JP3629075B2 - Rail welding mold - Google Patents

Description

【００１６】
表１から明らかなように、本発明に係るレール溶接用鋳型１０Ｂの供試片であるＡ、Ｂ、Ｃ、Ｄは、従来のレール溶接用鋳型１０の供試片であるＥ、Ｆ、Ｇ、Ｈと比較して、レール１１、１２の下部の引張曲げ疲労強度を向上することができるとともに、疲労亀裂発生点となるおそれのある足表部や止端部における疲労亀裂の発生を防止することができると共に、鋳張りの発生も防止することができることが判明した。
【図面の簡単な説明】
【図１】本発明の一実施の形態に係るレール溶接用鋳型によって形成されるレール連結部の断面図である。
【図２】図１の矢視Ｉ−Ｉ断面図である。
【図３】同他の実施の形態に係るレール溶接用鋳型の断面図である。
【図４】実験に用いたレール溶接用鋳型の寸法関係を示す説明図である。
【図５】実験に用いたレール溶接用鋳型の寸法関係を示す説明図である。
【図６】実験に用いたレール溶接用鋳型の寸法関係を示す説明図である。
【図７】従来のレール溶接用鋳型の分解斜視図である。
【図８】同レール溶接用鋳型によって形成されるレール連結部の断面図である。
【図９】同レール溶接用鋳型によって形成されるレール連結部の断面図である。
【図１０】同図９の矢視ＩＩ−ＩＩ断面図である。
【図１１】レール溶接用鋳型１０Ａの断面図である。
【符号の説明】
Ｆ 塑性材 Ｇ 隙間
Ｍ 溶融金属 Ｗ′余盛り形成凹部の止端部間の幅
Ｗ_１ ′レール断面表層部の溶け込み幅 Ｗ″余盛り形成凹部の止端部間の幅
Ｗ_１ ″レール断面表層部の溶け込み幅
１０Ｂ レール溶接用鋳型 １０Ｃ レール溶接用鋳型
１１ レール １１ａ 表面
１２ レール １２ａ 表面
１３ 分割上鋳型群 １４ 下鋳型
１５ 注湯口 １６ キャップ
１７ 上鋳型 １８ 上鋳型
１９ 上鋳型 ２０ 上鋳型
２１ キャビティ部 ２１ａ 線状突出部
２１ｂ 開先 ２１ｃ 余盛り形成凹部
２２ 空気孔 ２３ 空気孔
２４ 連通孔 ２５ 連通孔
２６ 余盛り形成凹部 ２６ａ 線状突出部
２６ｂ 開先 ２７ 余盛り
２８ レール足表部 ２９ 止端部
３０ 未融合部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rail welding mold capable of preventing a rail butt weld from being broken by stress concentration.
[0002]
[Prior art]
Conventionally, for thermite welding of rails, for example, Japanese Patent Publication No. 59-8477 discloses a rail thermite welding method and a mold that can be suitably used for the method. In this method, the ends of rails arranged opposite to each other with a predetermined gap are surrounded by a mold divided into left and right in the rail width direction, and molten metal manufactured by the thermite method from above is placed in the cavity portion. The rails are injected to join the rails together.
Also, Japanese Patent Publication No. 60-54145 discloses a method of providing a refractory compression felt belt on the contact surface between the mold components, and the welded molten metal injected into the mold cavity is made of the mold. The rails are joined in a sealed state so that they do not leak from the gap between the contact surfaces with the rails.
By the way, when one of the rails to be welded is in use and the other is a new one, the positions of the feet of both rails are not aligned to align the top ends of both rails. Accordingly, in some cases, a step of about 7 mm at maximum occurs. In this case, as shown in Japanese Patent Publication No. 59-8477 and Japanese Patent Publication No. 60-54145, when the welding is performed using a two-part mold, the upper and lower surfaces of the rail to be joined and the mold There is a vertical gap between the inner upper and lower surfaces. There are also small manufacturing errors in the rail, which also creates a gap between the outer surface of the rail and the inner surface of the mold. And since this gap causes the molten metal to leak out and cause casting, it has been tried to prevent this occurrence by press-fitting or stuffing mortar or clay-like refractories. The pore diameter is said to be 30 μm, and it was difficult to make the gap smaller than that. As a result, there is a problem that casting often occurs and the fatigue strength of the joint portion is reduced.
[0003]
In order to solve such a problem, the present inventors, in Japanese Patent Laid-Open No. 5-261596, divided the bottom of the mold, and further divided the mold that was divided facing the center of the rail into two in the rail direction. That is, the upper mold group was configured by dividing into four in the rail width direction and the length direction, and a rail welding mold in which linear protrusions were provided on at least the lower part and the bottom mold of the divided upper mold group was presented. .
The configuration of the rail welding mold 10 is shown in FIG.
As shown in the figure, the rail welding mold 10 includes a divided upper mold group 13 that surrounds the joint portion of the opposing rails 11 and 12, a lower mold 14 disposed at the bottom of the divided upper mold group 13, and an upper note. The cap 16 is attached to the gate 15. And the said division | segmentation upper casting_mold | template group 13 consists of the upper casting_mold | templates 17-20 divided into 4 by the center surface of the rails 11 and 12 which oppose, and the joint surface of this rails 11 and 12. FIG.
Inside the upper molds 17 to 20 and the lower mold 14, there is provided a cavity part 21 into which molten metal is injected into the joint part of the rails 11 and 12 to be mounted. A recess 21c is provided so that the joint between the rails 11 and 12 can be reinforced.
[0004]
Moreover, the linear protrusion part 21a which has a fixed width | variety is provided in the outer side of the said heap formation recessed part 21c of the lower part of the upper molds 17-20 which consist of refractories, and also the groove | channel 21b is provided in the outer side. Yes. In use, the linear protruding portion 21a comes into contact with the abdominal side surface, the foot surface and the toe portion of the rails 11, 12 and, if necessary, the head jaw lower portion (the lower surface of the head) of the rails 11, 12. The groove 21b can be filled with a plastic material F (see FIG. 10).
When the upper molds 17 to 20 are combined, air holes 22 and 23 are formed at the center of both sides, and the bottoms of the air holes 22 and 23 are formed with the inner cavity portion 21 and the narrow communication holes 24 and 25 (see FIG. 8), and the air accumulated in the cavity portion 21 during pouring can be smoothly discharged.
The lower mold 14 is also made of a refractory, and has a surplus formation recess 26 corresponding to the joint at the center of the surface, and the linear protrusion 26a (having a certain width) is further on the outside. A groove 26b is provided. When the divided upper mold group 13 and the lower mold 14 are assembled, the linear protrusions 26a come into contact with the bottoms of the rails 11 and 12 and the bottoms of the upper molds 17 to 20 to form a seal. Further, by filling the groove 26b with the plastic material F, even if the seal by the line contact contact is insufficient due to the surface roughness of the upper molds 17 to 20, etc., hot water leaks to the outside. Back up so that there is no.
[0005]
With such a configuration, the divided upper mold group 13 is divided not only in the direction of the center plane of the rails 11 and 12 but also in the direction of the joining surface. Therefore, as shown in FIG. Even if there is a slight dimensional difference between 12, the divided upper mold group 13 can be adjusted to the rails 11 and 12 by adjusting in the height direction, and when the molten metal M is injected and cured into the cavity portion 21, The occurrence of tension can be reduced, and the mold can be easily manufactured. In addition, the rail welding mold 10 uses a method of sealing the rails 11 and 12 and the adjacent molds, and joins the upper and lower molds 13 and 14 and the upper molds 17 to 20 via the linear protrusions 21a and 26a. Further, the grooves 21b and 26b are provided on the outer side so that the plastic material F can be filled after the assembly. Therefore, the casting can be reduced from this surface, and thus the rail 11 with less stress concentration is generated. , 12 welded joints became possible.
In addition, in the Japanese Patent Laid-Open No. 6-312609, the present applicant uses a refractory joint material that is heated and expanded as the plastic material F used in the rail welding mold 10 described above, and seals the upper mold groups 17 to 20 and the gap generating portion. Presented to improve sex.
[0006]
[Problems to be solved by the invention]
In this way, it is possible to prevent the occurrence of casting that occurs in the gaps between the rails 11 and 12 and the divided upper mold group 13 and the lower mold 14 and between the upper molds 17 to 20. 10 still had the following problems to be solved.
That is, generally, the boundary between the molten metal M and the base metal rails 11 and 12 in the longitudinal section of the rail welded portion of the rails 11 and 12, that is, the melted state of the molten metal M is shown in FIGS. As shown in FIG.
However, as shown in FIG. 9, the penetration width W ₁ of the molten metal M in the rail cross section surface portion of the rails 11 and 12 depends on the inner surface shape of the rail welding mold 10, whereas The width W between the toe portions 29 provided at both ends of the extra-cavity forming recess 21c (see FIG. 7) provided on the inner surfaces of the upper molds 17 to 20 to form is the same from the head to the bottom.
[0007]
Resulting Consequently, the difference between the width W between both toe portion 29 of the weld metal M of penetration width W ₁ and the remaining prime forming recess 21c at each cross section of the rails 11 and 12 shown in FIGS. 8 and 9 . At this time, the stress concentration at the time of bending fatigue of the rail connecting portion occurs, the fatigue crack generation point and tends rail foot table section 28, both toe of weld surplus Sheng forming recess 21c than the width W ₁ penetration of the weld metal Since the width W between 29 is large, as shown in FIG. 10, the unfused portion 30 is generated between the both end portions 29 of the surplus formation recess 21c and the surface 11a (12a) of the rail 11 (12). There was a possibility that it would become a starting point of fatigue cracks, and in order to prevent this, secondary processing or early repair was necessary.
As shown in FIG. 11, this was the same in the rail welding mold 10A in which the linear protrusion 21a and the groove 21b were not provided.
Therefore, as a result of research, the present inventors have made the toe portions 29 of the above-described extra-mounting concave portions 21c substantially coincide with both ends of the extra-top portions 27, or the widths between the two toe-end portions 29 of the extra-volume forming concave portions 21c. with proper selection of the relationship between the width W ₁ of the penetration of W and rails 11 and 12, and found that it is possible to enhance the fatigue strength of the toe portion 29 of the remaining prime forming recess 21c.
The present invention has been made based on such knowledge, and an object of the present invention is to provide a rail welding mold capable of increasing the bending fatigue strength of the rail connecting portion and improving the reliability of the rail connecting portion. And
[0008]
[Means for Solving the Problems]
The rail welding mold according to claim 1, which meets the above-mentioned purpose, has a joint portion of two rails whose ends are opposed to each other, surrounded by a divided mold from both sides thereof, and has a cavity portion in an assembled state. In the mold for rail welding used when pouring molten metal into the cavity and performing thermite welding,
The width between the toe ends of the overlying concave portion provided on the inner surface of the rail welding mold is the same as or smaller than the penetration width of the rail section surface layer portion formed by thermite welding within a range of 10 mm. During the thermite welding, unfused portions are prevented from being generated between the respective toe portions of the surplus formation recesses and the surface of the rail.
Here, the maximum upper limit of the width between the toe portions of the overfill forming recesses is the same as the penetration width of the rail section surface layer portion formed by thermite welding. This is because if the width is greater than the above penetration width, an unfused portion is formed between the toe portion formed at both ends of the surplus formation concave portion and the surface of the rail as in the conventional case, which becomes a point of occurrence of a fatigue crack. On the other hand, the minimum lower limit of the width between the toe portions of the overlying recesses is 10 mm smaller than the penetration width of the surface section of the rail cross section. When the difference is obtain ultra the 10 mm, since the surface layer portion penetration located on the rail surface and the same surface in direct contact with the mold, under the influence of seizure or mold roughness of the mold, irregularities causing stress concentration This is because it occurs.
[0009]
[Action]
In the rail welding mold according to the first aspect, the joint portion of the two rails whose end portions are opposed to each other is surrounded by the divided mold from both sides, and the rail welding mold having the cavity portion is assembled. Next, molten metal produced by the thermite method is poured into the cavity from the pouring port. As a result, the molten metal is filled in the cavity, and the air that is to be stored inside moves to the air hole through the communication hole and is discharged to the outside, thereby completing the connection by rail welding. At this time, the width between the two toe portions of the extra-cavity forming recess provided in the mold is the same as the penetration width of the rail cross-section surface layer portion formed by thermite welding or smaller in the range of 10 mm than the penetration width. Further, it is possible to prevent an unfused portion that becomes a point of occurrence of a fatigue crack between the toe portion formed at both ends of the surplus formation concave portion and the surface of the rail.
[0010]
【The invention's effect】
In the rail welding mold according to claim 1, the width between the both end portions of the overlying concave portion provided in the mold is equal to or equal to the penetration width of the rail cross-section surface layer portion formed by thermite welding. Since it is made small in the range of 10 mm, it is possible to prevent the occurrence of an unfused portion that becomes a fatigue crack starting point between the toe portion formed at both ends of the overfill forming concave portion and the surface of the rail. A shape with no excess is obtained, and the fatigue strength at the rail connecting portion can be improved.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Subsequently, an embodiment of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
In addition, the rail welding mold 10B according to the embodiment of the present invention is substantially the width between the both end portions of the overfilling concave portion provided in the mold, and the rail cross-section surface layer portion formed by thermite welding. Except for the relative relationship with the penetration width, the basic configuration of the conventional rail welding mold 10 described with reference to FIG. 7 is substantially the same, so the same components are denoted by the same reference numerals and their details. Description of the detailed configuration and operation will be omitted.
Hereinafter, with reference to FIGS. 1-3, the structure of the principal part of the mold 10B for rail welding which concerns on this invention is demonstrated. 1 is a cross-sectional view of a rail connecting portion formed by thermite welding, FIG. 2 is a cross-sectional view taken along the line II of FIG. 1, and FIG. 3 is a cross-sectional view of a rail welding mold according to another embodiment. 4, FIG. 5, and FIG. 6 are explanatory views showing the dimensional relationship of the rail welding mold 10B used in the experiment.
[0012]
As shown in FIGS. 1 and 2, in this embodiment, the width W ′ between the toe portions 29 provided at both ends of the extra recess forming recess 21c provided in the rail welding mold 10B is formed by thermite welding. It is the same as the penetration width W ₁ ′ of the surface section of the rail cross section, or smaller than the penetration width W ₁ ′ in the range of 10 mm (that is, in the range of 0 to 10 mm).
Therefore, when the molten metal manufactured by the thermite method is injected into the cavity portion 21 from the pouring port 15 and the rails 11 and 12 are connected by welding, as described above, the surplus formation provided in the rail welding mold 10B is formed. Since the width W ′ between the both end portions 29 of the recess 21c is the same as the penetration width W ₁ ′ of the rail cross-section surface layer portion formed by thermite welding, or is smaller in the range of 10 mm than the penetration width W ₁ ′. As shown in FIG. 2, an unfused portion that becomes a fatigue crack generation point is generated between each toe portion 29 formed at both ends of the surplus formation recess 21 c and the surface of the rail 11 (12). Thus, the shape of the surplus 27 without defects can be obtained, and the fatigue strength against stress concentration at the rail connecting portion can be improved.
[0013]
FIG. 3 relates to the rail welding mold 10C that does not include the linear protrusion 21a and the groove 21b shown in FIG. 2, and in this case as well, the overfill forming recess 21c provided in the rail welding mold 10C is shown. width W between Ryotometan portion 29 the same as "the rail cross-section the surface portion of the melt write-width W ₁ which is formed by the thermite welding", or is made smaller in a range of the penetration 10mm than the width W ₁ ' .
Accordingly, in the same manner as the rail welding mold 10B shown in FIG. 2, a fatigue crack generation point is formed between the respective toe portions 29 formed at both ends of the surplus formation recess 21c and the surface of the rail 11 (12). It is possible to prevent the unfused portion from being formed, to obtain the shape of the surplus 27 having no defect, and to improve the fatigue strength at the rail connecting portion.
In the above description, the example in which the present invention is applied to the upper mold provided on both sides of the rails 11 and 12 has been described. However, the present invention is naturally applicable to the lower mold, and further, as shown in FIG. The present invention can also be applied to molds that are not divided.
[0014]
【Example】
In the above-described rail welding mold 10B, when the width W ′ between the both end portions 29 of the overfilling concave portion 21c provided in the mold and the penetration width W ₁ ′ of the rail cross-section surface layer portion are changed, Table 1 shows the results of experiments on the change in tensile bending fatigue strength and the state of fatigue cracks at the bottom of the rails 11 and 12.
In addition, the dimension ae shown in Table 1 shows the dimension of each part in the mold 10B for rail welding shown in FIGS.
[0015]
[Table 1]

[0016]
As is apparent from Table 1, A, B, C, and D which are test pieces of the rail welding mold 10B according to the present invention are E, F and G which are test pieces of the conventional rail welding mold 10 respectively. Compared with H, the tensile bending fatigue strength of the lower part of the rails 11 and 12 can be improved, and the occurrence of fatigue cracks at the front and toe portions that may become fatigue crack initiation points is prevented. It was found that the occurrence of casting could be prevented.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a rail connecting portion formed by a rail welding mold according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along the line II in FIG.
FIG. 3 is a cross-sectional view of a rail welding mold according to another embodiment.
FIG. 4 is an explanatory diagram showing a dimensional relationship of a rail welding mold used in the experiment.
FIG. 5 is an explanatory view showing a dimensional relationship of a rail welding mold used in the experiment.
FIG. 6 is an explanatory view showing the dimensional relationship of a rail welding mold used in the experiment.
FIG. 7 is an exploded perspective view of a conventional rail welding mold.
FIG. 8 is a cross-sectional view of a rail connecting portion formed by the rail welding mold.
FIG. 9 is a cross-sectional view of a rail connecting portion formed by the rail welding mold.
10 is a sectional view taken along the line II-II in FIG.
FIG. 11 is a cross-sectional view of a rail welding mold 10A.
[Explanation of symbols]
F Plastic material G Gap M Molten metal W ′ Width between the toe portions of the overfill forming recess W ₁ ′ Penetration width of the rail cross section surface portion W ″ Width between the toe portions of the surplus formation recess portion W ₁ ″ Rail cross section surface layer Penetration width 10B Rail welding mold 10C Rail welding mold 11 Rail 11a Surface 12 Rail 12a Surface 13 Divided upper mold group 14 Lower mold 15 Pouring port 16 Cap 17 Upper mold 18 Upper mold 19 Upper mold 20 Upper mold 21 Cavity part 21a Linear protrusion 21b Groove 21c Extra-splitting formation recess 22 Air hole 23 Air hole 24 Communication hole 25 Communication hole 26 Extra-enclosure recess 26a Linear projection 26b Groove 27 Extra build 28 Rail foot surface 29 Stop end 30 Unfused part

Claims (1)

The joint of two rails with the ends facing each other is surrounded by a split mold from both sides, and has a cavity inside in an assembled state. Used when pouring molten metal into the cavity and performing thermite welding. In the rail welding mold
The width between the both end portions of the recess forming recess provided on the inner surface of the rail welding mold is the same as the penetration width of the rail cross-section surface layer portion formed by thermite welding or smaller in the range of 10 mm than the penetration width. A rail welding mold characterized by that.

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