Blank structure for casting processing of copper-steel bimetallic cylinder body

Abstract

The invention provides a blank structure for casting processing of a copper-steel bimetallic cylinder, the blank structure is integrally cylindrical, the center position of the blank structure is provided with a vertically through center hole, the center hole is divided into two sections with different diameters, and the diameter of a first center hole close to the upper end is smaller than that of a second center hole close to the lower end; a boss, an annular groove and a molten pool groove are sequentially arranged on the upper end face of the blank structure from inside to outside, the annular groove is arranged around the boss in the center, the inner side of the molten pool groove is communicated with the annular groove, the outer side of the molten pool groove extends to the side wall of the blank structure, and the depth of the annular groove is larger than that of the molten pool groove. By means of the structural design of the boss and the annular groove, the final solidification area of molten copper is controlled around the boss area, the final solidification area is all located in the range of a center hole of a finished product, accurate control over the final solidification area is achieved, and the casting yield is increased; the structure is reasonable in design, convenient to machine, low in cost and wide in application range.

Description

Technical Field

[0001] The present invention belongs to the technical field of pump body part processing, and relates to a blank structure for the melting and casting of a copper-steel bimetallic cylinder block. Background Art

[0002] As an important device in the hydraulic system, one of the key core parts of a piston pump is the cylinder block. The performance and quality of the cylinder block will directly affect the transmission efficiency and service life of the piston pump. At present, the most commonly used material for the cylinder block of a piston pump is a copper-steel bimetallic composite material, in which the steel material is used as the base, and the copper alloy forms the working layer and is clad on the surface of the steel base. One of the common methods for producing a copper-steel bimetallic composite cylinder block is the melting and casting method. It is necessary to first process the copper melting pool, then put the copper alloy into the copper melting pool, and put the workpiece as a whole into the sintering furnace for heating. After the copper alloy melts, it spreads on the surface of the steel base and forms a bimetallic cylinder block after cooling, which has the advantages of high production efficiency and low production cost.

[0003] According to the processing process of the bimetallic composite cylinder block, the copper alloy completes the processes of melting, filling the melting pool, and solidifying in the heating furnace. From the perspective of casting, the solid-liquid phase line temperature range of the copper alloy is large, and it is difficult to achieve simultaneous solidification during solidification. Currently, the most commonly used is the sequential solidification method. However, the volume and thickness of the steel base and the copper alloy layer in the cylinder block are quite different. The cooling rate of the copper alloy layer will be greater than that of the steel base, so that the last solidified area will be located at the position with the highest temperature in the steel base. Therefore, designing the blank structure to control the position of the last solidified area is the key to the successful melting and casting of the cylinder block, and it is of great significance for improving the melting and casting quality and broadening the melting and casting process window.

[0004] The prominent structural feature of the cylinder block product is the central hole. From the perspective of the copper melting surface, the area outside the central hole is the copper layer area, and solidification defects are generally not allowed in the copper layer area. Therefore, the last solidified area needs to be controlled within the central hole area. Thus, when designing the blank structure of the cylinder block, it should be considered to control the central hole area to have the slowest cooling rate. CN 118554670A discloses a copper-steel bimetallic rotor and its preparation method, including an alloy steel rotor, and the upper surface of the alloy steel rotor is covered with a copper layer; a central hole is arranged at the center of the alloy steel rotor, and the central hole is a stepped central hole, including a first cylindrical central hole and a second cylindrical central hole, the diameter of the former is larger than that of the latter, and the two are connected by a tapered central hole. The copper-steel bimetallic structure involved in this patent is a rotor, and its blank structure only improves the structure of the central hole, so that the last solidified area is concentrated in the central part. However, this structure is designed based on the basic structure and cooling method of the rotor and is not applicable to the piston pump cylinder block structure, and the last solidified area is still not easy to control.

[0005] CN 118558993 A discloses a method for inverted casting of a copper spherical friction pair of a plunger pump. This method involves the processing of a bimetallic cylinder block. After the processing of the steel matrix, a blank cylinder block composed of the steel matrix, a molten copper pool, and a central hole is obtained. Subsequently, a spherical mold is formed by stamping a steel plate. The spherical mold is welded to the edge of the molten copper pool. After the steel matrix is inverted, the molten copper pool faces downward. Copper alloy is added to the molten copper pool through the central hole, and the whole is compounded. After cooling, the spherical mold is cut off to obtain a bimetallic cylinder block blank. The processing of the cylinder block in this patent is a mold structure and processing method specifically designed for the spherical surface of the copper alloy, and does not involve the control of the last solidification area and does not improve the structure of the central hole.

[0006] In summary, according to the structure of the copper-steel bimetallic cylinder block, when designing the blank structure during its processing, it should be based on the central hole, and at the same time, the structure of the upper end face should be improved to control the last solidification area in the central hole area and improve the casting success rate of the product. Summary of the Invention

[0007] Aiming at the problems existing in the prior art, the purpose of the present invention is to provide a blank structure for the casting and processing of a copper-steel bimetallic cylinder block. Through the setting of a boss structure and an annular groove, the last solidification area of the copper liquid is controlled around the boss area, so that the solidification defects of the copper layer are controlled within the range of the central hole of the cylinder block finished product, realizing the precise control of the last solidification range and improving the finished product rate of casting.

[0008] To achieve this purpose, the present invention adopts the following technical solutions:

[0009] The present invention provides a blank structure for the casting and processing of a copper-steel bimetallic cylinder block. The blank structure is generally cylindrical. A central hole penetrating up and down is provided at the central position of the blank structure. The central hole is divided into two sections with different diameters. The diameter of the first central hole near the upper end is smaller than the diameter of the second central hole near the lower end. On the upper end face of the blank structure, a boss, an annular groove, and a molten pool groove are sequentially arranged from the inside to the outside. The first central hole is located at the center of the boss. The annular groove is arranged around the boss at the central position. The inner side of the molten pool groove is connected to the annular groove. The outer side of the molten pool groove extends to the side wall of the blank structure. The depth of the annular groove is greater than the depth of the molten pool groove.

[0010] In the present invention, for the casting process of the copper-steel bimetallic cylinder block, the design of the blank structure needs to take into account the different cooling rates of the copper layer and the steel matrix, as well as the control of the last solidification region, so as to avoid the presence of solidification defects in the finished cylinder block. In the present invention, a boss is provided on the upper end face of the blank structure, and its position is higher than the molten pool groove. Based on the fact that the cooling rate of the steel matrix is lower than that of the copper liquid, the last solidification region is controlled in the area around the boss. By providing a groove around the boss and controlling the depth of the groove to be greater than that of the molten pool groove, the last solidification region is further accurately controlled around the boss, and at the same time, the dependence on the volume of the boss can be weakened. Based on the setting of the boss, the size of the central hole at the upper end of the blank structure is smaller than that of the central hole at the lower end. On the one hand, it is restricted by the size of the boss, and on the other hand, it is for ventilation to facilitate cooling after casting. Through the above structural design, the accurate control of the last solidification region of the copper liquid is realized, the yield of casting is improved, and the casting process window is expanded. The structure design is reasonable, the processing is convenient, the cost is low, and the applicable range is wide.

[0011] The following are the preferred technical solutions of the present invention, but not the limitations of the technical solutions provided by the present invention. Through the following technical solutions, the technical objectives and beneficial effects of the present invention can be better achieved and realized.

[0012] As a preferred technical solution of the present invention, the size of the central hole in the blank structure is based on the size of the central hole in the finished cylinder block after processing.

[0013] Preferably, the diameter of the second central hole in the blank structure is 2 to 5 mm smaller than the diameter of the central hole in the finished cylinder block, such as 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm or 5 mm, etc., but not limited to the listed values. Other unlisted values within this numerical range are equally applicable.

[0014] In the present invention, in order to prevent the solidification defects from affecting the finished cylinder block, it is necessary to determine the boundary of the defects according to the size of the central hole in the finished cylinder block, that is, it is necessary to control the last solidification region within the range of the central hole of the finished product. For a cylinder block with a relatively small central hole diameter, the corresponding boss size is also restricted by the central hole size, and the problem of agglomeration defects cannot be effectively solved.

[0015] As a preferred technical solution of the present invention, the height of the second central hole accounts for 1 / 2 to 2 / 3 of the overall height of the blank structure, such as 1 / 2, 11 / 20, 14 / 25, 3 / 5, 16 / 25, 13 / 20 or 2 / 3, etc., but not limited to the listed values. Other unlisted values within this numerical range are equally applicable.

[0016] Preferably, the diameter-changing part between the second central hole and the first central hole adopts a transition with an angle of 45° to 90°, such as 45°, 50°, 55°, 60°, 70°, 75°, 80° or 90°, etc., but is not limited to the listed values, and other unlisted values within this value range are equally applicable.

[0017] In the present invention, the size of the central hole at the lower end of the blank structure is as close as possible to the central hole of the finished cylinder block, and the diameter-changing part between the two sections of the central hole adopts a right-angle transition, which can not only reduce the subsequent processing amount, but also increase the contact area between the cylinder block and the external cooling medium, and accelerate the cooling rate of the steel matrix part.

[0018] As a preferred technical solution of the present invention, the diameter size of the boss in the blank structure is 2 / 3 to 4 / 5 of the diameter size of the central hole of the finished cylinder block, such as 2 / 3, 7 / 10, 18 / 25, 3 / 4, 19 / 25 or 4 / 5, etc., but is not limited to the listed values, and other unlisted values within this value range are equally applicable.

[0019] In the present invention, the size of the boss diameter is an important factor affecting the processing effect of the finished cylinder block. If the boss diameter is too small, the hot spot ability of the boss will be too small to achieve the purpose of gathering defects; if the boss diameter is too large, the solidification defects brought by the last solidification area will exceed the range of the finished central hole, resulting in unqualified finished cylinder blocks.

[0020] Preferably, the diameter size of the first central hole is 1 / 6 to 1 / 5 of the boss diameter size, such as 1 / 6, 17 / 100, 9 / 50, 19 / 100 or 1 / 5, etc., but is not limited to the listed values, and other unlisted values within this value range are equally applicable.

[0021] In the present invention, the selection of the diameter size of the first central hole is mainly based on the boss diameter size. If the diameter of the first central hole is too large, the heat storage capacity of the boss will be reduced, resulting in the inability to gather solidification defects around the boss; if the diameter of the first central hole is too small, the boss will cool too slowly, and the copper liquid around it will solidify slowly, and the defect range will exceed the allowable range.

[0022] As a preferred technical solution of the present invention, the depth of the annular groove is 2 to 5 mm, such as 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm or 5 mm, etc., but is not limited to the listed values, and other unlisted values within this value range are equally applicable; the depth of the annular groove is the depth based on the bottom of the molten pool groove.

[0023] Preferably, the diameter of the outer boundary of the annular groove is 4 - 10 mm smaller than the diameter of the finished central hole of the cylinder block, such as 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm or 10 mm, etc., but not limited to the listed values, and other unlisted values within this range are equally applicable.

[0024] Preferably, the inner boundary of the annular groove coincides with the boundary of the boss, and the width of the annular groove is the difference between the radius of the outer boundary and the radius of the boss.

[0025] Preferably, the width of the annular groove is 4 - 7 mm, such as 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm or 7 mm, etc., but not limited to the listed values, and other unlisted values within this range are equally applicable.

[0026] In the present invention, the structural design of the annular groove can effectively control the last solidification area at the central hole of the cylinder block when the molten copper solidifies, reducing the dependence on the volume of the boss. Without the design of the annular groove, even if the size of the boss increases, due to the limitation of the maximum size, the defects cannot be effectively gathered. If the width of the annular groove is too large, the defects will overflow; if the width of the annular groove is too small, the heat dissipation ability will be weakened or even lost. If the depth of the annular groove is too large, excessive thermal stress will be generated during solidification, forming cracks; if the depth of the annular groove is too small, the heat sink ability will also be reduced.

[0027] As a preferred technical solution of the present invention, a chamfer design is adopted at the corner of the annular groove and the boss, and this chamfer is the first chamfer.

[0028] Preferably, the radius of the first chamfer is 1.2 - 2 mm, such as 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.8 mm or 2 mm, etc., but not limited to the listed values, and other unlisted values within this range are equally applicable.

[0029] As a preferred technical solution of the present invention, the depth of the molten pool groove is 4 - 12 mm, such as 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm or 12 mm, etc., but not limited to the listed values, and other unlisted values within this range are equally applicable.

[0030] Preferably, the side wall thickness of the blank structure at the outer boundary of the molten pool groove is 1 - 2.5 mm, such as 1 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2 mm, 2.2 mm or 2.5 mm, etc., but not limited to the listed values, and other unlisted values within this range are equally applicable.

[0031] As a preferred technical solution of the present invention, the junction of the annular groove and the molten pool groove is designed with a slope to form a ramp.

[0032] Preferably, the angle between the ramp and the horizontal line is 15 to 45 degrees, such as 15 degrees, 20 degrees, 25 degrees, 30 degrees, 35 degrees, 40 degrees or 45 degrees, etc., but not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0033] Preferably, the corner of the ramp and the bottom surface of the annular groove is also chamfered, and this chamfer is the second chamfer.

[0034] Preferably, the radius of the second chamfer is 1.2 to 2 mm, such as 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.8 mm or 2 mm, etc., but not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0035] In the present invention, the chamfer design on both sides of the annular groove helps to reduce the internal stress of the copper layer during solidification and reduce the risk of cracking caused by stress.

[0036] As a preferred technical solution of the present invention, when casting using the blank structure, the molten copper liquid solidifies in the molten pool groove and forms a composite whole with the steel matrix.

[0037] Preferably, during the solidification process of the copper liquid, the last solidification area is controlled to be located at the boss and annular groove parts, and does not exceed the area of the center hole of the finished cylinder block.

[0038] As a preferred technical solution of the present invention, after the upper end surface of the blank structure is cast with a copper layer, the blank structure is processed.

[0039] Preferably, the processing steps include: removing the boss and the side wall part of the molten pool groove that are higher than the copper layer, and reaming the center hole of the blank structure until it reaches the center hole size of the finished cylinder block.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] (1) Through the structural design of the boss and the annular groove, the present invention controls the last solidification area of the copper liquid around the boss area, making it all within the range of the finished center hole. Especially the design of the annular groove can also weaken the dependence on the volume of the boss, achieve precise control of the last solidification range, expand the casting process window, and improve the casting yield, which can reach more than 99%;

[0042] (2) The structure of the present invention is reasonably designed, easy to process, has a low cost, and has a wide application range. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 is the front view of the blank structure for the copper-steel bimetallic cylinder block casting and processing provided in Embodiment 1 of the present invention;

[0044] Figure 2 is the top view of the blank structure for the copper-steel bimetallic cylinder block casting and processing provided in Embodiment 1 of the present invention;

[0045] Figure 3 is the result of the chemical penetration flaw detection after the casting of the blank structure provided in Embodiment 1 of the present invention;

[0046] Figure 4 is the result of the chemical penetration flaw detection after the casting of the blank structure provided in Embodiment 4 of the present invention;

[0047] Figure 5 is the result of the chemical penetration flaw detection after the casting of the blank structure provided in Embodiment 5 of the present invention;

[0048] Figure 6 is the result of the chemical penetration flaw detection after the casting of the blank structure provided in Embodiment 6 of the present invention;

[0049] Figure 7 is the result of the chemical penetration flaw detection after the casting of the blank structure provided in Embodiment 7 of the present invention;

[0050] Figure 8 is the result of the chemical penetration flaw detection after the casting of the blank structure provided in Comparative Example 1 of the present invention;

[0051] Figure 9 is the result of the chemical penetration flaw detection after the casting of the blank structure provided in Comparative Example 2 of the present invention;

[0052] wherein, 1 - the first central hole, 2 - the second central hole, 3 - the boss, 4 - the annular groove, 5 - the melting pool groove. Detailed Embodiments

[0053] To better illustrate the present invention and facilitate the understanding of its technical solutions, the present invention is further described in detail below. However, the following embodiments are only simple examples of the present invention and do not represent or limit the scope of the protection of the present invention. The scope of protection of the present invention is subject to the claims.

[0054] The following are typical but non-limiting embodiments of the present invention:

[0055] Embodiment 1:

[0056] This embodiment provides a blank structure for the copper-steel bimetallic cylinder block casting and processing. The front view of the blank structure is as shown in Figure 1 and its top view is as shown in Figure 2As shown, the blank structure is generally cylindrical. A central hole penetrating through from top to bottom is provided at the central position of the blank structure. The central hole is divided into two sections with different diameters. The diameter of the first central hole 1 near the upper end is smaller than that of the second central hole 2 near the lower end; on the upper end surface of the blank structure, a boss 3, an annular groove 4, and a molten pool groove 5 are successively provided from the inside to the outside. The first central hole 1 is located at the central position of the boss 3. The annular groove 4 is arranged around the boss 3 at the central position. The inner side of the molten pool groove 5 is communicated with the annular groove 4. The outer side of the molten pool groove 5 extends to the side wall of the blank structure. The depth of the annular groove 4 is greater than that of the molten pool groove 5.

[0057] The size of the central hole in the blank structure is based on the size of the central hole in the finished cylinder block after machining. The diameter size of the central hole in the finished cylinder block is 58 mm.

[0058] The diameter of the second central hole 2 in the blank structure is 2 mm smaller than the diameter size of the central hole in the finished cylinder block, which is 56 mm.

[0059] The height of the second central hole 2 accounts for 1 / 2 of the overall height of the blank structure.

[0060] A 90° right-angle transition is adopted at the diameter-changing part between the second central hole 2 and the first central hole 1.

[0061] The diameter size of the boss 3 in the blank structure is 40 mm.

[0062] The diameter size of the first central hole 1 is 1 / 5 of the diameter size of the boss 3, which is 8 mm.

[0063] The depth of the annular groove 4 is 3 mm and the width is 6 mm.

[0064] A chamfering design is adopted at the corner between the annular groove 4 and the boss 3. The chamfer here is the first chamfer with a radius of 1.5 mm.

[0065] The depth of the molten pool groove 5 is 8 mm. The thickness of the side wall of the blank structure at the outer boundary of the molten pool groove 5 is 2 mm.

[0066] A slope design is adopted at the junction of the annular groove 4 and the molten pool groove 5 to form a slope. The angle between the slope and the horizontal line is 30 degrees.

[0067] A chamfering design is also carried out at the corner between the slope and the bottom surface of the annular groove 4. The chamfer here is the second chamfer with a radius of 1.5 mm.

[0068] In this embodiment, Figure 2The blue ring in it is the boundary of the central hole of the finished cylinder block, which does not actually exist in the blank structure. It is marked here to better show its positional relationship with the annular groove and the boss. The lines inside the ring are successively the boundary of the annular groove, the boundary of the boss, and the boundary of the first central hole.

[0069] Embodiment 2:

[0070] This embodiment provides a blank structure for the melting and casting process of a copper-steel bimetallic cylinder block. The overall shape of the blank structure is cylindrical. A central hole that penetrates up and down is provided at the central position of the blank structure. The central hole is divided into two sections with different diameters. The diameter of the first central hole 1 near the upper end is smaller than the diameter of the second central hole 2 near the lower end. On the upper end surface of the blank structure, there are successively a boss 3, an annular groove 4, and a melting pool groove 5 from the inside to the outside. The first central hole 1 is located at the central position of the boss 3. The annular groove 4 is arranged around the boss 3 at the central position. The inner side of the melting pool groove 5 is communicated with the annular groove 4. The outer side of the melting pool groove 5 extends to the side wall of the blank structure. The depth of the annular groove 4 is greater than the depth of the melting pool groove 5.

[0071] The size of the central hole in the blank structure is based on the size of the central hole in the finished cylinder block after processing. The diameter size of the central hole in the finished cylinder block is 58 mm.

[0072] The diameter of the second central hole 2 in the blank structure is 4 mm smaller than the diameter size of the central hole in the finished cylinder block, which is 54 mm.

[0073] The height of the second central hole 2 accounts for 2 / 3 of the overall height of the blank structure.

[0074] At the variable diameter part of the second central hole 2 and the first central hole 1, a 60° angle transition is adopted.

[0075] The diameter size of the boss 3 in the blank structure is 42 mm.

[0076] The diameter size of the first central hole 1 is 1 / 6 of the diameter size of the boss 3, which is 7 mm.

[0077] The depth of the annular groove 4 is 4 mm and the width is 5 mm.

[0078] At the corner of the annular groove 4 and the boss 3, a chamfer design is adopted. The chamfer here is the first chamfer with a radius of 1.2 mm.

[0079] The depth of the melting pool groove 5 is 4 mm. The thickness of the side wall of the blank structure at the outer boundary of the melting pool groove 5 is 1 mm.

[0080] At the junction of the annular groove 4 and the melting pool groove 5, a slope design is adopted to form a slope. The angle between the slope and the horizontal line is 45 degrees.

[0081] The corner of the slope and the bottom surface of the annular groove 4 is also chamfered. The chamfer here is the second chamfer, with a radius of 1.2 mm.

[0082] Embodiment 3:

[0083] This embodiment provides a blank structure for the melting and casting process of a copper-steel bimetallic cylinder block. The overall shape of the blank structure is cylindrical. A central hole that penetrates up and down is provided at the center of the blank structure. The central hole is divided into two sections with different diameters. The diameter of the first central hole 1 near the upper end is smaller than the diameter of the second central hole 2 near the lower end. On the upper end surface of the blank structure, a boss 3, an annular groove 4, and a melting pool groove 5 are provided in sequence from the inside out. The first central hole 1 is located at the center of the boss 3. The annular groove 4 is arranged around the boss 3 at the center position. The inner side of the melting pool groove 5 is communicated with the annular groove 4. The outer side of the melting pool groove 5 extends to the side wall of the blank structure. The depth of the annular groove 4 is greater than the depth of the melting pool groove 5.

[0084] The size of the central hole in the blank structure is based on the size of the central hole in the finished cylinder block after processing. The diameter size of the central hole in the finished cylinder block is 60 mm.

[0085] The diameter of the second central hole 2 in the blank structure is 3 mm smaller than the diameter size of the central hole in the finished cylinder block, which is 57 mm.

[0086] The height of the second central hole 2 accounts for 3 / 5 of the overall height of the blank structure.

[0087] The transition between the second central hole 2 and the first central hole 1 adopts a 45° angle transition.

[0088] The diameter size of the boss 3 in the blank structure is 45 mm.

[0089] The diameter size of the first central hole 1 is 1 / 5 of the diameter size of the boss 3, which is 9 mm.

[0090] The depth of the annular groove 4 is 2 mm, and the width is 4 mm.

[0091] The corner of the annular groove 4 and the boss 3 adopts a chamfer design. The chamfer here is the first chamfer, with a radius of 2 mm.

[0092] The depth of the melting pool groove 5 is 12 mm. The thickness of the side wall of the blank structure at the outer boundary of the melting pool groove 5 is 2.5 mm.

[0093] The junction of the annular groove 4 and the melting pool groove 5 adopts a slope design to form a slope. The angle between the slope and the horizontal line is 15 degrees.

[0094] The corner of the slope and the bottom surface of the annular groove 4 is also chamfered. The chamfer here is the second chamfer, with a radius of 2 mm.

[0095] Example 4:

[0096] This example provides a blank structure for the copper-steel bimetallic cylinder block casting and processing. The blank structure refers to the structure in Example 1, except that the depth of the annular groove 4 is 6 mm.

[0097] Example 5:

[0098] This example provides a blank structure for the copper-steel bimetallic cylinder block casting and processing. The blank structure refers to the structure in Example 1, except that the depth of the annular groove 4 is 1 mm.

[0099] Example 6:

[0100] This example provides a blank structure for the copper-steel bimetallic cylinder block casting and processing. The blank structure refers to the structure in Example 1, except that the width of the annular groove 4 is 8 mm.

[0101] Example 7:

[0102] This example provides a blank structure for the copper-steel bimetallic cylinder block casting and processing. The blank structure refers to the structure in Example 1, except that the width of the annular groove 4 is 3 mm.

[0103] Example 8:

[0104] This example provides a blank structure for the copper-steel bimetallic cylinder block casting and processing. The blank structure refers to the structure in Example 1, except that the diameter dimension of the boss 3 is 36 mm.

[0105] Example 9:

[0106] This example provides a blank structure for the copper-steel bimetallic cylinder block casting and processing. The blank structure refers to the structure in Example 1, except that the diameter dimension of the boss 3 is 46 mm.

[0107] Comparative Example 1:

[0108] This comparative example provides a blank structure for the copper-steel bimetallic cylinder block casting and processing. The blank structure refers to the structure in Example 1, except that the structure of the annular groove 4 is absent in the blank structure.

[0109] Comparative Example 2:

[0110] This comparative example provides a blank structure for the casting and processing of a copper-steel bimetallic cylinder block. The blank structure refers to the structure in Example 1, with the difference that: in the blank structure, the diameter of the boss 3 is 50 mm, and there is no annular groove 4 structure.

[0111] Using the blank structures in the above Examples 1-9 and Comparative Examples 1-2 for casting, after the molten copper solidifies, it forms a composite whole with the steel matrix. The copper layer is processed to reach the thickness of the copper layer in the finished product, and then chemical penetration flaw detection is carried out on the copper layer. The steps of the detection include: after cleaning the surface of the copper layer, evenly spraying the penetrant on the surface, after standing for 3-5 minutes, wiping the surface clean, and then evenly spraying the developer on the surface of the copper layer, and observing the results of the chemical penetration flaw detection. Among them, the results of the chemical penetration flaw detection in Example 1, Examples 4-7 and Comparative Examples 1-2 are respectively as Figures 3 - 9 shown.

[0112] In Examples 1-3, the dimensions of the boss and the annular groove in the blank structure meet the requirements, and the casting quality is qualified. It can be seen from Figure 3 that the casting defects do not exceed the range of the finished product center hole;

[0113] In Example 4, due to the excessive depth of the annular groove, the thermal stress during solidification is too large, resulting in cracks and overflowing beyond the range of the finished product center hole, as shown in Figure 4 described, the casting quality is unqualified; in Example 5, due to the too small depth of the annular groove, the pyrolysis ability is reduced, and the solidification defects overflow beyond the range of the finished product center hole, as shown in Figure 5 described, the casting quality is unqualified; in Example 6, due to the too large width of the annular groove, the solidification defects will overflow, as shown in Figure 6 described, the casting quality is unqualified; in Example 7, due to the too small width of the annular groove, the thermal joint ability is reduced, and the solidification defects overflow, as shown in Figure 7 described, the casting quality is unqualified;

[0114] In Example 8, due to the too small diameter of the boss, its thermal joint ability is weakened, and it cannot achieve the effect of gathering defects, and the solidification defects exceed the range of the finished product center hole, resulting in unqualified casting quality; in Example 9, due to the too large diameter of the boss and being close to the boundary of the finished product center hole, the solidification defects are likely to exceed the range of the finished product center hole, resulting in unqualified casting quality;

[0115] In Comparative Example 1, since there is no annular groove in the blank structure, the solidification defects cannot be effectively gathered, resulting in the overflow of the solidification defects, as shown in Figure 8 shown, the casting quality is unqualified; in Comparative Example 2, even if the diameter of the boss is increased, in the case of no annular groove, the solidification defects still cannot be effectively gathered, resulting in the overflow of the solidification defects, as shown in Figure 9 shown, the casting quality is unqualified.

[0116] As can be seen from the above-mentioned embodiments and comparative examples, through the structural design of the boss and the annular groove, the last solidification area of the molten copper is controlled around the boss area, and all of it is located within the range of the finished product central hole. In particular, the design of the annular groove can also weaken the dependence on the volume of the boss, achieve precise control of the last solidification range, expand the melting and casting process window, and improve the yield of melting and casting, which can reach more than 99%. The said structural design is reasonable, convenient to process, low in cost, and wide in application range.

[0117] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate the detailed structure of the present invention, but the present invention is not limited to the above-mentioned detailed structure, that is, it does not mean that the present invention must rely on the above-mentioned detailed structure to be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent replacement of the structure of the present invention, the addition of auxiliary structures, the selection of specific methods, etc. all fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A blank structure for copper-steel bimetallic cylinder casting, characterized in that: The blank structure is cylindrical as a whole, and a center hole is provided at the center position of the blank structure which passes through the center hole from top to bottom. The center hole is divided into two sections with different diameters, and the diameter of the first center hole near the upper end is smaller than the diameter of the second center hole near the lower end; a boss, an annular groove and a molten pool groove are provided on the upper end surface of the blank structure from the inside to the outside in sequence, and the first center hole is located at the center position of the boss, and the annular groove is arranged around the boss at the center position, the inner side of the molten pool groove is connected with the annular groove, and the outer side of the molten pool groove extends to the side wall of the blank structure, and the depth of the annular groove is greater than the depth of the molten pool groove.

2. The blank structure according to claim 1, characterized in that: The size of the center hole in the rough structure is based on the size of the center hole in the finished cylinder block after processing; And / or, the diameter of the second center hole in the rough structure is 2-5 mm smaller than the diameter of the center hole in the finished cylinder body.

3. The blank structure according to claim 1, characterized in that: The height of the second center hole accounts for 1 / 2 to 2 / 3 of the overall height of the blank structure; And / or, the diameter change point between the second center hole and the first center hole adopts a transition angle of 45° to 90°.

4. The blank structure according to claim 1, characterized in that: The diameter of the boss in the rough structure is 2 / 3 to 4 / 5 of the diameter of the center hole of the finished cylinder body; And / or, the diameter of the first center hole is 1 / 6 to 1 / 5 of the diameter of the boss.

5. The blank structure according to claim 1, characterized in that: The depth of the annular groove is 2-5 mm; And / or, the diameter of the outer boundary of the annular groove is 4-10 mm smaller than the diameter of the center hole of the finished cylinder body; And / or, the inner boundary of the annular groove coincides with the boundary of the boss, and the width of the annular groove is the difference between the radius of the outer boundary and the radius of the boss; And / or, the width of the annular groove is 4-7 mm.

6. The blank structure according to claim 1, characterized in that: The corners of the annular groove and the boss are chamfered, and the chamfer here is the first chamfer; And / or, the radius of the first chamfer is 1.2~2mm.

7. The blank structure according to claim 1, characterized in that: The depth of the molten pool groove is 4-12 mm; And / or, the side wall thickness of the blank structure at the outer boundary of the molten pool groove is 1~2.5mm.

8. The blank structure according to claim 1, characterized in that: The junction between the annular groove and the molten pool groove is designed with an inclination to form a slope; And / or, the angle between the slope and the horizontal line is 15 to 45 degrees; And / or, the corner between the slope and the bottom surface of the annular groove is also chamfered, and the chamfer here is a second chamfer; And / or, the radius of the second chamfer is 1.2~2mm.

9. The blank structure according to any one of claims 1 to 8, characterized in that: When the blank structure is used for melting and casting, the molten copper solidifies in the molten pool and forms a composite whole with the steel matrix; And / or, during the solidification process of the copper liquid, the final solidification area is controlled to be located at the boss and the annular groove, and does not exceed the area of ​​the center hole of the finished cylinder body.

10. The blank structure according to any one of claims 1 to 8, characterized in that: After the copper layer is melt-casted on the upper end surface of the blank structure, the blank structure is processed; And / or, the processing steps include: removing the boss higher than the copper layer and the side wall of the molten pool groove, and expanding the center hole of the blank structure to reach the size of the center hole of the finished cylinder body.

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