Double-slit atomizer for normalizing thick large-section high-performance ductile iron and multi-medium cooling method

Abstract

The atomizer comprises an upper part, a middle part and a lower part, the upper part, the middle part and the lower part are coaxially arranged, the lower end face of the upper part extends in the direction of a stainless steel liquid guide channel, air inlet channels are formed in the side wall of the upper part and are symmetrically distributed, and the air inlet channels are communicated with the middle part and the lower part. The middle part is connected to the lower surface of the upper part, the lower part is connected to the lower surface of the upper part, and a complete atomization gas cavity is formed and installed through a fixing flange. The multi-medium cooling method comprises the steps of high-pressure air source installation, liquid guide pipe connection, thick and large-section ductile iron heating, air cooling, water (10%-30% of saline water) atomization and the like. Through the double-slit atomizer, multi-medium rapid cooling can be achieved on the thick and large-section ductile iron subjected to normalizing treatment, the organization structure of the thick and large-section ductile iron is refined, and then the comprehensive performance of the thick and large-section ductile iron is improved.

Description

Technical Field

[0001] The invention relates to the field of heat treatment of thick and large-section metal castings, and in particular to a double-slit atomizer for normalizing thick and large-section high-performance ductile iron and a multi-medium cooling method. Background Art

[0002] Ductile iron materials have good comprehensive mechanical properties and casting properties, as well as low production costs. Among them, the industrial demand for ductile iron materials with high strength, high hardness and high ductility is continuing to grow. For example, with the continuous improvement of diesel engine power and speed, especially the widespread application of turbocharging technology, the requirements for the crankshaft, the heart of the diesel engine, are getting higher and higher. The high-grade ductile iron in the existing national standards, especially in terms of fatigue strength and toughness, cannot meet the performance requirements of the engine crankshaft. The research and development and preparation of higher-performance QT800-2, QT900-2 and even QT1000-5 ductile iron are on the agenda; at the same time, high-strength and tough QT800-2 and QT900-2 show broad application prospects in lightweighting, and the weight of high-strength and tough ductile iron can be greatly reduced under the same load. In addition to engine crankshafts, ductile iron is widely used in many industries such as internal combustion engines, engineering machinery, rail transportation, power generation equipment and electricity, ships, mining and metallurgy heavy machinery, machine tools, etc.

[0003] At present, most of the research literature reports on ductile iron QT800-2 and QT900-2 at home and abroad focus on small-sized and light-weight parts such as automotive crankshaft connecting rods, as well as standard specimens, and rarely mention thick and large-section ductile iron materials or parts. However, in recent years, with the upgrading and replacement of wind power generation equipment and the trend towards large-scale type, the actual demand for ductile iron that should meet the performance of QT800-2 and QT900-2 has been proposed. The rapid cooling characteristics of the double-slit atomizer combined with the heat treatment normalizing process can better refine the pearlite structure and improve the mechanical properties of QT800-2. Summary of the invention

[0004] Purpose of the invention: In order to solve the deficiencies of the prior art, the present invention provides a double-slit atomizer and a multi-medium cooling method for normalizing thick and large-section high-performance ductile iron, which can achieve a breakthrough in the technical problems mentioned in the above background technology.

[0005] Technical solution: A double-slit atomizer for normalizing high-performance ductile iron with a thick cross-section, the atomizer includes an upper part, a middle part and a lower part, the upper part is coaxially arranged with the middle part and the lower part, the lower end face of the upper part extends in the direction of the stainless steel liquid guide channel, the side wall of the upper part is provided with an air inlet channel, and the air inlet channels are symmetrically distributed, the middle part is connected to the lower surface of the upper part, and the lower part is connected to the lower surface of the upper part to form a complete atomizing gas chamber, which is installed by a fixed flange.

[0006] As an optimization: the upper piece is connected with the middle piece and the lower piece to form a first double ring seam and a second double ring seam, and the atomizing gas chamber is communicated with the first double ring seam and the second double ring seam.

[0007] As an optimization: the gap of the first ring seam is set to 0.02mm-0.05mm, and the gap of the second ring seam is set to 0.02mm-0.04mm.

[0008] As an optimization: the angle α formed by the center line of the first annular seam and the axis of the liquid guiding channel is set to 10°-30°, and the angle β formed by the center line of the second annular seam and the axis of the liquid guiding channel is set to 40°-60°.

[0009] As an optimization: the aperture of the symmetrical air intake channel is 8mm-12mm.

[0010] As an optimization: the outer diameter of the stainless steel catheter is 8mm-12mm, the inner diameter is 4mm-6mm, and the extended length of the catheter does not exceed the intersection of the second annular seam and the axis of the catheter channel, which is set to 3mm-5mm.

[0011] A multi-medium cooling method of a double-slit atomizer for normalizing thick and large-section high-performance ductile iron comprises the following steps: Step 1: Install the high-pressure gas source. Connect the high-pressure gas source outlet to the pressure reducing valve. Use the pressure reducing valve to adjust the gas source outlet pressure to 0.6MPa-1.0MPa. Then connect the pressure reducing valve to the angle valve and the atomizer air inlet channel through an explosion-proof metal hose. Ensure that the high-pressure gas switches normally. Step 2: Connect the liquid guide tube to the tap water pipe. The tap water flow rate of the stainless steel liquid guide tube is regulated by a liquid flow meter, and the liquid flow rate is controlled at 100ml / min-1000ml / min. Step 3: Heating: Heat the ductile iron with a wall thickness of 100mm-300mm to a normalizing temperature of 800℃-1000℃ through a high-temperature furnace according to a heating curve. The wall thickness of the casting is 100mm-300mm. After the thick and large-section ductile iron is kept warm for 1h-5h, it is taken out of the furnace for normalizing treatment to make its tensile strength 800MPa-900MPa and elongation 1-3%; Step 4: Air cooling + water (10%-30% brine) atomization, put the thick and large-section ductile iron after normalizing and insulation on the heat treatment platform, and then open the pressure reducing valve, angle valve and liquid flow meter switch at the same time according to the heat treatment normalizing conditions, and perform air cooling + water (10%-30% brine) atomization normalizing treatment on the thick and large-section ductile iron, and the atomization area is controlled at 50mm 2 -1000mm 2 .

[0012] Beneficial effects: The present invention can realize multi-medium rapid cooling of thick and large-section ductile iron subjected to normalizing treatment through a double-slit atomizer, refine its organizational structure, and thus improve its comprehensive performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the normalizing treatment structure of thick and large-section high-performance ductile iron of the present invention; Figure 2 It is a schematic diagram of the structure and mechanical properties of the thick and large-section high-performance ductile iron after normalizing treatment of the present invention; Figure 3 It is a schematic diagram of a double-slit atomizer for normalizing thick and large-section high-performance ductile iron and a method of using the present invention; Figure 4 It is a schematic diagram of an atomizer of the present invention. DETAILED DESCRIPTION

[0014] The technical solutions in the embodiments of the present invention will be described clearly and completely below so that those skilled in the art can better understand the advantages and features of the present invention, thereby making a clearer definition of the protection scope of the present invention. The embodiments described in the present invention are only a part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0015] The high-performance ductile iron normalizing atomizer of the present invention is composed of an upper part, a middle part and a lower part. The upper part of the atomizer is coaxially arranged with the middle part and the lower part. The lower end face of the upper part extends in the direction of the stainless steel liquid guide channel. The side wall of the upper part is provided with an air inlet channel, and the air inlet channels are symmetrically distributed. The middle part is connected to the lower surface of the upper part, and the lower part is connected to the lower surface of the upper part to form a complete atomizing gas chamber, which is installed by a fixed flange.

[0016] In the present invention, the upper component is connected with the middle component and the lower component to form a first double ring seam and a second double ring seam, and the atomizing gas chamber is communicated with the first double ring seam and the second double ring seam.

[0017] In the present invention, the gap of the first ring slit is set to 0.02mm-0.05mm, and the gap of the second ring slit is set to 0.02mm-0.04mm.

[0018] In the present invention, the angle α formed between the center line of the first annular seam and the axis of the liquid guiding channel is set to 10°-30°, and the angle β formed between the center line of the second annular seam and the axis of the liquid guiding channel is set to 40°-60°.

[0019] The aperture of the symmetrical air intake channel in the present invention is 8mm-12mm.

[0020] The stainless steel liquid guiding tube of the present invention has an outer diameter of 8mm-12mm and an inner diameter of 4mm-6mm. The extending length of the liquid guiding tube does not exceed the intersection of the second annular seam and the axis of the liquid guiding channel, which is set to 3mm-5mm.

[0021] The double-slit atomizer and multi-medium cooling method for normalizing thick and large-section high-performance ductile iron, by using the atomizer of the above scheme, comprises the following steps: a: Installation of high-pressure gas source: ordinary air is compressed by air compressor and stored in large gas tank. The air pressure in the gas tank is 8MPa-10MPa. A gas pressure reducing valve is installed at the outlet of the gas tank. The outlet pressure of the gas source can be adjusted to 0.6MPa-1.0MPa through the pressure reducing valve. The gas discharged from the pressure reducing valve is connected to the angle valve and the atomizer air inlet channel through the explosion-proof metal hose. This can provide sufficient gas source for the double-slit atomizer, ensuring that the double-slit atomizer can work normally for a long time.

[0022] b: Connect the liquid guide tube and inject sufficient tap water into the water reservoir through the tap water pipe. The outlet of the water reservoir can be connected in series with the stainless steel liquid guide tube by installing a liquid flow meter to regulate the liquid flow per unit time. The liquid flow can be controlled within 100ml / min-1000ml / min.

[0023] c: Heating: Heat the large-section ductile iron with a wall thickness of 100mm-300mm in a high-temperature furnace to a normalizing temperature of 800℃-1000℃ according to the heating curve. After insulation for 1h-5h, take it out of the furnace for normalizing treatment to make its tensile strength 800MPa-900MPa and elongation 1-3%.

[0024] d: Air cooling + water (10%-30% brine) atomization. Place the thick and large-section ductile iron after insulation on the heat treatment platform, then open the air pressure reducing valve to adjust the air source outlet pressure to 0.6MPa-1.0MPa. Open the angle valve and flow meter according to the requirements of air cooling + water (10%-30% brine) atomization. Adjust the liquid flow rate to 100ml / min-1000ml / min as required, and perform air cooling + water (10%-30% brine) atomization normalizing treatment on the thick and large-section ductile iron.

[0025] The atomization area described in the present invention is controlled at 50 mm 2 -1000mm 2 . Example

[0026] This embodiment discloses a double-slit atomizer for normalizing thick and large-section high-performance ductile iron and a multi-medium cooling method.

[0027] In this embodiment, the high-performance ductile iron normalizing atomizer consists of an upper part, a middle part and a lower part. The upper part of the atomizer is coaxially arranged with the middle part and the lower part. The lower end face of the upper part extends in the direction of the stainless steel liquid guide channel. The side wall of the upper part is provided with an air inlet channel, and the air inlet channels are symmetrically distributed. The middle part is connected to the lower surface of the upper part, and the lower part is connected to the lower surface of the upper part to form a complete atomizing gas chamber, which is installed by a fixed flange.

[0028] In this embodiment, the upper piece is connected with the middle piece and the lower piece to form a first double ring seam and a second double ring seam, and the atomizing gas chamber is communicated with the first double ring seam and the second double ring seam.

[0029] In this embodiment, the gap of the first ring slit is set to 0.02 mm, and the gap of the second ring slit is set to 0.02 mm.

[0030] In this embodiment, the angle α formed between the center line of the first annular seam and the axis of the liquid guiding channel is set to 10°, and the angle β formed between the center line of the second annular seam and the axis of the liquid guiding channel is set to 40° The aperture of the symmetrical air intake channel in this embodiment is 8 mm.

[0031] The stainless steel liquid guiding tube in this embodiment has an outer diameter of 8 mm and an inner diameter of 4 mm. The extending length of the liquid guiding tube does not exceed the intersection of the second annular seam and the axis of the liquid guiding channel, which is set to 3 mm.

[0032] The double-slit atomizer and multi-medium cooling method for normalizing thick and large-section high-performance ductile iron described in this embodiment, by using the atomizer of the above scheme, include the following steps: a: Installation of high-pressure gas source: ordinary air is compressed by air compressor and stored in large gas tank. The air pressure in the gas tank is 8MPa. A gas pressure reducing valve is installed at the outlet of the gas tank. The outlet pressure of the gas source can be adjusted to 0.6MPa through the pressure reducing valve. The gas discharged from the pressure reducing valve is connected to the angle valve and the atomizer air inlet channel through the explosion-proof metal hose. This can provide sufficient gas source for the double-slit atomizer, ensuring that the double-slit atomizer can work normally for a long time.

[0033] b: Connect the liquid guide tube and inject sufficient tap water into the water reservoir through the tap water pipe. The outlet of the water reservoir is connected in series with the stainless steel liquid guide tube by installing a liquid flow meter to regulate the liquid flow per unit time, which can control the liquid flow at 100ml / min.

[0034] c: Heating: Heat the 100mm thick large-section ductile iron through a high-temperature furnace to a normalizing temperature of 800°C according to the heating curve. After holding for 1 hour, take it out of the furnace for normalizing treatment to achieve a tensile strength of 800MPa and an elongation of 1%.

[0035] d: Air cooling + water (10% brine) atomization, place the thick and large-section ductile iron after the insulation on the heat treatment platform, then open the air pressure reducing valve to adjust the air source outlet pressure to 0.6MPa, open the angle valve and the flow meter switch of 100ml / min liquid flow per unit time according to the requirements of air cooling + water (10% brine) atomization, and perform air cooling + water (10% brine) atomization normalizing treatment on the thick and large-section ductile iron.

[0036] The atomization area described in this embodiment is controlled to be 50 mm 2 . Example

[0037] This embodiment discloses a double-slit atomizer for normalizing thick and large-section high-performance ductile iron and a multi-medium cooling method.

[0038] In this embodiment, the high-performance ductile iron normalizing atomizer consists of an upper part, a middle part and a lower part. The upper part of the atomizer is coaxially arranged with the middle part and the lower part. The lower end face of the upper part extends in the direction of the stainless steel liquid guide channel. The side wall of the upper part is provided with an air inlet channel, and the air inlet channels are symmetrically distributed. The middle part is connected to the lower surface of the upper part, and the lower part is connected to the lower surface of the upper part to form a complete atomizing gas chamber, which is installed by a fixed flange.

[0039] In this embodiment, the upper piece is connected with the middle piece and the lower piece to form a first double ring seam and a second double ring seam, and the atomizing gas chamber is communicated with the first double ring seam and the second double ring seam.

[0040] In this embodiment, the gap of the first ring seam is set to 0.025 mm, and the gap of the second ring seam is set to 0.03 mm.

[0041] In this embodiment, the angle α formed between the center line of the first annular seam and the axis of the liquid guiding channel is set to 20°, and the angle β formed between the center line of the second annular seam and the axis of the liquid guiding channel is set to 50° The aperture of the symmetrical air inlet channel in this embodiment is 10 mm.

[0042] The stainless steel liquid guiding tube in this embodiment has an outer diameter of 10 mm and an inner diameter of 5 mm. The extending length of the liquid guiding tube does not exceed the intersection of the second annular seam and the axis of the liquid guiding channel, which is set to 4 mm.

[0043] The double-slit atomizer and multi-medium cooling method for normalizing thick and large-section high-performance ductile iron described in this embodiment, by using the atomizer of the above scheme, include the following steps: a: Installation of high-pressure gas source: ordinary air is compressed by air compressor and stored in large gas tank. The air pressure in the gas tank is 9MPa. A gas pressure reducing valve is installed at the outlet of the gas tank. The outlet pressure of the gas source can be adjusted to 0.8MPa through the pressure reducing valve. The gas discharged from the pressure reducing valve is connected to the angle valve and the atomizer air inlet channel through the explosion-proof metal hose. This can provide sufficient gas source for the double-slit atomizer, ensuring that the double-slit atomizer can work normally for a long time.

[0044] b: Connect the liquid guide tube and inject sufficient tap water into the water reservoir through the tap water pipe. The outlet of the water reservoir is connected in series with the stainless steel liquid guide tube by installing a liquid flow meter to regulate the liquid flow per unit time, which can control the liquid flow at 500ml / min.

[0045] c: Heating: The 200mm thick large-section ductile iron is heated to the normalizing temperature of 900℃ through a high-temperature furnace according to the heating curve. After 2.5 hours of heat preservation, it is taken out of the furnace for normalizing treatment to achieve a tensile strength of 850MPa and an elongation of 2%.

[0046] d: Air cooling + water (20% brine) atomization, place the thick and large-section ductile iron after insulation on the heat treatment platform, then open the air pressure reducing valve to adjust the air source outlet pressure to 0.8MPa, open the angle valve and the flow meter switch according to the requirements of air cooling + water (20% brine) atomization and the liquid flow rate per unit time is 500ml / min, and perform air cooling + water (20% brine) atomization normalizing treatment on the thick and large-section ductile iron.

[0047] The atomization area described in this embodiment is controlled at 500mm 2 . Example

[0048] This embodiment discloses a double-slit atomizer for normalizing thick and large-section high-performance ductile iron and a multi-medium cooling method.

[0049] In this embodiment, the high-performance ductile iron normalizing atomizer consists of an upper part, a middle part and a lower part. The upper part of the atomizer is coaxially arranged with the middle part and the lower part. The lower end face of the upper part extends in the direction of the stainless steel liquid guide channel. The side wall of the upper part is provided with an air inlet channel, and the air inlet channels are symmetrically distributed. The middle part is connected to the lower surface of the upper part, and the lower part is connected to the lower surface of the upper part to form a complete atomizing gas chamber, which is installed by a fixed flange.

[0050] In this embodiment, the upper piece is connected with the middle piece and the lower piece to form a first double ring seam and a second double ring seam, and the atomizing gas chamber is communicated with the first double ring seam and the second double ring seam.

[0051] In this embodiment, the gap of the first ring seam is set to 0.05 mm, and the gap of the second ring seam is set to 0.04 mm.

[0052] In this embodiment, the angle α formed between the center line of the first annular seam and the axis of the liquid guiding channel is set to 30°, and the angle β formed between the center line of the second annular seam and the axis of the liquid guiding channel is set to 60° The aperture of the symmetrical air intake channel in this embodiment is 12 mm.

[0053] The stainless steel liquid guiding tube in this embodiment has an outer diameter of 12 mm and an inner diameter of 6 mm. The extending length of the liquid guiding tube does not exceed the intersection of the second annular seam and the axis of the liquid guiding channel, which is set to 5 mm.

[0054] The double-slit atomizer and multi-medium cooling method for normalizing thick and large-section high-performance ductile iron described in this embodiment, by using the atomizer of the above scheme, include the following steps: a: Installation of high-pressure gas source: ordinary air is compressed by air compressor and stored in large gas tank. The air pressure in the gas tank is 10MPa. A gas pressure reducing valve is installed at the outlet of the gas tank. The outlet pressure of the gas source can be adjusted to 1.0MPa through the pressure reducing valve. The gas discharged from the pressure reducing valve is connected to the angle valve and the atomizer air inlet channel through the explosion-proof metal hose. This can provide sufficient gas source for the double-slit atomizer, ensuring that the double-slit atomizer can work normally for a long time.

[0055] b: Connect the liquid guide tube and inject sufficient tap water into the water reservoir through the tap water pipe. The outlet of the water reservoir is connected in series with the stainless steel liquid guide tube by installing a liquid flow meter to regulate the liquid flow per unit time, which can control the liquid flow at 1000ml / min.

[0056] c: Heating: Heat the 300mm thick large-section ductile iron through a high-temperature furnace according to the heating curve to the normalizing temperature of 1000℃. After 5 hours of insulation, take it out of the furnace for normalizing treatment to make its tensile strength 900MPa and elongation 3%.

[0057] d: Air cooling + water (30% brine) atomization, place the thick and large-section ductile iron after the insulation is completed on the heat treatment platform, then open the air pressure reducing valve to adjust the air source outlet pressure to 1.0MPa, open the angle valve and the flow meter switch according to the requirements of air cooling + water (30% brine) atomization and the liquid flow rate per unit time is 1000ml / min, and perform air cooling + water (30% brine) atomization normalizing treatment on the thick and large-section ductile iron.

[0058] The atomization area described in this embodiment is controlled at 1000mm 2 .

Claims

1. A double-slit atomizer for normalizing thick and large-section high-performance ductile iron, characterized by: The atomizer includes an upper piece, a middle piece and a lower piece. The upper piece is coaxially arranged with the middle piece and the lower piece. The lower end surface of the upper piece extends in the direction of the stainless steel liquid guide channel. The side wall of the upper piece is provided with an air inlet channel, and the air inlet channels are symmetrically distributed. The middle piece is connected to the lower surface of the upper piece, and the lower piece is connected to the lower surface of the upper piece to form a complete atomizing gas chamber, which is installed by a fixed flange.

2. The double-slit atomizer for normalizing thick and large-section high-performance ductile iron according to claim 1, characterized in that: The upper piece is connected with the middle piece and the lower piece to form a first double ring seam and a second double ring seam, and the atomizing gas chamber is communicated with the first double ring seam and the second double ring seam.

3. The double-slit atomizer for normalizing thick and large-section high-performance ductile iron according to claim 1, characterized in that: The gap of the first ring seam is set to 0.02mm-0.05mm, and the gap of the second ring seam is set to 0.02mm-0.04mm.

4. The double-slit atomizer for normalizing thick and large-section high-performance ductile iron according to claim 1, characterized in that: The angle α formed between the center line of the first annular seam and the axis of the liquid guiding channel is set to 10°-30°, and the angle β formed between the center line of the second annular seam and the axis of the liquid guiding channel is set to 40°-60°.

5. The double-slit atomizer for normalizing thick and large-section high-performance ductile iron according to claim 1, characterized in that: The aperture of the symmetrical air intake channel is 8mm-12mm.

6. The double-slit atomizer for normalizing thick and large-section high-performance ductile iron according to claim 1, characterized in that: The outer diameter of the stainless steel liquid guiding tube is 8mm-12mm, the inner diameter is 4mm-6mm, and the extending length of the liquid guiding tube does not exceed the intersection of the second annular seam and the axis of the liquid guiding channel, which is set to 3mm-5mm.

7. A multi-medium cooling method for a double-slit atomizer for normalizing thick and large-section high-performance ductile iron according to claim 1, characterized in that: The following steps are involved: Step 1: Install the high-pressure gas source. Connect the air inlet channel to the high-pressure gas source. The outlet pressure of the high-pressure gas source is regulated by a pressure reducing valve. The outlet pressure is controlled at 0.6MPa-1MPa. Step 2: Connect the catheter to the water pipe. The flow rate of tap water in the catheter is regulated by a flow meter and the flow rate is set to 100ml / min-1000ml / min. Step 3: Heating: Heat the thick and large-section ductile iron to the normalizing temperature. The normalizing temperature is set to 800℃-1000℃. The wall thickness of the casting is 100mm-300mm, and the tensile strength is 800MPa-900MPa and the elongation is 1-3%. Step 4: Air cooling + water (10%-30% salt water) atomization, the atomization area is controlled at 50mm 2 -1000mm 2 .

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