CN111250637A - Processing method of high-strength bolt - Google Patents
Processing method of high-strength bolt Download PDFInfo
- Publication number
- CN111250637A CN111250637A CN201811451725.7A CN201811451725A CN111250637A CN 111250637 A CN111250637 A CN 111250637A CN 201811451725 A CN201811451725 A CN 201811451725A CN 111250637 A CN111250637 A CN 111250637A
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- CN
- China
- Prior art keywords
- carrying
- raw materials
- bolt
- treatment
- acid cleaning
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21H—MAKING PARTICULAR METAL OBJECTS BY ROLLING, e.g. SCREWS, WHEELS, RINGS, BARRELS, BALLS
- B21H3/00—Making helical bodies or bodies having parts of helical shape
- B21H3/02—Making helical bodies or bodies having parts of helical shape external screw-threads ; Making dies for thread rolling
- B21H3/06—Making by means of profiled members other than rolls, e.g. reciprocating flat dies or jaws, moved longitudinally or curvilinearly with respect to each other
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/0093—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for screws; for bolts
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
- C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
- C23C8/20—Carburising
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Articles (AREA)
Abstract
The invention discloses a processing method of a high-strength bolt, which comprises the steps of acidifying the surface of a raw material, quenching, gradually cooling, changing the internal structure of the raw material into harder martensite with higher strength, performing laser cutting, ensuring that the forming structure is accurate, the damage to the raw material structure is small, quenching the thread, enhancing the lightness and hardness of the thread, and improving the overall strength of the bolt.
Description
Technical Field
The invention relates to a bolt processing method, in particular to a processing method of a high-strength bolt.
Background
The bolt is a common fastener in the mechanical field, and has great requirements on the use strength of the bolt along with the rapid development of mechanical industry at present, for example, the running speed of a train on the existing high-speed railway is much faster than that of the existing high-speed railway, the point contact time of the train on the high-speed railway is shorter, the point contact force is higher, the connection and the fixation of the high-speed railway are firmer and more stable, and the connection strength and the hardness of the traditional bolt are lower and cannot meet the use requirements of high strength.
Disclosure of Invention
In order to solve the existing problems, the invention discloses a high-strength bolt processing method, which can produce a high-strength bolt with the strength higher than the existing standard.
The high-strength bolt processing method is characterized by comprising the following steps of:
(I) raw material treatment and shaping
(1) The raw materials are washed with acid to remove rust,
(2) the raw materials are acid washed and naturally dried for 0.5 hour,
(3) the acid-washed raw materials are quenched and directly put into an environment with a constant temperature of 820 +/-20 ℃ for 4.5 to 5.5 hours, the temperature is gradually reduced and annealed, the temperature is constant at 750 ℃, 650 ℃, 550 ℃, 400 ℃, 300 ℃ and 150 ℃, the raw materials are uniformly cooled for hours at normal temperature,
(4) acid washing the surface of the material obtained in the step (2) to remove impurities,
(5) carrying out laser cutting forming on the pickled and impurity-removed raw material to form a screw and a nut;
(II) thread rolling
Putting the obtained product in the step (I) into a thread rolling machine, and forming threads on the surface of a screw;
(III) Heat treatment
(1) Quenching the bolt formed in the step (II) at 980 ℃, keeping the temperature of 980 ℃ for 0.5 hour,
(2) gradually cooling and tempering the quenched bolt at the constant temperature of 800 ℃, 600 ℃, 400 ℃ and 200 ℃ for 70 minutes;
(IV) surface carbonization treatment
And (5) directly quenching the bolt obtained in the step (three) at 800-850 ℃ in a carbonization environment, and tempering at a low temperature.
The raw materials are 40 boron steel, 20 manganese titanium boron steel and 35 CrMoA.
The acid used for acid washing accounts for 25 percent of the mass fraction.
The invention adopts the quenching process, changes the arrangement of crystals in the raw materials, greatly improves the hardness, strength, wear resistance, fatigue strength and toughness of the raw materials, is applied to high-speed railways, can meet the requirements on strength, and is also suitable for other fields with high-strength requirements.
Detailed Description
The following description is presented to disclose the invention so as to enable any person skilled in the art to practice the invention. The preferred embodiments in the following description are given by way of example only, and other obvious variations will occur to those skilled in the art.
A processing method of a high-strength bolt is characterized by comprising the following steps:
(I) raw material treatment and shaping
(1) The raw materials are washed with acid to remove rust,
(2) the raw materials are acid washed and naturally dried for 0.5 hour,
(3) the acid-washed raw materials are quenched and directly put into an environment with a constant temperature of 820 +/-20 ℃ for 4.5 to 5.5 hours, the temperature is gradually reduced and annealed, the temperature is constant at 750 ℃, 650 ℃, 550 ℃, 400 ℃, 300 ℃ and 150 ℃, the raw materials are uniformly cooled for hours at normal temperature,
(4) acid washing the surface of the material obtained in the step (2) to remove impurities,
(5) carrying out laser cutting forming on the pickled and impurity-removed raw material to form a screw and a nut;
(II) thread rolling
Putting the obtained product in the step (I) into a thread rolling machine, and forming threads on the surface of a screw;
(III) Heat treatment
(1) Quenching the bolt formed in the step (II) at 980 ℃, keeping the temperature of 980 ℃ for 0.5 hour,
(2) gradually cooling and tempering the quenched bolt at the constant temperature of 800 ℃, 600 ℃, 400 ℃ and 200 ℃ for 70 minutes;
(IV) surface carbonization treatment
And (5) directly quenching the bolt obtained in the step (three) at 800-850 ℃ in a carbonization environment, and tempering at a low temperature.
The raw materials are 40 boron steel, 20 manganese titanium boron steel and 35 CrMoA.
The acid used for acid washing accounts for 25 percent of the mass fraction.
The rust on the surface of the raw material is removed by acid washing, the rust is an unavailable material and covers the surface of the raw material to influence the subsequent treatment of the raw material, hydrochloric acid and the rust are subjected to chemical reaction, the rust is dissolved in the hydrochloric acid, the mass fraction of the hydrochloric acid is 25%, after the surface of the raw material is cleaned and naturally dried for 0.5 hour, the hydrochloric acid can volatilize from the surface of the raw material, and the acid residue is avoided.
The quenching can transform the super-cooled austenite into martensite or bainite to obtain martensite or bainite structure, and then the tempering at different temperatures is matched to greatly improve the strength, hardness, wear resistance, fatigue strength, toughness and the like of the steel, thereby meeting different use requirements of various mechanical parts and tools.
High-temperature quenching and temperature gradual tempering in the raw material treatment stage are beneficial to the change of the internal structure of the raw material to form stable martensite; high-temperature quenching in the heat treatment stage, wherein the internal tissues of the bolt stem part and the head part are changed again, the structural tissues of the raw materials are changed according to the molding structures of the bolt head part and the rod part, and the center of the rod part of the bolt forms a strength central line; the surface treatment stage is a quenching treatment, which increases the carbon content on the surface of the thread and in a certain distance range below the surface and also enhances the strength and hardness of the thread teeth.
The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are merely illustrative of the principles of the invention, but that various changes and modifications may be made without departing from the spirit and scope of the invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (3)
1. A high-strength bolt machining method is characterized by comprising the following steps: carrying out acid cleaning and rust removal on the raw materials, carrying out natural air drying for 0.5 hour after the raw materials are subjected to acid cleaning, carrying out quenching treatment on the raw materials subjected to acid cleaning, directly putting the raw materials into an environment with the constant temperature of 820 +/-20 ℃, carrying out cooling annealing treatment at the constant temperature of 750 ℃, 650 ℃, 550 ℃, 400 ℃, 300 ℃ and 150 ℃ step by step, carrying out cooling treatment at the constant temperature of 650 ℃, 550 ℃ and 150 ℃ for one hour, carrying out acid cleaning and impurity removal on the surfaces of the materials obtained in the step (2), and carrying out laser cutting and forming on the raw materials subjected to acid cleaning and impurity removal to form a; thread rolling, namely putting the product obtained in the step (I) in a thread rolling machine, and forming threads on the surface of a screw; carrying out heat treatment on the bolt formed in the step (II) for quenching treatment at 980 ℃, keeping the temperature constant at 980 ℃ for 0.5 hour, and gradually cooling and tempering the quenched bolt at 800 ℃, 600 ℃, 400 ℃ and 200 ℃ for 70 minutes; and (3) performing surface carbonization treatment on the bolt obtained in the step (III), directly quenching at 800-850 ℃ in a carbonization environment, and tempering at a low temperature.
2. The method for processing a high-strength bolt according to claim 1, wherein the raw materials are 40 boron steel, 20 manganese titanium boron steel, and 35 CrMoA.
3. The method of processing a high-strength bolt according to claim 1, wherein the acid used for pickling is 25% by mass.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811451725.7A CN111250637A (en) | 2018-11-30 | 2018-11-30 | Processing method of high-strength bolt |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811451725.7A CN111250637A (en) | 2018-11-30 | 2018-11-30 | Processing method of high-strength bolt |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111250637A true CN111250637A (en) | 2020-06-09 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811451725.7A Pending CN111250637A (en) | 2018-11-30 | 2018-11-30 | Processing method of high-strength bolt |
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| CN (1) | CN111250637A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112962051A (en) * | 2021-01-29 | 2021-06-15 | 安徽合力股份有限公司合肥铸锻厂 | Boronizing method for austenitic stainless steel |
-
2018
- 2018-11-30 CN CN201811451725.7A patent/CN111250637A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112962051A (en) * | 2021-01-29 | 2021-06-15 | 安徽合力股份有限公司合肥铸锻厂 | Boronizing method for austenitic stainless steel |
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Application publication date: 20200609 |