Stress corrosion resistant anchor rod steel and method of making and using same

Abstract

The present application relates to the technical field of low alloy steel, and particularly relates to a stress corrosion resistant anchor rod steel and a preparation method and application thereof. The stress corrosion resistant anchor rod steel comprises the following components in percentage by mass: C 0.1% to 0.25%, Si 0.25% to 0.35%, Mn 0.5% to 0.7%, P≤0.03%, S≤0.03%, Ni 1% to 2%, Cu 0.4% to 0.5%, Cr 0.9% to 2%, V 0.06% to 0.1%, and the balance of Fe and inevitable impurities. The present application adds and adjusts the content of alloy elements such as Ni, Cu and Cr within a certain range on the basis of the traditional anchor rod material, and further controls 2.5%≤Ni+Cr+Cu≤4.5%, 2.5<Ni / Cu<4, 0.7<Ni / Cr<1.5, so that the stress corrosion resistance of the anchor rod steel can be significantly improved.

Description

Technical Field

[0001] This invention relates to the field of low alloy steel technology, and in particular to a stress corrosion resistant anchor steel, its preparation method, and its application. Background Technology

[0002] As mining depths increase and the operating environment deteriorates, many coal mines experience premature anchoring failure. Field investigations and laboratory studies have revealed that most premature anchoring failures are caused by corrosion. Stress corrosion, a major form of anchor failure in mining environments, can easily lead to sudden accidents, seriously threatening the safety and reliability of mine operations.

[0003] The service environment for anchor bolts in mines is complex, with a low pH value that easily leads to acidification. Chloride ions, sulfides, carbonates, and sulfates are highly corrosive, easily causing hydrogen embrittlement and stress corrosion cracking failures. Furthermore, anchor bolts in mines are subjected to axial tensile stress and lateral shear stress during service, and the stress state changes with the deformation of the surrounding rock, resulting in complex and multi-directional loads that easily reach the critical stress required for fracture. Therefore, currently available commercial mining anchor bolt steel has high stress corrosion sensitivity in mines, leading to frequent stress corrosion cracking accidents. However, traditional anchor bolt steel focuses only on improving strength, with relatively little research on stress corrosion resistance. Some common anti-corrosion measures, such as surface coatings, grouting, and cathodic protection, are still insufficient to prevent stress corrosion cracking under certain conditions, and may even increase the risk of cracking.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] One object of the present invention is to provide stress corrosion resistant anchor steel to solve the technical problems such as poor stress corrosion resistance of anchor steel in the prior art.

[0006] Another object of the present invention is to provide a method for preparing stress corrosion resistant anchor steel.

[0007] Another object of the present invention is to provide the application of stress corrosion resistant anchor steel in the preparation of mining anchors.

[0008] To achieve the above-mentioned objectives of the present invention, one aspect of the present invention provides stress corrosion resistant anchor steel, comprising the following components by mass percentage:

[0009] C 0.1%–0.25%, Si 0.25%–0.35%, Mn 0.5%–0.7%, P≤0.03%, S≤0.03%, Ni 1%–2%, Cu 0.4%–0.5%, Cr 0.9%–2%, V 0.06%–0.1%, with the balance being Fe and unavoidable impurities.

[0010] In a specific embodiment of the present invention, the mass percentages of Ni, Cr, and Cu in the stress corrosion resistant anchor steel satisfy the following: 2.5% ≤ Ni + Cr + Cu ≤ 4.5%.

[0011] In a specific embodiment of the present invention, the mass percentages of Ni, Cr and Cu in the stress corrosion resistant anchor steel satisfy the following conditions: 2.5 < Ni / Cu < 4, 0.7 < Ni / Cr < 1.5.

[0012] In a specific embodiment of the present invention, the stress corrosion resistant anchor steel further includes Sb. More specifically, the mass percentage of Sb in the stress corrosion resistant anchor steel is 0.05% to 0.12%.

[0013] In a specific embodiment of the present invention, the stress corrosion resistant anchor steel has a room temperature tensile strength ≥940MPa, a yield strength ≥850MPa, and an elongation ≥14%.

[0014] The present invention also provides a method for preparing any one of the stress corrosion resistant anchor steels described above, comprising the following steps:

[0015] Steel ingots are obtained by smelting and casting according to the alloy composition ratio; then the steel ingots are forged, homogenized, and then rolled.

[0016] In a specific embodiment of the present invention, the initial forging temperature is 1150-1250°C and the final forging temperature is 800-900°C.

[0017] In a specific embodiment of the present invention, the homogenization process includes: a temperature of 1150–1250°C and a holding time of ≥2 hours.

[0018] In a specific embodiment of the present invention, during the rolling process, the initial rolling temperature is 1010–1100°C, the final rolling temperature is 800–880°C, and the rolling reduction rate is 60%–70%. Furthermore, air cooling is performed after rolling.

[0019] This invention also provides a method for controlling the stress corrosion resistance of anchor bolt steel, comprising the following steps:

[0020] The content of Ni, Cu, and Cr in the anchor bolt steel formulation is adjusted so that the mass fractions of Ni, Cu, and Cr are 1%–2%, 0.4%–0.5%, and 0.9%–2%, respectively.

[0021] In a specific embodiment of the present invention, the contents of Ni, Cu, and Cr are adjusted to satisfy at least one of the following characteristics:

[0022] (1)2.5%≤Ni+Cr+Cu≤4.5%;

[0023] (2)2.5<Ni / Cu<4, 0.7<Ni / Cr<1.5.

[0024] In a specific embodiment of the present invention, the anchor steel further includes the following components by mass percentage:

[0025] C 0.1%–0.25%, Si 0.25%–0.35%, Mn 0.5%–0.7%, P≤0.03%, S≤0.03%, V 0.06%–0.1%, with the balance being Fe and unavoidable impurities.

[0026] The present invention also provides the application of any of the above-described stress corrosion resistant anchor steels in the preparation of mining anchors.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] (1) Based on traditional anchor materials, this invention adds and adjusts the content of alloying elements such as Ni, Cu and Cr within a certain range, and further controls 2.5%≤Ni+Cr+Cu≤4.5%, 2.5<Ni / Cu<4, 0.7<Ni / Cr<1.5, which can significantly improve the stress corrosion resistance of anchor steel.

[0029] (2) The anchor steel of the present invention significantly reduces the Ni content and material cost while still significantly improving the stress corrosion resistance of the anchor steel, thus combining economy and excellent performance.

[0030] (3) The anchor bolts made with the anchor bolt steel of the present invention have a stress corrosion sensitivity of 37% to 98% lower than those made with commercial anchor bolt steel in the mining environment. They have excellent comprehensive performance, meet the current service requirements for stress corrosion resistant anchor bolt steel, have important engineering practical value, and are suitable for industrial production and promotion. Attached Figure Description

[0031] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0032] Figure 1 This is a microstructure diagram of the anchor steel provided in Embodiment 1 of the present invention;

[0033] Figure 2 This is a microstructure diagram of the anchor steel provided in Embodiment 2 of the present invention;

[0034] Figure 3 This is a microstructure diagram of the anchor steel provided in Embodiment 3 of the present invention;

[0035] Figure 4 This is a microstructure diagram of the anchor steel provided in Embodiment 4 of the present invention;

[0036] Figure 5 This is a microstructure diagram of the anchor steel provided in Embodiment 5 of the present invention;

[0037] Figure 6 This is a microstructure diagram of the anchor steel provided in Comparative Example 1 of the present invention;

[0038] Figure 7 This is a microstructure diagram of the anchor steel provided in Comparative Example 2 of the present invention;

[0039] Figure 8 This is a microstructure diagram of the anchor steel provided in Comparative Example 3 of the present invention;

[0040] Figure 9 This is a microstructure diagram of the anchor steel provided in Comparative Example 4 of the present invention;

[0041] Figure 10 This is a microstructure diagram of the anchor steel provided in Comparative Example 5 of the present invention;

[0042] Figure 11 This is a microstructure diagram of the anchor steel provided in Comparative Example 6 of the present invention;

[0043] Figure 12 This is a comparison diagram of the stress corrosion susceptibility of anchor steel in the embodiments and comparative examples of the present invention. Detailed Implementation

[0044] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0045] By designing alloy composition to obtain stress corrosion resistant anchor steel, the corrosion resistance of the material can be improved while ensuring comprehensive mechanical properties such as strength and toughness, thereby extending the service life of the anchor and reducing material costs. This is of great significance for improving the performance of anchor steel.

[0046] Based on this, the present invention provides stress corrosion resistant anchor steel, comprising the following components by mass percentage:

[0047] C 0.1%–0.25%, Si 0.25%–0.35%, Mn 0.5%–0.7%, P≤0.03%, S≤0.03%, Ni 1%–2%, Cu 0.4%–0.5%, Cr 0.9%–2%, V 0.06%–0.1%, with the balance being Fe and unavoidable impurities.

[0048] This invention provides an anchor steel that combines stress corrosion resistance, comprehensive mechanical properties, and cost-effectiveness through the composite regulation of elements such as Ni, Cu, and Cr, filling the gap in existing stress corrosion resistant anchor steel systems for engineering applications.

[0049] Carbon (C) is the most basic element in steel. Increasing its content can improve strength, but it can also affect the overall performance of the material. A small amount of C can form carbides with microalloying elements in steel, playing a role in second-phase strengthening and grain refinement. However, when the C content is too high, it will affect the weldability of the steel. Therefore, this invention uses 0.1% to 0.25% C, combined with certain amounts of Ni, Cu, Cr, and other elements, to ensure both the comprehensive mechanical properties and stress corrosion resistance of the anchor steel.

[0050] Mn plays a role in solid solution strengthening in steel, improving both strength and toughness. However, the Mn content should not be too high, as excessive Mn content can lead to grain coarsening and an increased tendency for temper brittleness. Therefore, this invention uses 0.5% to 0.7% Mn, combined with certain amounts of C, Ni, Cu, Cr, and other elements, to ensure both comprehensive mechanical properties and resistance to stress corrosion.

[0051] Ni is a thermodynamically stable element. From the perspective of improving the properties of the corrosion product layer, it can promote the formation of fine α-FeOOH, thereby increasing the density of the inner rust layer. Furthermore, during corrosion, it mainly accumulates in the inner rust layer in the form of NiFe2O4, giving the inner rust layer ion selectivity, effectively inhibiting the intrusion of corrosive anions, significantly improving the protective properties of the rust layer, and thus reducing material corrosion. In addition, Ni can significantly increase the self-corrosion potential, improving its corrosion resistance. However, from an economic perspective, cost control is necessary; excessively high Ni content will increase the cost of anchor steel and reduce its practicality in engineering. Therefore, this invention uses 1%–2% Ni element, combined with Cr and Cu within a certain range, to significantly improve the stress corrosion resistance of the material while reducing costs.

[0052] On the one hand, Cu can promote the passivation process, forming a rust layer on the steel surface and thus improving corrosion resistance. On the other hand, during corrosion, Cu can increase the protective properties of the rust layer. It mainly accumulates in the inner rust layer in the form of CuFeO2, which can enhance the ion-selective permeability of the rust layer and inhibit corrosive ions from entering the matrix. Furthermore, the addition of Cu can promote the formation of α-FeOOH, enhancing the thermodynamic stability of the rust layer. However, excessive Cu content can easily reduce plasticity and cause grain boundary segregation. This invention uses 0.4%–0.5% Cu, combined with certain amounts of Ni and Cr, to improve the mechanical properties and stress corrosion resistance of the material.

[0053] Cr has an accelerating film-forming effect, promoting the formation of α-FeOOH, improving the density and stability of the rust layer, and effectively improving the corrosion resistance of steel. Furthermore, Cr significantly increases the strength of steel while reducing its plasticity. This invention uses 0.9%–2% Cr, combined with certain amounts of Ni and Cu, to improve both the mechanical properties and stress corrosion resistance of the material.

[0054] V can increase the grain coarsening temperature, reduce overheating sensitivity, and improve hardenability. A small amount of V in alloy steel can refine the grains, increase strength, and improve toughness. This invention, by controlling V within the range of 0.06% to 0.1%, and combining it with other elements, aims to improve both the mechanical properties and stress corrosion resistance of the material.

[0055] Impurity elements such as phosphorus (P) and sulfur (S) tend to segregate at grain boundaries, leading to intergranular brittle fracture of the material. Therefore, it is necessary to control the P and S content in steel to a low level. Thus, in this invention, the P and S content is controlled at P ≤ 0.03% and S ≤ 0.03%.

[0056] In different embodiments, the content of each element in the stress corrosion resistant anchor steel of the present invention, expressed as a mass percentage, can be exemplarily described as follows:

[0057] The content of C can be 0.1%, 0.12%, 0.15%, 0.18%, 0.2%, 0.22%, 0.25%, or any combination thereof;

[0058] The Si content can be 0.25%, 0.26%, 0.28%, 0.3%, 0.32%, 0.34%, 0.35%, or any combination thereof;

[0059] The Mn content can be 0.5%, 0.52%, 0.55%, 0.58%, 0.6%, 0.62%, 0.65%, 0.68%, 0.7%, or any combination thereof;

[0060] The Ni content can be 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, or any combination thereof;

[0061] The Cu content can be 0.4%, 0.41%, 0.42%, 0.43%, 0.44%, 0.45%, 0.46%, 0.47%, 0.48%, 0.49%, 0.5%, or any combination thereof;

[0062] The Cr content can be 0.9%, 1%, 1.2%, 1.4%, 1.5%, 1.55%, 1.6%, 1.8%, 2%, or any combination thereof.

[0063] The content of V can be 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, or any combination thereof;

[0064] The content of P can be ≤0.03%, ≤0.025%, ≤0.020%, ≤0.015%, ≤0.010%, or a range consisting of any two of these upper limits;

[0065] The content of S can be ≤0.03%, ≤0.025%, ≤0.020%, ≤0.015%, ≤0.010%, or a range consisting of any two of these upper limits.

[0066] In a specific embodiment of the present invention, the mass percentages of Ni, Cr, and Cu in the stress corrosion resistant anchor steel satisfy the following: 2.5% ≤ Ni + Cr + Cu ≤ 4.5%.

[0067] In different embodiments, the sum of the mass percentages of Ni, Cr, and Cu can be 2.5%, 2.8%, 3%, 3.2%, 3.5%, 3.8%, 4%, 4.2%, 4.5%, or any combination thereof.

[0068] In a specific embodiment of the present invention, the mass percentages of Ni, Cr, and Cu in the stress corrosion resistant anchor steel satisfy the following conditions: 2.5 < Ni / Cu < 4, 0.7 < Ni / Cr < 1.5.

[0069] In different embodiments, the mass percentage ratio of Ni to Cu can be a range of 2.51, 2.55, 2.6, 2.8, 3, 3.2, 3.5, 3.8, 3.9, 3.92, 3.95, 3.99, or any combination thereof; the mass percentage ratio of Ni to Cr can be a range of 0.71, 0.75, 0.8, 0.85, 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.49, or any combination thereof.

[0070] This invention achieves its goals by comprehensively regulating the content of Ni, Cr, and Cu elements, ensuring that each element's content meets the aforementioned requirements. Firstly, Ni, Cu, and Cr all promote the formation of α-FeOOH, enhancing the thermodynamic stability of the rust layer and improving its protective properties. Secondly, Ni exists primarily in the rust layer as NiFe₂O₄, and Cu primarily as CuFeO₂. Due to their electronegativity, these elements repel each other, enhancing the ion-selective permeability of the rust layer and resisting the erosion of corrosive ions in the environment, thereby inhibiting the corrosion reaction. Finally, the ratio of Ni, Cu, and Cr improves the material's mechanical properties. Therefore, through the synergistic effect of Ni, Cr, and Cu elements, the material's resistance to stress corrosion is effectively improved, its overall mechanical properties are enhanced, and material costs are reduced.

[0071] In a specific embodiment of the present invention, the stress corrosion resistant anchor steel further includes Sb. More specifically, the mass percentage of Sb in the stress corrosion resistant anchor steel is 0.05% to 0.12%.

[0072] In different embodiments, the mass percentage of Sb in the stress corrosion resistant anchor steel can be 0.05%, 0.06%, 0.08%, 0.1%, 0.12%, or any combination thereof.

[0073] On the one hand, sulfur (Sb) can significantly improve the acid corrosion resistance of low-alloy steel by inhibiting electrochemical reactions. On the other hand, Sb mainly accumulates in the inner rust layer in the form of Sb₂O₅, making the inner rust layer denser and enhancing its barrier effect against corrosive anions. In addition, Sb can also promote the enrichment of Ni and Cu in the rust layer, enhancing the anion-selective permeability of the rust layer.

[0074] In a specific embodiment of the present invention, the stress corrosion resistant anchor steel comprises the following components by mass percentage:

[0075] C 0.1%–0.25%, Si 0.25%–0.35%, Mn 0.5%–0.7%, P≤0.03%, S≤0.03%, Ni 1%–2%, Cu 0.4%–0.5%, Cr 0.9%–2%, V 0.06%–0.1%, Sb 0%–0.12%, with the balance being Fe and unavoidable impurities.

[0076] In a specific embodiment of the present invention, the room temperature tensile strength of the stress corrosion resistant anchor steel is ≥940MPa, the yield strength is ≥850MPa, and the elongation is ≥14%.

[0077] In different embodiments, the room temperature tensile strength of the stress corrosion resistant anchor steel can be ≥940MPa, ≥950MPa, ≥960MPa, ≥970MPa, ≥978MPa, or any two lower limits thereof; the room temperature yield strength can be ≥850MPa, ≥860MPa, ≥870MPa, ≥880MPa, ≥890MPa, ≥900MPa, ≥910MPa, or any two lower limits thereof; the room temperature elongation can be ≥14%, ≥14.2%, ≥14.4%, ≥14.6%, ≥14.8%, ≥15%, ≥15.2%, or any two lower limits thereof.

[0078] In a specific embodiment of the present invention, the stress corrosion susceptibility of the stress corrosion resistant anchor steel in the simulated solution of the underground coal mine environment is ≤15%, such as ≤10%.

[0079] In different implementations, the stress corrosion susceptibility of the stress corrosion resistant anchor steel in a simulated coal mine environment solution can be ≤10%, ≤8%, ≤5%, ≤2%, ≤1%, or a range consisting of any two upper limits. The stress corrosion susceptibility test includes: analyzing the stress-strain curve of the stress corrosion resistant anchor steel in a simulated coal mine environment solution, and quantifying the stress corrosion susceptibility of the anchor steel by elongation loss. Specifically, through I... δ Quantifying stress corrosion susceptibility, I δ =(1-δ s / δ0)×100%, where δ0 represents the elongation of the anchor bolt steel in air, δ s This indicates the elongation of the anchor steel in the simulated solution.

[0080] The stress corrosion resistant anchor steel of the present invention can not only ensure the comprehensive mechanical properties such as strength and toughness through the composite control of various elements, but also effectively improve the stress corrosion resistance of the anchor steel. Its stress corrosion sensitivity in the mining environment is reduced by 37% to 98% compared with commercial anchor steel.

[0081] This invention also provides a method for preparing any of the above-mentioned stress corrosion resistant anchor steels, comprising the following steps:

[0082] Steel ingots are obtained by smelting and casting according to the alloy composition ratio; then the steel ingots are forged, homogenized, and then rolled.

[0083] In a specific embodiment of the present invention, smelting includes vacuum melting. In actual operation, the smelting conditions can be adjusted according to conventional operation.

[0084] In a specific embodiment of the present invention, during forging, the initial forging temperature is 1150-1250℃, and the final forging temperature is 800-900℃.

[0085] In different embodiments, the initial forging temperature can be a range of 1150°C, 1180°C, 1200°C, 1220°C, 1250°C or any combination thereof; the final forging temperature can be a range of 800°C, 820°C, 850°C, 880°C, 900°C or any combination thereof.

[0086] In a specific embodiment of the present invention, the homogenization process includes: a temperature of 1150-1250°C and a holding time of ≥2h.

[0087] In different implementations, the homogenization temperature can be 1150℃, 1180℃, 1200℃, 1220℃, 1250℃ or any combination thereof; the holding time can be 2h, 4h, 6h, 8h, etc.

[0088] In a specific embodiment of the present invention, during rolling, the initial rolling temperature is 1010–1100°C, the final rolling temperature is 800–880°C, and the rolling reduction rate is 60%–70%. Furthermore, air cooling is performed after rolling.

[0089] In different embodiments, the initial rolling temperature can be a range of 1010°C, 1020°C, 1050°C, 1080°C, 1100°C, or any combination thereof; the final rolling temperature can be a range of 800°C, 820°C, 850°C, 880°C, or any combination thereof; the rolling process can be multi-pass rolling, with a total reduction rate of 60%, 62%, 65%, 68%, 70%, or any combination thereof.

[0090] This invention also provides a method for controlling the stress corrosion resistance of anchor bolt steel, comprising the following steps:

[0091] The content of Ni, Cu, and Cr in the anchor bolt steel formulation is adjusted so that the mass fractions of Ni, Cu, and Cr are 1%–2%, 0.4%–0.5%, and 0.9%–2%, respectively.

[0092] In a specific embodiment of the present invention, the contents of Ni, Cu, and Cr are adjusted to satisfy at least one of the following characteristics:

[0093] (1)2.5%≤Ni+Cr+Cu≤4.5%;

[0094] (2)2.5<Ni / Cu<4, 0.7<Ni / Cr<1.5.

[0095] In a specific embodiment of the present invention, the anchor steel further includes the following components by mass percentage:

[0096] C 0.1%–0.25%, Si 0.25%–0.35%, Mn 0.5%–0.7%, P≤0.03%, S≤0.03%, V 0.06%–0.1%, with the balance being Fe and unavoidable impurities.

[0097] In a specific embodiment of the present invention, the anchor steel further includes the following components by mass percentage:

[0098] C 0.1%–0.25%, Si 0.25%–0.35%, Mn 0.5%–0.7%, P≤0.03%, S≤0.03%, V 0.06%–0.1%, Sb 0%–0.12%, with the balance being Fe and unavoidable impurities.

[0099] This invention also provides the application of any of the above-mentioned stress corrosion resistant anchor steels in the preparation of mining anchors.

[0100] This invention, through the composite control of alloying elements, can not only ensure the comprehensive mechanical properties such as strength and toughness, but also effectively improve the stress corrosion resistance of anchor steel, thereby extending the service life of anchor materials. This is of great significance for ensuring safe production in underground coal mines and has important engineering practical value.

[0101] Example 1

[0102] This embodiment provides a stress corrosion resistant anchor steel, comprising the following components by mass percentage: C 0.21%, Mn 0.67%, Si 0.31%, P 0.006%, S 0.003%, Ni 1.47%, Cu 0.44%, Cr 0.99%, V 0.09%, with the remainder being Fe and unavoidable impurities.

[0103] The mass fractions of Ni, Cr, and Cu satisfy the following conditions: Ni + Cr + Cu = 2.9%, Ni / Cu = 3.34, and Ni / Cr = 1.48.

[0104] The specific preparation method may include the following steps:

[0105] (1) Steel ingots are prepared by melting the above chemical composition in a vacuum melting furnace;

[0106] (2) Heat the steel ingot to 1200℃, hold it for 2 hours and then forge it. The final forging temperature is 850℃. Then roll it. The rolling process includes: heating and homogenizing at 1200℃ for 2 hours, starting rolling at 1050-1060℃, rolling through multiple passes, and finishing rolling at 840-850℃ with a reduction rate of 67%. After rolling, air cool it.

[0107] The microstructure diagram of the anchor steel obtained in this embodiment is shown below. Figure 1 The grain size is grade 7-8 (GB / T 6394-2017), and the structure is uniform with fine grains.

[0108] Example 2

[0109] This embodiment provides a stress corrosion resistant anchor steel comprising the following components by mass percentage: C 0.13%, Mn 0.59%, Si 0.27%, P 0.005%, S 0.003%, Ni 1.48%, Cu 0.44%, Cr 1.81%, Sb 0.08%, V 0.07%, with the remainder being Fe and unavoidable impurities.

[0110] The mass fractions of Ni, Cr, and Cu satisfy the following conditions: Ni + Cr + Cu = 3.73%, Ni / Cu = 3.36, and Ni / Cr = 0.82.

[0111] For the specific preparation method, please refer to Example 1.

[0112] The microstructure diagram of the anchor steel obtained in this embodiment is shown below. Figure 2 The grain size is 7-8, and the structure is uniform with fine grains.

[0113] Example 3

[0114] This embodiment provides a stress corrosion resistant anchor steel comprising the following components by mass percentage: C 0.15%, Mn 0.63%, Si 0.3%, P 0.006%, S 0.003%, Ni 1.5%, Cu 0.44%, Cr 1.79%, V 0.08%, with the remainder being Fe and unavoidable impurities.

[0115] The mass fractions of Ni, Cr, and Cu satisfy the following conditions: Ni + Cr + Cu = 3.73%, Ni / Cu = 3.41, and Ni / Cr = 0.84.

[0116] For the specific preparation method, please refer to Example 1.

[0117] The microstructure diagram of the anchor steel obtained in this embodiment is shown below. Figure 3 The grain size is 7-8, and the structure is uniform with fine grains.

[0118] Example 4

[0119] This embodiment provides a stress corrosion resistant anchor steel, comprising the following components by mass percentage:

[0120] The composition is: C 0.22%, Mn 0.64%, Si 0.30%, P 0.005%, S 0.003%, Ni 1.05%, Cu 0.45%, Cr 0.94%, V 0.09%, with the remainder being Fe and unavoidable impurities.

[0121] The mass fractions of Ni, Cr, and Cu satisfy the following conditions: Ni + Cr + Cu = 2.44%, Ni / Cu = 2.33, and Ni / Cr = 1.12.

[0122] For the specific preparation method, please refer to Example 1.

[0123] The microstructure diagram of the anchor steel obtained in this embodiment is shown below. Figure 4 The grain size is 7-8, and the structure is uniform with fine grains.

[0124] Example 5

[0125] This embodiment provides a stress corrosion resistant anchor steel, comprising the following components by mass percentage:

[0126] The composition consists of 0.17% C, 0.68% Mn, 0.28% Si, 0.007% P, 0.002% S, 1.97% Ni, 0.43% Cu, 1.26% Cr, and 0.09% V, with the remainder being Fe and unavoidable impurities.

[0127] The mass fractions of Ni, Cr, and Cu satisfy the following conditions: Ni + Cr + Cu = 3.66%, Ni / Cu = 4.58, and Ni / Cr = 1.56.

[0128] For the specific preparation method, please refer to Example 1.

[0129] The microstructure diagram of the anchor steel obtained in this embodiment is shown below. Figure 5 The grain size is 7-8, and the structure is uniform with fine grains.

[0130] Comparative Example 1

[0131] Comparative Example 1 provides an anchor bolt steel comprising the following components by mass percentage:

[0132] The composition consists of 0.25% C, 1.34% Mn, 0.37% Si, 0.007% P, 0.003% S, with the remainder being Fe and unavoidable impurities.

[0133] For the specific preparation method, please refer to Example 1.

[0134] The microstructure of the anchor steel obtained in Comparative Example 1 is shown in the figure. Figure 6 The grain size is grade 6-7.

[0135] Comparative Example 2

[0136] Comparative Example 2 provides an anchor bolt steel comprising the following components by mass percentage:

[0137] The composition is 0.21% C, 0.75% Mn, 0.65% Si, 0.005% P, 0.003% S, 0.49% Cr, with the remainder being Fe and unavoidable impurities.

[0138] For the specific preparation method, please refer to Example 1.

[0139] The microstructure of the anchor steel obtained in Comparative Example 2 is shown in the figure. Figure 7 The grain size is grade 6-7.

[0140] Comparative Example 3

[0141] Comparative Example 3 provides an anchor bolt steel comprising the following components by mass percentage:

[0142] The composition is: C 0.23%, Mn 0.8%, Si 0.65%, P 0.005%, S 0.004%, Cu 0.43%, Cr 0.5%, with the remainder being Fe and unavoidable impurities.

[0143] For the specific preparation method, please refer to Example 1.

[0144] The microstructure of the anchor steel obtained in Comparative Example 3 is shown in the figure. Figure 8 The grain size is grade 6-7.

[0145] Comparative Example 4

[0146] Comparative Example 4 provides an anchor bolt steel comprising the following components by mass percentage:

[0147] The composition is: C 0.15%, Mn 0.75%, Si 0.6%, P 0.005%, S 0.003%, Ni 0.98%, Cu 0.43%, Cr 0.5%, V 0.08%, with the remainder being Fe and unavoidable impurities.

[0148] For the specific preparation method, please refer to Example 1.

[0149] The microstructure of the anchor steel obtained in Comparative Example 4 is shown in the figure. Figure 9 The grain size is grade 6-7.

[0150] Comparative Example 5

[0151] Comparative Example 5 provides an anchor bolt steel comprising the following components by mass percentage:

[0152] C 0.15%, Mn 0.65%, Si 0.31%, P 0.005%, S 0.003%, Ni 3.4%, Cu 0.55%, Cr 0.5%, V 0.08%, with the remainder being Fe and unavoidable impurities.

[0153] For the specific preparation method, please refer to Example 1.

[0154] The microstructure of the anchor steel obtained in Comparative Example 5 is shown in the figure. Figure 10 The grain size is grade 6-7.

[0155] Comparative Example 6

[0156] Comparative Example 6 provides an anchor bolt steel comprising the following components by mass percentage:

[0157] The composition consists of 0.18% C, 0.67% Mn, 0.35% Si, 0.005% P, 0.002% S, 1.2% Ni, 0.44% Cu, 0.88% Cr, with the remainder being Fe and unavoidable impurities.

[0158] For the specific preparation method, please refer to Example 1.

[0159] The microstructure of the anchor steel obtained in Comparative Example 6 is shown in the figure. Figure 11 The grain size is grade 6-7.

[0160] Experimental Example 1

[0161] The mechanical properties of the anchor steel obtained in different embodiments and comparative examples are shown in Table 1.

[0162] Table 1. Test results of mechanical properties of different anchor bolt steels

[0163] serial number Tensile strength (MPa) Yield strength (MPa) Elongation (%) Example 1 958 879 15.2 Example 2 975 910 14.9 Example 3 968 912 14.6 Example 4 940 863 14 Example 5 962 892 14.4 Comparative Example 1 817 706 15.5 Comparative Example 2 834 716 15 Comparative Example 3 874 758 13.9 Comparative Example 4 918 836 14.4 Comparative Example 5 934 852 15.3 Comparative Example 6 905 824 14.7

[0164] Experiment Example 2

[0165] Stress corrosion tests were conducted on the anchor steel obtained in the examples and comparative examples, respectively. The strain rate of the slow strain rate tensile test was 10. -6 s -1 The solution is a simulated solution for the underground environment of a coal mine, and its composition is shown in Table 2.

[0166] Table 2. Composition of the simulated underground coal mine environment solution (unit: g / L)

[0167] Solution components pH value NaCl KNO3 Na2SO4 NaHCO3 NaHSO3 Coal Mine Underground Environment Simulation Fluid 5 0.25 0.1 0.5 1 1

[0168] The stress-strain susceptibility (SCC) of different anchor steels was analyzed by stress-strain curve analysis, and the SCC susceptibility of the anchor steels was quantified by elongation loss. The results are shown in Table 3 and... Figure 12 As shown.

[0169] The test method refers to GB / T 15970.7:I δ =(1-δ s / δ0)×100% (where δ0 represents the elongation of the anchor bolt steel in air, δ s (This represents the elongation of the anchor steel in the simulated solution).

[0170] Table 3. Test results of stress corrosion susceptibility of different anchor bolt steels.

[0171] serial number Stress corrosion susceptibility value Example 1 6.17％ Example 2 0.5％ Example 3 3.6％ Example 4 14.2％ Example 5 12.6％ Comparative Example 1 22.53％ Comparative Example 2 29.8％ Comparative Example 3 28.9％ Comparative Example 4 28.7％ Comparative Example 5 15.65％ Comparative Example 6 13.2％

[0172] From Table 3 and Figure 12 As can be seen from the above, the anchor steel of the present invention has a lower stress corrosion susceptibility than the anchor steel of the comparative example. By evaluating the reduction in stress corrosion susceptibility of the examples compared to the comparative example, it can be seen that the stress corrosion resistance of the examples is significantly improved compared to the comparative example, indicating that the stress corrosion cracking resistance of the anchor steel can be effectively improved by controlling the alloying elements.

[0173] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. Stress corrosion resistant anchor steel, characterized in that, Includes the following components by mass percentage: C 0.1%~0.25%, Si 0.25%~0.35%, Mn 0.5%~0.67%, P≤0.03%, S≤0.03%, Ni 1%~2%, Cu 0.4%~0.5%, Cr 0.9%~2%, V 0.06%~0.1%, with the balance being Fe and unavoidable impurities; The mass percentages of Ni, Cr, and Cu satisfy the following conditions: 2.5% ≤ Ni + Cr + Cu ≤ 4.5%, 2.5 < Ni / Cu < 4, 0.7 < Ni / Cr < 1.5; The stress corrosion resistant anchor steel has a room temperature tensile strength ≥940MPa, a yield strength ≥850MPa, and an elongation ≥14%; the stress corrosion susceptibility of the stress corrosion resistant anchor steel in a simulated underground coal mine environment is ≤15%; the stress-strain curve analysis of the stress corrosion resistant anchor steel in a simulated underground coal mine environment, and the elongation loss quantifies the stress corrosion susceptibility of the anchor steel, are performed using a slow strain rate tensile test with a strain rate of 10... -6 s -1 The simulated underground coal mine environment had a pH of 5, a NaCl concentration of 0.25 g / L, a KNO3 concentration of 0.1 g / L, a Na2SO4 concentration of 0.5 g / L, a NaHCO3 concentration of 1 g / L, and a NaHSO3 concentration of 1 g / L.

2. The stress corrosion resistant anchor steel according to claim 1, characterized in that, It also includes Sb.

3. The stress corrosion resistant anchor steel according to claim 1, characterized in that, In stress corrosion resistant anchor steel, the mass percentage of Sb is 0.05% to 0.12%.

4. The method for preparing stress corrosion resistant anchor steel according to any one of claims 1 to 3, characterized in that, Includes the following steps: Steel ingots are obtained by smelting and casting according to the alloy composition ratio; then the steel ingots are forged, homogenized, and then rolled.

5. The method for preparing stress corrosion resistant anchor steel according to claim 4, characterized in that, It has at least one of the following characteristics: (1) In the forging process, the initial forging temperature is 1150-1250℃ and the final forging temperature is 800-900℃; (2) The homogenization process includes: a temperature of 1150-1250℃ and a holding time of ≥2h; (3) In the rolling process, the initial rolling temperature is 1010-1100℃, the final rolling temperature is 800-880℃, and the rolling reduction rate is 60%-70%.

6. A method for controlling the stress corrosion resistance of anchor bolt steel, characterized in that, Includes the following steps: The content of Ni, Cu, and Cr in the anchor bolt steel formulation is adjusted so that the mass fractions of Ni, Cu, and Cr are 1%–2%, 0.4%–0.5%, and 0.9%–2%, respectively. The content of Ni, Cu, and Cr is adjusted to meet the following characteristics: (1) 2.5%≤Ni+Cr+Cu≤4.5%; (2) 2.5<Ni / Cu<4, 0.7<Ni / Cr<1.5; The anchor steel also includes the following components by mass percentage: C 0.1%~0.25%, Si 0.25%~0.35%, Mn 0.5%~0.67%, P≤0.03%, S≤0.03%, V 0.06%~0.1%, with the balance being Fe and unavoidable impurities.

7. The application of the stress corrosion resistant anchor steel according to any one of claims 1 to 3 in the preparation of mining anchors.

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