CN113737098A

CN113737098A - Abrasion-resistant steel for automobile concrete mixing tank and preparation method thereof

Info

Publication number: CN113737098A
Application number: CN202111033090.0A
Authority: CN
Inventors: 吴刚; 刘志璞; 姜学锋; 董志鹏; 文小明; 韩宇; 许学力; 李霞; 陈红远; 吕建勋
Original assignee: Bengang Steel Plates Co Ltd
Current assignee: Bengang Steel Plates Co Ltd
Priority date: 2021-09-03
Filing date: 2021-09-03
Publication date: 2021-12-03
Anticipated expiration: 2041-09-03
Also published as: CN113737098B

Abstract

The invention provides a corrosion-resistant steel for an automobile concrete mixing tank and a preparation method thereof, wherein the steel comprises the following chemical components in percentage by mass: c: 0.15-0.20%; si is less than or equal to 0.01 percent; mn is less than or equal to 1.50 percent; s is less than or equal to 0.001 percent; p is less than or equal to 0.010 percent; al: 0.01-0.06%; o: 0.0010-0.0020%; n: 0.0010-0.0030%; ca: 0.0020-0.0040%; cr: 0.50-1.50%; ti: 0.20-0.40%; mo: 0.15-0.35%; cu: 0.19-0.40%, and the balance of Fe and other inevitable impurities. The preparation method comprises S1, steel making; s1.1, smelting; s1.2, refining in an LF ladle furnace; s1.3, continuously casting; s2, hot rolling; s2.1, heating; s2.2, controlling rolling; s2.3, cooling the layer; s2.4, coiling.

Description

Abrasion-resistant steel for automobile concrete mixing tank and preparation method thereof

Technical Field

The invention relates to the technical field of corrosion-resistant steel for an automobile concrete mixing tank, in particular to corrosion-resistant steel for the automobile concrete mixing tank and a preparation method thereof.

Background

In recent years, with the rapid development of large-scale projects, bridges, real estate and other constructions in China, the concrete mixer trucks are more and more widely used, and the demand of steel for the automobile mixing tanks is increased year by year. But the prior steel for the stirring tank has poor wear resistance and short service life; the corrosion resistance is poor; high yield ratio and difficult forming; poor welding performance; it is expensive. Therefore, it is urgently needed to design a steel material which has the characteristics of high strength, excellent abrasion resistance and welding performance, easy forming and easy processing under the conditions of corrosion and abrasion, can solve the contradiction of high strength and low yield ratio, and can not show heat and increase the manufacturing cost.

Disclosure of Invention

According to the technical problems, the steel for the abrasion-resistant automobile concrete mixing tank and the preparation method thereof are provided.

The technical means adopted by the invention are as follows:

the steel for the abrasion-resistant automobile concrete mixing tank comprises the following chemical components in percentage by mass:

c: 0.15-0.20%; si is less than or equal to 0.01 percent; mn is less than or equal to 1.50 percent; s is less than or equal to 0.001 percent; p is less than or equal to 0.010 percent; al: 0.01-0.06%; o: 0.0010-0.0020%; n: 0.0010-0.0030%; ca: 0.0020-0.0040%; cr: 0.50-1.50%; ti: 0.20-0.40%; mo: 0.15-0.35%; cu: 0.19-0.40%, and the balance of Fe and other inevitable impurities. Preferably, Mn: si is more than or equal to 10.

The steel for the abrasion-resistant automobile concrete mixing tank has the yield strength of not less than 600MPa, the tensile strength of over 1050MPa, the elongation after fracture of not less than 15 percent, the relative corrosion rate of 40 percent and the impact energy of minus 40 ℃ of over 47J.

In the aspect of chemical composition design, the invention reduces the addition of expensive alloy elements, adopts a small amount of Cr, Ti, Mo, Cu and other alloys, adopts pure steel and a new metamorphic inclusion technology, and reduces the manufacturing cost on the basis of ensuring excellent abrasion resistance and formability;

(2) controlling the heating temperature and the heat preservation time, wherein in order to avoid copper cracking, the heating temperature is required to be 1180-1220 ℃, and the heat preservation time is more than or equal to 30 minutes, so as to ensure that elements such as Mo, Ti, Cu, Cr and the like are fully blended, and meet the requirements of a rolling process;

(3) adopting a forced cooling process to enable the yield ratio to reach about 0.55;

(4) the thickness of the intermediate blank is controlled to be 55-60 mm under a high compression ratio (not less than 5.0), so that the structure of the steel plate is sufficiently fine and uniform;

(5) the final rolling temperature and the coiling temperature are controlled to obtain the required complex phase structure and performance, the 2300mm machine set forced cooling process is utilized to refine crystal grains, so that the tensile strength reaches more than 1050MPa, and the corrosion resistance is improved by more than 2.5 times.

The invention also discloses a preparation method of the corrosion-resistant steel for the concrete mixing tank of the automobile, which comprises the following steps:

s1, steel making:

s1.1, smelting: adding molten iron and scrap steel into a converter, lowering a gun to blow oxygen, carrying out C-O reaction, blowing nitrogen at the bottom, carrying out temperature measurement and sampling after blowing for 20 minutes, when the tapping temperature reaches 1670 ℃, pushing off slag by using a sliding plate to tap steel, and adding copper, ferromolybdenum and ferrochromium in the tapping process to carry out alloying; so that Cu, Mo and Cr in the steel reach certain values. The steel comprises the following chemical components in percentage by mass:

c: 0.15-0.20%; si is less than or equal to 0.01 percent; mn is less than or equal to 1.50 percent; s is less than or equal to 0.001 percent; p is less than or equal to 0.010 percent; al: 0.01-0.06%; o: 0.0010-0.0020%; n: 0.0010-0.0030%; ca: 0.0020-0.0040%; cr: 0.50-1.50%; mo: 0.15-0.35%; cu: 0.19-0.40%, and the balance of Fe and other inevitable impurities;

s1.2, refining in an LF ladle furnace:

adding ferrotitanium into molten steel in a refining process, wherein the mass percent of Ti element in the molten steel is 0.20-0.40%; the three-phase electrode is used for heating in the refining process, and titanium is more active in steel and is easy to cause burning loss, so that ferrotitanium is added in the LF refining process, and the requirement of the steel on gas content is strict. And the micro-positive pressure is required to be kept in the refining treatment process, the calcium silicate wire is added after the refining is finished, and when the S in the molten steel is less than or equal to 0.005 percent, 400 meters of the calcium silicate wire is added, so that the inclusions are fully spheroidized, and the product performance is improved.

S1.3, continuous casting:

adding molten steel into a tundish, and casting to obtain a continuous casting billet; the injection speed is controlled to be 1.2m/min, the superheat degree is controlled to be less than or equal to 30 ℃, and the injection temperature and the injection speed are strictly controlled to ensure the surface and internal quality of the continuous casting billet;

s2, hot rolling:

s2.1, heating:

heating the continuous casting billet at 1180-1220 ℃ for more than or equal to 30 minutes; controlling the heating temperature and the heat preservation time, wherein high-temperature rapid heating is required to avoid copper cracking, the heating temperature is 1180-1220 ℃, the heat preservation time is more than or equal to 30 minutes, the full fusion of Cu, Mo, Ti and Cr alloys is ensured, and steel has good plasticity and good plate shape during rolling, so that the requirements of the rolling process are met;

s2.2, rolling control:

carrying out rough rolling on the heated continuous casting billet, wherein the rough rolling adopts a 3+3 mode to obtain an intermediate billet, and the continuous casting billet is rolled by adopting large reduction in the rough rolling stage, and the pass reduction rate is more than 25%;

performing finish rolling on the intermediate blank to obtain a finished product, wherein the compression ratio of the intermediate blank and the finished product is more than 5, and the finish rolling temperature is less than or equal to 900 ℃; and the final pass reduction rate of the finish rolling is not lower than 20%.

S2.3, carrying out laminar cooling, wherein a water cooling mode is adopted, the cooling rate of the first five groups of water cooling is more than or equal to 50m/min, and the cooling rate of the later groups of water cooling is 10-15 m/min; s2.4, coiling:

and coiling the cooled finished product at 350-450 ℃.

The required complex phase structure and performance are obtained by controlling the finish rolling temperature and the coiling temperature, and crystal grains are refined by utilizing a 2300mm machine set forced laminar cooling process of the steel, so that the tensile strength reaches over 1050MPa, the yield ratio reaches about 0.55, and the corrosion resistance is improved by over 2.5 times.

Preferably, in step S2.2, the thickness of the intermediate blank is 55mm to 60 mm. The structure of the steel plate is fully fine and uniform.

Compared with the prior art, the invention has the following advantages:

1. the invention develops a novel special steel for a concrete mixing tank by adopting a mode of improving wear resistance and corrosion resistance on the basis of carbon-manganese, wherein the high wear resistance is obtained by compounding and strengthening carbon, manganese, molybdenum and titanium alloy elements; in the aspect of corrosion control, the matrix current is reduced by adding elements such as copper, chromium and the like, the matrix potential is increased, the corrosion process is inhibited by reducing the matrix current, and the corrosion resistance of the steel plate is improved. The toughness is improved on the basis of reducing corrosion, so that the steel grade has good corrosion resistance, and particularly, the abrasion resistance of a steel plate for manufacturing a concrete mixer truck tank body and a blade is more than 2.5 times that of steel plates of 520JJ and Q355B.

2. The steel grade has good low-temperature impact toughness and cold bending processability, meets the subsequent processing requirements, and can realize the light-weight design of the steel for the automobile stirring tank on the basis of the existing equipment.

3. The invention relates to a steel grade with simple production process and low content of noble alloy elements, which reduces the production difficulty and the manufacturing cost and is beneficial to the large-scale popularization of the steel grade.

4. The steel for the abrasion-resistant automobile concrete mixing tank has the yield strength of no less than 600MPa, the yield ratio of about 0.55, the tensile strength of over 1050MPa, the elongation after fracture of no less than 15 percent and the relative corrosion rate of 40 percent, and is improved by 2.5 times and the impact energy at minus 40 ℃ of over 47J. Solves the problems of high yield ratio, difficult forming and the like of the traditional steel plate with high strength.

5. The lightweight design and development of the novel concrete mixer truck are realized by utilizing the characteristics of high hardness, high wear resistance and easy processing of the high-performance wear-resistant steel. The weight reduction of the tank body of the new vehicle type reaches 15-25%, the tank body replaces an original 520JJ steel plate, the abrasion resistance of the tank body is more than 2.5 times of that of 520JJ and Q355B, and the tank body has the characteristics of high abrasion resistance and high toughness, so that the tank body can well bear the impact of an air cannon when excess materials are removed, and the upgrading and updating of the automobile concrete mixer are realized.

Based on the reasons, the invention can be widely popularized in the fields of corrosion-resistant steel for the concrete mixing tank of the automobile and the like.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a metallographic structure diagram of a steel for an abrasion-resistant concrete mixing tank for an automobile according to an embodiment of the present invention.

FIG. 2 is a graph showing non-metallic inclusions of a corrosion-resistant steel for a concrete mixer tank of an automobile according to an embodiment of the present invention.

FIG. 3 is a metallographic structure diagram of a comparative example in an embodiment of the present invention.

FIG. 4 is a diagram showing non-metallic inclusions in a comparative example in an embodiment of the present invention.

Detailed Description

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. 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.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

The relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate. Any specific values in all examples shown and discussed herein are to be construed as exemplary only and not as limiting. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

In the description of the present invention, it is to be understood that the orientation or positional relationship indicated by the directional terms such as "front, rear, upper, lower, left, right", "lateral, vertical, horizontal" and "top, bottom", etc., are generally based on the orientation or positional relationship shown in the drawings, and are used for convenience of description and simplicity of description only, and in the absence of any contrary indication, these directional terms are not intended to indicate and imply that the device or element so referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore should not be considered as limiting the scope of the present invention: the terms "inner and outer" refer to the inner and outer relative to the profile of the respective component itself.

Spatially relative terms, such as "above … …," "above … …," "above … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial relationship to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary term "above … …" can include both an orientation of "above … …" and "below … …". The device may be otherwise variously oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

It should be noted that the terms "first", "second", and the like are used to define the components, and are only used for convenience of distinguishing the corresponding components, and the terms have no special meanings unless otherwise stated, and therefore, the scope of the present invention should not be construed as being limited.

As shown in fig. 1 to 4, the steel for the abrasion-resistant automobile concrete mixing tank comprises the following chemical components in percentage by mass:

s1, steel making:

s1.2, refining in an LF ladle furnace:

S1.3, continuous casting:

s2, hot rolling:

s2.1, heating:

s2.2, rolling control:

S2.3, carrying out laminar cooling, wherein a water cooling mode is adopted, the cooling rate of the first five groups of water cooling is more than or equal to 50m/min, and the cooling rate of the later groups of water cooling is 10-15 m/min;

s2.4, coiling:

and coiling the cooled finished product at 350-450 ℃.

In step S2.2, the thickness of the intermediate blank is 55mm to 60 mm. The structure of the steel plate is fully fine and uniform.

The steel grade Q355B was used as comparative example 1, the steel grade 520JJ was used as comparative example 2, the relative corrosion rates of comparative example 1 and comparative example 2 were 100% and 85%, respectively, and the relative corrosion rate of the steel for an abrasion-resistant concrete mixing tank of this embodiment was 40%. Fig. 1 and 2 show the metallographic structure and nonmetallic inclusions of a steel for an abrasion-resistant concrete mixer tank according to this embodiment. The metallographic structure shown in fig. 1 is ferrite and bainite, the metallographic structure is favorable for formability and abrasion resistance, the grain size is 12 grades, and the percentage content of the second phase is as follows: 17 percent, the nonmetallic inclusion shown in figure 2 is B0.5, the rest is grade 0, and the steel quality is relatively pure. Fig. 3 and 4 show the metallographic structure and nonmetallic inclusions of comparative example 2520 JJ. The metallographic structure shown in fig. 3 is: ferrite plus pearlite, second phase percentage: 20% of the non-metallic inclusions shown in FIG. 4 were A1.5B1.5, and the inclusions were present in a chain form, which adversely affected the performance of the steel.

The chemical components and the mass percentages of the chemical components of the embodiments 1-8 are shown in the following table 1:

TABLE 1

Table 1 continues the table:

the parameters of the heating temperature, the heat preservation time, the thickness, the finish rolling temperature, the coiling temperature and the cooling rate of the steel for the abrasion-resistant automobile concrete mixing tank of the embodiment 1-8 are shown in the following table 2:

TABLE 2

The properties of the corrosion-resistant steel for the concrete mixing tank of the automobile of examples 1 to 8 are shown in table 3:

TABLE 3

The properties of comparative examples 1 and 2 are shown in table 4:

TABLE 4

As can be seen from a comparison of tables 3 and 4, the yield strength, tensile strength and impact energy at-40 ℃ of the present application are significantly superior to those of the comparative example.

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. The steel for the abrasion-resistant automobile concrete mixing tank is characterized by comprising the following chemical components in percentage by mass:

c: 0.15-0.20%; si is less than or equal to 0.01 percent; mn is less than or equal to 1.50 percent; s is less than or equal to 0.001 percent; p is less than or equal to 0.010 percent; al: 0.01-0.06%; o: 0.0010-0.0020%; n: 0.0010-0.0030%; ca: 0.0020-0.0040%; cr: 0.50-1.50%; ti: 0.20-0.40%; mo: 0.15-0.35%; cu: 0.19-0.40%, and the balance of Fe and other inevitable impurities.

2. The steel for an abrasion-resistant automobile concrete mixing tank according to claim 1, wherein the steel for an abrasion-resistant automobile concrete mixing tank has a yield strength of not less than 600MPa, a tensile strength of more than 1050MPa, a relative corrosion rate of 40%, and an impact energy of more than 47J at-40 ℃.

3. The preparation method of the corrosion-resistant steel for the concrete mixing tank of the automobile is characterized by comprising the following steps of:

s1, steel making:

s1.1, smelting:

adding molten iron and scrap steel into a converter, wherein the tapping temperature is 1670 ℃, and adding copper, ferromolybdenum and ferrochromium for alloying in the tapping process; the steel comprises the following chemical components in percentage by mass:

s1.2, refining in an LF ladle furnace:

adding ferrotitanium into molten steel in a refining process, wherein the mass percent of Ti element in the molten steel is 0.20-0.40%;

s1.3, continuous casting:

adding molten steel into a tundish, and casting to obtain a continuous casting billet;

s2, hot rolling:

s2.1, heating:

heating the continuous casting billet at 1180-1220 ℃ for more than or equal to 30 minutes;

s2.2, rolling control:

carrying out rough rolling on the heated continuous casting billet to obtain an intermediate billet, wherein the pass reduction rate is more than 25% in the rough rolling process;

performing finish rolling on the intermediate blank to obtain a finished product, wherein the compression ratio of the intermediate blank and the finished product is more than 5, and the finish rolling temperature is less than or equal to 900 ℃;

s2.4, coiling:

and coiling the cooled finished product at 350-450 ℃.

4. The method for preparing the steel for the abrasion-resistant automobile concrete mixing tank according to the claim 3, wherein in the step S1.2, the molten steel adopts slight positive pressure in the refining process; and adding the calcium silicate wire after refining, and adding the calcium silicate wire 400 m when S in molten steel is less than or equal to 0.005 percent.

5. The method for preparing the steel for the abrasion-resistant automobile concrete mixing tank according to the claim 3, wherein in the step S1.3, the pouring speed is 1.2m/min, and the superheat degree is less than or equal to 30 ℃.

6. The method for preparing the steel for the abrasion-resistant automobile concrete mixing tank according to the claim 3, wherein in the step S2.2, the rough rolling adopts a 3+3 mode; and the final pass reduction rate of the finish rolling is not lower than 20%.

7. The method for preparing the steel for the abrasion-resistant automobile concrete mixing tank according to the claim 3, wherein in the step S2.2, the thickness of the intermediate blank is 55mm to 60 mm.