JP2016137535A - Repair method of casting steel member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely repair a crack caused in a casting steel member at a job site.SOLUTION: A method for repairing a casting steel member 10 by burying a repair member 30 in a provided hole 17, by providing the hole 17 by cutting a crack 11 caused on a surface of the casting steel member 10, comprises a repair member insertion process of inserting the repair member 30 of inserting a wedge member 20 into the hole 17 in a state of turning the wedge member 20 to the side of a bottom surface 18 of the hole 17 and a repair member filling process of filling the hole 17 when the repair member 30 is deformed by the inserted wedge member 20 by striking the inserted repair member 30.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a technique for reliably repairing a crack generated in a cast steel member on site in a crack repair method for a cast steel member.

  Some cast steel members in power plant facilities, such as steam turbine casings and valves, are subjected to thermal stress when starting and stopping, and this causes cracks mainly. If a crack occurs, that part is ground and removed. When the thickness after removing the crack becomes thinner than the minimum required thickness, the member becomes unusable and must be replaced with a new one, and overlay welding is performed.

  However, many cast steel members in power plant facilities are large, and welding must be performed in the field. Since the temperature control is difficult in the field welding, the welded part is rapidly cooled after welding and cracking occurs. There is a possibility.

  As a method of preventing the recurrence of cracks after repair, Patent Document 1 describes a method of repairing the outside by inserting a low-melting-point metal containing lead or zinc into a gap before welding. ing.

JP 2003-240447 A

  However, even with the method described in Patent Document 1, cracks may recur from the welded portion, and further technical improvements have been desired.

  This invention is made | formed in view of such the present condition, The objective is to provide the crack repair method of the cast steel member for repairing the crack which generate | occur | produced in the cast steel member on the spot reliably.

  One of the present invention for achieving the above-mentioned object is a method of repairing the cast steel member by cutting a crack generated on the surface of the cast steel member to provide a hole, and embedding the repair member in the provided hole. The repair member into which the wedge member is inserted is inserted into the hole in a state where the wedge member is directed to the bottom surface side of the hole, and by hitting the inserted repair member, A repair member filling step in which the repair member is deformed by the inserted wedge member to fill the hole.

  As in the present invention, when the repair member with the wedge member inserted is inserted into the hole with the wedge member facing the bottom surface of the hole and the repair member is struck, the repair member is inserted into the hole by the inserted wedge member. As a result, the wedge member is filled in the hole. Thereby, the space between the repair member and the cast steel member is filled without a gap, and the repair member can be reliably fixed to the cast steel member. Thus, according to the present invention, a crack generated on the surface of the cast steel member can be reliably repaired on site only by using the repair member and the wedge member.

  Another aspect of the present invention for achieving the above-mentioned object is to cut the crack generated on the surface of the cast steel member to provide a hole, and to bury the repair member in the provided hole, thereby A method for repairing, wherein the repair member is inserted into the hole in which the wedge member is installed on the bottom surface thereof, and the wedge in which the repair member is installed by hitting the inserted repair member. And a repair member filling step in which the deformed wedge member fills the hole.

  As in the present invention, by installing a wedge member in advance on the bottom surface of the hole and inserting the repair member into the hole, the repair member can be securely fixed to the cast steel member, and the same as in the above invention An effect is obtained. Also according to the present invention, the crack generated on the surface of the cast steel member can be reliably repaired on site only by using the repair member and the wedge member.

  In each of the above-mentioned inventions, the repair member may be made of a metallic material having a higher extensibility than the cast steel member. If it does in this way, while a repair member will change easily in a hole, even if it is a case where thermal stress is applied to a repair part after repair, this can be reduced and durability of a repair part can be improved.

  In each of the above inventions, the inner surface of the hole may be formed so as to be substantially perpendicular to the surface of the cast steel member. In this way, when the repair member in the hole is struck, the repair member easily expands toward the inner surface of the hole by the wedge member, and the repair member can be easily packed in the entire hole. In addition, the grinding of the holes in the substantially vertical direction is technically easy.

  Further, in each of the above inventions, in the case where the crack is linear on the surface, a plurality of hole forming steps in which a plurality of the holes are provided apart from each other at each position on the crack, and the plurality of holes are provided. A groove forming step of providing grooves to be communicated with each other so as to include the crack along the crack, and in the repair member inserting step, the first repair member having a shape to be fitted into the hole is formed in the hole. And inserting the second repair member shaped to fit into the groove into each of the grooves, and hitting the inserted first repair member in the repair member filling step The hole may be filled with the first repair member, and the groove may be filled with the second repair member by hitting the inserted second repair member.

  As in the present invention, when the crack is linear on the surface, a plurality of holes are provided separately at each position on the crack, and grooves are provided to communicate the holes with each other. Even if the crack is generated by inserting the repair members (the first repair member and the second repair member) to be combined and hitting and filling the inserted repair member, the entire crack is removed. It can be easily filled with repair members and repairs can be reliably performed on site.

  Moreover, in each said invention, you may make it have the welding process of joining the said cast steel member and the said repair member by heating the boundary part of the said cast steel member and the said embedded repair member. Thus, by welding a cast steel member and a repair member, it can prevent that a crack generate | occur | produces in the boundary part of a cast steel member and a repair member.

  According to the present invention, a crack generated on the surface of a cast steel member can be reliably repaired on site.

It is a figure explaining the outer shell member of a steam turbine casing. It is a figure which shows an example of the crack which generate | occur | produces on the surface of an outer shell member. 3 is a flowchart illustrating a procedure of a repair method according to the first embodiment. 3 is a plan view of the crack 12 as viewed from above the surface 11 of the outer shell member 10. FIG. 3 is a cross-sectional view of the cutting hole 17 cut along a plane perpendicular to the surface 11. FIG. 4 is an upper view of the repair member 30. FIG. 4 is an upper view of the wedge member 20. FIG. It is sectional drawing which cut | disconnected the cutting hole 17 in which the repair member 30 was inserted in the surface perpendicular | vertical to the surface 11. FIG. FIG. 5 is a cross-sectional view of the cutting hole 17 filled with the repair member 30 cut along a plane perpendicular to the surface 11. 6 is a flowchart illustrating a procedure of a repair method according to a second embodiment. It is sectional drawing which cut | disconnected the cutting hole 17 in which the repair member 40 was inserted in the surface perpendicular | vertical to the surface 11. FIG. FIG. 3 is a plan view of a crack 41 as viewed from above the surface 11 of the outer shell member 10. 10 is a flowchart illustrating a procedure of a repair method according to a third embodiment. It is the figure which looked at the surface 11 of the outer shell member 10 from upper direction. It is the figure which looked at the surface 11 of the outer shell member 10 from upper direction. It is the figure which looked at the surface 11 of the outer shell member 10 from upper direction. It is a figure which shows an example of a wedge member. It is a figure which shows an example of a wedge member.

<Example 1>
The method for repairing a cast steel member according to the present embodiment can be applied to repair of a crack generated in a cast steel member due to thermal stress, and steam provided in a thermal power plant or a nuclear power plant as shown in FIG. It can be applied to the outer shell member 10 of the turbine casing.

  The outer shell member 10 of the steam turbine casing is made of, for example, CrMoV cast steel or the like, and is subjected to thermal stress as it starts and stops. As a result, the outer shell member 10 is subjected to creep damage, and a linear crack 12 is generated on the inner surface 11. In this embodiment, a case where the crack 12 is repaired will be described.

  FIG. 2 is a flowchart for explaining the procedure of the repair method of this embodiment. As shown in the figure, first, the direction and dimensions of the crack 12 are confirmed (S11).

  FIG. 3 is a plan view for explaining this process (hereinafter referred to as crack confirmation process S11), as seen from above the surface 11 of the outer shell member 10. FIG. In this embodiment, as shown in the figure, a substantially circular region 13 having a diameter D is defined on the surface 11 so as to surround the entire crack 12, and a cutting hole is formed with the outline 14 of the region 13 as a base line. Let it start.

  Next, the surface 11 including the crack 12 is cut to form a cutting hole (S12 in FIG. 2).

  FIG. 4 is a cross-sectional view illustrating this step (hereinafter, referred to as a cutting hole forming step S12), in which the cutting hole is cut along a plane perpendicular to the surface 11. As shown in the figure, along the contour line 14, the surface 11 of the outer shell member 10 is cut vertically downward with a drill, a cutter or the like, thereby forming a cylindrical cutting hole 17. The depth H2 of the cutting hole 17 is at least the maximum depth H of the crack 12.

  Next, the repair member into which the wedge member is inserted is inserted into the cutting hole 17 (S13 in FIG. 2).

  FIG. 5 is a cross-sectional view of the cutting hole 17 cut along a plane perpendicular to the surface 11 for explaining this process (hereinafter referred to as a repair member insertion process S13). As shown in the drawing, a columnar repair member 30 in which a wedge member 20 described later is inserted into the bottom surface 31 thereof, and the cutting hole 17 in a state where the bottom surface 21 of the wedge member 20 faces the bottom surface 18 side of the cutting hole 17 is shown. Insert into.

  Here, FIG. 6 is a perspective view of the repair member 30. As shown in the figure, the repair member 30 is a cylindrical member, and the top surface 32 and the bottom surface 31 have a diameter D2 and a height H3. The height H3 of the repair member 30 is designed to be slightly longer than the height H2 of the cutting hole 17. The repair member 30 is made of a metallic material having a higher spreadability than the outer shell member 10. For example, pure nickel, pure chromium, pure silver, silver-tin alloy and the like.

  FIG. 7 is an upper view of the wedge member 20. As shown in the figure, the wedge member 20 is a conical member, the bottom surface 21 has a diameter D3 shorter than the top surface 32 and the bottom surface 31 of the repair member 30, and the height thereof is higher than the height of the repair member 30. Short H4. The wedge member 20 is made of a metal having a higher strength than the repair member 30. For example, the wedge member 20 is made of CrMo steel, CrMoV steel, 9% Cr steel, 12% Cr steel, Ni-base alloy, Co-base alloy, SUS-based material, or the like. It is a high temperature heat resistant material.

  Next, the repair member 30 having the wedge member 20 inserted therein is struck and deformed in the cutting hole 17 (S14 in FIG. 2).

  FIG. 8 is a cross-sectional view of the cutting hole 17 into which the repair member 30 is inserted, cut along a plane perpendicular to the surface 11, explaining this step (hereinafter referred to as a repair member hitting step S <b> 14). As shown in the figure, the top surface 32 of the repair member 30 inserted to the bottom surface 18 of the cutting hole 17 is hit with a hammer or the like (reference numeral 35). Since the repair member 30 is made of a highly malleable metal as described above, when the tapping on the top surface 32 is repeated, the repair member 30 is deformed to the outside centering on the portion where the wedge member 20 is inserted. It expands toward the side 19. Eventually, the repair member 30 fills the entire cutting hole 17.

  As described above, since the height H3 of the repair member 30 is higher than the depth H2 of the cutting hole 17, even if the repair member 30 is filled in the cutting hole 17, the repair member 30 after filling. The height of the top surface 32 is close to the height of the surface 11. In addition, when the height of the top surface 32 protrudes from the height of the surface 11, the protruding portion may be ground.

  Finally, the repair member 30 filled in the cutting hole 17 is welded to the outer shell member 10 (S15 in FIG. 2).

  FIG. 9 is a cross-sectional view of the cutting hole 17 filled with the repair member 30 taken along a plane perpendicular to the surface 11 for explaining this process (hereinafter referred to as a welding process S15). As shown in the figure, the boundary between the repair member 30 and the outer shell member 10 (periphery 33 of the top surface 32 of the repair member 30) is heated by a laser welding machine or the like, whereby the outer shell member 10 and the repair member 30 are Are joined (welded) (reference numeral 34). As a result, it is possible to prevent a gap from being generated between the outer shell member 10 and the repair member 30 and high-temperature steam from entering and cracking at the boundary between the outer shell member 10 and the repair member 30.

  Instead of joining using a laser welding machine, the repair member 30 may be melted (for example, melted at 900 ° C. or lower) by TIG welding using a welding torch (TIG torch or the like) (for example, When the material of the repair member 30 is pure silver).

  Further, instead of directly welding the boundary portion between the outer shell member 10 and the repair member 30, a groove is provided to straddle the outer shell member 10 and the repair member 30, and a predetermined metal member is built up on the groove. You may make it weld (laser welding).

  As described above, according to the method for repairing a cast steel member of the present embodiment, the repair member 30 into which the wedge member 20 is inserted is cut in the cutting hole 17 with the wedge member 20 facing the bottom surface 18 side of the cutting hole 17. When the repair member 30 is beaten and inserted, the repair member 30 is deformed in the cutting hole 17 by the inserted wedge member 20, and as a result, the cutting hole 17 is filled. Thereby, the space between the repair member 30 and the outer shell member 10 is filled with no gap, and the repair member 30 can be reliably fixed to the outer shell member 10. Thus, according to the repair method of the cast steel member of the present embodiment, the crack 12 generated on the surface 11 of the outer shell member 10 can be reliably repaired on-site only by using the repair member 30 and the wedge member 20. Can do.

<Example 2>
In the first embodiment, the wedge member 20 is inserted into the repair member 30 in advance, and the repair member 30 is inserted into the cutting hole 17, but the wedge member 20 is first installed in the cutting hole 17 and repaired there. The member 30 may be inserted.

  FIG. 10 is a flowchart for explaining the procedure of the repair method of this embodiment. As shown in the figure, first, the direction and dimensions of the crack 12 are confirmed (S21). Next, a cutting hole including the crack 12 is formed on the surface 11 (S22). These are the same as the crack confirmation process S11 and the cutting hole formation process S12 of the first embodiment.

  Next, a wedge member is installed on the bottom surface of the cutting hole (S23), and the repair member is inserted into the cutting hole in which the wedge member is installed (S24).

  FIG. 11 is a cross-sectional view of the cutting hole 17 into which the repair member 40 is inserted, taken along a plane perpendicular to the surface 11 for explaining this process (hereinafter referred to as a repair member insertion process). As shown in the figure, a wedge member 20 is installed at the center of the bottom surface 18 of the cutting hole 17 with the top portion 22 facing upward. Then, the repair member 30 is inserted into the cutting hole 17 with the bottom surface 31 of the repair member 30 facing downward until the bottom surface 31 of the repair member 30 contacts the top 22 of the wedge member 20. Then, by hitting the top surface 32 of the repair member 30 inserted into the cutting hole 17 with a hammer or the like, the repair member 30 is deformed by the wedge member 20, and the cutting hole is cut in the same manner as in the repair member hitting step S14 of the first embodiment. 17 is filled with the repair member 30 (S25).

  Finally, the repair member 30 is welded to the outer shell member 10 (S26 in FIG. 10). This is the same as the welding step S15 of the first embodiment.

  As in the present embodiment, the repair member 30 is securely fixed to the outer shell member 10 by installing the wedge member 20 in advance on the bottom surface 18 of the cutting hole 17 and inserting the repair member 30 into the cutting hole 17. Thus, the same effect as in the first embodiment can be obtained. As described above, the crack 12 generated on the surface 11 of the outer shell member 10 can be reliably repaired in the field only by using the repair member 30 and the wedge member 20 even by the repair method of the cast steel member of the present embodiment. it can.

<Example 3>
In Examples 1 and 2, a cylindrical cutting hole 17 was provided so as to surround the entire crack 12. However, when the length of the crack 12 is long, when such a cutting hole is provided, the cutting hole becomes too large, and the durability of the repaired portion is lowered and the appearance is impaired. Therefore, in the present embodiment, a repair method in the case where the crack 41 is long in the form of a line (a broken line) (the crack 41 as shown in FIG. 12) will be described.

  FIG. 13 is a flowchart for explaining the procedure of the repair method of this embodiment. As shown in the figure, first, as in the crack confirmation step S11, the direction and dimensions of the crack 41 are confirmed (S31).

  Next, a plurality of smaller cutting holes are provided at various locations on the crack 41 (S32), and a groove communicating these cutting holes is provided (S33).

  FIG. 14 is a view of the surface 11 of the outer shell member 10 as viewed from above, explaining the steps S32 and S33. As shown in the figure, cylindrical cutting holes 43 are provided at various positions in the cracks 41 generated in a polygonal line (each bent portion 42 in this embodiment), as in the first embodiment. However, the diameter (diameter of the opening) d of each cutting hole 43 is made smaller so that it does not overlap with other adjacent cutting holes 43.

  And the groove | channel 45 which connects each cutting hole 43 is provided so that the crack 41 may be included along the crack 41. FIG. In addition, since the width | variety of the groove | channel 45 should just be a width | variety including the crack 41, you may be shorter than the diameter d of the cutting hole 43. FIG.

  As described above, the one-stroke repair hole 48 constituted by the cutting hole 43 and the groove 45 is formed.

  Next, as shown in S <b> 34 of FIG. 13, the repair member into which the wedge member is inserted is inserted into the repair hole 48 and struck and embedded.

  FIG. 15 is a view of the repair member inserted and embedded in the repair hole 48 from above. As shown in the figure, a plurality of repair members are used in this embodiment. That is, a cylindrical member 63 having a shape corresponding to the shape of the cutting hole 43 (hereinafter also referred to as a first repair member) and a bridging member 64 having a shape corresponding to the shape of the groove 45 (hereinafter also referred to as a second repair member). The cylindrical member 63 is inserted and embedded in the cutting hole 43 and the bridging member 64 is inserted in the groove 45, respectively.

  The diameter of the top surface and the bottom surface of the cylindrical member 63 is preferably slightly shorter than the diameter of the cutting hole 43, and the height of the cylindrical member 63 is preferably slightly higher (longer) than the depth of the cutting hole 43. The width and length of the bridging member 64 are preferably slightly shorter than that of the groove 45, and the height of the bridging member 64 is preferably higher (longer) than the depth of the groove 45.

  A wedge member 50, which is a conical member similar to that of the first embodiment, is inserted into the bottom surface of the cylindrical member 63. The diameter of the bottom surface of the wedge member 50 is preferably shorter than the diameter of the bottom surface of the cylindrical member 63, and the height of the wedge member 50 is preferably lower than the height of the cylindrical member 63.

  A wedge member 55, which is a conical member smaller than the wedge member 50, is inserted into the bottom surface of the bridging member 64 (the material is the same as that of the wedge member 50). The diameter of the bottom surface of the wedge member 55 is preferably shorter than the width of the bridging member 64, and the height of the wedge member 55 is preferably lower than the height of the bridging member 64. Further, one or more wedge members 55 are provided along the longitudinal direction of the bridging member 64 according to the length of the bridging member 64.

  FIG. 16 is a view of the surface 11 of the outer shell member 10 as viewed from above, illustrating the above-described step S34 using each repair member (hereinafter referred to as a repair member hitting step). As shown in the figure, in the repairing member hitting process, the cylindrical member 63 into which the wedge member 50 is inserted is inserted into the repairing hole 48 in the same manner as in the first embodiment, and the top surface 61 of the cylindrical member 63 is hit with a hammer or the like. (Reference numeral 62). Thereby, the cylindrical member 63 expands toward the inner surface 44 of the cutting hole 43 and fills the cutting hole 43 (reference numeral 47).

  Each bridging member 64 into which the wedge member 55 is inserted is inserted into the groove 45, and the top surface of the bridging member 64 is hit with a hammer or the like (reference numeral 65). As a result, the bridging member 64 extends over the entire groove 45 and fills the groove 45 (reference numeral 49).

  As described above, each cutting hole 43 is filled with the cylindrical member 63, and each groove 45 is filled with the bridging member 64.

  When the filling of the repair members (cylindrical member 63, bridge member 64) is completed, each repair member is finally welded to the outer shell member 10 (S37 in FIG. 13). That is, as in the first embodiment, the outer edge portions of the cylindrical member 63 and the bridging member 64 are heated and welded to the outer shell member 10.

  As described above, according to the repair method of the cast steel member of the present embodiment, when the crack 41 has a linear shape on the surface, the plurality of cutting holes 43 are provided separately at each position on the crack 41, and the cutting is performed. After providing a groove 45 that allows the holes 43 to communicate with each other, a repair member (a first repair member or a second repair member) that fits into the cutting hole 43 and the groove 45 is inserted, and the inserted repair member is tapped. By performing filling, even if the crack 41 is long, the entire crack 41 can be easily filled with the repair member, and the repair can be reliably performed on site. Moreover, since it is not necessary to provide the large cutting hole 43, durability of a repair site | part is maintained and an external appearance is not impaired.

  In this embodiment, the cutting hole 43 is provided in the bent portion 42 of the crack 41. However, when the bent portion 42 is not provided (such as when the crack 41 is linear) or when the bent portions 42 are separated from each other. Is provided with a cutting hole 43 in the straight part of the crack 41 as appropriate.

  In this embodiment, a plurality of repair members (first repair member, second repair member) are combined to fill the repair hole 48. However, one repair member corresponding to the shape of the repair hole 48 is repaired. The holes 48 may be filled.

  As for the method of using the wedge member 50, in this embodiment, the wedge member 50 is inserted into the repair member 60 in advance, as in the first embodiment, and then inserted into the repair hole 48. The wedge member 50 may be installed on the bottom surface of 43 and the wedge member 50 may be inserted therein by inserting the repair member 60 into the repair hole 48.

<Other examples>
In the above embodiment, the wedge member has a conical shape, but the shape of the wedge member is not limited to this as long as it has a tip that can be inserted into the surface of the repair member.

  For example, the wedge member may be an arbitrary cone other than the conical shape, or may be a wedge member 70 having a triangular pyramid shape as shown in FIG.

  Further, as shown in FIG. 18, a wedge member 80 having a triangular cross section in the longitudinal direction and a common side 82 of the inclined surface 81 forming a tip portion may be used.

  The above description of the embodiments is intended to facilitate understanding of the present invention and is not intended to limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and the present invention includes equivalents thereof.

  For example, when the repair member having a larger volume than the groove portion is filled in the groove portion without a gap, the welding process can be omitted.

10 outer shell member, 11 surface, 12 crack, 13 region, 14 contour line, 17 cutting hole, 18 bottom surface, 19 inner surface, 20 wedge member, 22 top portion, 30 repair member, 31 bottom surface, 32 top surface, 33 peripheral edge, 40 repair member, 41 crack, 42 bent portion, 43 cutting hole, 44 inner surface, 45 groove, 48 repair hole, 50 wedge member, 55 wedge member, 60 repair member, 61 top surface, 63 cylindrical member, 64 bridging member, 70 wedge member, 71 apex, 80 wedge member, 81 inclined surface, 82 common side

Claims (6)

A method of repairing the cast steel member by cutting a crack generated on the surface of the cast steel member to provide a hole, and embedding the repair member in the provided hole,
A repair member inserting step of inserting the repair member into which the wedge member is inserted into the hole in a state where the wedge member faces the bottom surface of the hole;
A repair method for a cast steel member, comprising: a repair member filling step in which the repair member is deformed by the inserted wedge member to fill the hole by tapping the inserted repair member. A method of repairing the cast steel member by cutting a crack generated on the surface of the cast steel member to provide a hole, and embedding the repair member in the provided hole,
A repair member insertion step of inserting the repair member into the hole in which a wedge member is installed on the bottom surface;
By hitting the inserted repair member, the repair member is inserted into the installed wedge member and deformed, and the deformed wedge member has a repair member filling step of filling the hole. Repair method for cast steel members.   The method for repairing a cast steel member according to claim 1, wherein the repair member is made of a metallic material having a higher extensibility than the cast steel member.   The method for repairing a cast steel member according to any one of claims 1 to 3, wherein an inner surface of the hole is formed so as to be substantially perpendicular to a surface of the cast steel member. In the case where the crack is linear on the surface,
A plurality of hole forming steps in which a plurality of the holes are provided apart from each other at each position on the crack; and
A groove forming step of providing a groove for communicating the plurality of holes with each other so as to include the crack along the crack;
In the repair member inserting step, the first repair member shaped to fit into the hole is inserted into each of the holes, and the second repair member shaped to fit into the groove is inserted into each of the grooves. Inserted into
In the repairing member filling step, the hole is filled with the first repairing member by tapping the inserted first repairing member, and the groove is formed by tapping the inserted second repairing member. The method for repairing a cast steel member according to any one of claims 1 to 4, wherein the second repair member is used for filling the steel plate.   6. The method according to claim 1, further comprising a welding step of joining the cast steel member and the repair member by heating a boundary portion between the cast steel member and the filled repair member. The repair method of the cast steel member of description.

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