Hinge beam pouring method

Abstract

The invention provides a hinge beam pouring method which comprises a cavity, a heat preservation riser and a multi-layer pouring system, and the multi-layer pouring system comprises two cylinder opening bottom return inner water gaps, four lug piece bottom return inner water gaps, an annular transverse pouring gate and a straight pouring gate; the insulated feeder is arranged at the top of the cavity, two cylinder opening bottom return inner water gaps are arranged at a cylinder opening of the cavity, four lug bottom return inner water gaps are uniformly arranged at lug holes of the cavity, and the annular cross gate is respectively communicated with the two cylinder opening bottom return inner water gaps, the four lug bottom return inner water gaps and the straight gate; a multi-layer pouring system is adopted, molten steel ascends synchronously, the gradient problem that the molten steel descends and then ascends is avoided, inclusions at the front end of the molten steel float upwards along with flowing of the molten steel and are discharged, and therefore the phenomenon that floating sand and steel slag are accumulated at the bottoms of the lugs is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of hinge beam casting, and particularly relates to a hinge beam casting method. Background Art

[0002] The hinge beam includes a cylinder block and lugs. As a core component of a diamond press, the hinge beam is made of chrome molybdenum steel. The hinge beam has extremely high requirements for internal quality and needs to meet the acceptance standards of Class I for special parts and Class II for general parts in ultrasonic flaw detection.

[0003] Currently, the traditional casting process uses a bottom-return casting system, including a vertical sprue, three ingates, and a cross runner. However, the bottom positions of the 10 lugs in the cavity are lower than the outlet position of the water inlet in the cylinder block, and as the shape and size of the hinge beam increase. If the traditional process is used for casting, there is a gradient problem that the molten steel first descends and then rises when the front end of the molten steel flows inside the cavity, resulting in the easy accumulation of suspended impurities and steel slag in the molten steel at the bottom of the lugs and difficult to discharge. As a result, the casting defects such as sand holes and slag holes increase, the internal quality does not meet the standard, and because chrome molybdenum steel is sensitive to temperature, cracks are easily generated if the temperature control is slightly improper during subsequent welding repair of the defective parts, affecting the service life of the hinge beam. Summary of the Invention

[0004] Based on the above technical problems, the purpose of the present invention is to provide a hinge beam casting method, which adopts a multi-layer casting system to make the molten steel rise synchronously, avoiding the gradient problem that the molten steel first descends and then rises, so that the inclusions at the front end of the molten steel float up and are discharged along with the flow of the molten steel, thereby reducing the phenomenon of accumulated floating sand and steel slag at the bottom of the lugs.

[0005] The specific technical solution thereof is as follows: A hinge beam casting method includes: a cavity, a hot top, and a multi-layer casting system. The multi-layer casting system includes two bottom-return ingates at the cylinder mouth, four bottom-return ingates at the lugs, an annular runner, and a sprue; the hot top is arranged at the top of the cavity, two bottom-return ingates at the cylinder mouth are arranged at the cylinder mouth of the cavity, four bottom-return ingates at the lugs are evenly arranged at the ear holes of the cavity, and the annular runner is respectively connected to the two bottom-return ingates at the cylinder mouth, the four bottom-return ingates at the lugs, and the sprue; The hinge beam casting method includes the following steps: S1: Molten steel pretreatment: The steel block is smelted into molten steel through an electric arc furnace, and then the molten steel is sent into a ladle refining furnace for refining to remove gases and inclusions, thereby realizing the pretreatment of the molten steel, reducing the impurity content in the molten steel, and reducing the influence of inclusions on the quality of the casting during the subsequent casting process; S2: Pouring: Pour the pre-treated molten steel into the sprue. The molten steel enters the annular runner through the sprue and simultaneously enters the cylinder block and lugs of the cavity through six bottom return water inlets, enabling the molten steel in the lugs and cylinder block to rise simultaneously. This causes the inclusions in the molten steel to float and be discharged as the molten steel flows, avoiding the accumulation of impurities caused by the molten steel flow gradient problem. During pouring, the temperature of the molten steel is controlled between 1550 - 1560 °C, and the flow rate is controlled at 150 kg / s to ensure the fluidity and floating effect of the inclusions, while ensuring the stability of the pouring process and the uniformity of the casting quality.

[0006] In addition, a hinge beam pouring method in the above technical solution provided by the present invention may further have the following additional technical features: In the above technical solution, a conical funnel is provided on the sprue to expand the area of the sprue feed inlet.

[0007] In the above technical solution, the pipe diameters of the inner water inlet and the return water inlet are both ∮70 mm, the pipe diameter of the sprue is ∮90 mm, and the pipe diameter of the runner is ∮90 mm.

[0008] In the above technical solution, the included angle between the four bottom return inner water inlets of the lugs is 90 degrees.

[0009] A hinge beam pouring method of the present invention, compared with the prior art, has the following beneficial effects: 1. By adopting a multi-layer pouring system, it is ensured that the molten steel in the lugs and cylinder block in the cavity rises simultaneously, avoiding the gradient problem of the molten steel first descending and then rising. This causes the inclusions at the front end of the molten steel to float and be discharged as the molten steel flows, thereby reducing the phenomenon of accumulated floating sand and steel slag at the bottom of the lugs, and further reducing the casting defects such as sand holes and slag holes. The quality of the hinge beam is improved, enabling it to meet the acceptance standards of Grade I for special parts and Grade II for general parts in ultrasonic flaw detection.

[0010] 2. Due to the reduction of casting defects, the subsequent cleaning and welding repair workload is significantly reduced, reducing the risk of invisible crack defects caused by welding repair, avoiding the scrapping of castings due to improper welding repair, thereby reducing the repair cost and production cycle of the hinge beam and improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a structural schematic diagram of a hinge beam pouring method of the present invention; Figure 2 is a structural schematic diagram of a pouring method of traditional technology; Figure 3 is a structural schematic diagram of the cavity of the present invention; Among them, Figures 1 to 3 the corresponding relationship between the reference numerals in the drawings and the component names is: 10 cavities, 101 cylinder block, 102 lugs, 11 insulating riser, 12 bottom return internal sprue at cylinder opening, 13 bottom return internal sprue at lug bottom, 14 annular cross sprue, 15 sprue, 16 conical funnel, 17 vertical sprue, 18 internal sprue, 19 cross cross sprue. Specific embodiments

[0012] The following combines specific implementation cases and attachments Figures 1-3 to further illustrate the present invention, but the present invention is not limited to these embodiments.

[0013] A pouring method for a hinge beam, as Figure 1 and Figure 3 shown, includes: a cavity 10, an insulating riser 11, and a multi-layer pouring system. The multi-layer pouring system includes two bottom return internal sprues 12 at the cylinder opening, four bottom return internal sprues 13 at the lug bottom, an annular cross sprue 14, and a sprue 15; the insulating riser 11 is arranged at the top of the cavity 10, two bottom return internal sprues 12 are arranged at the cylinder opening of the cavity 10, four bottom return internal sprues 13 are evenly arranged at the ear holes of the cavity 10, and the annular cross sprue 14 is respectively connected and communicated with the two bottom return internal sprues 12 at the cylinder opening, the four bottom return internal sprues 13 at the lug bottom, and the sprue 15; The pouring method for the hinge beam includes the following steps: S1: Molten steel pretreatment: The steel block is smelted into molten steel by an electric arc furnace, and then the molten steel is sent into a ladle refining furnace for refining to remove gases and inclusions, so as to realize the pretreatment of the molten steel, reduce the impurity content in the molten steel, and reduce the influence of inclusions on the casting quality during the subsequent pouring process; S2: Pouring: Inject the pretreated molten steel into the sprue 15. The molten steel enters the annular cross sprue 14 through the sprue 15, and at the same time enters the 101 cylinder block and the lugs 102 of the cavity 10 through 6 bottom return sprues, so that the molten steel in the lugs 102 and the cylinder block 101 rises simultaneously, so that the inclusions in the molten steel float up and are discharged along with the flow of the molten steel, avoiding the accumulation of impurities caused by the molten steel flow gradient problem; During pouring, the temperature of the molten steel is controlled between 1550 - 1560 °C, and the flow rate is controlled at 150 kg / s to ensure the fluidity and floating effect of the inclusions, and at the same time ensure the stability of the pouring process and the uniformity of the casting quality.

[0014] As Figure 2 shown, the existing pouring system adopts a bottom return pouring system, including a vertical sprue 17, three internal sprues 18, and a cross cross sprue 19. In this way, the molten steel enters the cavity from the cylinder opening at the bottom of the cavity. The molten steel first flows downward to the bottom of the lug and then rises into the cylinder block. In this structure and method, when the front end of the molten steel flows inside the cavity 10, there is a gradient problem that the molten steel first descends and then rises. As Figure 1As shown, in the casting method of the present invention, a multi-layer casting system is used to make the molten steel in the cylinder block 101 and the lug 102 of the cavity 10 rise synchronously, avoiding the gradient problem that the molten steel first descends and then rises in the existing casting method, making the inclusions at the front end of the molten steel float up to the riser and be discharged, reducing the casting defects such as sand holes and slag holes in the ear holes, thereby improving the service life of the hinge beam and reducing the cost of subsequent welding repair.

[0015] Specifically, the volume of the insulating riser 11 accounts for 58%-62% of the cavity 10. By extending the solidification time of the molten steel through the insulating riser 11, the feeding effect is enhanced, thereby improving the density of the casting.

[0016] In an embodiment of the present invention, a conical funnel 16 is provided on the sprue 15 to enlarge the area of the feeding port of the sprue 15.

[0017] By setting the conical funnel 16, the area of the feeding port of the sprue 15 is enlarged, facilitating the pouring of the molten steel into the sprue 15.

[0018] Specifically, the outlet diameter of the funnel is ∮90mm, the inlet diameter of the funnel is ∮300mm, and the height is 350mm.

[0019] In an embodiment of the present invention, the pipe diameters of the return water port 13 and the bottom return inner water port 12 of the cylinder mouth are both ∮70mm, the pipe diameter of the sprue 15 is ∮90mm, and the pipe diameter of the cross gate is ∮90mm.

[0020] In an embodiment of the present invention, the temperature of the molten steel during casting is 1550-1560°C, and the flow rate is 150kg / s, thereby ensuring the fluidity and floating effect of the inclusions.

[0021] In an embodiment of the present invention, the included angle between the four bottom return inner water ports 13 of the lugs is 90 degrees, ensuring the uniform flow of the molten steel.

[0022] Experimental results: By using the casting method of the present invention, 96 hinge beams of model 900 are produced. During the processing, only 8 products are welded. Among the 8 products, there are only 12 small sand holes in the holes of the lugs 102 in total. The welding repair rate is reduced by 48% compared with the products produced by the existing casting process. The defect rate in the traditional process is usually as high as 10%-20%. Thus, the defects such as sand holes and slag holes in the ear hole area are significantly reduced, and the internal quality of the product is greatly improved.

[0023] The multi-layer pouring system of the present invention is provided with a plurality of lug bottom-return internal water inlets 13 and cylinder mouth bottom-return internal water inlets 12, and they are evenly distributed, so that the molten steel can rise synchronously after entering the cavity 10; this synchronous rising flow pattern avoids the high and low gradient changes of the molten steel in the cavity 10, thereby reducing the accumulation of suspended impurities and steel slag at the bottom of the lugs at the front end of the molten steel. When the molten steel enters the cavity 10, due to the even distribution and reasonable design of the return water inlets 13 and the cylinder mouth bottom-return internal water inlets 12, a relatively stable upward flow field can be formed during the flow of the molten steel. Driven by the flow of the molten steel, the inclusions can smoothly float to the riser 11 and be discharged, thus effectively reducing the inclusion defects inside the casting.

[0024] Chrome molybdenum steel is sensitive to temperature. During the pouring process, the control of temperature is crucial for the quality of the casting; the present invention controls the temperature of the molten steel during pouring within the range of 1550 - 1560 °C. This temperature range can not only ensure the good fluidity of the molten steel, but also enable the inclusions to maintain a certain fluidity for easy floating and discharging; at the same time, by setting the riser 11, the solidification time of the molten steel is extended, so that the casting can be fully compensated during solidification, reducing the generation of defects such as shrinkage cavities and porosity, and improving the density and mechanical properties of the casting.

[0025] In the description of the present invention, the term "a plurality of" means two or more, unless otherwise clearly defined. The orientation or positional relationship indicated by terms such as "upper", "lower", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention; terms such as "connection", "installation", "fixation", etc. should all be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A casting method for a hinge beam, characterized in that, Comprising: A cavity, a heat-insulating riser, and a multi-layer gating system. The multi-layer gating system includes two bottom-return inner gateways at the cylinder mouth, four bottom-return inner gateways at the lugs, an annular runner, and a sprue. The heat-insulating riser is arranged at the top of the cavity. Two bottom-return inner gateways at the cylinder mouth are arranged at the cylinder mouth of the cavity. Four bottom-return inner gateways at the lugs are evenly arranged at the ear holes of the cavity. The annular runner is respectively communicated with the two bottom-return inner gateways at the cylinder mouth, the four bottom-return inner gateways at the lugs, and the sprue. The hinge beam casting method includes the following steps: S1: Molten steel pretreatment: Molten steel is smelted from steel blocks through an electric arc furnace, and then the molten steel is sent into a ladle refining furnace for refining to remove gases and inclusions, thereby realizing the pretreatment of the molten steel, reducing the impurity content in the molten steel, and reducing the influence of inclusions on the quality of castings during subsequent casting. S2: Casting: The pretreated molten steel is injected into the sprue. The molten steel enters the annular runner through the sprue and simultaneously enters the cylinder body and lugs of the cavity through 6 bottom-return gateways, realizing the simultaneous rise of the molten steel in the lugs and the cylinder body, so that the inclusions in the molten steel float and are discharged along with the flow of the molten steel, avoiding the accumulation of impurities caused by the molten steel flow gradient problem. During casting, the temperature of the molten steel is controlled between 1550 - 1560 °C, and the flow rate is controlled at 150 kg / s to ensure the fluidity and floating effect of inclusions, and at the same time ensure the stability of the casting process and the uniformity of the quality of castings.

2. A method for casting a hinge beam according to claim 1, characterized in that, A conical funnel is provided on the sprue to enlarge the area of the sprue inlet.

3. A method for casting a hinge beam according to claim 1, characterized in that, The pipe diameters of both the bottom-return inner gateway at the cylinder mouth and the bottom-return inner gateway at the lugs are ∮70 mm, the pipe diameter of the sprue is ∮90 mm, and the pipe diameter of the runner is ∮90 mm.

4. A method for casting a hinge beam according to claim 1, characterized in that, The included angle between the four bottom-return inner gateways at the lugs is 90 degrees.

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