CN115255607A - Method for improving quality of U76CrRE heat treatment steel rail aluminum hot welding joint - Google Patents
Method for improving quality of U76CrRE heat treatment steel rail aluminum hot welding joint Download PDFInfo
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- CN115255607A CN115255607A CN202210932272.XA CN202210932272A CN115255607A CN 115255607 A CN115255607 A CN 115255607A CN 202210932272 A CN202210932272 A CN 202210932272A CN 115255607 A CN115255607 A CN 115255607A
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- welding
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- preheating
- rail
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K23/00—Alumino-thermic welding
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K37/00—Auxiliary devices or processes, not specially adapted to a procedure covered by only one of the preceding main groups
Abstract
The invention discloses a method for improving the quality of an aluminum hot welding joint of a U76CrRE heat-treated steel rail, which comprises the following steps: preheating a section to be welded, wherein the preheating temperature range of the steel rail is 850-950 ℃, the preheating time range is 5 minutes to 5 minutes and 40 seconds, a preheating gun is vertically centered with a rail gap, and the rail head of the steel rail is heated to be slightly red; the welding flux is ready to ignite, the time interval from preheating of the steel rail to ignition does not exceed 25 seconds, the last drop of molten steel flowing out after pouring starts to be timed, the solidification time is 5 minutes 30 seconds to 5 minutes 55 seconds, the mould is removed after the pouring is finished, and the beading pushing time lasts for the shortest time 6 minutes 45 seconds to 7 minutes after the pouring is finished. The invention is beneficial to improving the stability of the quality of the thermite welding joint of the steel rail by controlling the welding process parameters in the thermite welding process of the steel rail.
Description
Technical Field
The invention relates to the technical field of metallurgy and steel rail welding, in particular to a method for improving the quality of an aluminum hot welding joint of a U76CrRE heat-treated steel rail.
Background
The thermit welding of the steel rail is an essential welding method for the line repair and the connection of the steel rail of a station platform, and the quality of a steel rail welding joint is directly related to the safety of railway transportation. The thermite welding process is flexible, and the process parameter control in the welding process is relatively wide. Each link in the welding process influences the quality of the steel rail welding joint, and after the steel rail thermite welding flux is determined, the quality of the steel rail joint depends on the accuracy of parameter control in the welding process. The two performance indexes, which have the greatest influence on the aluminothermic welding joint, namely static bending and fatigue performance, are a pair of mutually contradictory indexes, the influence of parameter control in the steel rail welding process on the static bending and fatigue performance is large, and the influence on the static bending and fatigue performance of the joint is most prominent in the operation stability and control accuracy in the welding process.
Disclosure of Invention
The invention aims to provide a method for improving the quality of an aluminothermic welding joint of a U76CrRE heat-treated steel rail, which is beneficial to improving the stability of the quality of the aluminothermic welding joint of the steel rail by controlling the welding process parameters in the process of aluminothermic welding of the steel rail.
In order to solve the technical problems, the invention adopts the following technical scheme:
the invention relates to a method for improving the quality of an aluminothermic welding joint of a U76CrRE heat-treated steel rail, which comprises the following steps:
selecting a welding flux as a normal welding flux for thermite welding of the steel rail;
the rail thermite welding comprises preparation before welding, welding and post-welding treatment;
polishing the steel rail before welding and performing rail alignment operation in the horizontal and vertical directions of the steel rail according to a method welding flux thermite welding process;
preheating, pouring, pushing and polishing the welding line of the steel rail after welding;
preheating the end face of a welding seam before welding the welding seam, preheating by adopting oxygen and propane flame, wherein the oxygen pressure value is 65-75PSI, the propane pressure value is 9.5-10.5PIS, the section to be welded is preheated, the preheating temperature range of a steel rail is 850-950 ℃, the preheating aim is to reduce the temperature difference between the surface to be welded of the steel rail and an thermite welding pool, improve the stress state distribution of a steel rail joint, and simultaneously remove moisture in a steel rail sand mold, the preheating temperature time range is 5 minutes to 5 minutes and 40 seconds, a preheating gun is vertically centered with the rail seam, and the rail head of the steel rail is heated to slightly reddish;
the welding flux is ready to ignite, the time interval from preheating of the steel rail to ignition does not exceed 25 seconds, the last drop of molten steel flowing out after pouring starts to be timed, the solidification time is 5 minutes 30 seconds to 5 minutes 55 seconds, the mould is removed after the pouring is finished, and the beading pushing time lasts for the shortest time 6 minutes 45 seconds to 7 minutes after the pouring is finished.
Furthermore, the time of three welding stages of the steel rail is strictly controlled in the welding process, the pressure of oxygen and propane is ensured in the heating process, and the opening degree of the gas is adjusted according to the bottling amount.
Furthermore, before welding, the two ends of the steel rail to be welded are subjected to derusting and polishing, the polishing length is 100-150mm, and the verticality of the end face is less than 1mm.
Further, according to the environment temperature and the state of the steel rail, the surface of the steel rail is dried, the interval between the sections of the welded steel rail is 26-28mm, and in order to ensure the welding stability of each joint, the interval between welding seams is controlled to be a certain fixed value as much as possible.
Compared with the prior art, the invention has the beneficial technical effects that:
the method for improving the quality of the U76CrRE heat treatment steel rail thermite welding joint provides welding process parameters in the steel rail thermite welding process, and is beneficial to improving the stability of the quality of the steel rail thermite welding joint.
Detailed Description
A method for improving the quality of an aluminothermic welding joint of a U76CrRE heat treated steel rail comprises the following steps: the steel rail material and the welding flux used by the steel rail are matched, firstly, the two ends of the steel rail to be welded are derusted and polished, the polishing length is 100-150mm, the end face verticality is less than 1mm, the surface of the steel rail is dried according to the environment temperature and the state of the steel rail, the interval between the sections of the welded steel rail is 26-28mm, in order to guarantee the welding stability of each joint, the interval between welding seams is controlled at a certain fixed value as much as possible, and the determined interval in the patent is 27 +/-0.5 mm. Adjusting the horizontal and vertical positions of the end of the steel rail, eliminating the gap in the installation process of the sand mold, and plastering for 2 times after the sand mold is installed. Preheating the end face of the steel rail to be welded, wherein the preheating temperature is 850-950 ℃, the pressure of heating gas is constant, the preheating time is controlled, the preheating time ranges from 5 minutes to 5 minutes and 40 seconds, then, igniting and melting the welding flux are carried out, timing is started after the last drop of molten steel flows out after pouring, the mold removal is proper after the solidification time is controlled to be 5 minutes and 30 seconds to 5 minutes and 55 seconds, and the time for pushing the knurls is 6 minutes, 45 seconds to 7 minutes after the mold removal. The nodule pushing time is not less than 6 minutes and 45 seconds, and the quality of a welding joint is influenced due to the short nodule pushing time.
Comparative example 1:
after the straightness and the verticality of the steel rails on the two sides to be welded are adjusted, the welding seam interval is 26mm, the preheating temperature of the steel rails is 850 ℃, the heating time is 5 minutes, the solidification time is 5 minutes and 30 seconds, the weld seam overlap pushing time is 6 minutes and 45 seconds, and the steel rails are polished according to the standard.
Example 1:
after the straightness and the verticality of the steel rails on the two sides to be welded are adjusted, the welding seam interval is 27mm, the preheating temperature of the steel rails is 900 ℃, the heating time is 5 minutes and 20 seconds, the solidification time is 5 minutes and 45 seconds, the welding seam tumor pushing time is 7 minutes, and the steel rails are polished according to the standard.
Example 2:
after the straightness and the verticality of the steel rails on the two sides to be welded are adjusted, the welding seam interval is 28mm, the preheating temperature of the steel rails is 900 ℃, the heating time is 5 minutes and 40 seconds, the solidification time is 5 minutes and 55 seconds, the welding seam tumor pushing time is 7 minutes, and the steel rails are polished according to the standard.
Table 1 comparative example 1
TABLE 2 comparative example 1 aluminothermic welding joint fatigue test results
Table 3 example 1 aluminothermic weld joint static bend test results
TABLE 4 comparative example 1 aluminothermic welding joint fatigue test results
TABLE 5 example 2 static bending test results for aluminothermic weld joint
TABLE 6 comparative example 2 aluminothermic weld joint fatigue test results
The above-described embodiments are only intended to illustrate the preferred embodiments of the present invention, and not to limit the scope of the present invention, and various modifications and improvements made to the technical solution of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.
Claims (4)
1. A method for improving the quality of an aluminothermic welding joint of a U76CrRE heat-treated steel rail is characterized by comprising the following steps:
selecting a welding flux as a normal welding flux for thermite welding of the steel rail;
the rail thermite welding comprises preparation before welding, welding and post-welding treatment;
polishing the steel rail before welding and performing rail alignment operation in the horizontal and vertical directions of the steel rail according to a method welding flux thermite welding process;
preheating, pouring, pushing and polishing the welding line of the steel rail after welding;
preheating the end face of a welding seam before welding the welding seam, preheating by adopting oxygen and propane flame, wherein the oxygen pressure value is 65-75PSI, the propane pressure value is 9.5-10.5PIS, the section to be welded is preheated, the preheating temperature range of a steel rail is 850-950 ℃, the preheating aim is to reduce the temperature difference between the surface to be welded of the steel rail and an thermite welding pool, improve the stress state distribution of a steel rail joint, and simultaneously remove moisture in a steel rail sand mold, the preheating temperature time range is 5 minutes to 5 minutes and 40 seconds, a preheating gun is vertically centered with the rail seam, and the rail head of the steel rail is heated to slightly reddish;
the welding flux is ready to ignite, the time interval from preheating of the steel rail to ignition does not exceed 25 seconds, the last drop of molten steel flowing out after pouring starts to be timed, the solidification time is 5 minutes 30 seconds to 5 minutes 55 seconds, the mould is removed after the pouring is finished, and the beading pushing time lasts for the shortest time 6 minutes 45 seconds to 7 minutes after the pouring is finished.
2. The method for improving the quality of the U76CrRE heat treated steel rail aluminothermic welding head of claim 1, wherein the time of three welding stages of the steel rail is strictly controlled in the welding process, the pressure of oxygen and propane is ensured in the heating process, and the opening degree of gas is adjusted according to the bottling amount.
3. The method for improving the quality of the U76CrRE heat treated steel rail aluminothermic welding joint according to claim 1, wherein before welding, the two ends of the steel rail to be welded are firstly derusted and ground, the grinding length is 100-150mm, and the perpendicularity of the end surfaces is less than 1mm.
4. The method for improving the quality of the U76CrRE heat treated steel rail thermit weld joint according to claim 1, wherein the surface of the steel rail is dried according to the ambient temperature and the state of the steel rail, the section spacing of the welded steel rail is 26-28mm, and the spacing of the welding seams is controlled to be a fixed value as much as possible to ensure the welding stability of each joint.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210932272.XA CN115255607A (en) | 2022-08-04 | 2022-08-04 | Method for improving quality of U76CrRE heat treatment steel rail aluminum hot welding joint |
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| CN202210932272.XA CN115255607A (en) | 2022-08-04 | 2022-08-04 | Method for improving quality of U76CrRE heat treatment steel rail aluminum hot welding joint |
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| CN115255607A true CN115255607A (en) | 2022-11-01 |
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Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1158042A (en) * | 1997-08-27 | 1999-03-02 | Nippon Steel Corp | Thermit welding method for bainting steel rail |
| JP2008137053A (en) * | 2006-12-04 | 2008-06-19 | Nippon Steel Corp | Thermit welding method for rail |
| CN108581181A (en) * | 2018-04-17 | 2018-09-28 | 中国铁道科学研究院金属及化学研究所 | A kind of processing method of Thermit Welds in Rails hurt |
| CN111014942A (en) * | 2019-12-28 | 2020-04-17 | 江苏韦尔汀轨道工程技术有限公司 | Stable welding process for thermite welding of steel rail |
| CN111283380A (en) * | 2020-04-03 | 2020-06-16 | 株洲时代电子技术有限公司 | Steel rail welding operation method at low temperature |
| CN111590192A (en) * | 2019-11-26 | 2020-08-28 | 北京特冶工贸有限责任公司 | Thermite welding method for seamless steel rail |
| CN111843181A (en) * | 2020-08-11 | 2020-10-30 | 陕西空天动力研究院有限公司 | Thermite welding method for special-shaped steel rail |
| CN113305417A (en) * | 2021-06-10 | 2021-08-27 | 中国二十二冶集团有限公司 | Thermite welding method for crane track |
| CN113894463A (en) * | 2021-09-30 | 2022-01-07 | 武汉钢铁有限公司 | Corrosion-resistant thermite welding flux suitable for U68CuCr steel rail and welding method thereof |
-
2022
- 2022-08-04 CN CN202210932272.XA patent/CN115255607A/en active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1158042A (en) * | 1997-08-27 | 1999-03-02 | Nippon Steel Corp | Thermit welding method for bainting steel rail |
| JP2008137053A (en) * | 2006-12-04 | 2008-06-19 | Nippon Steel Corp | Thermit welding method for rail |
| CN108581181A (en) * | 2018-04-17 | 2018-09-28 | 中国铁道科学研究院金属及化学研究所 | A kind of processing method of Thermit Welds in Rails hurt |
| CN111590192A (en) * | 2019-11-26 | 2020-08-28 | 北京特冶工贸有限责任公司 | Thermite welding method for seamless steel rail |
| CN111014942A (en) * | 2019-12-28 | 2020-04-17 | 江苏韦尔汀轨道工程技术有限公司 | Stable welding process for thermite welding of steel rail |
| CN111283380A (en) * | 2020-04-03 | 2020-06-16 | 株洲时代电子技术有限公司 | Steel rail welding operation method at low temperature |
| CN111843181A (en) * | 2020-08-11 | 2020-10-30 | 陕西空天动力研究院有限公司 | Thermite welding method for special-shaped steel rail |
| CN113305417A (en) * | 2021-06-10 | 2021-08-27 | 中国二十二冶集团有限公司 | Thermite welding method for crane track |
| CN113894463A (en) * | 2021-09-30 | 2022-01-07 | 武汉钢铁有限公司 | Corrosion-resistant thermite welding flux suitable for U68CuCr steel rail and welding method thereof |
Non-Patent Citations (2)
| Title |
|---|
| 李东侠: "钢轨接头铝热焊焊接质量的控制", 铁道建筑, no. 05, pages 70 - 71 * |
| 杨建平: "低温环境下无缝线路应力放散施工铝热焊焊接质量的控制", 铁道标准设计, no. 03, pages 56 - 58 * |
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