance of high-strength thick plates for ultra-large container ships. The International Association of Classification Societies (IACS) uniformly requires UR W31 "YP47 Thick Plate and Brittle Crack Arrest Plate" to specify that the technical index of steel plate crack arrest performance is the crack arrest toughness K at -10°C. ca ≥6000N / mm 3 / 2 (Steel plate on upper deck) or K ca ≥8000N / mm 3 / 2 (side steel plate), the determination method is the gradient temperature type double tension test method or the gradient temperature type ESSO test method. During the test, the K ca Then, the experimental data is fitted using formula (1) to determine the temperature correlation coefficient K 0 And temperature correlation index T 0 Finally, K 0 and T 0 Substitute the value of into formula (1) and calculate K at -10℃ ca .

[0003] Specifically, when using the gradient temperature double tensile test method, such as Figure 1 As shown in the figure, during the test, the crack starts from the notch of the crack initiation plate, expands into the main tensile plate and then stops. According to the crack arrest length and temperature gradient, the temperature T at the crack arrest point can be calculated. k , as shown in formula (2); according to the principal tensile stress and crack arrest length, the crack arrest toughness K can be calculated ca , as shown in formula (3); according to the IACS specification requirements, the four groups of T k and K ca Substituting the value into formula (1) can determine K 0 and T 0 The numerical value of .

[0004]

[0005] Among them, T i is the cold end temperature, a is the crack arrest length, △T is the temperature gradient, σ is the main tensile stress, W s is the sample width, K 0 is the temperature dependence coefficient, T 0 is the temperature dependence index.

[0006] From formula (1), it can be seen that the crack arrest toughness K ca The temperature dependence is mainly determined by K 0 and T 0 Determine that these two parameters are K at -10℃ ca The value has an important influence. It is of great significance to explore the correlation between these two parameters and other material factors for accurately estimating the crack arrest performance of hull steel and then proposing effective improvement measures. At present, there is not much work in this regard in China. For example, CN115216685A discloses a thick steel plate with high crack arrest performance and a manufacturing method thereof, which only involves obtaining a thick steel plate with high strength performance, good impact toughness and excellent crack arrest performance through reasonable chemical composition design combined with optimized process, but does not explore the relationship between chemical composition and temperature correlation index and crack arrest toughness. Summary of the invention

[0007] In view of this, the present invention aims to propose a prediction model of crack arrest toughness temperature correlation index of shipbuilding high-strength steel thick plate based on chemical composition and its establishment method and application, so as to clarify the crack arrest toughness temperature correlation index T 0 The main influencing factors of the crack arrest performance are analyzed, providing strong support for the evaluation and research and development technology of high-strength thick plates for ships.

[0008] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0009] A method for establishing a prediction model for the temperature correlation index of crack arrest toughness of a shipbuilding high-strength steel thick plate based on chemical composition comprises the following steps:

[0010] S1. Analysis of main influencing factors,

[0011] The crack arrest steel for high-strength steel thick plates for ships is ferritic steel with a body-centered cubic structure. The short-range obstacle in the dislocation sliding process is mainly the Pierre-Nelson force. The carbon equivalent (C eq ) characterizes the effect of substitutional solid solution elements on lattice resistance, and the oxygen equivalent (O eq ) characterizes the effect of interstitial solid solution elements on lattice resistance;

[0012] S2. Establishment of temperature correlation index prediction model,

[0013] As the content of substitutional solid solution elements increases, the lattice resistance increases, the temperature sensitivity increases, and the temperature correlation index increases. As the content of interstitial solid solution elements increases, the activation volume decreases, the temperature sensitivity increases, and the temperature correlation index increases. Based on the effects of substitutional solid solution elements and interstitial solid solution elements on the lattice resistance, the chemical composition and temperature correlation index T is obtained. 0 The correlation model.

[0014] Furthermore, the temperature correlation index T 0 The prediction model is:

[0015]

[0016] Among them, T 0 is the temperature dependence index, C eq is carbon equivalent, O eq is the oxygen equivalent.

[0017] Furthermore, the carbon equivalent (C eq ) is calculated as:

[0018] .

[0019] Furthermore, the oxygen equivalent (O eq ) is calculated as:

[0020] .

[0021] The present invention also proposes a chemical composition-based prediction model for the temperature correlation index of crack arrest toughness of a thick plate of high-strength shipbuilding steel, which is constructed using the above-mentioned method for establishing a temperature correlation index prediction model.

[0022] The present invention also proposes a prediction model for the temperature correlation index of crack arrest toughness of shipbuilding high-strength steel thick plates based on chemical composition. ca In the application, the above-mentioned temperature correlation index prediction model establishment method and / or prediction model are adopted.

[0023] Furthermore, based on the thermal activation theory, the temperature dependence index T is determined 0 And temperature correlation coefficient K 0 According to the temperature correlation index T 0 And temperature correlation coefficient K 0 The crack arrest toughness K at -10℃ is obtained by ca .

[0024] Furthermore, the temperature correlation index T 0 And temperature correlation coefficient K 0 The correlations between them are as follows:

[0025] .

[0026] Compared with the prior art, the prediction model of the temperature correlation index of crack arrest toughness of shipbuilding high-strength steel thick plate based on chemical composition and its establishment method and application have the following advantages:

[0027] (1) The temperature correlation index prediction model of the present invention can be used to reasonably design the material composition during the development stage of shipbuilding high-strength steel thick plate materials, and the temperature correlation index K 0 Prediction model to obtain the crack arrest toughness K ca Better steel;

[0028] (2) In the process of production quality control and crack arrest performance evaluation of high-strength steel thick plates for ships, the carbon equivalent (C eq ) and oxygen equivalent (O eq ), and further calculate the temperature correlation index T 0 And temperature correlation coefficient K 0 , the crack arrest toughness K at -10℃ can be obtained ca The value can be obtained to quickly evaluate whether the crack arrest performance of the steel plate meets the requirements of the UR W31 specification, without the need to conduct a large-scale gradient temperature double tensile test, which can effectively reduce costs and improve efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0030] Figure 1 Schematic diagram of the gradient temperature double tensile test;

[0031] Figure 2 is the temperature correlation index T of the present invention 0 Carbon equivalent C eq relevance;

[0032] Figure 3 is the temperature correlation index T of the present invention 0 Oxygen equivalent O eq relevance;

[0033] Figure 4 is the temperature correlation index T of the present invention 0 and ln(C eq 0.2 ) / O eq 2 relevance;

[0034] Figure 5 is the temperature correlation coefficient K described in the present invention 0 Temperature correlation index T 0 relevance;

[0035] Figure 6 is the temperature correlation index T of the present invention 0Comparison of calculated and measured values. DETAILED DESCRIPTION

[0036] The present invention will be further described below in conjunction with specific embodiments. It should be noted that the data in the following experimental examples are obtained by the inventor through a large number of experiments. Due to space limitations, only a part of them is shown in the specification, and those of ordinary skill in the art can understand and implement the present invention under these data. These embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these changes or modifications also fall within the scope protected by the present application.

[0037] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0038] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0039] The crack arrest steel for high-strength thick plates used in container ships is mainly ferritic steel, and its lattice structure type is mainly a body-centered cubic structure. According to the theory of dislocation motion, the deformation mechanism of ship crack arrest steel within the operating temperature range is mainly the thermal activation mechanism of dislocation slip. In this mechanism, the microstructure that determines the temperature correlation of crack arrest steel is mainly the short-range obstacle in the dislocation slip process (Reference: Dynamic Behavior of Materials, MA Meyers, National Defense Industry Press, 2006), and this obstacle is closely related to the chemical composition. The present invention first conducts theoretical analysis to determine the crack arrest toughness temperature correlation index T 0 The main influencing factors of the temperature are given, and the temperature correlation index T is given on this basis. 0 prediction model.

[0040] The method for establishing a prediction model of the temperature correlation index of crack arrest toughness of a shipbuilding high-strength steel thick plate based on chemical composition of the present invention is as follows:

[0041] S1. Analysis of main influencing factors,

[0042] For body-centered cubic structure, the short-range obstacle in the dislocation sliding process is mainly the Pierce-Norman force (PN force), that is, the lattice resistance of the lattice. An important factor that determines the lattice resistance is the alloying elements, including substitutional solid solution elements represented by Mn, Cr, Mo, V, Ni, Cu, etc. and interstitial solid solution elements represented by C, N, O. The effect of these elements on the lattice resistance is often not presented in the form of a single element, and needs to be considered as a whole. For this reason, the present invention adopts carbon equivalent (C eq ) characterizes the effect of substitutional solid solution elements on lattice resistance, and the oxygen equivalent (O eq ) characterizes the effect of interstitial solid solution elements on lattice resistance.

[0043] The carbon equivalent (C eq ) is calculated as shown in formula (4), the oxygen equivalent (O eq ) The calculation method is shown in formula (5).

[0044]

[0045] Among them, C is the content percentage of C element, Mn is the content percentage of Mn element, Cr is the content percentage of Cr element, Mo is the content percentage of Mo element, V is the content percentage of V element, Ni is the content percentage of Ni element, Cu is the content percentage of Cu element, O is the content percentage of O element, and N is the content percentage of N element.

[0046] S2. Establishment of temperature correlation index prediction model,

[0047] The effects of substitutional solid solution elements and interstitial solid solution elements on lattice resistance are different. Generally speaking, as the content of substitutional solid solution elements increases, the lattice resistance increases, the temperature sensitivity increases, and the temperature correlation index increases, such as Figure 2 As shown in Figure 2, with the increase of interstitial solid solution element content, the activation volume decreases, the temperature sensitivity increases, and the temperature correlation index increases, as shown in Figure 2. Figure 3 Based on the effect of substitutional solid solution elements and interstitial solid solution elements on lattice resistance, the chemical composition and temperature correlation index T is obtained. 0 The correlation model.

[0048] The specific form of the temperature correlation index prediction model is as follows: Figure 4 shown.

[0049]

[0050] Among them, T 0 is the temperature dependence index, C eq is carbon equivalent, O eq is the oxygen equivalent.

[0051] The present invention starts from the crack arrest behavior of high-strength steel thick plate, based on the analysis of the thermal activation mechanism of dislocation, comprehensively considers the effects of substitutional solid solution elements and interstitial solid solution elements on lattice resistance, and proposes a method based on carbon equivalent (C eq ) and oxygen equivalent (O eq ) characterizes the temperature dependence index T of chemical elements 0 The influence of the model is analyzed and a prediction equation is given, which has the advantages of clear physical mechanism, concise equation form and high prediction accuracy.

[0052] The present invention also proposes a temperature correlation index T 0The prediction model is used to obtain the crack arrest toughness K ca Specifically, based on the thermal activation theory, the temperature correlation index T is determined. 0 And temperature correlation coefficient K 0 The correlation between them.

[0053] Crack arrest toughness K ca With test temperature T K The correlation formula between them is as follows:

[0054] .

[0055] For marine arrest steel, the temperature dependence is related to the short-range barrier, namely the temperature dependence index T 0 And temperature correlation coefficient K 0 The values ​​of are closely related to the short-range barrier represented by the lattice resistance, so the temperature correlation index T can be inferred. 0 And temperature correlation coefficient K 0 Based on the existing thermal activation theory, it can be deduced that for the main chemical components at 0.355≤C eq ≤0.493,0.030≤O eq Crack arrest steel, temperature dependence index T ≤ 0.067 0 And temperature correlation coefficient K 0 The correlation between Figure 5 shown.

[0056]

[0057] Then, by measuring the chemical composition of the steel plate, the carbon equivalent (C eq ) and oxygen equivalent (O eq ), if the values ​​of these two parameters satisfy 0.355≤C eq ≤0.493,0.030≤O eq ≤0.067, the temperature correlation index T can be further calculated by formula (6): 0 , and then according to equation (7) and equation (1), the crack arrest toughness K at -10°C can be obtained ca value.

[0058] The temperature correlation index prediction model of the present invention can be used to reasonably design the composition of the material during the development stage of the shipbuilding high-strength steel thick plate material, and the temperature correlation index K 0 Prediction model to obtain the crack arrest toughness K ca In addition, in the process of production quality control and crack arrest performance evaluation of high-strength steel thick plates for ships, the carbon equivalent (C eq) and oxygen equivalent (O eq ), and further calculated by formula (6) to obtain the temperature correlation index T 0 , the temperature correlation coefficient K is obtained by formula (7) 0 , the crack arrest toughness K at -10℃ can be obtained ca The value can be obtained to quickly evaluate whether the crack arrest performance of the steel plate meets the requirements of the UR W31 specification, without the need to conduct a large-scale gradient temperature double tensile test, which can effectively reduce costs and improve efficiency.

[0059] The high-strength steel thick plate described in the present invention has a thickness of 50-95 mm.

[0060] Example 1

[0061] 1. According to UR W31 "YP47 thick plate and brittle crack arrest plate", a gradient temperature double tensile test was carried out on a typical batch of shipbuilding high-strength steel thick plates, and the temperature correlation index T of the steel plate was measured. 0 , the results are shown in Table 1.

[0062] Table 1 Temperature correlation index T 0 Test Results

[0063]

[0064] 2. Chemical composition analysis was carried out on the shipbuilding high-strength steel thick plate, and the contents of the main elements were measured. The carbon equivalent (C eq ) and oxygen equivalent (O eq ), and the results are shown in Table 2.

[0065] Table 2 Carbon equivalent (C eq ) and oxygen equivalent (O eq ) Test Results

[0066]

[0067] 3. Substituting the data in Table 2 into formula (6), the comparison between the calculated values ​​and the measured values ​​in Table 1 is shown in Table 3 and Figure 6 It can be seen that the deviation between the calculated value obtained by the prediction model of the present invention and the measured value obtained by the gradient temperature type double tensile test is no more than ±10%, indicating that the prediction model proposed by the present invention can effectively predict the temperature correlation index T of the shipbuilding high-strength steel thick plate. 0 .

[0068] Table 3 Temperature correlation index T 0 Comparison of calculated and measured values

[0069]

[0070] The present invention proposes to use carbon equivalent (C eq ) and oxygen equivalent (O eq ) characterizes the temperature dependence index T of chemical elements 0 The influence of the temperature on the crack arrest toughness K can be obtained without conducting a large-scale gradient temperature double tensile test. ca value.

[0071] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for establishing a prediction model for the temperature correlation index of crack arrest toughness of high-strength steel thick plates for ships based on chemical composition, characterized in that: The steps include: S1. Analysis of main influencing factors, The crack arrest steel for high-strength steel thick plates for ships is ferritic steel with a body-centered cubic structure. The short-range obstacle in the dislocation sliding process is mainly the Pierre-Nelson force. The carbon equivalent (C eq ) characterizes the effect of substitutional solid solution elements on lattice resistance, and the oxygen equivalent (O eq ) characterizes the effect of interstitial solid solution elements on lattice resistance; S2. Establishment of temperature correlation index prediction model, As the content of substitutional solid solution elements increases, the lattice resistance increases, the temperature sensitivity increases, and the temperature correlation index increases. As the content of interstitial solid solution elements increases, the activation volume decreases, the temperature sensitivity increases, and the temperature correlation index increases. Based on the effects of substitutional solid solution elements and interstitial solid solution elements on the lattice resistance, the correlation model between chemical composition and temperature correlation index T0 is obtained as follows: ， Where T0 is the temperature correlation index, C eq is carbon equivalent, O eq is the oxygen equivalent.

2. The method for establishing a temperature correlation index prediction model according to claim 1, characterized in that: The carbon equivalent (C eq ) is calculated as: ， Among them, C is the content percentage of C element, Mn is the content percentage of Mn element, Cr is the content percentage of Cr element, Mo is the content percentage of Mo element, V is the content percentage of V element, Ni is the content percentage of Ni element, and Cu is the content percentage of Cu element.

3. The method for establishing a temperature correlation index prediction model according to claim 1, characterized in that: The oxygen equivalent (O eq ) is calculated as: ， Wherein, C is the content percentage of C element, O is the content percentage of O element, and N is the content percentage of N element.

4. A prediction model for the temperature correlation index of crack arrest toughness of high-strength steel thick plates for ships based on chemical composition, characterized in that: The temperature correlation index prediction model is constructed by using the method for establishing the temperature correlation index prediction model described in any one of claims 1 to 3.

5. A prediction model for the temperature correlation index of crack arrest toughness of high-strength steel thick plates for shipbuilding based on chemical composition in obtaining the crack arrest toughness K ca The application is characterized in that The method for establishing the temperature correlation index prediction model described in any one of claims 1 to 3 and / or the prediction model described in claim 4 are adopted.

6. The prediction model for crack arrest toughness temperature correlation index of high-strength shipbuilding steel thick plate based on chemical composition according to claim 5 is used to obtain the crack arrest toughness K ca The application is characterized in that Based on the thermal activation theory, the correlation between the temperature correlation index T0 and the temperature correlation coefficient K0 is determined; the crack arrest toughness K at -10°C is obtained according to the relationship between the temperature correlation index T0 and the temperature correlation coefficient K0. ca .

7. The prediction model for crack arrest toughness temperature correlation index of high-strength steel thick plate for shipbuilding based on chemical composition according to claim 6 is used to obtain the crack arrest toughness K ca The application is characterized in that The correlation between the temperature correlation index T0 and the temperature correlation coefficient K0 is as follows: 。

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