Low carbon chromium stainless steel 410 wire rod and preparation method thereof

Abstract

The invention provides a low-carbon chromium stainless steel 410 wire rod and a preparation method thereof, which belongs to the field of stainless steel manufacturing, and comprises: performing UHP furnace smelting, AOD furnace smelting, LF furnace smelting and continuous casting processing according to the following chemical compositions in weight percentage to obtain a cast billet: carbon content is 0.11-0.13%, chromium content is 12.00-13.50%, silicon content is 0.20-1.00%, manganese content is 0.20-1.00%, nickel content is 0.20-0.60%, copper content is 0.10-0.25%, phosphorus content is 0.005-0.025%, sulfur content is 0.005-0.008%, and the rest is iron content; continuously rolling the cast billet to obtain a wire rod; annealing the wire rod to obtain a low-carbon chromium stainless steel 410 wire rod. The process can reduce the forging and blanking process or the initial rolling and blanking process, and shorten the production process.

Description

Technical Field

[0001] The invention belongs to the field of stainless steel manufacturing, and particularly relates to a low-carbon chromium stainless steel 410 wire rod and a preparation method thereof. Background Art

[0002] Low carbon chromium stainless steel 410 wire rod has high strength, toughness, good corrosion resistance and machinability. It is mainly used for parts that require high toughness, certain stainlessness and withstand impact loads, such as cutting tools, blades, fasteners, hydraulic press valves, thermal cracking anti-sulfur corrosion equipment, etc. It can also be used to make equipment and parts that are resistant to weak corrosive media at room temperature.

[0003] At present, the commonly used method for manufacturing low-carbon chromium stainless steel 410 wire rod in China is to send the annealed steel ingot to the forging plant for forging or initial rolling, and then roll it into wire rod for annealing before leaving the factory. This method has the disadvantages of complex process, long production cycle, high production cost and low wire rod yield rate.

[0004] Therefore, there is an urgent need to develop a method for manufacturing low-carbon chromium stainless steel 410 wire rod with simple process, low production cost, good physical and chemical properties and high yield. Summary of the invention

[0005] In view of the above problems, the present invention provides a method for preparing low-carbon chromium stainless steel 410 wire rod.

[0006] The method for preparing low carbon chromium stainless steel 410 wire rod comprises the following steps:

[0007] According to the following chemical compositions in weight percentage, UHP furnace smelting, AOD furnace smelting, LF furnace smelting and continuous casting are carried out to obtain ingots:

[0008] The carbon content is 0.11-0.13%.

[0009] The chromium content is 12.00-13.50%.

[0010] The silicon content is 0.20-1.00%.

[0011] The content of manganese is 0.20-1.00%.

[0012] The nickel content is 0.20-0.60%,

[0013] The copper content is 0.10-0.25%,

[0014] The phosphorus content is 0.005-0.025%,

[0015] The sulfur content is 0.005-0.008%,

[0016] The rest is iron content;

[0017] The ingot is continuously rolled to obtain wire rod;

[0018] Anneal the wire rod.

[0019] Furthermore, in the UHP furnace smelting, the temperature of the charge after full melting is ≥1620°C, and the tapping temperature is controlled at 1630-1660°C.

[0020] Furthermore, the smelting temperature of the AOD furnace is 1670-1690°C.

[0021] Furthermore, during the continuous casting, the temperature of the ladle is 1590-1600°C, and the temperature of the turntable is 1585-1595°C.

[0022] Furthermore, in the continuous casting, the working pulling speed is determined according to the superheat of the molten steel; when the superheat is below 20°C, the working pulling speed is 0.90-1.05 m / min; when the superheat is 20-25°C, the working pulling speed is 0.85-0.89 m / min; when the superheat is 26-35°C, the working pulling speed is 0.80-0.84 m / min; when the superheat is 36°C-40°C, the working pulling speed is 0.75-0.79 m / min; when the superheat is above 40°C, the working pulling speed is 0.75-0.78 m / min.

[0023] Furthermore, the cast billet is a 200 mm square billet.

[0024] Furthermore, the continuous rolling process includes heating, rolling and controlled cooling, the heating includes preheating section, heating section one, heating section two and soaking section temperature and soaking section insulation time; the rolling includes rough rolling, intermediate rolling, finishing rolling, sizing unit and wire rod unit; the controlled cooling is air cooling line cooling.

[0025] Furthermore, the temperature of the preheating section is 680-720°C, the temperature of the first heating section is 850-950°C, the temperature of the second heating section is 1020-1160°C, and the temperature of the soaking section is 1140-1180°C; the preheating time is 60-65 minutes, the soaking section insulation time is 45-60 minutes, and the total heating time is 120-140 minutes.

[0026] Furthermore, the annealing process parameters are: 850-870°C for 5-6h, 750-770°C for 1-2h, 850-870°C for 2-3h, 750-770°C for 9-10h, cooling to 650°C and removing the cover, and then cooling to 200-220°C and taking out of the furnace.

[0027] Furthermore, the annealing atmosphere is nitrogen.

[0028] Furthermore, the tensile strength of the 410 wire rod is 480-500 MPa.

[0029] Furthermore, the annealing hardness of the 410 wire rod is 170-185 HB.

[0030] Beneficial effects of the present invention:

[0031] The low carbon chromium stainless steel 410 continuous casting and rolling provided by the present invention can reduce the forging process or the initial rolling process, shorten the production process, save energy and improve production efficiency. The above method for producing 410 cold heading steel wire has a wide application prospect.

[0032] (Advantages of the invention). Other features and advantages of the invention will be described in the following description, and partly become apparent from the description, or understood by practicing the invention. The purpose and other advantages of the invention can be realized and obtained by the structures indicated in the description and claims. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. 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.

[0034] Embodiment 1

[0035] This embodiment provides a method for manufacturing a low-carbon chromium stainless steel 410 wire rod, which specifically includes the following steps:

[0036] Step 1, continuously casting the molten steel after smelting in a 40t UHP furnace, an AOD furnace and an LF furnace into a 200mm square billet; wherein, in the UHP furnace smelting, the temperature of the charge after full melting is 1620°C, the tapping temperature is 1630°C, the temperature of the AOD furnace smelting is 1670-1680°C, and during continuous casting: when the superheat is below 20°C, the working pulling speed is 0.90m / min; when the superheat is between 20 and 25°C, the working pulling speed is 0.85m / min; when the superheat is between 26 and 35°C, the working pulling speed is 0.80m / min; when the superheat is between 36 and 40°C, the working pulling speed is 0.75m / min; when the superheat is above 40°C, the working pulling speed is 0.75m / min;

[0037] The smelting steel grade is 410; the carbon content is controlled to be 0.11% by weight, the chromium content is 12.00% by weight, the silicon content is 0.20% by weight, the manganese content is 0.20% by weight, the nickel content can be 0.20% by weight, the copper content can be 0.10% by weight, the phosphorus content can be 0.005% by weight, the sulfur content can be 0.005% by weight, and the rest is iron content. After the continuous casting billet is collected, the surface is peeled and finished;

[0038] Step 2: The continuous rolling production line inspects the surface quality of the ingot, loads the furnace and heats the ingot in turn. The temperature of the preheating section is 680-700°C, the temperature of the first heating section is 850-900°C, the temperature of the second heating section is 1020-1100°C, and the temperature of the soaking section is 1140-1160°C; the preheating time is 60 minutes, the soaking section holding time is 45 minutes, and the total heating time is 120 minutes;

[0039] Step 3, after the above heating process is completed, the steel billet is taken out of the furnace and put on the conveyor roller; the conveyor roller sends the steel billet to 2 750mm and 4 650mm roughing mill rolls for 6 horizontal and vertical staggered rolling, and the roughing billet enters 6 535mm medium rolling units for horizontal and vertical staggered rolling after head cutting, and then enters 6 385mm finishing mills for horizontal and vertical staggered rolling after head cutting, and enters high-speed wire rolling after rolling by 4 385mm reducing mills; the high-speed wire mill is rolled by 8 216mm top-crossing 45° high-speed twist-free finishing mills manufactured by the British Arcilo Company, and finally enters the Φ212mm×2+Φ158mm×2 TMB unit to be rolled into Φ5.5mm wire rod;

[0040] Step 4, collecting the wire rods obtained in step 3 for annealing in a furnace, or annealing after stack cooling; it can also include directly annealing the obtained wire rods, wherein the annealing treatment is as follows: heating to 860±10°C, keeping warm for 6 hours, cooling to 750±10°C, keeping warm for 2 hours, heating to 860±10°C again, keeping warm for 3 hours, cooling to 760±10°C again, keeping warm for 9 hours, and finally cooling to 650°C, removing the outer cover, and then cooling to 200-220°C and taking out of the furnace.

[0041] 100 batches of 410 wire rods were produced continuously, with a product yield rate of 95.36%.

[0042] After inspection (taking furnace number 119F-2502 as an example), the tensile strength is 492-495Mpa, the cross-sectional shrinkage is 78-79%, the annealing hardness is 184-185HB, A coarse 0 grade, A fine 0.5 grade, B coarse 0 grade, B fine 0.5-1.5 grade, C coarse 0 grade, C fine 0 grade, D coarse 0 grade, D fine 0.5-1 grade; macrostructure ingot segregation, center looseness and general looseness are all 0.5 grade. The performance of the product prepared by the method provided in this embodiment fully meets the standard requirements.

[0043] Embodiment 2

[0044] This embodiment provides a method for manufacturing a low-carbon chromium stainless steel 410 wire rod, which specifically includes the following steps:

[0045] Step 1, continuously casting the molten steel after smelting in a 40t UHP furnace, an AOD furnace and an LF furnace into a 200mm square billet; wherein, in the UHP furnace smelting, the temperature of the charge after full melting is 1650°C, the tapping temperature is controlled at 1650°C, the temperature of the AOD furnace smelting is 1670-1690°C, and during continuous casting: when the superheat is below 20°C, the working pulling speed is 1.00m / min; when the superheat is between 20 and 25°C, the working pulling speed is 0.88m / min; when the superheat is between 26 and 35°C, the working pulling speed is 0.82m / min; when the superheat is between 36 and 40°C, the working pulling speed is 0.79m / min; when the superheat is above 40°C, the working pulling speed is 0.76m / min;

[0046] The smelting steel grade is 410; the carbon content is controlled to be 0.12% by weight, the chromium content is 12.50% by weight, the silicon content is 0.4% by weight, the manganese content is 0.6% by weight, the nickel content is 0.40% by weight, the copper content is 0.15% by weight, the phosphorus content is 0.015% by weight, the sulfur content is 0.006% by weight, and the rest is iron content. After the continuous casting billet is collected, the surface is peeled and finished;

[0047] Step 2: The continuous rolling production line inspects the surface quality of the ingot, loads the furnace and heats the ingot in turn. The temperature of the preheating section is 690-700°C, the temperature of the first heating section is 860-910°C, the temperature of the second heating section is 1030-1100°C, and the temperature of the soaking section is 1150-1160°C; the preheating time is 65min, the soaking section holding time is 60min, and the total heating time is 140min;

[0048] Step 3, after the above heating process is completed, the steel billet is taken out of the furnace and onto the conveyor roller, which feeds the steel billet into two 750mm and four 650mm roughing mill rolls for six horizontal and vertical staggered rolling. After the roughing billet is head-cut, it enters six 535mm intermediate rolling mills for horizontal and vertical staggered rolling. After the head-cut, it enters six 385mm finishing mills for horizontal and vertical staggered rolling. After rolling by four 385mm reducing mills, it enters high-speed wire rolling; the high-speed wire mill is rolled by eight 216mm top-crossing 45° high-speed twist-free finishing mills manufactured by the British Arcilo Company, and finally enters the Φ212mm×2+Φ158mm×2 TMB mill to be rolled into Φ9.5mm wire rod;

[0049] Step 4, collect the wire rod obtained in step 3 and charge it for annealing in a furnace, or anneal it after stack cooling; preferably, the method can also include directly annealing the obtained wire rod, wherein the annealing treatment is as follows: heating to 860±10°C, keeping warm for 6 hours, cooling to 750±10°C, keeping warm for 2 hours, heating to 860±10°C again, keeping warm for 3 hours, cooling to 760±10°C again, keeping warm for 9 hours, and finally cooling to 650°C to remove the outer cover, and then cooling to 200-220°C and taking out of the furnace.

[0050] 100 batches of 410 wire rods were produced continuously, with a product yield rate of 95.25%.

[0051] After inspection (taking furnace number 121F-994 as an example), the tensile strength is 464-499Mpa, the cross-sectional shrinkage is 75-76%, the annealing hardness is 177-179HB, A coarse 0 grade, A fine 0.5 grade, B coarse 0 grade, B fine 0.5-1.0 grade, C coarse 0 grade, C fine 0 grade, D coarse 0 grade, D fine 1 grade; macrostructure ingot segregation, center looseness and general looseness are all 0.5 grade. The performance of the product prepared according to the method provided in this embodiment fully meets the standard requirements.

[0052] Embodiment 3

[0053] This embodiment provides a method for manufacturing a low-carbon chromium stainless steel 410 wire rod, which specifically includes the following steps:

[0054] Step 1, continuously casting the molten steel after smelting in a 40t UHP furnace, AOD furnace and LF furnace into a 200mm square billet; wherein, in the UHP furnace smelting, the temperature of the charge after full melting is 1700°C, the tapping temperature is controlled at 1630-1660°C, the temperature of the AOD furnace smelting is 1670-1690°C, and during continuous casting: when the superheat is below 20°C, the working pulling speed is 1.05m / min; when the superheat is between 20 and 25°C, the working pulling speed is 0.89m / min; when the superheat is between 26 and 35°C, the working pulling speed is 0.84m / min; when the superheat is between 36 and 40°C, the working pulling speed is 0.79m / min; when the superheat is above 40°C, the working pulling speed is 0.77m / min;

[0055] The smelting steel grade is 410; the carbon content is controlled to be 0.13% by weight, the chromium content is 13.50% by weight, the silicon content is 1.00% by weight, the manganese content is 1.00% by weight, the nickel content is 0.60% by weight, the copper content is 0.25% by weight, the phosphorus content is 0.025% by weight, the sulfur content is 0.008% by weight, and the rest is iron content. After the continuous casting billet is collected, the surface is peeled and finished;

[0056] Step 2: The continuous rolling production line inspects the surface quality of the ingot, loads the furnace and heats it in turn. The temperature of the preheating section is 700-720°C, the temperature of the first heating section is 900-950°C, the temperature of the second heating section is 1050-1160°C, and the temperature of the soaking section is 1160-1180°C; the preheating time is 63 minutes, the holding time in the soaking section is 55 minutes, and the total heating time is 135 minutes.

[0057] Step 3: After the above heating process is completed, the steel billet is taken out of the furnace and placed on the conveyor roller. The conveyor roller conveys the steel billet into two 750mm and four 650mm roughing mill rolls for six horizontal and vertical staggered rolling. After the roughing billet is cut, it enters the six 535mm medium rolling mills for horizontal and vertical staggered rolling. After the roughing billet is cut, it enters the six 385mm finishing mills for horizontal and vertical staggered rolling. After rolling by four 385mm reducing mills, it enters the high-speed wire rolling; the high-speed wire rolling mill is rolled by eight 216mm top-crossing 45° high-speed twist-free finishing mills manufactured by the British Arcilo Company, and finally enters the Φ212mm×2+Φ158mm×2 TMB mill to be rolled into Φ7.5mm wire rod.

[0058] Step 4, collecting the wire rod obtained in step 3 for annealing in a furnace, or annealing after stack cooling; it can also include directly annealing the obtained wire rod, wherein the annealing treatment is as follows: heating to 860±10°C, keeping warm for 6 hours, cooling to 750±10°C, keeping warm for 2 hours, heating to 860±10°C again, keeping warm for 3 hours, cooling to 760±10°C again, keeping warm for 9 hours, and finally cooling to 650°C, removing the outer cover, and then cooling to 200-220°C and taking out of the furnace.

[0059] 100 batches of 410 wire rods were produced continuously, with a product yield rate of 95.20%.

[0060] After inspection (taking furnace number 120F-1618 as an example), the tensile strength is 489-491Mpa, the cross-sectional shrinkage is 72%, the annealing hardness is 170-179HB, A coarse 0 grade, A fine 0.5 grade, B coarse 0 grade, B fine 0.5-1.0 grade, C coarse 0 grade, C fine 0 grade, D coarse 1 grade, D fine 0.5 grade; low-magnification structure ingot segregation, center looseness and general looseness are all 0.5 grade. The performance of the product prepared according to the method provided in this embodiment fully meets the standard requirements.

[0061] Embodiment 4

[0062] This embodiment provides a method for manufacturing a low-carbon chromium stainless steel 410 wire rod, which specifically includes the following steps:

[0063] Step 1, continuously casting the molten steel after smelting in a 40t UHP furnace, AOD furnace and LF furnace into a 200mm square billet; wherein, in the UHP furnace smelting, the temperature of the charge after full melting is ≥1620°C, the tapping temperature is controlled at 1630-1660°C, the temperature of the AOD furnace smelting is 1670-1690°C, and during continuous casting: when the superheat is below 20°C, the working pulling speed is 0.95m / min; when the superheat is between 20 and 25°C, the working pulling speed is 0.89m / min; when the superheat is between 26 and 35°C, the working pulling speed is 0.84m / min; when the superheat is between 36 and 40°C, the working pulling speed is 0.79m / min; when the superheat is above 40°C, the working pulling speed is 0.78m / min;

[0064] The smelting steel grade is 410; the carbon content is controlled to be 0.13% by weight, the chromium content is 13.50% by weight, the silicon content can be 0.85% by weight, the manganese content can be 0.85% by weight, the nickel content is 0.60% by weight, the copper content is 0.25% by weight, the phosphorus content is 0.025% by weight, the sulfur content is 0.008% by weight, and the rest is iron content. After the continuous casting billet is collected, the surface is peeled and finished;

[0065] Step 2: The continuous rolling production line inspects the surface quality of the ingot, loads the furnace and heats the ingot in turn. The temperature of the preheating section is 710-720°C, the temperature of the first heating section is 900-930°C, the temperature of the second heating section is 1100-1160°C, and the temperature of the soaking section is 1150-1180°C; the preheating time is 65 minutes, the soaking section holding time is 60 minutes, and the total heating time is 140 minutes;

[0066] Step three, after the above heating process is completed, the steel billet is taken out of the furnace and onto the conveyor roller. The conveyor roller sends the steel billet to two 750mm and four 650mm rough rolling mills for six horizontal and vertical staggered rolling. After the rough rolling billet is head cut, it enters the six 535mm medium rolling mills for horizontal and vertical staggered rolling. After the head cut, it enters the six 385mm finishing mills for horizontal and vertical staggered rolling. After rolling by four 385mm reducing mills, it enters the high-speed wire rolling; the high-speed wire mill is rolled by eight 216mm top-crossing 45° high-speed twist-free finishing mills manufactured by the British Arcelor Company, and finally enters the Φ212mm×2+Φ158mm×2 TMB mill to be rolled into Φ6.5mm wire rod;

[0067] Step 4, collect the wire rod obtained in step 3 and charge it for annealing in a furnace, or anneal it after stack cooling; preferably, the method can also include directly annealing the obtained wire rod, wherein the annealing treatment is as follows: heating to 860±10°C, keeping warm for 6 hours, cooling to 750±10°C, keeping warm for 2 hours, heating to 860±10°C again, keeping warm for 3 hours, cooling to 760±10°C again, keeping warm for 9 hours, and finally cooling to 650°C to remove the outer cover, and then cooling to 200-220°C and taking out of the furnace.

[0068] 100 batches of 410 wire rods were produced continuously, with a product yield rate of 95.20%.

[0069] After inspection (taking furnace number 120F-90 as an example), the tensile strength is 480-486Mpa, the cross-sectional shrinkage is 77-79%, the annealing hardness is 174-177HB, A coarse 0 grade, A fine 0.5 grade, B coarse 0 grade, B fine 0.5-1.0 grade, C coarse 0 grade, C fine 0 grade, D coarse 0 grade, D fine 0.5-1.0 grade; macrostructure ingot segregation, center looseness and general looseness are all 0.5 grade. The performance of the product prepared according to the method provided in this embodiment fully meets the standard requirements.

[0070] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing low carbon chromium stainless steel 410 wire rod, characterized in that: The following steps are involved: According to the following chemical compositions in weight percentage, UHP furnace smelting, AOD furnace smelting, LF furnace smelting and continuous casting are carried out to obtain ingots: The carbon content is 0.11-0.13%. The chromium content is 12.00-13.50%. The silicon content is 0.20-1.00%. The content of manganese is 0.20~1.00%, The nickel content is 0.20-0.60%. The copper content is 0.10-0.25%. The phosphorus content is 0.005-0.025%. The sulfur content is 0.005-0.008%. The rest is iron content; The ingot is continuously rolled to obtain wire rod; Anneal the wire rod; In the continuous casting, the working pulling speed is determined according to the superheat of the molten steel; when the superheat is below 20°C, the working pulling speed is 0.90-1.05 m / min; when the superheat is between 20°C and 25°C, the working pulling speed is 0.85-0.89 m / min; when the superheat is between 26°C and 35°C, the working pulling speed is 0.80-0.84 m / min; when the superheat is between 36°C and 40°C, the working pulling speed is 0.75-0.79 m / min; when the superheat is above 40°C, the working pulling speed is 0.75-0.78 m / min; The continuous rolling process includes heating, rolling and controlled cooling, wherein the heating includes the preheating section, the first heating section, the second heating section, the soaking section temperature and the soaking section holding time; the rolling includes rough rolling, intermediate rolling, finishing rolling, sizing mill and wire rod mill; the controlled cooling includes air cooling line cooling; The annealing process parameters are as follows: keeping at 850-870°C for 5-6h, keeping at 750-770°C for 1-2h, keeping at 850-870°C for 2-3h, keeping at 750-770°C for 9-10h, cooling to 650°C and removing the outer cover, and then cooling to 200-220°C and taking out of the furnace.

2. The method for preparing low carbon chromium stainless steel 410 wire rod according to claim 1, characterized in that: In the UHP furnace smelting, the temperature of the charge after full melting is ≥1620°C, and the tapping temperature is controlled at 1630-1660°C.

3. The method for preparing low carbon chromium stainless steel 410 wire rod according to claim 1, characterized in that: The smelting temperature of the AOD furnace is 1670-1690°C.

4. The method for preparing low carbon chromium stainless steel 410 wire rod according to claim 1, characterized in that: The ladle temperature during continuous casting is 1590-1600°C, and the turntable temperature is 1585-1595°C.

5. The method for preparing low carbon chromium stainless steel 410 wire rod according to claim 1, characterized in that: The cast billet is a 200 mm square billet.

6. The method for preparing low carbon chromium stainless steel 410 wire rod according to claim 1, characterized in that: The temperature of the preheating section is 680-720°C, the temperature of the first heating section is 850-950°C, the temperature of the second heating section is 1020-1160°C, and the temperature of the soaking section is 1140-1180°C; the preheating time is 60-65 minutes, the insulation time of the soaking section is 45-60 minutes, and the total heating time is 120-140 minutes.

7. The method for preparing low carbon chromium stainless steel 410 wire rod according to claim 1, characterized in that: The annealing atmosphere is nitrogen.

8. Low carbon chromium stainless steel 410 wire rod, characterized in that: Prepared by the preparation method according to any one of claims 1 to 7.

9. The low carbon chromium stainless steel 410 wire rod according to claim 8, characterized in that: The tensile strength of the 410 wire rod is 480-500 MPa.

10. The low carbon chromium stainless steel 410 wire rod according to claim 8, characterized in that: The annealing hardness of the 410 wire rod is 170-185 HB.