CN113416822A - Heat treatment method for improving hardness of U76CrRE heat treatment steel rail gas pressure welding joint - Google Patents
Heat treatment method for improving hardness of U76CrRE heat treatment steel rail gas pressure welding joint Download PDFInfo
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- CN113416822A CN113416822A CN202110551565.9A CN202110551565A CN113416822A CN 113416822 A CN113416822 A CN 113416822A CN 202110551565 A CN202110551565 A CN 202110551565A CN 113416822 A CN113416822 A CN 113416822A
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- steel rail
- cooling
- welding
- heat treatment
- heating
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/26—Methods of annealing
- C21D1/28—Normalising
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/34—Methods of heating
- C21D1/52—Methods of heating with flames
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D11/00—Process control or regulation for heat treatments
- C21D11/005—Process control or regulation for heat treatments for cooling
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/002—Heat treatment of ferrous alloys containing Cr
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/005—Heat treatment of ferrous alloys containing Mn
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/008—Heat treatment of ferrous alloys containing Si
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/50—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for welded joints
- C21D9/505—Cooling thereof
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/005—Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/24—Ferrous alloys, e.g. steel alloys containing chromium with vanadium
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Articles (AREA)
Abstract
The invention discloses a heat treatment method for improving the hardness of a U76CrRE heat-treated steel rail gas pressure welding joint, and by the heat treatment method, the U76CrRE heat-treated steel rail meets the following requirements: the tread hardness is more than or equal to 370HB, the tensile strength Rm is more than or equal to 1280MPa, and the top surface of the steel rail and the test line 1 are ensured to meet the requirements that HJ is more than or equal to 0.9Hp and HJ I is more than or equal to 0.80Hp after welding.
Description
Technical Field
The invention relates to the technical field of metallurgy and steel rail welding, in particular to a heat treatment method for improving the hardness of a U76CrRE heat treatment steel rail gas pressure welding joint.
Background
The welding of the steel rail is an essential intermediate link for laying a seamless line, and the quality of a welded joint of the steel rail is directly related to the safety of railway transportation. The welded joint not only influences the service life of line equipment and train hubs, but also influences the comfort of passenger transportation body feeling, the consumption of train transportation energy and the like. The gas pressure welding is a mode of welding the steel rail, the hardness of the tread of the U76CrRE heat-treated steel rail is more than or equal to 370HB, the tensile strength Rm is more than or equal to 1280MPa, and the top surface of the steel rail and the test line 1 are ensured to meet the requirements that HJ is more than or equal to 0.9Hp and HJI is more than or equal to 0.80Hp after welding.
Disclosure of Invention
In order to solve the technical problems, the invention aims to provide a heat treatment method for improving the hardness of a U76CrRE heat-treated steel rail gas pressure welding joint.
In order to solve the technical problems, the invention adopts the following technical scheme:
a heat treatment method for improving the hardness of a U76CrRE heat-treated steel rail gas pressure welding joint comprises a normalizing process after welding, and is characterized in that the normalizing process comprises the following steps: after welding, controlling the cooling temperature of a welding seam, controlling the normalizing heating temperature and time, and controlling the heat preservation time and the cooling air pressure;
wherein: the process of carrying out forced air cooling on the welding seam after the steel rail is welded is called cooling after the steel rail is welded, the swing range of the air nozzle in the process is kept between 5 and 26mm, cooling for 200s with the cooling wind pressure of 0.53 +/-0.02 MPa, cooling the surface of the steel rail welding seam to 450-500 ℃, newly carrying out flame heating on the weld joint, wherein the acetylene flow is 74SLM, the oxygen flow is 68SLM, the initial swing amplitude of normalizing heating is 5mm, the swing amplitude of the normalizing heating tail end is 30mm, the heating time is 190 plus 220s, the temperature of the weld joint of the steel rail reaches 890-920 ℃, uniformly heating the welding seam heating part for 5-10s, carrying out forced air cooling with the air pressure of 0.5 +/-0.02 MPa for 200s, actually swinging the air nozzle for 10-20mm, setting the value to be 35mm, cooling the surface of the steel rail to below 300 ℃, and ensuring that the surface temperature of the welding seam of the steel rail is lower than 450 ℃ after the pearlite structure on the surface of the welding seam is transformed.
Further, the U76CrRE heat-treated steel rail comprises the following chemical components in percentage by mass: 0.71-0.81% of C, 0.50-0.80% of Si, 0.8-1.10% of Mn, 0.25-0.35% of Cr and 0.04-0.08% of V, wherein the addition amount of rare earth is more than 0.020%, P is less than or equal to 0.025%, S is less than or equal to 0.025%, and the balance of Fe and inevitable impurity elements.
The normalizing treatment after the steel rail is welded aims at controlling the grain size of the structures of a welding seam area and a heat affected zone of a welding joint, the normalizing process after the steel rail is welded influences the tread hardness and the longitudinal hardness of the welding seam of the steel rail, the compressed air cooling forced treatment is adopted after the steel rail welding seam is turned into new austenite, and the clamping of two sections of the steel rail welding joint is loosened after the surface of the steel rail is forcibly cooled to a certain temperature. And straightening, polishing and detecting a flaw of the welded steel rail to finish the welding operation of the steel rail.
Compared with the prior art, the invention has the beneficial technical effects that:
by the heat treatment method, the U76CrRE heat-treated steel rail meets the following requirements: the tread hardness is more than or equal to 370HB, the tensile strength Rm is more than or equal to 1280MPa, and the top surface of the steel rail and the test wire 1 are ensured to meet the requirement of H after weldingJ≥0.9Hp，HJI≥0.80HpThe requirements of (1).
Detailed Description
In the embodiment, the technological parameters of the U76CrRE heat treatment steel rail gas pressure welding stage are controlled according to the technological parameters of the welding stage in the patent [202010411423.8], and the invention mainly explains the normalizing process after gas pressure welding: after welding, performing forced air cooling on the welding line, keeping the swing range of the air nozzle at 30mm, cooling for 200s with the strength of cooling air pressure of 0.5 +/-0.02 MPa, and cooling the surface of the steel rail to 450-500 ℃, wherein the process is called cooling after welding. Newly carrying out flame heating on a steel rail cooled below 500 ℃, controlling the heating time to be 200s, the working pressure of a swing oil cylinder to be 3MPa, the initial swing amplitude of normalizing heating to be 5mm, the swing time to be 120s, the final swing amplitude of normalizing heating to be 25mm, controlling the swing time to be 80s, heating the welding seam of the steel rail to be 890-920 ℃, carrying out soaking on the heating part of the welding seam after heating, and controlling the soaking time to be 5-10s at the moment. And then carrying out forced air cooling normalizing treatment under the condition that the air pressure is not lower than 0.5MPa, cooling for 200s, actually swinging the air nozzle for 10-20mm, setting the value to be 30mm, and cooling to the surface temperature of the steel rail below 300 ℃ to loosen the clamping of the two ends of the steel rail. And (3) polishing the welded steel rail, wherein the polished surface is a steel rail head tread and a steel rail side face, the polished profile should keep the profile of the original steel rail head as much as possible, the weld beading at the part below the rail web must be completely polished and tightened, the other part of the weld beading is excessive to the arc of the base metal, and the extra height range of the weld bead of the steel rail web is less than or equal to 1.5 mm.
Comparative example 1:
and heating the welded seam with the welding seam temperature of 510 ℃ after welding, wherein the heating temperature is 920 ℃, preserving heat for 10s, then cooling by using the air pressure of 0.46MPa, the cooling time is 200s, the swing of a cooling air nozzle is 15mm, the final cooling temperature is 330 ℃, and the anti-temperature of the surface of the welded seam is 465 ℃.
Example 1:
and heating the welding seam with the welding seam temperature of 480 ℃ after welding, wherein the heating temperature is 900 ℃, the heat preservation is carried out for 10s, then cooling is carried out with the wind pressure of 0.52MPa, the cooling time is 200s, the swing of a cooling air nozzle swings for 15mm, the final cooling temperature is 265 ℃, and the anti-temperature of the welding seam is 410 ℃.
Example 2:
and heating the welding seam with the welding seam temperature of 500 ℃ after welding, wherein the heating temperature is 920 ℃, preserving the heat for 10s, then cooling by using the air pressure of 0.54MPa, the cooling time is 200s, the swing of a cooling air nozzle is 18mm, the final cooling temperature is 290 ℃, and the welding seam anti-temperature is 440 ℃.
Table 1 comparative example 1 joint tread hardness test results
Table 2 results of testing the hardness of the longitudinal section of the joint of comparative example 1
Table 3 example 1 joint tread hardness test results
Table 4 example 1 test results for joint profile hardness
Table 5 example 2 results of testing joint tread hardness
Table 6 example 2 results of joint profile hardness test
The above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solutions of the present invention can be made by those skilled in the art without departing from the spirit of the present invention, and the technical solutions of the present invention are within the scope of the present invention defined by the claims.
Claims (2)
1. A heat treatment method for improving the hardness of a U76CrRE heat-treated steel rail gas pressure welding joint comprises a normalizing process after welding, and is characterized in that the normalizing process comprises the following steps: after welding, controlling the cooling temperature of a welding seam, controlling the normalizing heating temperature and time, and controlling the heat preservation time and the cooling air pressure;
wherein: the process of carrying out forced air cooling on the welding seam after the steel rail is welded is called cooling after the steel rail is welded, the swing range of the air nozzle in the process is kept between 5 and 26mm, cooling for 200s with the cooling wind pressure of 0.53 +/-0.02 MPa, cooling the surface of the steel rail welding seam to 450-500 ℃, newly carrying out flame heating on the weld joint, wherein the acetylene flow is 74SLM, the oxygen flow is 68SLM, the initial swing amplitude of normalizing heating is 5mm, the swing amplitude of the normalizing heating tail end is 30mm, the heating time is 190 plus 220s, the temperature of the weld joint of the steel rail reaches 890-920 ℃, uniformly heating the welding seam heating part for 5-10s, carrying out forced air cooling with the air pressure of 0.5 +/-0.02 MPa for 200s, actually swinging the air nozzle for 10-20mm, setting the value to be 35mm, cooling the surface of the steel rail to below 300 ℃, and ensuring that the surface temperature of the welding seam of the steel rail is lower than 450 ℃ after the pearlite structure on the surface of the welding seam is transformed.
2. The heat treatment method for improving the hardness of the air pressure welding joint of the U76CrRE heat treated steel rail as claimed in claim 1, wherein the chemical components of the U76CrRE heat treated steel rail are as follows by mass percent: 0.71-0.81% of C, 0.50-0.80% of Si, 0.8-1.10% of Mn, 0.25-0.35% of Cr and 0.04-0.08% of V, wherein the addition amount of rare earth is more than 0.020%, P is less than or equal to 0.025%, S is less than or equal to 0.025%, and the balance of Fe and inevitable impurity elements.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110551565.9A CN113416822A (en) | 2021-05-20 | 2021-05-20 | Heat treatment method for improving hardness of U76CrRE heat treatment steel rail gas pressure welding joint |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110551565.9A CN113416822A (en) | 2021-05-20 | 2021-05-20 | Heat treatment method for improving hardness of U76CrRE heat treatment steel rail gas pressure welding joint |
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| CN113416822A true CN113416822A (en) | 2021-09-21 |
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105483347A (en) * | 2015-12-10 | 2016-04-13 | 内蒙古包钢钢联股份有限公司 | Heat treatment technology for pearlite steel rail hardening |
| CN105548235A (en) * | 2015-12-10 | 2016-05-04 | 内蒙古包钢钢联股份有限公司 | Test method for accurate determination of optimal heat treatment process for pearlitic steel rail |
| CN109022747A (en) * | 2018-10-24 | 2018-12-18 | 攀钢集团攀枝花钢铁研究院有限公司 | The post weld heat treatment method of U71MnH rail flash welding connector |
| CN109022749A (en) * | 2018-10-24 | 2018-12-18 | 攀钢集团攀枝花钢铁研究院有限公司 | The post weld heat treatment method of U71MnH steel rail weld joint |
| CN109022746A (en) * | 2018-10-24 | 2018-12-18 | 攀钢集团攀枝花钢铁研究院有限公司 | The heat treatment method of U71MnH rail flash welding connector |
| CN109022748A (en) * | 2018-10-24 | 2018-12-18 | 攀钢集团攀枝花钢铁研究院有限公司 | The heat treatment method of U71MnH steel rail weld joint |
| CN111659973A (en) * | 2020-05-15 | 2020-09-15 | 包头钢铁（集团）有限责任公司 | Gas welding method for U76CrRE heat-treated steel rail |
-
2021
- 2021-05-20 CN CN202110551565.9A patent/CN113416822A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105483347A (en) * | 2015-12-10 | 2016-04-13 | 内蒙古包钢钢联股份有限公司 | Heat treatment technology for pearlite steel rail hardening |
| CN105548235A (en) * | 2015-12-10 | 2016-05-04 | 内蒙古包钢钢联股份有限公司 | Test method for accurate determination of optimal heat treatment process for pearlitic steel rail |
| CN109022747A (en) * | 2018-10-24 | 2018-12-18 | 攀钢集团攀枝花钢铁研究院有限公司 | The post weld heat treatment method of U71MnH rail flash welding connector |
| CN109022749A (en) * | 2018-10-24 | 2018-12-18 | 攀钢集团攀枝花钢铁研究院有限公司 | The post weld heat treatment method of U71MnH steel rail weld joint |
| CN109022746A (en) * | 2018-10-24 | 2018-12-18 | 攀钢集团攀枝花钢铁研究院有限公司 | The heat treatment method of U71MnH rail flash welding connector |
| CN109022748A (en) * | 2018-10-24 | 2018-12-18 | 攀钢集团攀枝花钢铁研究院有限公司 | The heat treatment method of U71MnH steel rail weld joint |
| CN111659973A (en) * | 2020-05-15 | 2020-09-15 | 包头钢铁（集团）有限责任公司 | Gas welding method for U76CrRE heat-treated steel rail |
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