High-strength bolt and preparation method thereof

Abstract

The invention relates to the technical field of bolt machining methods, and provides a high-strength bolt and a preparation method thereof.The high-strength bolt is formed by machining a steel billet, the steel billet is composed of an iron matrix and a reinforcing phase, and the iron matrix is composed of, by weight, 0.3%-0.5% of C, 0.17%-0.37% of Si, 0.5%-0.8% of Mn, 0.05%-0.25% of Cr, 0.1%-0.3% of Ni, 0.2%-0.25% of Cu and the balance iron and inevitable impurities; the reinforcing phase is an amorphous alloy material, and the mass ratio of the iron matrix to the reinforcing phase is 100: (1-20). Through the technical scheme, the problem of low bolt strength in related technologies is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of bolt processing methods, and in particular to a high-strength bolt and a preparation method thereof. Background Art

[0002] In the field of modern engineering, with the continuous emergence of various large-scale and complex structural projects, and the increasingly stringent requirements for engineering safety, reliability and durability, the strength of bolts, as key connecting elements, has become increasingly necessary.

[0003] Traditional bolts often expose the defect of insufficient strength when facing high-load and complex working conditions in fields such as super high-rise buildings, large bridges, heavy machinery and equipment, and aerospace. In these projects, the connection parts need to withstand huge tension, shear, pressure and various complex stress combinations. If the bolts are not strong enough, they are very likely to deform, break or loosen during long-term operation due to the inability to withstand these strong forces, resulting in connection failure, which will not only affect the normal operation of the entire structure, but may also cause serious safety accidents, resulting in huge casualties and property losses. Therefore, the development of a high-strength bolt and its preparation method has become an urgent need in the engineering field. Summary of the invention

[0004] The invention provides a high-strength bolt and a preparation method thereof, which solves the problem of low bolt strength in the related art.

[0005] The technical solution of the present invention is as follows: The present invention provides a high-strength bolt, which is processed from a steel billet, wherein the steel billet consists of an iron matrix and a reinforcement phase, wherein the iron matrix consists of the following components by weight percentage: C 0.3%-0.5%, Si 0.17%-0.37%, Mn 0.5%-0.8%, Cr 0.05%-0.25%, Ni 0.1%-0.3%, Cu 0.2%-0.25%, and the balance is iron and unavoidable impurities; The reinforcement phase is an amorphous alloy material, and the mass ratio of the iron matrix to the reinforcement phase is 100:1-20.

[0006] As a further technical solution, the mass ratio of the iron matrix to the reinforcement phase is 20:2~3.

[0007] As a further technical solution, the amorphous alloy material is composed of an iron-based amorphous alloy and a zirconium-based amorphous alloy, and the mass ratio of the iron-based amorphous alloy to the zirconium-based amorphous alloy is 10:2~3.

[0008] As a further technical solution, the iron-based amorphous alloy is composed of Fe: 44wt%~50wt%, Cr: 11wt%~17wt%, Mo: 10wt%~16wt%, C: 11wt%~17wt%, M: 1wt%~3wt%, and B: 2wt%~8wt%.

[0009] As a further technical solution, the zirconium-based amorphous alloy is composed of Zr: 59wt%~65wt%, Ti: 7wt%~13wt%, Cu: 9wt%~15wt%, Ni: 6wt%~12wt%, and M: 1wt%~3wt%.

[0010] In the present invention, the iron-based amorphous alloy and the zirconium-based amorphous alloy constitute the reinforcing phase. Mixing the two and limiting the ratio reasonably can fully exert the synergistic effect of the two and improve the strength of the bolt.

[0011] As a further technical solution, the preparation of the steel billet includes the following steps: batching according to the composition of the iron matrix, smelting to obtain molten steel, adding a reinforcing phase, mixing evenly, and then casting and heating and rolling to obtain a steel billet.

[0012] As a further technical solution, the smelting temperature is 1550~1650℃.

[0013] As a further technical solution, the casting temperature is 1500~1550℃.

[0014] As a further technical solution, the temperature of the heated rolling is 1200~1250℃.

[0015] The present invention also provides a method for preparing a high-strength bolt, comprising the following steps: S1. Cold forging: After the steel billet is cold headed, the masterbatch is obtained; S2, thread processing: the masterbatch is thread processed to obtain a semi-finished product; S3. Heat treatment and surface treatment: The semi-finished product is subjected to blackening treatment after quenching and tempering to obtain a high-strength bolt.

[0016] As a further technical solution, the quenching temperature is 850-870°C, the quenching time is 10-15 minutes, the tempering temperature is 360-380°C, and the tempering time is 70-80 minutes.

[0017] As a further technical solution, the temperature of the blackening treatment is 90-110° C., and the time of the blackening treatment is 15-25 minutes.

[0018] The working principle and beneficial effects of the present invention are: In the present invention, an amorphous alloy material is added as a reinforcing phase. After the reinforcing phase is combined with the iron matrix, it can effectively share the load and improve the strength of the bolt. By reasonably controlling the mass ratio of the amorphous alloy reinforcing phase to the iron matrix, a uniformly distributed reinforcement area can be formed in the iron matrix, so that the bolt can bear stress more evenly when subjected to external force, reduce local stress concentration, and improve the strength of the bolt. DETAILED DESCRIPTION

[0019] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] In the following examples and comparative examples: Ferromanganese alloy: manganese content 68wt%, ferrochrome alloy: chromium content 75wt%, iron-nickel alloy: nickel content 80wt%, ferrosilicon alloy: silicon content 75wt%, scrap steel: iron content 98wt%; Copper powder: copper content 99.95wt%; Iron-based amorphous alloy: Cr 15wt%, Mo 12%, C 15wt%, M 2wt%, B 6wt%, the balance is Fe, the manufacturer is Panxing New Alloy Materials (Changzhou) Co., Ltd.; Zirconium-based amorphous alloy: Ti 10wt%, Cu 12wt%, Ni 10wt%, M 2wt%, balance Zr, manufacturer is Panxing New Alloy Materials (Changzhou) Co., Ltd.

[0021] Example 1 The iron matrix is ​​composed of the following components in weight percentage: C 0.3%, Si 0.17%, Mn 0.5%, Cr 0.05%, Ni 0.1%, Cu 0.2%, and the balance is iron and inevitable impurities; The preparation of the steel billet comprises the following steps: mixing ferromanganese alloy (manganese content 68wt%), ferrochrome alloy (chromium content 75wt%), iron-nickel alloy (nickel content 80wt%), ferrosilicon alloy (silicon content 75wt%), copper powder (copper content 99.95wt%), and scrap steel (iron content 98wt%) according to target composition, heating to 1550° C. for smelting to obtain molten steel, adding a reinforcing phase (wherein the mass ratio of the iron matrix to the reinforcing phase is 100:1), mixing evenly, casting at a temperature of 1500° C., and heating and rolling at 1200° C. to obtain a steel billet, wherein the reinforcing phase is an iron-based amorphous alloy; A method for preparing a high-strength bolt comprises the following steps: S1. Cold forging: Put the steel billet into the mold cavity, and after cold forging, obtain the masterbatch; S2, thread processing: use a thread rolling machine to form threads on the masterbatch to obtain semi-finished products; S3. Heat treatment and surface treatment: The semi-finished product is quenched at 850℃ for 15min, tempered at 360℃ for 90min, and then subjected to blackening treatment. The blackening treatment temperature is 90℃ and the time is 25min, and high-strength bolts are obtained.

[0022] Example 2 The iron matrix is ​​composed of the following components by weight percentage: C 0.36%, Si 0.19%, Mn 0.58%, Cr0.2%, Ni 0.2%, Cu 0.22%, and the balance is iron and inevitable impurities; The preparation of the steel billet comprises the following steps: mixing ferromanganese alloy (manganese content 68wt%), ferrochrome alloy (chromium content 75wt%), iron-nickel alloy (nickel content 80wt%), ferrosilicon alloy (silicon content 75wt%), copper powder (copper content 99.95wt%), and scrap steel (iron content 98wt%) according to target composition, heating to 1600° C. for smelting to obtain molten steel, adding a reinforcing phase (wherein the mass ratio of the iron matrix to the reinforcing phase is 100:5), mixing evenly, casting at a temperature of 1525° C., and heating and rolling at 1225° C. to obtain a steel billet, wherein the reinforcing phase is an iron-based amorphous alloy; A method for preparing a high-strength bolt comprises the following steps: S1. Cold forging: Put the steel billet into the mold cavity, and after cold forging, obtain the masterbatch; S2, thread processing: use a thread rolling machine to form threads on the masterbatch to obtain semi-finished products; S3. Heat treatment and surface treatment: The semi-finished product is quenched at 860℃ for 12min, tempered at 370℃ for 80min, and then subjected to blackening treatment. The blackening treatment temperature is 100℃ and the time is 20min to obtain high-strength bolts.

[0023] Example 3 The iron matrix is ​​composed of the following components in weight percentage: C 0.5%, Si 0.37%, Mn 0.8%, Cr 0.25%, Ni 0.3%, Cu 0.25%, and the balance is iron and inevitable impurities; The preparation of the steel billet comprises the following steps: mixing ferromanganese alloy (manganese content 68wt%), ferrochrome alloy (chromium content 75wt%), iron-nickel alloy (nickel content 80wt%), ferrosilicon alloy (silicon content 75wt%), copper powder (copper content 99.95wt%), and scrap steel (iron content 98wt%) according to target composition, heating to 1650° C. for smelting to obtain molten steel, adding a reinforcing phase (wherein the mass ratio of the iron matrix to the reinforcing phase is 100:20), mixing evenly, casting at a temperature of 1550° C., and heating and rolling at 1250° C. to obtain a steel billet, wherein the reinforcing phase is an iron-based amorphous alloy; A method for preparing a high-strength bolt comprises the following steps: S1. Cold forging: Put the steel billet into the mold cavity, and after cold forging, obtain the masterbatch; S2, thread processing: use a thread rolling machine to form threads on the masterbatch to obtain semi-finished products; S3. Heat treatment and surface treatment: The semi-finished product is quenched at 870℃ for 10min, tempered at 380℃ for 70min, and then subjected to blackening treatment. The blackening treatment temperature is 110℃ and the time is 15min, and high-strength bolts are obtained.

[0024] Example 4 Compared with Example 2, Example 4 is different in that the amount of reinforcement phase added is different, wherein the mass ratio of the iron matrix to the reinforcement phase is 10:1.

[0025] Example 5 Compared with Example 2, the difference of Example 5 is that the amount of reinforcement phase added is different, wherein the mass ratio of the iron matrix to the reinforcement phase is 10:1.5.

[0026] Example 6 Compared with Example 2, Example 6 is different in that the amount of reinforcement phase added is different, wherein the mass ratio of the iron matrix to the reinforcement phase is 10:2.

[0027] Example 7 Compared with Example 5, the difference of Example 7 is that the reinforcement phase is only a zirconium-based amorphous alloy.

[0028] Example 8 Compared with Example 5, the difference of Example 8 is that the reinforcement phase is composed of an iron-based amorphous alloy and a zirconium-based amorphous alloy in a mass ratio of 10:1.

[0029] Example 9 Compared with Example 5, the difference of Example 9 is that the reinforcement phase is composed of an iron-based amorphous alloy and a zirconium-based amorphous alloy in a mass ratio of 10:2.

[0030] Example 10 Compared with Example 5, the difference of Example 10 is that the reinforcement phase is composed of an iron-based amorphous alloy and a zirconium-based amorphous alloy in a mass ratio of 10:3.

[0031] Embodiment 11 Compared with Example 5, the difference of Example 11 is that the reinforcement phase is composed of an iron-based amorphous alloy and a zirconium-based amorphous alloy in a mass ratio of 10:4.

[0032] Comparative Example 1 Compared with Example 2, Comparative Example 1 is different in that no reinforcing phase is added.

[0033] The high-strength bolts prepared in Examples 1 to 11 and Comparative Example 1 were tested according to the following method: 1. Tensile strength: Test the tensile strength of the sample according to the test method specified in GB∕T 901-1988.

[0034] 2. Yield strength: Test the yield strength of the sample according to the test method specified in GB∕T 901-1988.

[0035] The test results are shown in the following table: Table 1 Performance test results of high strength bolts prepared in Examples 1 to 11 and Comparative Example 1

[0036] Compared with Comparative Example 1, Example 2 adds an iron-based amorphous alloy as a reinforcing phase. As a result, the tensile strength and yield strength of Example 2 are better than those of Comparative Example 1, indicating that the addition of the reinforcing phase can improve the strength of the bolt; in Example 2 and Examples 4 to 6, different masses of reinforcing phases are added. As a result, the tensile strength and yield strength of Examples 4 and 5 are better than those of Examples 2 and 6, indicating that when the mass ratio of the iron matrix to the reinforcing phase is 20:2 to 3, the strength of the obtained bolt is better.

[0037] Compared with Examples 5 and 7, Examples 8 to 11 simultaneously add iron-based amorphous alloys and zirconium-based amorphous alloys. As a result, the tensile strength and yield strength of Examples 8 to 11 are better than those of Examples 5 and 7, indicating that the iron-based amorphous alloys and zirconium-based amorphous alloys play a synergistic role and can improve the strength of the bolt. In Examples 8 to 11, different mass ratios of iron-based amorphous alloys and zirconium-based amorphous alloys are added. As a result, the tensile strength and yield strength of Examples 9 and 10 are better than those of Examples 8 and 11, indicating that when the mass ratio of iron-based amorphous alloys to zirconium-based amorphous alloys is 10:2 to 3, the strength of the obtained bolt is better.

[0038] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high strength bolt, characterized in that: The steel billet is processed from a steel billet, which consists of an iron matrix and a reinforcement phase. The iron matrix consists of the following components by weight: C 0.3%-0.5%, Si 0.17%-0.37%, Mn 0.5%-0.8%, Cr 0.05%-0.25%, Ni 0.1%-0.3%, Cu 0.2%-0.25%, and the balance is iron and inevitable impurities; the reinforcement phase is an amorphous alloy material, and the mass ratio of the iron matrix to the reinforcement phase is 100:1-20.

2. A high-strength bolt according to claim 1, characterized in that: The mass ratio of the iron matrix to the reinforcement phase is 20:2-3.

3. A high-strength bolt according to claim 1, characterized in that: The amorphous alloy material consists of an iron-based amorphous alloy and a zirconium-based amorphous alloy, and the mass ratio of the iron-based amorphous alloy to the zirconium-based amorphous alloy is 10:2-3.

4. A high-strength bolt according to claim 1, characterized in that: The preparation of the steel billet comprises the following steps: The materials are prepared according to the composition of the iron matrix, smelted to obtain molten steel, added with a reinforcing phase, mixed evenly, and cast, heated and rolled to obtain a steel billet.

5. A high strength bolt according to claim 4, characterized in that: The smelting temperature is 1550~1650℃.

6. A high strength bolt according to claim 4, characterized in that: The casting temperature is 1500-1550°C.

7. A high strength bolt according to claim 4, characterized in that: The temperature of the heating rolling is 1200-1250°C.

8. A method for preparing a high-strength bolt according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Cold forging: After the steel billet is cold headed, the masterbatch is obtained; S2, thread processing: the masterbatch is thread processed to obtain a semi-finished product; S3. Heat treatment and surface treatment: The semi-finished product is subjected to blackening treatment after quenching and tempering to obtain a high-strength bolt.

9. A method for preparing a high-strength bolt according to claim 8, characterized in that: The quenching temperature is 850-870° C., the quenching time is 10-15 min, the tempering temperature is 360-380° C., and the tempering time is 70-80 min.

10. The method for preparing a high-strength bolt according to claim 8, characterized in that: The temperature of the blackening treatment is 90-110° C., and the time of the blackening treatment is 15-25 minutes.

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