CN117821838A - Pipe jacking roller for CPE unit and preparation method thereof - Google Patents
Pipe jacking roller for CPE unit and preparation method thereof Download PDFInfo
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- 238000002360 preparation method Methods 0.000 title abstract description 13
- 239000000126 substance Substances 0.000 claims abstract description 20
- 239000012535 impurity Substances 0.000 claims abstract description 8
- 238000004519 manufacturing process Methods 0.000 claims abstract description 7
- 238000010438 heat treatment Methods 0.000 claims description 80
- 238000001816 cooling Methods 0.000 claims description 26
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 21
- 229910001562 pearlite Inorganic materials 0.000 claims description 19
- 238000005496 tempering Methods 0.000 claims description 17
- 238000000034 method Methods 0.000 claims description 14
- 229910001567 cementite Inorganic materials 0.000 claims description 13
- KSOKAHYVTMZFBJ-UHFFFAOYSA-N iron;methane Chemical group C.[Fe].[Fe].[Fe] KSOKAHYVTMZFBJ-UHFFFAOYSA-N 0.000 claims description 13
- FBPFZTCFMRRESA-JGWLITMVSA-N D-glucitol Chemical compound OC[C@H](O)[C@@H](O)[C@H](O)[C@H](O)CO FBPFZTCFMRRESA-JGWLITMVSA-N 0.000 claims description 12
- 238000005266 casting Methods 0.000 claims description 9
- 238000004321 preservation Methods 0.000 claims description 7
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 6
- 238000009750 centrifugal casting Methods 0.000 claims description 6
- 229910002804 graphite Inorganic materials 0.000 claims description 6
- 239000010439 graphite Substances 0.000 claims description 6
- 229910052742 iron Inorganic materials 0.000 claims description 5
- 229910001349 ledeburite Inorganic materials 0.000 claims description 5
- 238000011081 inoculation Methods 0.000 claims description 4
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- 238000004512 die casting Methods 0.000 claims description 3
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Abstract
The invention discloses a pipe jacking roller for CPE units and a preparation method thereof, wherein the pipe jacking roller comprises the following chemical components in percentage by mass: c:3.0 to 3.3 percent; si:1.3 to 1.8 percent; mn:0.5 to 0.7 percent; p: less than or equal to 0.050%; s is less than or equal to 0.020%; cr:0.5 to 0.9 percent; ni:1.5 to 2.5 percent; 0.4 to 0.6 percent of Mo; mg is more than or equal to 0.04 and less than or equal to 0.1 percent, and the balance is Fe and unavoidable impurities, and the total is 100 percent. The wear-resisting performance of the CPE jacking pipe can be improved, the steel pipe passing amount of the CPE jacking pipe is improved, the service life of the CPE jacking pipe is prolonged, and meanwhile the roller breaking rate in the production process of the CPE jacking pipe can be reduced.
Description
Technical Field
The invention relates to a pipe jacking roller for a CPE unit and a preparation method thereof, and belongs to the technical field of rollers.
Background
At present, the roller adopted by the CPE jacking technology is a passive roller which is not driven to rotate by an active motor, in the CPE jacking technology, a steel pipe capillary is wrapped on the surface of a core rod, and forward power is provided by pushing by a rear jacking rod, in the use process of the passive roller, not only adhesive abrasion and furrow abrasion but also frequent impact force are received, the roller conventionally used on a CPE unit adopts the specification of SGPII in the classification of 'nodular cast iron' in the cast iron roller with the standard number of GB/T1504-2008, the breaking rate is high, once the roller is broken, rolling damage occurs, if the roller is not found in time, batch rolling damage of the waste pipe occurs, and meanwhile, the machine frame is required to be replaced, once the roller is broken, not only the loss of the machine frame but also the phenomenon of rolling damage of the pipe occurs, the production efficiency of the steel pipe is reduced, and the quality control cost is increased.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide the pipe jacking roller for the CPE unit, which not only can improve the wear resistance, the steel pipe passing amount and the service life of the pipe jacking roller, but also can reduce the roller breaking rate in the production process of the CPE pipe jacking.
In order to solve the technical problems, the technical scheme of the invention is as follows: the pipe jacking roller for the CPE unit comprises the following chemical components in percentage by mass: c:3.0 to 3.3 percent; si:1.3 to 1.8 percent; mn:0.5 to 0.7 percent; p: less than or equal to 0.050%; s is less than or equal to 0.020%; cr:0.5 to 0.9 percent; ni:1.5 to 2.5 percent; 0.4 to 0.6 percent of Mo; mg is more than or equal to 0.04 and less than or equal to 0.1 percent, and the balance is Fe and unavoidable impurities, and the total is 100 percent.
Further, the hardness of the surface chilling layer of the pipe jacking roller after heat treatment is 52-65 HSD and/or the hardness unevenness of the same circumference is less than or equal to 5HSD.
Further, the metallographic structure of the surface chilling layer of the top pipe roller after heat treatment is granular pearlite, sorbite, ledeburite and graphite.
Further, the metallographic structure of the matrix after the heat treatment of the top tube roll is granular pearlite and sorbite, and the dispersed secondary cementite is formed in the matrix.
Further, the pipe jacking roller is treated by a heat treatment procedure, in the heat treatment, the normalizing temperature is 950-1000 ℃, the heat preservation is carried out for 3-7 hours, air cooling is carried out after the normalizing, the air cooling is carried out to 280-300 ℃, then the stress relief tempering is carried out, the tempering temperature is 400-480 ℃, the heat preservation time is 4-7 hours, and the air cooling is carried out after the stress relief tempering.
Further, the normalizing temperature is 980 ℃, the air cooling is carried out to 280 ℃ after the normalizing, and the tempering temperature is 450 ℃.
Further, the temperature is raised at a temperature raising rate of 45 to 55 ℃/h after air cooling to 280 to 300 ℃.
Further, in the heat treatment, the temperature is raised to 120-180 ℃ at a heating rate of 30-35 ℃/h, then to 550-650 ℃ at a heating rate of 45-55 ℃/h, the temperature is kept for 1-3 h, and then to the normalizing temperature at a heating rate of 45-55 ℃/h.
Further, in the heat treatment, the temperature is raised to 150 ℃ at a heating rate of 33 ℃/h, then to 600 ℃ at a heating rate of 50 ℃/h, and the temperature is kept for 1 to 3 hours, and then to the normalizing temperature at a heating rate of 50 ℃/h.
The invention also provides a preparation method of the pipe jacking roller for the CPE unit, which comprises the following steps:
mixing according to chemical components and mass percentages thereof, and then carrying out iron making, spheroidizing inoculation treatment and casting to obtain a roller blank;
performing heat treatment on the roller blank;
and turning to obtain the pipe jacking roller for the CPE unit.
The casting adopts static die casting or centrifugal casting; the chemical components and the mass percentages of the surface working layers at the outer sides of the top tube rolls are in particular the chemical components and the mass percentages of the surface working layers at the outer sides of the top tube rolls during centrifugal casting, and the surface chilling layers correspond to the surface working layers.
After the technical scheme is adopted, the upper limit of the content of C is compressed, the content of C is limited to 3.0-3.3%, the content of Si is limited to 1.3-1.8% in order to be matched with the content of C, and the content of Mn is limited to 0.5-0.7% in order to improve the wear resistance of a matrix, so that the lower limit of the content of Mn is improved; ni can play a role in solid solution strengthening, and the largest role in solid solution strengthening is to control the reduction of the hardness of a roller to be within 4HSD (compared with the prior art adopting standard roller ratio), and meanwhile, a matrix can better grasp or hold carbide without falling the carbide; cr, mo being carbide-promoting elementsThe element, mo can also play a role of fine crystal, and the content of the components of Mo and Ni is reduced as far as possible in an acceptable range in order to control the cost in consideration of the fact that the Mo and Ni are high-value metals; in the present invention, primary cementite (Fe) is allowed to react with high temperature (i.e., normalizing at 950 to 1000 ℃ C.) during the heat treatment 3 CI) dissolution degradation to form granular carbide, and during the carbide dissolution degradation, C element diffuses toward the matrix, during air cooling, secondary cementite (Fe 3 CII), the reduction of brittle phase after heat treatment improves the impact toughness of the roller; the diffusion of the element C in the heat treatment process strengthens the hardness of the matrix, and secondary cementite is precipitated in the matrix, so that the wear resistance of the roller is further improved, therefore, the roller reduces the possibility that the tip of the ledeburite forms a crack source after the specific heat treatment, the high-temperature diffusion heat treatment is applied to roller production, and the roller matrix material is converted into granular pearlite and sorbite tissues after the heat treatment, so that the toughness of the material can be effectively improved on the premise of ensuring the hardness and the strength of the material. Meanwhile, the dissolved carbide can greatly improve the strength of the roller matrix, and the dissolved carbide and the dispersed secondary cementite can improve the wear resistance of the material, thereby improving the steel passing amount level of the steel pipe.
Drawings
FIG. 1 (a) is a metallographic view of the carbide distribution of a D-like matrix;
FIG. 1 (b) is a metallographic structure diagram of the carbide distribution of the A-sample matrix;
FIG. 2 (a) is a metallographic view of the D-sample carbide tip;
FIG. 2 (b) is a metallographic view of the tip of the A-type carbide;
FIG. 3 (a) is a metallographic view of the interior of the D-like carbide;
FIG. 3 (b) is a metallographic view of the inside of the A-type carbide;
FIG. 4 (a) is a 500-fold metallographic structure of sample B;
FIG. 4 (b) is a 1000 Xmetallographic structure of sample A;
FIG. 5 (a) is a graph of the morphology of sample A at 3000 x after scanning by a scanning electron microscope;
fig. 5 (b) is a 2000-fold profile of sample D after scanning by scanning electron microscopy.
Detailed Description
The invention provides a pipe jacking roller for a CPE unit and a preparation method thereof, and the technical parameters can be properly improved by a person skilled in the art by referring to the content of the text. It is expressly noted that all such similar substitutions and modifications will be apparent to those skilled in the art, and they are intended to be within the scope of the present invention. While the methods and applications of this invention have been described in terms of preferred embodiments, it will be apparent to those skilled in the relevant art that the invention can be practiced and practiced with modification and alteration and combination of the methods and applications herein without departing from the spirit and scope of the invention.
The pipe jacking roller for the CPE unit comprises the following chemical components in percentage by mass: c:3.0 to 3.3 percent; si:1.3 to 1.8 percent; mn:0.5 to 0.7 percent; p: less than or equal to 0.050%; s is less than or equal to 0.020%; cr:0.5 to 0.9 percent; ni:1.5 to 2.5 percent; 0.4 to 0.6 percent of Mo; mg is more than or equal to 0.04 and less than or equal to 0.1 percent, and the balance is Fe and unavoidable impurities, which account for 100 percent.
Specifically, the hardness of the surface chilling layer of the pipe jacking roller after heat treatment is 52-65 HSD, and the hardness unevenness of the same circumference is less than or equal to 5HSD.
Specifically, the metallographic structure of the surface chilling layer of the pipe jacking roller after heat treatment is granular pearlite, sorbite, ledeburite and graphite; specifically, the graphite is spherical or agglomerate, uniformly distributed, the spheroidization grade is less than or equal to 3 grades, and the graphite size is less than or equal to 6 grades. The surface chilling layer is more than or equal to 50mm.
Specifically, the metallographic structure of the matrix after the heat treatment of the pipe jacking roller is granular pearlite+sorbite, and the dispersed secondary cementite is formed in the matrix.
Specifically, in the heat treatment, 4 sections of heating, 3 sections of heat preservation and 2 sections of cooling are adopted;
the first section is heated to 120-180 ℃ at a heating rate of 30-35 ℃/h, because the roller collar is a thick-wall piece, the heating is too fast, and the temperature difference between the inner surface and the outer surface of the casting blank is too large, so that cracking is easy to cause; the slow temperature rise is only 120-180 ℃, which is the angle for energy saving and efficiency;
the second section is heated to 550-650 ℃ at a heating rate of 45-55 ℃/h, and the temperature is kept for 1-3 h; according to TTT curve, the material is a pearlite isothermal transformation area at 385-735 ℃, the temperature of nose tip is 625 ℃, namely, the temperature is over 400 ℃, recrystallization reaction can occur, and the temperature is kept for 1-3 hours at 550-650 ℃, so that crystal nuclei of casting blanks are as uniform as possible, which is one of cores of heat treatment design, and preparation of tissues is made for subsequent air cooling;
the third section is heated to the normalizing temperature at the heating rate of 45-55 ℃/h, the normalizing temperature is 950-1000 ℃, and the temperature is kept for 3-7 h; the method is one of the cores of the heat treatment design, because if carbide dissolution degradation is needed, the carbide dissolution degradation is promoted to diffuse to a matrix, the temperature is more than 950 ℃, the heat preservation time is determined according to the proportion requirement of carbide dissolution by diffusion, and if more carbide is needed to be reserved, the heat preservation time is reduced;
fourth section: air cooling is carried out after normalizing, and the air cooling is carried out to 280-300 ℃;
fifth stage air cooling to 280-300 deg.c, heating to 400-480 deg.c at 45-55 deg.c/hr, stress eliminating tempering and heat maintaining for 4-7 hr to reduce cracking tendency of the roller; on the other hand, the thermal stress in the roller is eliminated by tempering; the temperature is reduced to 280-300 ℃ to start heating, but not to normal temperature and then heating, so that the energy saving is considered.
And (3) performing air cooling to room temperature after tempering in the sixth section.
Preferably, in the heat treatment, the temperature is raised to 150 ℃ at a temperature raising rate of 33 ℃/h, then to 600 ℃ at a temperature raising rate of 50 ℃/h, the temperature is kept for 2h, the temperature is raised to a normalizing temperature at a temperature raising rate of 50 ℃/h again, the normalizing temperature is 980 ℃, the temperature is cooled to 280 ℃ after normalizing, the temperature is raised to a tempering temperature at a temperature raising rate of 50 ℃/h again, and the tempering temperature is 450 ℃.
The preparation method of the pipe jacking roller for the CPE unit comprises the following steps:
mixing according to chemical components and mass percentages thereof, and then carrying out iron making, spheroidizing inoculation treatment and casting to obtain a roller blank;
performing heat treatment on the roller blank;
and turning (including rough turning and finish turning) to obtain the pipe jacking roller for the CPE unit.
The casting adopts static die casting or centrifugal casting; the chemical components and the mass percentages of the surface working layers at the outer sides of the top tube rolls are in particular the chemical components and the mass percentages of the surface working layers at the outer sides of the top tube rolls during centrifugal casting, and the surface chilling layers correspond to the surface working layers.
In the invention, the upper limit of the C content is compressed, the C mass content is limited to 3.0-3.3%, the Si content is limited to 1.3-1.8% for matching with the C mass content, and the Mn content is limited to 0.5-0.7% for improving the abrasion resistance of a matrix, thereby improving the lower limit of the Mn content; ni can play a role in solid solution strengthening, and the largest role in solid solution strengthening is to control the reduction of the hardness of a roller to be within 4HSD (compared with the prior art adopting standard roller ratio), and meanwhile, a matrix can better grasp or hold carbide without falling the carbide; cr and Mo are carbide promoting elements, mo also plays a role of fine crystal, and in consideration of Mo and Ni being high-value metals, the component content thereof is reduced as much as possible within an acceptable range so as to control the cost; in the present invention, primary cementite (Fe) is allowed to react with high temperature (i.e., normalizing at 950 to 1000 ℃ C.) during the heat treatment 3 CI) dissolution degradation to form granular carbide, and during the carbide dissolution degradation, C element diffuses toward the matrix, during air cooling, secondary cementite (Fe 3 CII), the reduction of brittle phase after heat treatment improves the impact toughness of the roller; diffusion of C element in the heat treatment process strengthens the hardness of the matrix, secondary cementite precipitation is carried out in the matrix, and the wear resistance of the roller is further improved, so that the roller reduces the possibility of crack source formation at the tip of ledeburite after the specific heat treatment, the high-temperature diffusion heat treatment is applied to roller production, and the roller matrix material is converted into granular pearlite and sorbite tissues after the heat treatment, thus ensuring the hardness of the materialAnd on the premise of strength, the toughness of the material is effectively improved. Meanwhile, the dissolved carbide can greatly improve the strength of the roller matrix, and the dissolved carbide and the dispersed secondary cementite can improve the wear resistance of the material, thereby improving the steel passing amount level of the steel pipe.
In order that the invention may be more readily understood, a more particular description of the invention will be rendered by reference to specific embodiments that are illustrated in the appended drawings.
Example 1
The pipe jacking roller for the CPE unit comprises the following chemical components in percentage by mass: c:3.0%; si:1.3%; mn:0.5%; p:0.02%; s:0.02%; cr:0.5%; ni:1.5%; 0.4% of Mo; mg:0.04%, the balance Fe and unavoidable impurities, totaling 100%.
The preparation method of the pipe jacking roller for the CPE unit comprises the following steps:
mixing according to chemical components and mass percentages thereof, and then carrying out iron making, spheroidizing inoculation treatment and static casting to obtain a roller blank;
performing heat treatment on the roller blank;
and turning (including rough turning and finish turning) to obtain the pipe jacking roller for the CPE unit.
In the heat treatment, the temperature is raised by 4 sections, the temperature is kept by 3 sections, and the temperature is lowered by 2 sections;
the first stage is heated to 150 ℃ at a heating rate of 33 ℃/h;
the second stage is heated to 600 ℃ at a heating rate of 50 ℃/h, and the temperature is kept for 2h;
the third stage is heated to the normalizing temperature at the heating rate of 50 ℃/h, the normalizing temperature is 950 ℃, and the temperature is kept for 2 to 7 hours;
fourth section: air cooling is carried out after normalizing, and the air cooling is carried out to 280 ℃;
fifth stage air cooling to 280 deg.c, heating at 50 deg.c/hr to 450 deg.c, stress eliminating tempering and heat maintaining for 5 hr;
and (3) performing air cooling to room temperature after tempering in the sixth section.
Sampling the roller after steel passing:
sample a: the sample is taken outside the roll neck, belongs to a place which is not contacted with the red hot steel pipe when the steel is passed, and the observation surface is also outside the roll, and the tissue, the hardness and the roll which is not passed through the steel after the heat treatment of the sample A are basically consistent although the roll is passed through the steel in a large quantity.
Sample B: the vertical line is cut downwards, a section is formed by the vertical line and the roll pass, the middle section is taken, the contact surface is used for passing steel, and the influence of the passing steel on tissues, hardness and the like can be observed;
c sample: cutting a roller vertical line, cutting a sample which is not damaged and is cut off simultaneously below the sample B, and comparing a fracture area with the sample B;
example two
The pipe jacking roller for the CPE unit comprises the following chemical components in percentage by mass: c:3.3%; si:1.8%; mn:0.7%; p:0.050%; s:0.020%; cr:0.9%; ni:2.5%; 0.6% of Mo; mg:0.1% Fe and the balance of unavoidable impurities, totaling 100%.
The preparation method of the top tube roll for the CPE unit in the embodiment is the same as that in the first embodiment.
Example III
The pipe jacking roller for the CPE unit comprises the following chemical components in percentage by mass: c:3.2%; si:1.5%; mn:0.6%; p:0.030%; s:0.030%; cr:0.7%; ni:2%; 0.5% of Mo; mg:0.04%, the balance Fe and unavoidable impurities, totaling 100%.
The preparation method of the top tube roll for the CPE unit in the embodiment is the same as that in the first embodiment.
Example IV
The chemical composition and the mass percentage of the top tube roller for the CPE unit are the same as those of the embodiment.
The preparation method of the top tube roll for the CPE unit in the embodiment is basically the same as that in the third embodiment, and the difference is that: the heat treatment is different, specifically as follows:
in the heat treatment, the temperature is raised by 4 sections, the temperature is kept by 3 sections, and the temperature is lowered by 2 sections;
the first stage is heated to 130 ℃ at a heating rate of 30 ℃/h;
the second stage is heated to 650 ℃ at a heating rate of 45 ℃/h, and the temperature is kept for 2h;
the third stage is heated to a normalizing temperature at a heating rate of 45 ℃/h, the normalizing temperature is 1000 ℃, and the temperature is kept for 5h;
fourth section: air cooling is carried out after normalizing, and the air cooling is carried out to 300 ℃;
fifth stage air cooling to 300 deg.C, heating at 45 deg.C/h heating rate to 420 deg.C, stress-relieving tempering, and holding for 4 hr;
and (3) performing air cooling to room temperature after tempering in the sixth section.
Comparative example one
The chemical components and the mass percentages of the top tube roll in the comparative example are the same as those in the first embodiment, and the preparation method of the top tube roll in the comparative example is basically the same as that in the first embodiment, except that: the method does not comprise the following steps: and carrying out heat treatment on the roller blank.
Sampling: taking a sample of the pipe jacking roller prepared in the embodiment, which is hereinafter referred to as a D sample;
comparative example two
The chemical components and mass percentages of the top tube roll of the comparative example are as follows: c:3.6%; si:1.2%; mn:0.4%; p:0.10%; s:0.030%; cr:0.3%; ni:2.2%; 0.3% of Mo; mg:0.04%, the balance of Fe and unavoidable impurities, and 100% in total, which accords with the roller component and composition of the specification of SGPII in the "pearlite spheroidal graphite II" in the "spheroidal graphite cast iron" classification in the cast iron roller with the standard number of GB/T1504-2008.
The method for manufacturing the top tube roll of this comparative example was the same as that of comparative example one.
Sampling: taking a sample of the pipe jacking roller prepared in the embodiment, which is hereinafter referred to as an E sample;
as can be seen from FIGS. 1 (a) and 1 (b), the carbide distribution in the roll after the heat treatment is greatly changed, and primary cementite Fe 3 CI undergoes extensive dissolution degradation and the matrix structure also changes from pure pearlite to a granular pearlite + sorbite structure.
As can be seen from fig. 2 (a) and fig. 2 (b), after the heat treatment, the initial purposes of passivation of the sharp corners and penetration of the thin walls are achieved, which greatly reduces the probability of forming crack sources inside the roller and is beneficial to improving the impact resistance of the roller.
As can be seen from fig. 3 (a) and 3 (b), after heat treatment, the structure is significantly changed, and the matrix structure is pearlite before heat treatment, and the pearlite+sorbite granules after heat treatment are beneficial to improving the crack propagation resistance of the matrix.
As can be seen from fig. 4 (a) and 4 (B), no significant changes in the a-and B-type structures occurred, indicating that the matrix remained stable enough during operation of the roll.
As can be seen from fig. 5 (a) and 5 (b), sample a is granular pearlite+sorbite; while the untreated D-sample is a typical pearlitic structure.
Hardness comparison was performed on samples D and C, see Table 1 below:
table 1D sample and C sample hardness test table
As can be seen from the above table, the hardness of the roll material after heat treatment is not increased by the set heat treatment process, and the design is satisfied because the carbide is melted after heat treatment, and the carbide is F e3 C, the C enters the matrix of the granular pearlite, so that the hardness of the matrix is improved:
on one hand, the proportion of the matrix under the optical field of the optical lens is improved, and the influence brought by the matrix is two: (1) the brittleness of the carbide is very large, the toughness is almost zero, and the toughness of the granular pearlite is far higher than that of the carbide, so that the impact resistance of the roller is greatly improved, and the roller is more suitable for CPE units; (2) the cast carbide is in a block aggregation form, and the carbide which forms dispersion distribution after heat treatment is surrounded by a matrix.
On the other hand, the hardness of the matrix is greatly improved by nearly 10%, which brings about three changes: (1) the ability of the matrix to grip the carbide is improved (continuing (2) above); (2) the wear resistance of the matrix is improved; (3) once the crack is formed, propagation in the matrix will be limited.
Microhardness analysis was performed on samples a, B, D and E, data as in table 2 below:
table 2 microhardness data summary table
From table 2 we can see:
(1) the heat-treated A-type carbide 654HV and B-type carbide 646HV showed a significant hardness drop relative to the untreated D-type carbide 928HV, indicating primary cementite Fe 3 CI dissolves and degenerates in the heat treatment process, and simultaneously reduces the hardness difference of carbide and matrix, and further improves the impact resistance.
(2) The as-cast D-like carbide (not heat treated) 928HV of the inventive material was higher than 856HV of standard SGPII E-like carbide.
(3) The carbide dissolves and degenerates during heat treatment and diffuses toward the matrix, and the matrix structure is transformed from pearlite to a structure of granular pearlite+sorbite, the a-sample matrix microhardness 432HV, the b-sample matrix microhardness 425HV, are all higher than 394HV of the D-sample as-cast (not heat treated). The higher strength and toughness of the matrix structure will effectively increase the ability of the matrix to grip the carbide and provide better wear resistance.
(4) D-sample matrix microhardness HV394HV, higher than 355HV of E-sample (standard SGPII).
The technical problems, technical solutions and advantageous effects solved by the present invention have been further described in detail in the above-described embodiments, and it should be understood that the above-described embodiments are only illustrative of the present invention and are not intended to limit the present invention, and any modifications, equivalent substitutions, improvements, etc. within the spirit and principle of the present invention should be included in the scope of protection of the present invention.
Claims (11)
1. The pipe jacking roller for the CPE unit is characterized by comprising the following chemical components in percentage by mass: c:3.0 to 3.3 percent; si:1.3 to 1.8 percent; mn:0.5 to 0.7 percent; p: less than or equal to 0.050%; s is less than or equal to 0.020%; cr:0.5 to 0.9 percent; ni:1.5 to 2.5 percent; 0.4 to 0.6 percent of Mo; mg is more than or equal to 0.04 and less than or equal to 0.1 percent, and the balance is Fe and unavoidable impurities, and the total is 100 percent.
2. The top tube roll for the CPE unit according to claim 1, wherein the hardness of the surface chilling layer of the top tube roll after heat treatment is 52-65 HSD and/or the same circumference hardness unevenness is less than or equal to 5HSD.
3. The top tube roll for CPE units according to claim 1, characterized in that the metallographic structure of the surface chilled layer of the top tube roll after heat treatment is granular pearlite + sorbite + ledeburite + graphite.
4. The top tube roll for CPE unit according to claim 1, characterized in that the metallographic structure of the base body of the top tube roll after heat treatment is granular pearlite+sorbite, and dispersed secondary cementite is formed in the base body.
5. The top tube roll for CPE unit according to claim 1, characterized in that,
the pipe jacking roller is subjected to heat treatment, in the heat treatment, the normalizing temperature is 950-1000 ℃, the heat preservation is carried out for 3-7 h, air cooling is carried out after normalizing, the air cooling is carried out to 280-300 ℃, then the stress relief tempering is carried out, the tempering temperature is 400-480 ℃, the heat preservation time is 4-7 h, and the air cooling is carried out after the stress relief tempering.
6. The top tube roll for CPE unit according to claim 5, wherein,
the normalizing temperature is 980 ℃, the air cooling is carried out to 280 ℃ after the normalizing, and the tempering temperature is 450 ℃.
7. The top tube roll for CPE unit according to claim 5, wherein,
air cooling to 280-300 deg.c and heating at 45-55 deg.c/hr.
8. The top tube roll for CPE unit according to claim 5, wherein,
in the heat treatment, the temperature is raised to 120-180 ℃ at the temperature rising rate of 30-35 ℃/h, then is raised to 550-650 ℃ at the temperature rising rate of 45-55 ℃/h, is kept for 1-3 h, and is raised to the normalizing temperature at the temperature rising rate of 45-55 ℃/h again.
9. The top tube roll for CPE unit according to claim 8, characterized in that,
in the heat treatment, the temperature is raised to 150 ℃ at a heating rate of 33 ℃/h, then to 600 ℃ at a heating rate of 50 ℃/h, the temperature is kept for 1 to 3 hours, and the temperature is raised to the normalizing temperature at a heating rate of 50 ℃/h again.
10. A method for manufacturing a top tube roll for a CPE unit according to any one of claims 1 to 9, characterized in that the method comprises the steps of:
mixing according to chemical components and mass percentages thereof, and then carrying out iron making, spheroidizing inoculation treatment and casting to obtain a roller blank;
performing heat treatment on the roller blank;
and turning to obtain the pipe jacking roller for the CPE unit.
11. The method according to claim 10, wherein the casting is static die casting or centrifugal casting; the chemical components and the mass percentages of the surface working layers at the outer sides of the top tube rolls are in particular the chemical components and the mass percentages of the surface working layers at the outer sides of the top tube rolls during centrifugal casting, and the surface chilling layers correspond to the surface working layers.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311361382.6A CN117821838A (en) | 2023-10-20 | 2023-10-20 | Pipe jacking roller for CPE unit and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311361382.6A CN117821838A (en) | 2023-10-20 | 2023-10-20 | Pipe jacking roller for CPE unit and preparation method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117821838A true CN117821838A (en) | 2024-04-05 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311361382.6A Pending CN117821838A (en) | 2023-10-20 | 2023-10-20 | Pipe jacking roller for CPE unit and preparation method thereof |
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| Country | Link |
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| CN (1) | CN117821838A (en) |
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2023
- 2023-10-20 CN CN202311361382.6A patent/CN117821838A/en active Pending
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