CN109666863B

CN109666863B - Preparation method of crankshaft material, crankshaft, engine and application

Info

Publication number: CN109666863B
Application number: CN201910148218.4A
Authority: CN
Inventors: 易文; 代永斌
Original assignee: Pangang Group Jiangyou Changcheng Special Steel Co Ltd
Current assignee: Pangang Group Jiangyou Changcheng Special Steel Co Ltd
Priority date: 2019-02-27
Filing date: 2019-02-27
Publication date: 2020-04-24
Anticipated expiration: 2039-02-27
Also published as: CN109666863A

Abstract

本发明属于曲轴材料制造工艺技术领域，涉及一种曲轴材料的制备方法、曲轴材料、曲轴、发动机及应用。本发明提供的一种曲轴材料的制备方法，包括：(a)依次采用电炉炼钢、炉外精炼和真空脱气的工艺对炉料进行冶炼，得到钢液；(b)将钢液浇注成钢锭并锻造，得到锻材；(c)将锻材进行热处理，得到曲轴材料；其中，所述炉外精炼中，包括一次性喂Al线的步骤。该方法使钢液脱氧良好，最终确保制得的曲轴材料氧含量低、夹杂物水平低，保证了曲轴材料的内部质量。此外，该方法工艺简单，实用性强，适用于大规模工业化生产。本发明提供的曲轴以上述曲轴材料为原料制得，可广泛应用在轮船、汽车及机械等不同的领域。The invention belongs to the technical field of crankshaft material manufacturing technology, and relates to a preparation method of a crankshaft material, a crankshaft material, a crankshaft, an engine and applications. A method for preparing a crankshaft material provided by the present invention includes: (a) smelting the charge by successively adopting the processes of electric furnace steelmaking, out-of-furnace refining and vacuum degassing to obtain molten steel; (b) pouring the molten steel into a steel ingot and forging to obtain a forging material; (c) heat-treating the forging material to obtain a crankshaft material; wherein, the refining outside the furnace includes the step of feeding Al wire at one time. The method enables good deoxidation of molten steel, and finally ensures that the obtained crankshaft material has low oxygen content and low inclusion level, thereby ensuring the internal quality of the crankshaft material. In addition, the method has simple process and strong practicability, and is suitable for large-scale industrial production. The crankshaft provided by the present invention is prepared from the above-mentioned crankshaft material, and can be widely used in different fields such as ships, automobiles and machinery.

Description

Preparation method of crankshaft material, crankshaft, engine and application

Technical Field

The invention belongs to the technical field of crankshaft material manufacturing processes, and particularly relates to a crankshaft material, a preparation method of the crankshaft material, a crankshaft, an engine and application of the crankshaft material.

Background

The crankshaft is the most important component in the engine. It takes the force from the connecting rod and converts it into torque to be output by the crankshaft and drive other accessories on the engine. With respect to marine crankshafts, ships with larger hulls and advanced technology cannot get water without "shafts" with excessively hard specifications. During use, the crankshaft is subjected to the combined action of centrifugal force of the rotating mass, gas inertia force which changes periodically and reciprocating inertia force to bear bending and torsion loads, so that the crankshaft is required to have sufficient strength and rigidity. In addition, the crankshaft has higher requirements on the purity, the fine grains, the structure and the like of the crankshaft. Therefore, how to manufacture the crankshaft material meeting the requirements still needs to be solved urgently.

In view of the above, the present invention is particularly proposed to solve at least one of the above technical problems.

Disclosure of Invention

The invention aims to provide a preparation method of a crankshaft material, which is simple in process, strong in practicability and suitable for large-scale industrial production.

The second purpose of the invention is to provide a crankshaft material, which has low content of non-metallic impurities such as N, H, O and the like, good performance and wide market prospect.

The third object of the present invention is to provide a crankshaft having high tensile strength, high purity and fine grain size.

A fourth object of the present invention is to provide an engine including the crankshaft.

A fifth object of the invention is to provide a use of said crankshaft in the field of ships, automobiles or machinery.

In order to achieve the purpose, the invention adopts the technical scheme that:

according to an aspect of the present invention, there is provided a method of manufacturing a crankshaft material, including:

(a) smelting furnace burden by adopting the processes of electric furnace steelmaking, external refining and vacuum degassing in sequence to obtain molten steel;

(b) pouring molten steel into a steel ingot and forging to obtain a forged material;

(c) carrying out heat treatment on the forged material to obtain a crankshaft material;

wherein, the secondary refining comprises the step of feeding Al wire once.

As a further preferable technical scheme, in the one-time Al wire feeding, the mass of the Al wire accounts for 0.05-0.07 percent of the mass of the furnace burden, and is preferably 0.06-0.07 percent.

As a further preferable technical scheme, in the external refining, argon blowing treatment is carried out during and before and after one-time Al wire feeding.

As a further preferable technical scheme, the ultimate vacuum degree of the vacuum degassing is 0-67Pa, and preferably 0-50 Pa;

the time for maintaining the ultimate vacuum degree is 15-30min, preferably 20-30 min.

As a further preferable embodiment, the heat treatment method includes a method of combining isothermal annealing and normalizing.

As a further preferable technical solution, the combination of isothermal annealing and normalizing comprises the following steps: cooling the forged material to a first temperature, heating to a second temperature, preserving heat, cooling to a third temperature, preserving heat, cooling to a fourth temperature, heating to a fifth temperature, preserving heat, and air-cooling to obtain a crankshaft material;

preferably, the first temperature is 25-200 ℃, preferably 25-100 ℃;

preferably, the second temperature is 830-850 ℃, preferably 840-850 ℃;

preferably, the third temperature is 640-660 ℃, preferably 650-660 ℃;

preferably, the fourth temperature is 250-350 ℃, preferably 300-350 ℃;

preferably, the fifth temperature is 810-.

According to another aspect of the invention, the crankshaft material is prepared by the preparation method of the crankshaft material;

preferably, the crankshaft material comprises the following chemical components in mass fraction: 0.43 to 0.46 percent of C, 0.7 to 0.8 percent of Mn, 0.17 to 0.3 percent of Si, less than or equal to 0.012 percent of P, less than or equal to 0.006 percent of S, 0.15 to 0.25 percent of Cr, 0.25 to 0.35 percent of Ni, 0.07 to 0.12 percent of Mo, less than or equal to 0.2 percent of Cu, 0.015 to 0.04 percent of Al, less than or equal to 0.00015 percent of H, less than or equal to 0.002 percent of O, less than or equal to 0.007 percent of N, and the balance of Fe.

According to another aspect of the invention, the crankshaft is mainly made of the crankshaft material prepared by the preparation method of the crankshaft material or the crankshaft material.

According to another aspect of the present invention, there is also provided an engine including the crankshaft.

According to another aspect of the invention, the use of said crankshaft in the field of ships, automobiles or machinery is also provided.

Compared with the prior art, the invention has the beneficial effects that:

1. the method for preparing the crankshaft material, provided by the invention, has the advantages that the external refining process in the method can improve the quality of the crankshaft material, shorten the smelting time, optimize the process and reduce the production cost, particularly, the step of feeding Al wire in one step is adopted in the external refining process, so that molten steel can be well deoxidized, the oxygen content of the prepared crankshaft material is finally ensured to be low, the level of impurities is low, and the internal quality of the crankshaft material is ensured. In addition, the method has simple process and strong practicability, and is suitable for large-scale industrial production.

2. The crankshaft material provided by the invention is prepared by the method, and the crankshaft material N, H, O and other non-metallic impurities are low in content, good in performance and wide in market prospect.

3. The crankshaft provided by the invention is prepared from the crankshaft material, has high tensile strength, high purity and fine grain size, and can be widely applied to different fields of ships, automobiles, machinery and the like.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to embodiments and examples, but those skilled in the art will understand that the following embodiments and examples are only illustrative of the present invention and should not be construed as limiting the scope of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. Those who do not specify the conditions are performed according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

It should be noted that:

in the present invention, all the embodiments and preferred methods mentioned herein can be combined with each other to form a new technical solution, if not specifically stated.

In the present invention, all the technical features mentioned herein and preferred features may be combined with each other to form a new technical solution, if not specifically stated.

The "ranges" disclosed herein may have one or more lower limits and one or more upper limits, respectively, in the form of lower limits and upper limits.

In the present invention, unless otherwise specified, the individual reactions or operation steps may or may not be performed in sequence. Preferably, the methods herein are performed sequentially.

Unless otherwise defined, technical and scientific terms used herein have the same meaning as is familiar to those skilled in the art. In addition, any methods or materials similar or equivalent to those described herein can also be used in the present invention.

In a first aspect, in at least one embodiment, there is provided a method of making a crankshaft material, comprising:

wherein, the external refining comprises the step of feeding Al wire once.

Aiming at the problem that the crankshaft material meeting the requirements in the prior art is few, the invention provides the preparation method of the crankshaft material, which adopts the step of feeding the Al wire once in the secondary refining, so that the molten steel is well deoxidized, and finally the low oxygen content and the low inclusion level of the prepared crankshaft material are ensured. The crankshaft material prepared by the preparation method has good quality and can be used as the original material of the crankshaft. In addition, the method has simple process and strong practicability, and is suitable for large-scale industrial production.

The main components of the furnace burden comprise scrap steel and pig iron, and the furnace burden used by the invention adopts high-quality scrap steel and high-quality pig iron (high-quality slag iron) with low residual elements such as low five-harm, low P, low S and the like.

Compared with S44SY steel and 45 steel which are used as crankshaft materials in the prior art, the crankshaft material provided by the invention has larger improvement in the aspects of tensile strength, grain size, brittle inclusion and the like.

Electric furnace steelmaking is a process mainly utilizing electric arc heat for smelting. The smelting process of electric furnace steel-making is generally divided into melting period, oxidation period and reduction period, not only oxidation atmosphere but also reduction atmosphere can be formed in the furnace, and the efficiency of dephosphorization and desulfurization is high.

The secondary refining is a process for refining primarily refined molten steel, and is also called ladle metallurgy or secondary metallurgy. The external refining is carried out, so that the quality of the crankshaft material can be improved, the smelting time is shortened, the process is optimized, and the production cost is reduced.

The vacuum degassing is carried out in a special vacuum chamber, and the process comprises the following steps: molten steel is sucked into the vacuum chamber, argon is blown into the molten steel from the side walls of the two ascending pipes, and gas is released from a mixture of the molten steel and the gas entering the vacuum chamber under the action of high vacuum, so that degassing is realized.

The wire-feeding method is a method in which a refining additive having a low density and being easily oxidized is formed into a wire rod, and the wire rod is put into the deep part of molten steel by a wire-feeding machine to refine the molten steel outside the furnace. The wire feeding method can be divided into a ladle wire feeding method, a tundish wire feeding method and a tundish wire feeding method. The invention adopts the method of feeding Al wire once, which can ensure good deoxidation of the molten steel.

Compared with the step-by-step Al wire feeding in the prior art, the one-step Al wire feeding method has the advantages that: not only can ensure good deoxidation, but also can reduce Al₂O₃The risk of inclusion of classes.

It should be noted that the casting method and the forging method are not particularly limited in the present invention, and may be performed by a conventional method in the art.

In a preferred embodiment, the mass of the Al wire in the disposable Al wire feed is 0.05 to 0.07%, preferably 0.06 to 0.07% of the mass of the charge.

The amount of Al wire fed is critical to the quality of the crankshaft material produced, and typically, but not by way of limitation, in a single-use Al wire feed, the mass of Al wire may be 0.05%, may be 0.06%, and may be 0.07% of the mass of the charge.

In a preferred embodiment, the external refining is performed with argon blowing during and before and after the Al wire is once fed.

It is noted that the purpose of argon blowing treatment before feeding Al wire for one time is to create an environment for molten steel to flow in advance; the argon blowing treatment is carried out during the one-time Al wire feeding period so as to keep the flowing of the molten steel and ensure that the Al wires fed into the steel ladle can be quickly and uniformly distributed in the molten steel; the purpose of argon blowing treatment after feeding the Al wire for one time is to purify molten steel and provide guarantee for preparing high-quality crankshaft materials.

In a preferred embodiment, the ultimate vacuum of the vacuum degassing is from 0 to 67Pa, preferably from 0 to 50 Pa;

In order to ensure a good degassing effect and avoid the tendency of the produced crankshaft material to produce white spots and brittle cracks, it is necessary to control the ultimate vacuum degree of vacuum degassing and the time for maintaining the ultimate vacuum degree. Typically, but not by way of limitation, the ultimate vacuum of vacuum degassing is in the range of 0 to 67Pa, for example: the ultimate vacuum degree of vacuum degassing can be 0Pa, 5Pa, 10Pa, 20Pa, 30Pa, 40Pa, 50Pa, 60Pa, 63Pa, 65Pa or 67 Pa; the time for maintaining the ultimate vacuum degree can be 15min, 20min, 25min or 30 min.

In a preferred embodiment, the means of heat treatment comprises a combination of isothermal annealing and normalizing.

It should be noted that isothermal annealing refers to a process of cooling at a certain temperature at a relatively high speed, holding the temperature for a certain period of time, and then cooling in air; normalizing refers to the process of heating the steel above a critical temperature and holding it for a period of time, followed by cooling in air. The invention adopts a heat treatment mode combining isothermal annealing and normalizing, can convert the structure of molten steel according to the required structure, can fully control the content of harmful widmannstatten structures and banded structures, enables the grade to reach the required requirement, and obtains the required fine ferrite and pearlite.

In a preferred embodiment, isothermal annealing in combination with normalizing comprises the steps of: cooling the forged material to a first temperature, heating to a second temperature, preserving heat, cooling to a third temperature, preserving heat, cooling to a fourth temperature, heating to a fifth temperature, preserving heat, and air-cooling to obtain a crankshaft material;

preferably, the first temperature is 25-200 ℃, preferably 25-100 ℃;

preferably, the second temperature is 830-850 ℃, preferably 840-850 ℃;

preferably, the third temperature is 640-660 ℃, preferably 650-660 ℃;

preferably, the fourth temperature is 250-350 ℃, preferably 300-350 ℃;

preferably, the fifth temperature is 810-.

It should be noted that, the temperature should be raised to the second temperature immediately after the temperature is cooled to the first temperature, and should be raised to the fifth temperature immediately after the temperature is cooled to the fourth temperature;

it should be understood that the conditions of the heat treatment (temperature and holding time) are also important factors affecting the quality of the crankshaft material, and therefore, the ranges of the temperature and holding time need to be properly selected. Typically, but not by way of limitation, the first temperature may be 25 ℃, 50 ℃, 70 ℃, 100 ℃, 130 ℃, 150 ℃, 170 ℃ or 200 ℃; the second temperature may be 830 ℃, 835 ℃, 840 ℃, 845 ℃ or 850 ℃; the third temperature may be 640 ℃, 645 ℃, 650 ℃, 655 ℃ or 660 ℃; the fourth temperature may be 250 ℃, 260 ℃, 270 ℃, 280 ℃, 290 ℃, 300 ℃, 310 ℃, 320 ℃, 330 ℃, 340 ℃ or 350 ℃; the fifth temperature may be 810 ℃, 815 ℃, 820 ℃, 825 ℃ or 830 ℃;

the holding time at the second temperature can be 5h, 6h, 7h, 8h or 9 h; the holding time at the third temperature can be 18h, 19h, 20h, 21h or 22 h; the incubation time at the fifth temperature may be 5h, 6h, 7h, 8h or 9 h.

In a second aspect, in at least one embodiment, a crankshaft material is provided that is made using a method of making a crankshaft material.

The crankshaft material provided by the invention is prepared by the method, and the crankshaft material N, H, O and other non-metallic impurities are low in content, good in performance and wide in market prospect.

In a preferred embodiment, the crankshaft material comprises the following chemical components in mass fractions: 0.43 to 0.46 percent of C, 0.7 to 0.8 percent of Mn, 0.17 to 0.3 percent of Si, less than or equal to 0.012 percent of P, less than or equal to 0.006 percent of S, 0.15 to 0.25 percent of Cr, 0.25 to 0.35 percent of Ni, 0.07 to 0.12 percent of Mo, less than or equal to 0.2 percent of Cu, 0.015 to 0.04 percent of Al, less than or equal to 0.00015 percent of H, less than or equal to 0.002 percent of O, less than or equal to 0.007 percent of N, and the balance of Fe.

The content of each element of the crankshaft material prepared by the preparation method of the invention is within a certain specific range. Typically, but not by way of limitation, for example: a crankshaft material comprises the following chemical components in percentage by mass: 0.43% of C, 0.7% of Mn, 0.17% of Si, 0.012% of P, 0.006% of S, 0.15% of Cr, 0.25% of Ni, 0.07% of Mo, 0.2% of Cu, 0.015% of Al, 0.00015% of H, 0.002% of O, 0.007% of N and the balance of Fe;

for another example: a crankshaft material comprises the following chemical components in percentage by mass: 0.46% of C, 0.8% of Mn, 0.3% of Si, 0.010% of P, 0.005% of S, 0.25% of Cr, 0.35% of Ni, 0.12% of Mo, 0.1% of Cu, 0.04% of Al, 0.0001% of H, 0.001% of O, 0.005% of N, and the balance of Fe;

the following steps are repeated: a crankshaft material comprises the following chemical components in percentage by mass: 0.45% of C, 0.75% of Mn, 0.23% of Si, 0.012% of P, 0.004% of S, 0.2% of Cr, 0.3% of Ni, 0.1% of Mo, 0.1% of Cu, 0.03% of Al, 0.00015% of H, 0.002% of O, 0.004% of N, and the balance of Fe.

In a third aspect, in at least one embodiment, a crankshaft is provided that is made primarily of crankshaft material or crankshaft material made from a method of making crankshaft material.

The crankshaft is the most important component in the engine. It takes the force from the connecting rod and converts it into torque to be output by the crankshaft and drive other accessories on the engine. During use, the crankshaft is subjected to the combined action of centrifugal force of rotating mass, gas inertia force with periodic change and reciprocating inertia force to bear bending and torsion load, so that the crankshaft is required to have enough strength and rigidity, and the journal surface of the crankshaft is required to be wear-resistant.

The crankshaft provided by the invention is prepared from the crankshaft material prepared by the preparation method. Because the content of non-metallic impurities such as N, H, O and the like in the crankshaft material as the raw material is low, the purity of the manufactured crankshaft is high; meanwhile, due to the fact that the proportion of the other chemical components of the crankshaft material is proper, the manufactured crankshaft is high in tensile strength and fine in grain size, and actual requirements can be met.

In a fourth aspect, an engine is provided in at least one embodiment that includes a crankshaft.

In a fifth aspect, in at least one embodiment, a crankshaft is provided for use in the marine, automotive or mechanical arts.

Any machine which needs to convert rotary motion into linear reciprocating motion needs to use a crankshaft, such as a transmission mechanism of an internal combustion engine, a transmission mechanism of an external combustion steam engine and the like. The crankshaft provided by the invention can be widely applied to different fields of ships, automobiles, machinery and the like.

The present invention will be further described with reference to specific examples, comparative examples and experimental examples.

Example 1

The embodiment provides a preparation method of a crankshaft material, which comprises the following steps:

(1) firstly, performing primary smelting on furnace burden by adopting an electric furnace steelmaking process, then performing external refining, performing argon blowing treatment in the external refining, then feeding an Al wire once according to 0.05% of the mass of the furnace burden and continuously blowing argon to ensure good deoxidation, then continuously blowing argon, finally performing vacuum degassing, setting the limit vacuum degree of the vacuum degassing to be 67Pa and keeping the vacuum degree for 20min to obtain molten steel;

(2) casting molten steel into a 4.6t octagonal ingot by adopting a low-temperature slow casting process, then conveying the 4.6t octagonal ingot to a forging workshop, preserving heat for 3h at 1220 ℃, cogging by adopting a production mode of secondary upsetting and drawing to ensure that a crankshaft material is fully deformed, forging to an intermediate blank with the diameter of 500mm, forging to the intermediate blank without returning to a furnace in the whole forging process, cleaning the surface of the intermediate blank by using a grinding wheel after forging, then continuously heating the cleaned intermediate blank for 2h in a heating furnace with the temperature of 1180 ℃, finally using a 1800KN precision forging machine to forge the blank to a black skin material with the diameter of 225mm, slowly cooling at the temperature of 750 ℃, and obtaining a forged material after slow cooling;

(3) and (3) putting the forged material into a cooling bed as soon as possible, hoisting the forged material into a furnace by using a crown block for furnace cooling, cooling the furnace to 100 ℃, heating to 840 ℃, preserving heat for 6h, cooling to 650 ℃ at the speed of about 30 ℃/h, preserving heat for 19h, cooling to 300 ℃, heating to 820 ℃, preserving heat for 6h, and finally air cooling to obtain the crankshaft material.

The crankshaft material obtained in the embodiment comprises the following chemical components in percentage by mass: 0.435% of C, 0.73% of Mn0.24% of Si, 0.009% of P, 0.003% of S, 0.21% of Cr0.08% of Mo0.08% of Ni0.28% of Cu0.07% of Al, 0.015% of O, 0.0016% of H, 0.0001% of N, and the balance of Fe.

Example 2

(1) firstly, performing primary smelting on furnace burden by adopting an electric furnace steelmaking process, then performing external refining, performing argon blowing treatment in the external refining, then feeding an Al wire once according to 0.06% of the mass of the furnace burden and continuously blowing argon to ensure good deoxidation, then continuously blowing argon, finally performing vacuum degassing, setting the limit vacuum degree of the vacuum degassing to be 50Pa and keeping the vacuum degree for 30min to obtain molten steel;

(3) and (3) putting the forged material into a cooling bed as soon as possible, hoisting the forged material into a furnace by using a crown block for furnace cooling, cooling the furnace to 25 ℃, heating to 830 ℃, preserving heat for 6h, cooling to 640 ℃ at the speed of about 30 ℃/h, preserving heat for 18h, cooling to 250 ℃, heating to 810 ℃, preserving heat for 7h, and finally air cooling to obtain the crankshaft material.

The crankshaft material obtained in the embodiment comprises the following chemical components in percentage by mass: 0.46% of C, 0.8% of Mn0.3% of Si, 0.012% of P, 0.006% of S, 0.25% of Cr0.12% of Mo0.12% of Ni, 0.35% of Cu0.08% of Al, 0.04% of O, 0.00015% of H, 0.007% of N and the balance of Fe.

Example 3

(1) firstly, performing primary smelting on furnace burden by adopting an electric furnace steelmaking process, then performing external refining, performing argon blowing treatment in the external refining, then feeding an Al wire at one time according to 0.07 percent of the mass of the furnace burden and continuously blowing argon to ensure good deoxidation, then continuously blowing argon, finally performing vacuum degassing, setting the limit vacuum degree of the vacuum degassing to be 0Pa and keeping the vacuum degree for 15min to obtain molten steel;

(3) and (3) putting the forged material on a cooling bed as soon as possible, hoisting the forged material into a furnace by using a crown block for furnace cooling, cooling the furnace to 200 ℃, heating to 850 ℃, preserving heat for 6h, cooling to 660 ℃ at the speed of about 30 ℃/h, preserving heat for 20h, cooling to 350 ℃, heating to 830 ℃, preserving heat for 6h, and finally air cooling to obtain the crankshaft material.

The crankshaft material obtained in the embodiment comprises the following chemical components in percentage by mass: 0.43 percent of C, 0.7 percent of Mn0.17 percent of Si, 0.009 percent of P, 0.004 percent of S, 0.15 percent of Cr0.07 percent of Mo0.07 percent of Ni0.25 percent of Cu0.1 percent of Al, 0.001 percent of O, 0.0001 percent of H, 0.005 percent of N and the balance of Fe.

Example 4

This example provides a method of manufacturing a crankshaft material, which is the same as example 1 except that the amount of the one-time Al wire feeding in step (1) was changed from 0.05% to 0.07%.

The crankshaft material obtained in the embodiment comprises the following chemical components in percentage by mass: 0.46% of C, 0.7% of Mn0.17% of Si, 0.009% of P, 0.004% of S, 0.15% of Cr0.07% of Mo0.07% of Ni0.25% of Cu0.1% of Al, 0.0015% of O, 0.00015% of H, 0.005% of N and the balance of Fe.

Example 5

This example provides a method of manufacturing a crankshaft material, which is the same as example 1 except that the amount of the one-time Al wire feeding in step (1) was changed from 0.05% to 0.06%.

The crankshaft material obtained in the embodiment comprises the following chemical components in percentage by mass: 0.43 percent of C, 0.75 percent of Mn0.17 percent of Si, 0.009 percent of P, 0.004 percent of S, 0.15 percent of Cr0.07 percent of Mo0.07 percent of Ni, 0.25 percent of Cu0.10 percent of Al, 0.025 percent of O, 0.0014 percent of H, 0.0001 percent of N, and the balance of Fe.

Example 6

This example provides a method of manufacturing a crankshaft material, which is the same as that of example 1 except that the amount of the one-time Al wire feeding in step (1) was changed from 0.05% to 0.02%.

The crankshaft material obtained in the embodiment comprises the following chemical components in percentage by mass: 0.44% of C, 0.71% of Mn0.27% of Si, 0.012% of P, 0.006% of S, 0.19% of Cr0.08% of Mo0.08% of Ni, 0.26% of Cu0.08% of Al, 0.0019% of O, 0.00015% of H, 0.0069% of N and the balance of Fe.

Example 7

This example provides a method of manufacturing a crankshaft material, which is the same as example 1 except that the amount of the one-time Al wire feeding in step (1) was changed from 0.05% to 0.10%.

The crankshaft material obtained in the embodiment comprises the following chemical components in percentage by mass: 0.43 percent of C, 0.74 percent of Mn0.27 percent of Si, 0.011 percent of P, 0.006 percent of S, 0.20 percent of Cr0.07 percent of Mo0.07 percent of Ni, 0.26 percent of Cu0.09 percent of Al, 0.04 percent of O, 0.0015 percent of H, 0.00015 percent of N, 0.0068 percent of N and the balance of iron.

Example 8

The embodiment provides a preparation method of a crankshaft material, which comprises the following specific steps except that the heat treatment mode is changed in the step (3):

the forged material is put on a cooling bed as soon as possible, hoisted into a furnace by a crown block for furnace cooling, the furnace is cooled to 200 ℃, heated to 870 ℃, and kept for 7 hours, cooled to 660 ℃ at the speed of about 30 ℃/h, kept for 8 hours, and then air-cooled to obtain the crankshaft material, and the rest preparation steps are the same as those of the example 1.

The crankshaft material obtained in the embodiment comprises the following chemical components in percentage by mass: 0.43 percent of C, 0.75 percent of Mn0.17 percent of Si, 0.009 percent of P, 0.004 percent of S, 0.15 percent of Cr0.07 percent of Mo, 0.25 percent of Ni0, 0.2 percent of Cu0.02 percent of Al, 0.001 percent of O, 0.0001 percent of H, 0.005 percent of N and the balance of Fe.

Comparative example 1

This comparative example provides a method of producing a crankshaft material, which is the same as example 1 except that no Al wire was fed in step (1).

The crankshaft material obtained by the comparative example comprises the following chemical components in percentage by mass: 0.43 percent of C, 0.71 percent of Mn0.28 percent of Si, 0.012 percent of P, 0.008 percent of S, 0.15 percent of Cr0.07 percent of Mo0.07 percent of Ni, 0.25 percent of Cu0.13 percent of Al, 0.005 percent of O, 0.0032 percent of H, 0.00015 percent of N, 0.0076 percent of N and the balance of Fe.

Comparative example 2

This comparative example provides a method of producing a crankshaft material, which was the same as in example 1 except that the step of feeding an Al wire in step (1) was replaced with twice wire feeding in an LF furnace and a VD furnace.

The crankshaft material obtained by the comparative example comprises the following chemical components in percentage by mass: 0.425% of C, 0.71% of Mn0.71% of Si 027%, 0.013% of P, 0.009% of S, 0.3% of Cr0.3%, 0.07% of Mo0.24% of Ni0.14% of Cu0.02% of Al, 0.0018% of O, 0.00015% of H, 0.00072% of N and the balance of Fe.

Examples of the experiments

The crankshaft materials prepared in the above examples and comparative examples were subjected to straightening, peeling, flaw detection, sizing, and other relevant processes to obtain crankshafts of a desired size (i.e., 255mm), and finally, relevant tests were performed on the obtained crankshafts, and the results are shown in table 1.

TABLE 1 relevant parameters of the crankshafts obtained in the experimental examples

As can be seen from the data in table 1: the tensile strength and impact of the crankshafts made from the crankshaft materials prepared in examples 1-8 were higher than those of the crankshafts made from the crankshaft materials prepared in comparative examples 1-2; the actual grain sizes (worst field) of the crankshafts prepared from the crankshaft materials prepared in examples 1 to 8 were all greater than 5 grades, and the actual grain sizes (worst field) of the crankshafts prepared from the crankshaft materials prepared in comparative examples 1 to 2 were all less than 5 grades; the brittle inclusions of the crankshafts prepared from the crankshaft materials prepared in examples 1-8 were all no greater than 2.0 grade, and the brittle inclusions of the crankshafts prepared from the crankshaft materials prepared in comparative examples 1-2 were all greater than 2.0 grade.

In conclusion, the preparation method of the crankshaft material provided by the invention adopts the step of feeding the Al wire once in the external refining, so that the molten steel is well deoxidized, the content of non-metallic impurities such as N, H, O and the like of the prepared crankshaft material is finally ensured to be low, the level of impurities is low, and the internal quality of the crankshaft material is ensured. The crankshaft prepared from the crankshaft material has high tensile strength, high purity and fine grain size, and can be widely applied to different fields of ships, automobiles, machinery and the like.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. a preparation method of crankshaft material, is characterized in that, comprises:

(a) successively adopt the process of electric furnace steelmaking, out-of-furnace refining and vacuum degassing to smelt the charge to obtain molten steel;

(b) casting molten steel into ingots and forging to obtain forgings;

(c) heat-treating the forging material to obtain crankshaft material;

Wherein, the out-of-furnace refining includes the step of feeding Al wire at one time; in the one-time feeding Al wire, the quality of the Al wire accounts for 0.05-0.07% of the mass of the charge;

The heat treatment method includes a combination of isothermal annealing and normalizing, and the method of combining isothermal annealing and normalizing includes the following steps: cooling the forging material to a first temperature, heating to a second temperature for heat preservation, and cooling to a third temperature. Three-temperature heat preservation, cooling to the fourth temperature, heating to the fifth temperature for heat preservation, and air cooling to obtain the crankshaft material;

The first temperature is 25-200°C, the second temperature is 830-850°C, the third temperature is 640-660°C, the fourth temperature is 250-350°C, and the fifth temperature is 810-830°C, the temperature is cooled to the first temperature and then immediately raised to the second temperature, and when the temperature is cooled to the fourth temperature, the temperature is immediately raised to the fifth temperature.

2 . The method for preparing a crankshaft material according to claim 1 , wherein, in the one-time Al feeding wire, the mass of the Al wire accounts for 0.06-0.07% of the mass of the charge. 3 .

3 . The method for preparing crankshaft material according to claim 1 , wherein, in the refining outside the furnace, argon blowing is performed during and before and after the one-time Al line feeding. 4 .

4 . The preparation method of crankshaft material according to claim 1 , wherein the ultimate vacuum degree of the vacuum degassing is 0-67 Pa, and the time that the ultimate vacuum degree is maintained is 15-30 min. 5 .

5 . The preparation method of crankshaft material according to claim 4 , wherein the ultimate vacuum degree of the vacuum degassing is 0-50 Pa. 6 .

6 . The preparation method of crankshaft material according to claim 4 , wherein the time for maintaining the ultimate vacuum degree is 20-30 min. 7 .

7 . The method for preparing a crankshaft material according to claim 1 , wherein the first temperature is 25-100° C. 8 .

8 . The method for preparing a crankshaft material according to claim 1 , wherein the second temperature is 840-850° C. 9 .

9 . The method for preparing a crankshaft material according to claim 1 , wherein the third temperature is 650-660° C. 10 .

10 . The method for preparing a crankshaft material according to claim 1 , wherein the fourth temperature is 300-350° C. 11 .

11 . The method for preparing a crankshaft material according to claim 1 , wherein the fifth temperature is 810-820° C. 11 .

12. A crankshaft material, characterized in that, it is prepared by the method for preparing a crankshaft material according to any one of claims 1-11.

13. The crankshaft material according to claim 12, wherein the crankshaft material comprises the following chemical components by mass fraction: the content of C is 0.43-0.46%, the content of Mn is 0.7-0.8%, and the content of Si is 0.7-0.8%. 0.17-0.3%, P content ≤ 0.012%, S content ≤ 0.006%, Cr content 0.15-0.25%, Ni content 0.25-0.35%, Mo content 0.07-0.12%, Cu content ≤0.2%, the content of Al is 0.015-0.04%, the content of H is ≤0.00015%, the content of O is ≤0.002%, the content of N is ≤0.007%, and the balance is iron.

14. A crankshaft, mainly made from the crankshaft material obtained by the method for preparing a crankshaft material according to any one of claims 1-11 or the crankshaft material according to claim 12 or 13.

15. An engine comprising the crankshaft of claim 14.

16. The application of the crankshaft of claim 14 in the fields of ships, automobiles or machinery.