Application of stainless steel alloy powder in powder metallurgy

Abstract

The invention belongs to the technical field of metal powder manufacturing, and discloses stainless steel alloy powder and a preparation method thereof. The preparation method comprises the following steps: smelting pure iron, electrolytic nickel, micro-carbon ferrochrome and ferromanganese in certain parts by mass, adding silicon-calcium particles after the pure iron, the electrolytic nickel, the micro-carbon ferrochrome and the ferromanganese are completely molten, standing, and fishing out slag to obtain alloy liquid; preheating a leakage ladle, heating the alloy liquid, enabling the alloy liquid to flow out of the leakage ladle, atomizing the alloy liquid through water to generate powdery alloy, and starting to cast steel; and after steel pouring is finished, the powdery alloy is subjected to centrifugal dewatering, drying and screening, and stainless steel alloy powder is obtained. According to the preparation method disclosed by the invention, the oxygen content, the loose specific gravity and the particle size of the finished product powder are effectively reduced, and compared with the addition of pure silicon, the production cost is also reduced, so that the oxygen content of the finished product powder is only 1600-1780ppm, the loose specific gravity is only 2.47-2.65 g / cm < 3 >, and the performance requirements of the PM field are better met.

Description

[0001] This application is a divisional application. The application number of the parent application is 202211500490.2, the application date is November 28, 2022, and the name of the invention is "A stainless steel alloy powder and its preparation method". Technical Field

[0002] The invention relates to the technical field of metal powder manufacturing, and in particular to a stainless steel alloy powder and a preparation method thereof. Background Art

[0003] There are various methods for manufacturing stainless steel alloy powder for powder metallurgy (PM), and water atomization is the most commonly used method. However, during the water atomization powder making process, a large amount of water vapor is generated instantly when high-pressure water contacts the metal liquid flow. The water vapor decomposes when in contact with the metal powder, and the powder is easily oxidized, resulting in a high oxygen content in the final powder, which leads to poor mechanical properties and rough appearance of the final product during downstream use. In addition, due to the characteristics of the metal powder itself, in order to obtain a small matte ratio metal powder, the metal powder must be cooled in a very short time, so a high-pressure water pump with a large flow rate must be selected. When the high-pressure water pump is determined, its pressure and flow rate are proportional. Due to the performance requirements of the stainless steel powder for PM, its particle size cannot be too fine, so the pressure cannot be too large, and the flow rate is also limited.

[0004] Therefore, there is an urgent need to provide a method for preparing stainless steel alloy powder with low oxygen content and small looseness ratio to meet the performance requirements of PM. Summary of the invention

[0005] The object of the present invention is to provide a stainless steel alloy powder and a preparation method thereof, so as to solve the problems of high oxygen content and large particle size of the powder in the prior art.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing stainless steel alloy powder, comprising the following steps:

[0008] Step 1: Smelt a certain amount of pure iron, electrolytic nickel, low-carbon ferrochrome and ferromanganese, add silicon-calcium particles after they are completely melted, let stand, remove slag, and obtain alloy liquid;

[0009] Step 2: Preheat the ladle, heat up the alloy liquid and let it flow out of the ladle. The alloy liquid is atomized by water to produce powdered alloy, and then steel pouring begins;

[0010] Step 3: After the steel pouring is completed, the powdered alloy is centrifugally dehydrated, dried, and sieved to obtain stainless steel alloy powder.

[0011] Furthermore, in a method for preparing a stainless steel alloy powder, in step one, the mass fraction of pure iron is 68 to 70 parts, the mass fraction of electrolytic nickel is 10 to 12 parts, the mass fraction of micro-carbon ferrochrome is 18 to 20 parts, the mass fraction of ferromanganese is 0.5 to 2.0 parts, and the mass fraction of silicon-calcium particles is 1.8 to 2.2 parts.

[0012] Furthermore, in a method for preparing stainless steel alloy powder, in step 1, the smelting temperature is 1645-1655°C.

[0013] Furthermore, in a method for preparing a stainless steel alloy powder, in step 1, the mass fraction of silicon in the silicon-calcium particles is 58-62%, and the standing time is 2-3 minutes.

[0014] Furthermore, in a method for preparing stainless steel alloy powder, in step 2, the preheating temperature of the ladle is 300-500°C, and the temperature of the alloy liquid is 1650-1685°C.

[0015] Furthermore, in a method for preparing a stainless steel alloy powder, in the step 2, the water atomization equipment is a ring-shaped hole spray disk, and the hole diameter of the ring-shaped hole spray disk is 0.6-0.9 mm.

[0016] Furthermore, in a method for preparing a stainless steel alloy powder, in the step 2, the pressure of water atomization is 15-22 MPa, and the water flow rate of water atomization is 260-300 L / min.

[0017] Furthermore, in a method for preparing a stainless steel alloy powder, in the step three, the rotation speed of the centrifugal dehydration is 790 to 810 r / min, and the time of the centrifugal dehydration is 8 to 12 min.

[0018] Furthermore, in a method for preparing a stainless steel alloy powder, in the step three, the drying temperature is 110-130° C., the drying time is 25-35 min, and the sieving mesh size is 80-120 meshes.

[0019] The invention also provides a stainless steel alloy powder prepared by the method for preparing the stainless steel alloy powder.

[0020] It can be seen from the above technical solution that compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention adopts silicon-calcium particles to replace metal silicon. The silicon element and the calcium element in the silicon-calcium particles have strong affinity with oxygen, and in particular, the calcium element has good affinity with not only oxygen but also sulfur and nitrogen. The use of silicon-calcium particles to replace metal silicon as raw materials can not only reduce the oxygen content of molten steel, but also reduce the oxygen content of finished powder, so that the oxygen content of the finished stainless steel alloy powder is only 1600-1780ppm, and the production cost is reduced compared with adding pure silicon. In addition, a high-pressure water pump with a large flow rate is used to effectively reduce the bulk ratio and particle size of the metal powder, and the bulk ratio of the finally obtained finished stainless steel alloy powder is only 2.47-2.65g / cm 3 . DETAILED DESCRIPTION

[0022] The present invention provides a method for preparing stainless steel alloy powder, comprising the following steps:

[0023] Step 1: Smelt a certain amount of pure iron, electrolytic nickel, low-carbon ferrochrome and ferromanganese, add silicon-calcium particles after they are completely melted, let stand, remove slag, and obtain alloy liquid;

[0024] Step 2: Preheat the ladle, heat up the alloy liquid and let it flow out of the ladle. The alloy liquid is atomized by water to produce powdered alloy, and then steel pouring begins;

[0025] Step 3: After the steel pouring is completed, the powdered alloy is centrifugally dehydrated, dried, and sieved to obtain stainless steel alloy powder.

[0026] In the present invention, in step 1, the smelting equipment is preferably a medium frequency furnace.

[0027] In the present invention, in step 1, the mass fraction of pure iron is preferably 68 to 70 parts, more preferably 68.2 to 69.4 parts, and more preferably 68.6 parts.

[0028] In the present invention, in the step 1, the mass fraction of electrolytic nickel is preferably 10 to 12 parts, more preferably 10.2 to 11.1 parts, and more preferably 10.5 parts.

[0029] In the present invention, in the step 1, the mass fraction of the low carbon ferrochrome is preferably 18 to 20 parts, more preferably 18.4 to 19.2 parts, and more preferably 19 parts.

[0030] In the present invention, in the step 1, the mass fraction of ferromanganese is preferably 0.5 to 2.0 parts, more preferably 0.9 to 1.6 parts, and more preferably 1 part.

[0031] In the present invention, in step 1, the mass fraction of calcium silicate particles is preferably 1.8 to 2.2 parts, more preferably 1.8 to 2 parts, and more preferably 2 parts.

[0032] In the present invention, in the step 1, the smelting temperature is preferably 1645-1655°C, more preferably 1648-1652°C, and more preferably 1650°C.

[0033] In the present invention, in the step 1, the mass fraction of silicon in the calcium-silicon particles is preferably 58-62%, more preferably 59.4-60.8%, and more preferably 60%.

[0034] In the present invention, in the step 1, the standing time is preferably 2 to 3 minutes, more preferably 2.4 to 3 minutes, and more preferably 3 minutes.

[0035] In the present invention, in the step 2, the preheating temperature of the leaking bag is preferably 300-500°C, more preferably 365-445°C, and more preferably 395°C.

[0036] In the present invention, in the step 2, the temperature at which the alloy liquid is heated is preferably 1650-1685°C, more preferably 1668-1682°C, and even more preferably 1680°C.

[0037] In the present invention, in step 2, the water atomization equipment is preferably an annular hole spray disk.

[0038] In the present invention, the aperture of the annular hole spray disc is preferably 0.6-0.9 mm, more preferably 0.7-0.8 mm, and more preferably 0.8 mm.

[0039] In the present invention, in the step 2, the pressure of water atomization is preferably 15 to 22 MPa, more preferably 18.5 to 21.2 MPa, and more preferably 20 MPa.

[0040] In the present invention, in the step 2, the water flow rate of water atomization is preferably 260 to 300 L / min, more preferably 275 to 290 L / min, and more preferably 280 L / min.

[0041] In the present invention, in step three, the rotation speed of the centrifugal dehydration is preferably 790-810 r / min, more preferably 795-805 r / min, and more preferably 800 r / min.

[0042] In the present invention, in step 3, the time for centrifugal dehydration is preferably 8 to 12 min, more preferably 9.6 to 11.4 min, and more preferably 10 min.

[0043] In the present invention, in the step three, the drying temperature is preferably 110-130°C, more preferably 118-126°C, and more preferably 120°C.

[0044] In the present invention, in step 3, the drying time is preferably 25 to 35 minutes, more preferably 27 to 33 minutes, and more preferably 30 minutes.

[0045] In the present invention, in the step three, the mesh size of the sieving is preferably 80 to 120 meshes, more preferably 90 to 110 meshes, and more preferably 100 meshes.

[0046] The invention also provides a stainless steel alloy powder prepared by the method for preparing the stainless steel alloy powder.

[0047] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] Example 1

[0049] This embodiment provides a method for preparing stainless steel alloy powder, comprising the following steps:

[0050] Step 1: Add 68 parts of pure iron, 10.5 parts of electrolytic nickel, 19 parts of low-carbon ferrochrome and 1 part of ferromanganese into a medium frequency furnace, and smelt at 1650°C. After the materials are completely melted, add 2 parts of silicon-calcium particles, in which the mass fraction of silicon is 60%. After standing for 2 minutes, start to remove the slag to obtain alloy liquid;

[0051] Step 2: Preheat the ladle to 390℃, raise the temperature of the alloy liquid to 1680℃, start the hydraulic equipment and turn on the lifting button to lift one side of the medium frequency furnace, and the alloy liquid flows into the ladle through the flow trough, and then flows out from the leakage hole at the bottom of the ladle. Use a ring hole spray disc with an aperture of 0.8mm, under the conditions of atomization pressure of 20MPa and water flow rate of 280L / min, the alloy liquid is atomized by water to produce powdered alloy, and start pouring steel;

[0052] Step 3: After the steel pouring is completed, the powdered alloy is sent to a centrifuge for dehydration. The speed of the centrifuge is 800r / min. After centrifugal dehydration for 10 minutes, the powdered alloy is sent to a dryer for drying. The drying temperature is set to 120°C and the drying time is 30 minutes. Finally, a 100-mesh rotary vibrating screen is used for screening to obtain stainless steel alloy powder.

[0053] In the finished stainless steel alloy powder, the content of iron is 69%, nickel is 10.5%, chromium is 18.5%, manganese is 0.8%, silicon is 1.0%, and the balance is inevitable impurities.

[0054] Example 2

[0055] This embodiment provides a method for preparing stainless steel alloy powder, comprising the following steps:

[0056] Step 1: Add 68 parts of pure iron, 10 parts of electrolytic nickel, 18 parts of low-carbon ferrochrome and 0.5 parts of ferromanganese into a medium frequency furnace, and smelt at 1650°C. After the materials are completely melted, add 1.8 parts of silicon-calcium particles, in which the mass fraction of silicon is 60%. After standing for 3 minutes, start to remove the slag to obtain alloy liquid;

[0057] Step 2: Preheat the ladle to 425℃, raise the temperature of the alloy liquid to 1680℃, start the hydraulic equipment and turn on the lifting button to lift one side of the medium frequency furnace, and the alloy liquid flows into the ladle through the flow trough, and then flows out from the leakage hole at the bottom of the ladle. Use a ring hole spray disc with an aperture of 0.6mm, under the conditions of atomization pressure of 15MPa and water flow rate of 260L / min, the alloy liquid is atomized by water to produce powdered alloy, and start pouring steel;

[0058] Step 3: After the steel pouring is completed, the powdered alloy is sent to a centrifuge for dehydration. The speed of the centrifuge is 800r / min. After centrifugal dehydration for 10 minutes, the powdered alloy is sent to a dryer for drying. The drying temperature is set to 110°C and the drying time is 35 minutes. Finally, a 100-mesh rotary vibrating screen is used for screening to obtain stainless steel alloy powder.

[0059] Example 3

[0060] This embodiment provides a method for preparing stainless steel alloy powder, comprising the following steps:

[0061] Step 1: Add 70 parts of pure iron, 12 parts of electrolytic nickel, 20 parts of low-carbon ferrochrome and 2 parts of ferromanganese into a medium frequency furnace, and smelt at 1655°C. After the materials are completely melted, add 2.2 parts of silicon-calcium particles, in which the mass fraction of silicon is 60%. After standing for 2.5 minutes, start to remove the slag to obtain alloy liquid;

[0062] Step 2: Preheat the ladle to 465℃, raise the temperature of the alloy liquid to 1685℃, start the hydraulic equipment and turn on the lifting button to lift one side of the medium frequency furnace, and the alloy liquid flows into the ladle through the flow trough, and then flows out from the leakage hole at the bottom of the ladle. Use a ring hole spray disc with an aperture of 0.7mm, under the conditions of atomization pressure of 20MPa and water flow rate of 280L / min, the alloy liquid is atomized by water to produce powdered alloy, and steel pouring begins;

[0063] Step 3: After the steel pouring is completed, the powdered alloy is sent to a centrifuge for dehydration. The speed of the centrifuge is 800r / min. After centrifugal dehydration for 10 minutes, the powdered alloy is sent to a dryer for drying. The drying temperature is set to 120°C and the drying time is 30 minutes. Finally, a 100-mesh rotary vibrating screen is used for screening to obtain stainless steel alloy powder.

[0064] Example 4

[0065] This embodiment provides a method for preparing stainless steel alloy powder, comprising the following steps:

[0066] Step 1: Add 69 parts of pure iron, 11 parts of electrolytic nickel, 19 parts of low-carbon ferrochrome and 1.5 parts of ferromanganese into a medium frequency furnace, and smelt at 1645°C. After the materials are completely melted, add 1.9 parts of silicon-calcium particles, in which the mass fraction of silicon is 60%. After standing for 3 minutes, start to remove the slag to obtain alloy liquid;

[0067] Step 2: Preheat the ladle to 345℃, raise the temperature of the alloy liquid to 1675℃, start the hydraulic equipment and turn on the lifting button to lift one side of the medium frequency furnace, and the alloy liquid flows into the ladle through the flow trough, and then flows out from the leakage hole at the bottom of the ladle. Use a ring hole spray disc with an aperture of 0.8mm, under the conditions of atomization pressure of 22MPa and water flow rate of 300L / min, the alloy liquid is atomized by water to produce powdered alloy, and start pouring steel;

[0068] Step 3: After the steel pouring is completed, the powdered alloy is sent to a centrifuge for dehydration. The speed of the centrifuge is 800r / min. After centrifugal dehydration for 10 minutes, the powdered alloy is sent to a dryer for drying. The drying temperature is set to 130°C and the drying time is 25 minutes. Finally, a 100-mesh rotary vibrating screen is used for screening to obtain stainless steel alloy powder.

[0069] Example 5

[0070] This embodiment provides a method for preparing stainless steel alloy powder, comprising the following steps:

[0071] Step 1: Add 69.5 parts of pure iron, 11.5 parts of electrolytic nickel, 18.5 parts of low-carbon ferrochrome and 2 parts of ferromanganese into a medium frequency furnace, and smelt at 1650°C. After the materials are completely melted, add 2.1 parts of silicon-calcium particles, in which the mass fraction of silicon is 60%. After standing for 3 minutes, start to remove the slag to obtain alloy liquid;

[0072] Step 2: Preheat the ladle to 500℃, raise the temperature of the alloy liquid to 1680℃, start the hydraulic equipment and turn on the lifting button to lift one side of the medium frequency furnace, and the alloy liquid flows into the ladle through the flow trough, and then flows out from the leakage hole at the bottom of the ladle. Use a ring hole spray disc with an aperture of 0.8mm, under the conditions of atomization pressure of 18MPa and water flow rate of 270L / min, the alloy liquid is atomized by water to produce powdered alloy, and steel pouring begins;

[0073] Step 3: After the steel pouring is completed, the powdered alloy is sent to a centrifuge for dehydration. The speed of the centrifuge is 790r / min. After centrifugal dehydration for 10 minutes, the powdered alloy is sent to a dryer for drying. The drying temperature is set to 120°C and the drying time is 30 minutes. Finally, a 100-mesh rotary vibrating screen is used for screening to obtain stainless steel alloy powder.

[0074] Example 6

[0075] This embodiment provides a method for preparing stainless steel alloy powder, comprising the following steps:

[0076] Step 1: Add 68.5 parts of pure iron, 10.5 parts of electrolytic nickel, 19.5 parts of low-carbon ferrochrome and 1 part of ferromanganese into a medium frequency furnace, and smelt at 1650°C. After the materials are completely melted, add 2 parts of silicon-calcium particles, in which the mass fraction of silicon is 60%. After standing for 2.4 minutes, start to remove the slag to obtain alloy liquid;

[0077] Step 2: Preheat the ladle to 300℃, raise the temperature of the alloy liquid to 1680℃, start the hydraulic equipment and turn on the lifting button to lift one side of the medium frequency furnace, and the alloy liquid flows into the ladle through the flow trough, and then flows out from the leakage hole at the bottom of the ladle. Use a ring hole spray disc with an aperture of 0.9mm, under the conditions of atomization pressure of 18MPa and water flow rate of 270L / min, the alloy liquid is atomized by water to produce powdered alloy, and start pouring steel;

[0078] Step 3: After the steel pouring is completed, the powdered alloy is sent to a centrifuge for dehydration. The speed of the centrifuge is 810r / min. After centrifugal dehydration for 10 minutes, the powdered alloy is sent to a dryer for drying. The drying temperature is set to 120°C and the drying time is 30 minutes. Finally, a 100-mesh rotary vibrating screen is used for screening to obtain stainless steel alloy powder.

[0079] Comparative Example 1

[0080] This comparative example provides a method for preparing a stainless steel alloy powder, comprising the following steps:

[0081] Step 1: Add 68 parts of pure iron, 10.5 parts of electrolytic nickel, 19 parts of low-carbon ferrochrome and 1 part of ferromanganese into a medium frequency furnace, and smelt them at 1650°C. After the materials are completely melted, add 0.5 parts of silicon-calcium particles, in which the mass fraction of silicon is 60%. After standing for 2 minutes, start to remove the slag to obtain alloy liquid;

[0082] Step 2: Preheat the ladle to 390℃, raise the temperature of the alloy liquid to 1680℃, start the hydraulic equipment and turn on the lifting button to lift one side of the medium frequency furnace, and the alloy liquid flows into the ladle through the flow trough, and then flows out from the leakage hole at the bottom of the ladle. Use a ring hole spray disc with an aperture of 0.8mm, under the conditions of atomization pressure of 20MPa and water flow rate of 280L / min, the alloy liquid is atomized by water to produce powdered alloy, and start pouring steel;

[0083] Step 3: After the steel pouring is completed, the powdered alloy is sent to a centrifuge for dehydration. The speed of the centrifuge is 800r / min. After centrifugal dehydration for 10 minutes, the powdered alloy is sent to a dryer for drying. The drying temperature is set to 120°C and the drying time is 30 minutes. Finally, a 100-mesh rotary vibrating screen is used for screening to obtain stainless steel alloy powder.

[0084] Comparative Example 2

[0085] This comparative example provides a method for preparing a stainless steel alloy powder, comprising the following steps:

[0086] Step 1: Add 68 parts of pure iron, 10.5 parts of electrolytic nickel, 19 parts of low-carbon ferrochrome and 1 part of ferromanganese into a medium frequency furnace, and smelt them at 1650°C. After the materials are completely melted, add 3 parts of silicon-calcium particles, in which the mass fraction of silicon is 60%. After standing for 2 minutes, start to remove the slag to obtain alloy liquid;

[0087] Step 2: Preheat the ladle to 390℃, raise the temperature of the alloy liquid to 1680℃, start the hydraulic equipment and turn on the lifting button to lift one side of the medium frequency furnace, and the alloy liquid flows into the ladle through the flow trough, and then flows out from the leakage hole at the bottom of the ladle. Use a ring hole spray disc with an aperture of 0.8mm, under the conditions of atomization pressure of 20MPa and water flow rate of 280L / min, the alloy liquid is atomized by water to produce powdered alloy, and start pouring steel;

[0088] Step 3: After the steel pouring is completed, the powdered alloy is sent to a centrifuge for dehydration. The speed of the centrifuge is 800r / min. After centrifugal dehydration for 10 minutes, the powdered alloy is sent to a dryer for drying. The drying temperature is set to 120°C and the drying time is 30 minutes. Finally, a 100-mesh rotary vibrating screen is used for screening to obtain stainless steel alloy powder.

[0089] Comparative Example 3

[0090] This comparative example provides a method for preparing a stainless steel alloy powder, comprising the following steps:

[0091] Step 1: Add 68 parts of pure iron, 10.5 parts of electrolytic nickel, 19 parts of low-carbon ferrochrome and 1 part of ferromanganese into a medium frequency furnace, and smelt at 1650°C. After the materials are completely melted, add 2 parts of metallic silicon, let it stand for 2 minutes, and then start to remove the slag to obtain alloy liquid;

[0092] Step 2: Preheat the ladle to 390℃, raise the temperature of the alloy liquid to 1680℃, start the hydraulic equipment and turn on the lifting button to lift one side of the medium frequency furnace, and the alloy liquid flows into the ladle through the flow trough, and then flows out from the leakage hole at the bottom of the ladle. Use a ring hole spray disc with an aperture of 0.8mm, under the conditions of atomization pressure of 20MPa and water flow rate of 280L / min, the alloy liquid is atomized by water to produce powdered alloy, and start pouring steel;

[0093] Step 3: After the steel pouring is completed, the powdered alloy is sent to a centrifuge for dehydration. The speed of the centrifuge is 800r / min. After centrifugal dehydration for 10 minutes, the powdered alloy is sent to a dryer for drying. The drying temperature is set to 120°C and the drying time is 30 minutes. Finally, a 100-mesh rotary vibrating screen is used for screening to obtain stainless steel alloy powder.

[0094] Comparative Example 4

[0095] This comparative example provides a method for preparing a stainless steel alloy powder, comprising the following steps:

[0096] Step 1: Add 68 parts of pure iron, 10.5 parts of electrolytic nickel, 19 parts of low-carbon ferrochrome and 1 part of ferromanganese into a medium frequency furnace, and smelt at 1650°C. After the materials are completely melted, add 2 parts of silicon-calcium particles, in which the mass fraction of silicon is 60%. After standing for 2 minutes, start to remove the slag to obtain alloy liquid;

[0097] Step 2: Preheat the ladle to 390℃, raise the temperature of the alloy liquid to 1680℃, start the hydraulic equipment and turn on the lifting button to lift one side of the medium frequency furnace, and the alloy liquid flows into the ladle through the flow trough, and then flows out from the leakage hole at the bottom of the ladle. Use a ring hole spray disc with an aperture of 0.8mm, under the conditions of atomization pressure of 30MPa and water flow rate of 340L / min, the alloy liquid is atomized by water to produce powdered alloy, and steel pouring begins;

[0098] Step 3: After the steel pouring is completed, the powdered alloy is sent to a centrifuge for dehydration. The speed of the centrifuge is 800r / min. After centrifugal dehydration for 10 minutes, the powdered alloy is sent to a dryer for drying. The drying temperature is set to 120°C and the drying time is 30 minutes. Finally, a 100-mesh rotary vibrating screen is used for screening to obtain stainless steel alloy powder.

[0099] Comparative Example 5

[0100] This comparative example provides a method for preparing a stainless steel alloy powder, comprising the following steps:

[0101] Step 1: Add 68 parts of pure iron, 10.5 parts of electrolytic nickel, 19 parts of low-carbon ferrochrome and 1 part of ferromanganese into a medium frequency furnace, and smelt at 1650°C. After the materials are completely melted, add 2 parts of silicon-calcium particles, in which the mass fraction of silicon is 60%. After standing for 2 minutes, start to remove the slag to obtain alloy liquid;

[0102] Step 2: Preheat the ladle to 390℃, raise the temperature of the alloy liquid to 1680℃, start the hydraulic equipment and turn on the lifting button to lift one side of the medium frequency furnace, and the alloy liquid flows into the ladle through the flow trough, and then flows out from the leakage hole at the bottom of the ladle. Use a ring hole spray disc with an aperture of 0.8mm, under the conditions of atomization pressure of 12MPa and water flow rate of 200L / min, the alloy liquid is atomized by water to produce powdered alloy, and start pouring steel;

[0103] Step 3: After the steel pouring is completed, the powdered alloy is sent to a centrifuge for dehydration. The speed of the centrifuge is 800r / min. After centrifugal dehydration for 10 minutes, the powdered alloy is sent to a dryer for drying. The drying temperature is set to 120°C and the drying time is 30 minutes. Finally, a 100-mesh rotary vibrating screen is used for screening to obtain stainless steel alloy powder.

[0104] The data comparison of some preparation conditions of Examples 1 to 6 and Comparative Examples 1 to 5 and the oxygen content and powder bulk ratio of the stainless steel alloy powder is shown in Table 1:

[0105] Table 1. Data comparison of Examples 1 to 6 and Comparative Examples 1 to 5

[0106]

[0107] Under the same atomization water pressure, less silicon-calcium particles were added in Comparative Example 1 than in Example 1, more silicon-calcium particles were added in Comparative Example 2 than in Example 1, and no silicon-calcium particles were used in Comparative Example 3 than in Example 1, and the same amount of metallic silicon was used, and Comparative Examples 1 to 3 all resulted in an increase in oxygen content. In summary, when the mass fraction of silicon-calcium particles is less than 1.8 parts or greater than 2.2 parts, the oxygen content of the finished powder will increase, and the performance requirements in the PM field cannot be met.

[0108] Under the condition of equal amount of calcium silicate particles, the atomization water pressure of Comparative Example 4 is higher than that of Example 1, and the atomization water pressure of Comparative Example 5 is lower than that of Example 1. Comparative Examples 4 to 5 all lead to an increase in the powder bulk ratio. In summary, when the atomization pressure is less than 18 MPa or greater than 22 MPa, the powder bulk ratio will increase, which cannot meet the performance requirements in the PM field.

[0109] In summary, the stainless steel alloy powder obtained by the above scheme of the present invention effectively reduces the oxygen content, bulk ratio and particle size of the finished powder, and reduces the production cost compared with adding pure silicon, so that the oxygen content of the finished stainless steel alloy powder is only 1600-1780ppm, and the bulk ratio is only 2.47-2.65g / cm 3 , better meet the performance requirements in the PM field.

[0110] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. Application of a stainless steel alloy powder in powder metallurgy, characterized in that: The oxygen content of the stainless steel alloy powder is 1600-1780 ppm, and the bulk ratio of the stainless steel alloy powder is 2.47-2.65 g / cm 3 ; The preparation method of the stainless steel alloy powder is: Step 1: Smelt pure iron, electrolytic nickel, low-carbon ferrochrome and ferromanganese, add silicon-calcium particles after they are completely melted, let stand, remove slag, and obtain alloy liquid; Step 2: Preheat the ladle, heat up the alloy liquid and let it flow out of the ladle. The alloy liquid is atomized by water to produce powdered alloy, and then steel pouring begins; Step 3: After the steel pouring is completed, the powdered alloy is centrifugally dehydrated, dried, and sieved to obtain stainless steel alloy powder; In the step 1, the mass fraction of pure iron is 68-70 parts, the mass fraction of electrolytic nickel is 10-12 parts, the mass fraction of micro-carbon ferrochrome is 18-20 parts, the mass fraction of ferromanganese is 0.5-2.0 parts, and the mass fraction of silicon-calcium particles is 1.8-2.2 parts; In the step 1, the mass fraction of silicon in the calcium-silicon particles is 58-62%; In the step 2, the pressure of water atomization is 15-22 MPa, and the water flow rate of water atomization is 260-300 L / min.

2. The use of a stainless steel alloy powder in powder metallurgy according to claim 1, characterized in that: In the step 1, the smelting temperature is 1645-1655°C.

3. The use of a stainless steel alloy powder in powder metallurgy according to claim 2, characterized in that: In the step 1, the standing time is 2 to 3 minutes.

4. The use of a stainless steel alloy powder according to any one of claims 1 to 3 in powder metallurgy, characterized in that: In the step 2, the preheating temperature of the ladle is 300-500°C, and the temperature of the alloy liquid is 1650-1685°C.

5. The use of a stainless steel alloy powder in powder metallurgy according to claim 4, characterized in that: In the step 2, the water atomization equipment is a ring-shaped hole spray disk, and the hole diameter of the ring-shaped hole spray disk is 0.6-0.9 mm.

6. The use of a stainless steel alloy powder in powder metallurgy according to claim 5, characterized in that: In the step 3, the rotation speed of the centrifugal dehydration is 790-810 r / min, and the time of the centrifugal dehydration is 8-12 min.

7. The use of a stainless steel alloy powder in powder metallurgy according to claim 6, characterized in that: In the step 3, the drying temperature is 110-130° C., the drying time is 25-35 min, and the sieving mesh size is 80-120 meshes.

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