阅读说明：本技术 高速动车组电机轴用42CrMoS4含硫钢的冶炼工艺 (Smelting process of 42CrMoS4 sulfur-containing steel for motor shaft of high-speed motor train unit ) 是由 潘小娟 陈金虎 王之香 于 2021-09-16 设计创作，主要内容包括：高速动车组电机轴用42CrMoS4含硫钢的冶炼工艺,属于钢铁冶炼技术领域,解决现有含硫钢机械性能差、S元素含量无法精准控制等技术问题。本发明通过以下技术方案予以实现：1)EBT电炉冶炼；2)EBT出钢；3)LF精炼工序；4)增硫工序；5)VD真空处理工序；6)注模工序。本发明具有成分易控制、切削性能好、机械性能高等优点。(A smelting process of 42CrMoS4 sulfur-containing steel for a motor shaft of a high-speed motor train unit belongs to the technical field of steel smelting, and solves the technical problems that the existing sulfur-containing steel is poor in mechanical property, cannot accurately control the content of S elements and the like. The invention is realized by the following technical scheme: 1) smelting in an EBT electric furnace; 2) EBT tapping; 3) an LF refining process; 4) a vulcanization process; 5) VD vacuum treatment process; 6) and (5) an injection molding process. The invention has the advantages of easy component control, good cutting performance, high mechanical performance and the like.)

1. The smelting process of the 42CrMoS4 sulfur-containing steel for the motor shaft of the high-speed motor train unit is characterized by comprising the following steps of: the method comprises the following steps:

1) smelting in an EBT electric furnace: 15200 parts of scrap steel and 47600 parts of molten iron are put into an electric furnace for smelting, and oxygen blowing melting, foam slag making and carbon and phosphorus reduction are carried out on the scrap steel and the molten iron;

2) and (4) EBT tapping: after the smelting is finished, 330 parts by weight of SiMn is added into the ladle₃650 parts of lime, 150 parts of fluorite, 200 parts of synthetic slag, 200 parts of Si-Al-Ba, 800 parts of high chromium, 150 parts of ferromolybdenum and 200 parts of carbon and manganese, and then tapping; the temperature of the molten steel is 1635-1665 ℃;

3) an LF refining procedure: after molten steel enters LF refining, feeding 100 parts by weight of Al wire, and conveying electric melting slag;

adding 220 parts by weight of lime, 77 parts by weight of carbon powder, 100 parts by weight of carbon manganese, 60 parts by weight of ferrosilicon, 30 parts by weight of high chromium, 10 parts by weight of ferromolybdenum and 240 parts by weight of synthetic slag in sequence;

160 parts of fluorite, 26 parts of ferrosilicon and CaO/SiO by weight are added into the mixture₂The alkalinity R = 3.5-5.5;

finally, 180 parts by weight of silica is added and the steel is tapped, wherein the temperature of the molten steel is 1660 ℃, and CaO/SiO is added₂The alkalinity R = 2.0-2.5;

4) a vulcanization procedure: feeding 22.5 parts by weight of S wire, wherein the sulfur wire rapidly penetrates through a slag layer during wire feeding and is conveyed to the bottom of a steel ladle to be melted in the deep part of molten steel; after the sulfur wire is fed, weakly blowing argon and stirring for 3-5 min, and leaving the station, wherein the leaving temperature T = 1620-1640 ℃;

5) VD vacuum treatment process: transferring the molten steel to a VD smelting furnace, carrying out vacuum treatment, feeding 40 parts by weight of calcium silicon wire after breaking the vacuum, feeding 15 parts by weight of sulfur wire, and carrying out argon soft stirring for more than 10 minutes; when the sulfur content is 0.026% and the temperature of molten steel is 1550 ℃, adding a covering agent into the steel ladle and then taking out of the ladle;

6) and (3) injection molding: pouring under the protection of argon, and simultaneously controlling the pouring temperature and the pouring speed;

5.8t ingot: the casting temperature is 1535-1545 ℃; the ingot body pouring time is 7-9 minutes, and the riser pouring time is 6.5-9 minutes;

8.4t ingot: the pouring temperature is 1540-1550 ℃; pouring time of the first tray ingot body is 14-16 minutes, and pouring time of a riser is 8-10 minutes; the casting time of the second plate ingot body is 12-14 minutes, and the casting time of a riser is more than or equal to 6.5 minutes.

2. The smelting process of the 42CrMoS4 sulfur-containing steel for the motor shaft of the high-speed motor train unit according to claim 1, characterized by comprising the following steps: the synthetic slag comprises the following components: al (Al)₂O₃ 34%、CaO 53%、MgO 9%、SiO₂ 3%、Fe₂O₃ 1%。

3. The smelting process of the 42CrMoS4 sulfur-containing steel for the motor shaft of the high-speed motor train unit according to claim 1, characterized by comprising the following steps: the covering agent comprises the following components: SiO2₂ 57%、CaO 12%、Al₂O₃ 19%、MgO 5%、C 7%。

4. The smelting process of the 42CrMoS4 sulfur-containing steel for the motor shaft of the high-speed motor train unit according to claim 1, characterized by comprising the following steps: vacuumizing in the step 5) to the limit vacuum degree of 60Pa, wherein the vacuum breaking temperature is 1574 ℃, and H =0.7 × 10^-4%，S=0.010%。

Technical Field

The invention belongs to the technical field of steel smelting, and particularly relates to a smelting process of 42CrMoS4 sulfur-containing steel for a motor shaft of a high-speed motor train unit.

Background

The 42CrMo steel as medium carbon alloy steel has good toughness matching after quenching and tempering, and is widely used for manufacturing important components in mechanical parts, such as motor shafts, crankshafts, connecting rods, gears and the like. However, when the hardness of the 42CrMo steel after hardening and tempering exceeds 280HB, the machinability of the steel deteriorates. In order to improve the machinability of 42CrMo steel, a certain amount of sulphur is added to the steel. The sulfur-containing steel contains a large amount of sulfide plastic inclusions mainly comprising MnS, and can play a role of a stress concentration source, so that the product is easy to break in the cutting process, and the cutting performance of the product can be improved. Meanwhile, the lubricating device can also play a role in lubricating the cutter, reducing the abrasion of the cutter and prolonging the service life of the cutter. However, sulfide inclusions in the sulfur-containing steel are generally distributed in clusters and are not uniformly distributed, and are easy to deform along the rolling direction in the rolling process, so that the mechanical properties of the steel are influenced.

Disclosure of Invention

The invention provides a smelting process of 42CrMoS4 sulfur-containing steel for a motor shaft of a high-speed motor train unit, aiming at overcoming the defects of the prior art and solving the technical problems that the prior sulfur-containing steel is poor in mechanical property, cannot accurately control the content of an S element and the like.

The invention is realized by the following technical scheme.

The smelting process of the 42CrMoS4 sulfur-containing steel for the motor shaft of the high-speed motor train unit comprises the following steps:

1) smelting in an EBT electric furnace: 15200 parts of scrap steel and 47600 parts of molten iron are put into an electric furnace for smelting, and oxygen blowing melting, foam slag making and carbon and phosphorus reduction are carried out on the scrap steel and the molten iron;

2) and (4) EBT tapping: after the smelting is finished, 330 parts by weight of SiMn is added into the ladle₃650 parts of lime, 150 parts of fluorite, 200 parts of synthetic slag, 200 parts of Si-Al-Ba, 800 parts of high chromium, 150 parts of ferromolybdenum and 200 parts of carbon and manganese, and then tapping; at this time, the temperature of molten steel was 1635~1665℃；

3) An LF refining procedure: after molten steel enters LF refining, feeding 100 parts by weight of Al wire, and conveying electric melting slag;

adding 220 parts by weight of lime, 77 parts by weight of carbon powder, 100 parts by weight of carbon manganese, 60 parts by weight of ferrosilicon, 30 parts by weight of high chromium, 10 parts by weight of ferromolybdenum and 240 parts by weight of synthetic slag in sequence;

160 parts of fluorite, 26 parts of ferrosilicon and CaO/SiO by weight are added into the mixture₂The alkalinity R = 3.5-5.5;

finally, 180 parts by weight of silica is added and the steel is tapped, wherein the temperature of the molten steel is 1660 ℃, and CaO/SiO is added₂The alkalinity R = 2.0-2.5;

4) a vulcanization procedure: feeding 22.5 parts by weight of S wire, wherein the sulfur wire rapidly penetrates through a slag layer during wire feeding and is conveyed to the bottom of a steel ladle to be melted in the deep part of molten steel; after the sulfur wire is fed, weakly blowing argon and stirring for 3-5 min, and leaving the station, wherein the leaving temperature T = 1620-1640 ℃;

5) VD vacuum treatment process: transferring the molten steel to a VD smelting furnace, carrying out vacuum treatment, feeding 40 parts by weight of calcium-silicon wire after breaking the vacuum, feeding 15 parts by weight of sulfur wire (phi 13 mm), and carrying out argon soft stirring for more than 10 minutes; when the sulfur content is 0.026% and the temperature of molten steel is 1550 ℃, adding a covering agent into the steel ladle and then taking out of the ladle;

6) and (3) injection molding: pouring under the protection of argon, and simultaneously controlling the pouring temperature and the pouring speed;

5.8t ingot: the casting temperature is 1535-1545 ℃; the ingot body pouring time is 7-9 minutes, and the riser pouring time is 6.5-9 minutes;

8.4t ingot: the pouring temperature is 1540-1550 ℃; pouring time of the first tray ingot body is 14-16 minutes, and pouring time of a riser is 8-10 minutes; the casting time of the second plate ingot body is 12-14 minutes, and the casting time of a riser is more than or equal to 6.5 minutes.

Further, the synthetic slag comprises the following components: the synthetic slag comprises the following components: al (Al)₂O₃ 34%、CaO 53%、MgO 9%、SiO₂ 3%、Fe₂O₃ 1%。

Further, the method can be used for preparing a novel materialThe covering agent comprises the following components: the covering agent comprises the following components: SiO2₂ 57%、CaO 12%、Al₂O₃ 19%、MgO 5%、C 7%。

Further, in the step 5), the vacuum treatment is carried out until the vacuum degree is 60Pa, the breaking temperature is 1574 ℃, and H =0.7 × 10^-4%，S=0.010%。

The invention adopts the process method to stably control the tapping components and temperature of the electric furnace. The LF refining operation adopts early-stage high-alkalinity slag deep deoxidation and desulfurization, and CaO/SiO of molten slag is controlled₂The alkalinity R = 4.0-6.0, when the molten steel reaches a certain purity, the slag is adjusted to be weakly alkaline slag after the deoxidation and desulfurization task is finished, and the alkalinity target is (CaO/SiO)₂) And =2.5 to 3.5. The sulfur increasing adopts a method of feeding a sulfur wire before VD treatment and then supplementing the sulfur wire according to the content of S after VD treatment, calcium treatment in the VD furnace refining process adopts a calcium-silicon wire, and the feeding amount is 0.5-0.8 kg/ton of steel, thereby being beneficial to removing inclusions. Realizes 42CrMoS under the condition of low oxygen₄The stable and accurate control of the S element and the control of the purity of the steel realize the accurate control that the yield of the S element is more than or equal to 40 percent and the S content is between 0.02 and 0.04 percent. The grade of the non-metallic inclusion of the steel reaches the B-class fineness system which is less than or equal to 2.5 grade and the coarse system which is less than or equal to 1.0 grade; the C-class fineness is less than or equal to 0.5 grade, and the C-class fineness is less than or equal to 0.5 grade; the D-class fineness is less than or equal to 1.5 grade, and the D-class fineness is less than or equal to 0.5 grade.

Compared with the prior art, the invention has the advantages of easy component control, good cutting performance, high mechanical performance and the like.

Detailed Description

The following examples further describe the present invention in detail.

The smelting process of the 42CrMoS4 sulfur-containing steel for the motor shaft of the high-speed motor train unit comprises the following steps:

1) smelting in an EBT electric furnace: 15200 parts of scrap steel and 47600 parts of molten iron are put into an electric furnace for smelting, and oxygen blowing melting, foam slag making and carbon and phosphorus reduction are carried out on the scrap steel and the molten iron;

2) and (4) EBT tapping: after the smelting is finished, 330 parts by weight of SiMn is added into the ladle₃650 parts of lime, 150 parts of fluorite and 200 parts of waterThe synthetic slag, 200 parts by weight of Si-Al-Ba, 800 parts by weight of high chromium, 150 parts by weight of ferromolybdenum and 200 parts by weight of carbon and manganese, and then tapping; the temperature of the molten steel is 1635-1665 ℃ (1660 ℃), and the molten steel comprises the following chemical components: c =0.67%, Si =0.02%, Mn =0.05%, P =0.008%, S =0.020%, Cr =0.10%, Ni =0.04%, Cu = 0.01%;

3) an LF refining procedure: after molten steel enters LF refining, feeding 100 parts by weight of Al wire, and conveying electrolytic slag, wherein the molten steel comprises the following chemical components: c =0.25%, Si =0.14%, Mn =0.64%, P =0.008%, S =0.003%, Ni =0.05%, Cr =1.02%, Cu =0.01%, Al =0.033%, Mo = 0.15%;

adding 220 parts by weight of lime, 77 parts by weight of carbon powder, 100 parts by weight of carbon manganese, 60 parts by weight of ferrosilicon, 30 parts by weight of high chromium, 10 parts by weight of ferromolybdenum and 240 parts by weight of synthetic slag into the molten steel in sequence, wherein the molten steel comprises the following chemical components: c =0.37%, Si =0.19%, Mn =0.72%, P =0.008%, S =0.001%, Ni =0.05%, Cr =1.05%, Cu =0.01%, Al =0.013%, Mo = 0.16%;

160 parts of fluorite and 26 parts of ferrosilicon are added into the steel, and the molten steel comprises the following chemical components in parts by weight: c =0.39%, Si =0.23%, Mn =0.71%, P =0.009%, S =0.001%, Ni =0.05%, Cr =1.04%, Cu =0.01%, Al =0.018%, Mo =0.16%, and the basicity R = 3.5-5.5 of CaO/SiO 2;

finally, adding 180 parts by weight of silica, and tapping, wherein the temperature of molten steel is 1660 ℃, and the alkalinity R of CaO/SiO2 is = 2.0-2.5;

4) a vulcanization procedure: feeding 22.5 parts by weight of S wire, wherein the sulfur wire rapidly penetrates through a slag layer during wire feeding and is conveyed to the bottom of a steel ladle to be melted in the deep part of molten steel; after the sulfur wire is fed, weakly blowing argon and stirring for 3-5 min, and leaving the station, wherein the leaving temperature T = 1620-1640 ℃;

5) VD vacuum treatment process: transferring the molten steel to a VD smelting furnace, carrying out vacuum treatment, feeding 40 parts by weight of calcium-silicon wire after breaking the vacuum, feeding 15 parts by weight of sulfur wire (phi 13 mm), and carrying out argon soft stirring for more than 10 minutes; when the sulfur content is 0.026% and the temperature of molten steel is 1550 ℃, adding a covering agent into the steel ladle and then taking out of the ladle;

6) and (3) injection molding: pouring under the protection of argon, and simultaneously controlling the pouring temperature and the pouring speed;

5.8t ingot: the casting temperature is 1535-1545 ℃; the ingot body pouring time is 7-9 minutes, and the riser pouring time is 6.5-9 minutes;

8.4t ingot: the pouring temperature is 1540-1550 ℃; pouring time of the first tray ingot body is 14-16 minutes, and pouring time of a riser is 8-10 minutes; the casting time of the second plate ingot body is 12-14 minutes, and the casting time of a riser is more than or equal to 6.5 minutes.

Further, the synthetic slag comprises the following components: al (Al)₂O₃ 34%、CaO 53%、MgO 9%、SiO₂ 3%、Fe2O3 1%。

Further, the covering agent comprises the following components: SiO2₂ 57%、CaO 12%、Al₂O₃ 19%、MgO 5%、C 7%。

Further, in the step 5), the vacuum treatment is carried out until the vacuum degree is 60Pa, the breaking temperature is 1574, and H =0.7 × 10^-4%，S=0.010%；

The inspection results of the finished product are as follows:

chemical components: c =0.42%, Si =0.25%, Mn =0.74%, P =0.009%, S =0.030%, Ni =0.06%, Cr =1.05%, Cu =0.01%, Al =0.030%, Mo = 0.16%.

Gas content: [ H ]]=0.82×10^-4%，[O]=0.0009%。

Grade of inclusions: class B coarse class 0, fine class 0; class C coarse is class 0, fine is class 0; class D is coarse class 0 and fine class 0.5.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.