Round steel for anchor chain and production method

Abstract

The invention relates to the field of steel, in particular to round steel for an anchor chain and a production method. The round steel is prepared from the following raw materials in parts by weight: 0.29 to 0.34 part of C, 0.20 to 0.40 part of Si, 1.60 to 1.85 parts of Mn, 0.05 to 0.30 part of Cr, 0 to 0.030 part of P, 0 to 0.025 part of S, 0.025 to 0.045 part of Al, 0 to 0.25 part of Cu, 0 to 0.25 part of Ni, 0.015 to 0.025 part of Ti, 0 to 0.05 part of Nb, 0 to 0.10 part of V and 96.3 to 97.9 parts of Fe. The prepared round steel has high strength, low-temperature impact toughness and surface quality, the material performance meets various requirements about M4-level anchor chains in GB / 549-2017 Electric Welding Anchor Chain, and the requirements of the ship industry for large-scale, heavy-duty and green high-strength anchor chains are met.

Description

Technical Field

[0001] The invention relates to the field of steel materials, in particular to round steel for anchor chains and a production method thereof. Background Art

[0002] In recent years, my country's marine shipbuilding industry has continued to develop, gradually moving towards large-scale, heavy-duty, and green, and the demand for high-strength marine anchor chains has also gradually increased. Therefore, the GB / 549-2017 "Electric Welded Anchor Chain" standard has added M4-level anchor chains and their performance requirements on the basis of the original M1~M3-level marine anchor chains, but there are no clear requirements for the materials used to manufacture M4-level anchor chains. Similarly, in GBT18669-2012 "Marine Anchor Chain Round Steel" and China Classification Society CCS "Materials and Welding Specifications" (2023), there are only M1~M3-level marine anchor chain material requirements, and no M4-level anchor chain material requirements. Therefore, there is currently no M4-level round steel for anchor chains. Summary of the invention

[0003] In order to overcome the disadvantage that the material requirements of the existing round steel for anchor chains are insufficient, the present invention provides round steel for anchor chains and a production method.

[0004] The technical solution adopted by the present invention to solve the technical problem is: a round steel for anchor chain, wherein the weight proportions of various raw materials in the round steel are: C: 0.29-0.34 part, Si: 0.20-0.40 part, Mn: 1.60-1.85 part, Cr: 0.05-0.30 part, P: 0-0.030 part, S: 0-0.025 part, Al: 0.025-0.045 part, Cu: 0-0.25 part, Ni: 0-0.25 part, Ti: 0.015-0.025 part, Nb: 0-0.05 part, V: 0-0.10 part, and Fe: 96.3-97.9 parts.

[0005] According to another embodiment of the present invention, the composition further comprises 0.29 parts of C, 0.20 parts of Si, 1.60 parts of Mn, 0.05 parts of Cr, 0.025 parts of Al, 0.015 parts of Ti and 97.9 parts of Fe.

[0006] According to another embodiment of the present invention, it further includes C: 0.34 parts, Si: 0.40 parts, Mn: 1.85 parts, Cr: 0.30 parts, P: 0.030 parts, S: 0.025 parts, Al: 0.045 parts, Cu: 0.25 parts, Ni: 0.25 parts, Ti: 0.025 parts, Nb: 0.05 parts, V: 0.10 parts, Fe: 96.3 parts.

[0007] According to another embodiment of the present invention, it further includes C: 0.31 parts, Si: 0.30 parts, Mn: 1.68 parts, Cr: 0.10 parts, Al: 0.030 parts, Ti: 0.020 parts, and Fe: 97.5 parts.

[0008] A method for producing round steel for anchor chain comprises the following steps: S1, BOF furnace smelts molten iron and scrap steel to remove impurities and form qualified primary molten steel; S2, LF refining uses LF ladle refining furnace, through the electrode power, temperature rise, add deoxidation material, alloy and slag, make the molten steel fully deoxidized, alloyed, slag after melting completely cover the ladle surface, remove the inclusions in the molten steel; S3, using a full arc continuous casting machine to cast molten steel into continuous casting billets, the billets are slowly cooled, inspected and judged to become qualified billets; S4, fully heating the ingot with a heating furnace; S5, rolling the ingot by a rolling mill; S6. The round steel formed by rolling is finished by finishing.

[0009] According to another embodiment of the present invention, the BOF smelting further includes using a BOF basic oxygen converter, adding a slag-making agent, passing oxygen for smelting, removing impurities in the molten steel, and using a deoxidizer, silicon manganese, ferromanganese, ferrosilicon, ferrochrome, lime, and refined slag for deoxidation and alloying after the BOF furnace to form qualified primary molten steel.

[0010] According to another embodiment of the present invention, the LF refining step further comprises: 1. Introduce argon into the LF furnace, stir it thoroughly, and mix the molten steel components; 2. Add deoxidizing materials such as aluminum particles, SiCa, and SiC for multiple times to diffuse deoxidize the slag surface; 3. Form white slag through diffusion deoxidation on the slag surface, and keep the white slag for 20-40 minutes, thereby deoxidizing and adsorbing inclusions; 4. Use silicon-manganese, ferromanganese, ferrosilicon, and ferrochrome alloys to micro-alloy the molten steel and adjust the molten steel composition so that the main components of the molten steel meet the requirements; 5. The soft argon blowing operation keeps the ladle slag surface slightly moving for 15-30 minutes to promote the full floating of inclusions and improve the cleanliness of the molten steel.

[0011] According to another embodiment of the present invention, the continuous casting step further comprises: 1. Use R10m full-arc continuous casting machine with integral water nozzle to protect the pouring during the whole continuous casting process and control the air absorption and secondary oxidation of molten steel; 2. Control the cooling water, tundish superheat and billet drawing speed during the continuous casting process to produce continuous casting billets with different cross-sections of 150*150, 165*225, 200*200, and 280*320; 3. After slow cooling, inspection and judgment, the billet becomes a qualified billet.

[0012] According to another embodiment of the present invention, the steel rolling further includes using a walking beam heating furnace for sufficient heating and high-temperature diffusion, keeping warm in a soaking section at 1130-1180°C for 30-60 minutes, and after the steel is discharged from the heating furnace, using high-pressure water to descale the steel, so that there is no iron oxide scale on the surface of the billet, using several horizontal and vertical alternating short stress rolling mills and KOCKS sizing mills, and undergoing initial rolling, intermediate rolling, finishing rolling, sawing, and slow cooling, the size accuracy of the round steel is controlled to be 0~+0.2mm, and the starting rolling temperature, final rolling temperature, sawing temperature, and slow cooling temperature are controlled to ensure that the round steel has good surface quality and structure.

[0013] According to another embodiment of the present invention, the finishing further includes straightening and chamfering the round steel after slow cooling, and performing ultrasonic and magnetic leakage testing to ensure that the round steel is defect-free. The round steel is finally formed into a finished product after inspection and packaging.

[0014] The beneficial effect of the present invention is that the round steel prepared by the invention has high strength, low-temperature impact toughness and surface quality, and the material properties meet the requirements of GB / 549-2017 "Electric Welded Anchor Chain" for M4-level anchor chains, and meet the future shipbuilding industry's demand for large-scale, heavy-duty and green high-strength marine anchor chains. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0016] Figure 1 is a flow chart of the method of the present invention; DETAILED DESCRIPTION

[0017] Figure 1 It is a flow chart of the method of the present invention. Example

[0018] The weight proportions of various raw materials in a round steel for an M4 grade anchor chain are as follows: C: 0.29 part, Si: 0.20 part, Mn: 1.60 part, Cr: 0.05 part, Al: 0.025 part, Ti: 0.015 part, and Fe: 97.9 part.

[0019] The preparation method is: S1. BOF smelting removes impurities to form qualified primary molten steel; the BOF smelting adopts a BOF basic oxygen converter, adds a slag-making agent, introduces oxygen for smelting, removes impurities in the molten steel, and uses a deoxidizer, silicon manganese, ferromanganese, ferrosilicon, ferrochrome, lime, and refined slag for deoxidation and alloying after the BOF furnace to form qualified primary molten steel.

[0020] S2 and LF refining adopts LF ladle refining furnace. By electrifying and heating the electrodes, the alloy and slag added by BOF are fully melted to fully alloy the molten steel. After the slag is melted, it completely covers the surface of the ladle to form qualified components and remove impurities in the steel.

[0021] The specific steps of LF refining are: 1. Introduce argon gas into the LF furnace, stir it thoroughly, and mix the molten steel components; 2. Add deoxidizing materials such as aluminum particles, SiCa, and SiC in small batches and multiple times to diffuse deoxidize the slag surface; 3. Form white slag through slag surface diffusion deoxidation, and keep the white slag for 20-40 minutes, thereby deoxidizing and adsorbing inclusions; 4. Use silicon manganese, ferrosilicon, ferrochrome and other alloys to micro-alloy the molten steel and adjust the molten steel composition so that the main components of the molten steel meet the requirements; 5. The soft argon blowing operation keeps the ladle slag surface slightly moving for 15-30 minutes to promote the full floating of inclusions and improve the cleanliness of the molten steel.

[0022] S3, continuous casting, using a full-arc continuous casting machine, the molten steel is cast into continuous casting billets, the billets are slowly cooled, inspected and judged to become qualified billets.

[0023] The specific steps of continuous casting are: 1. Use R10m full-arc continuous casting machine, adopt integral water nozzle, protect pouring throughout the continuous casting process, and control molten steel absorption and secondary oxidation; 2. Control cooling water, tundish superheat and billet drawing speed during continuous casting to produce continuous casting billets with different cross-sections of 150*150, 165*225, 200*200, and 280*320; 3. The billets are slowly cooled, inspected and judged to become qualified billets.

[0024] S4. Use a rolling mill to roll the ingot. The rolling process uses a walking beam heating furnace for sufficient heating and high-temperature diffusion. The steel is kept warm in a soaking section at 1130-1180℃ for 30-60min. After the steel is discharged from the heating furnace, high-pressure water is used to remove scale. There is no iron oxide scale on the surface of the ingot. Several horizontal and vertical alternating short stress rolling mills and KOCKS sizing mills are used. After initial rolling, intermediate rolling, finishing rolling, sawing and slow cooling, the size accuracy of the round steel is controlled within 0~+0.2mm. The starting rolling temperature, final rolling temperature, sawing temperature and slow cooling temperature are also controlled to ensure that the round steel has good surface quality and structure.

[0025] S6. Finishing the round steel into finished products. Finishing is to straighten and chamfer the round steel after slow cooling, and perform ultrasonic and magnetic leakage testing to ensure that the round steel has no defects. The round steel is finally formed into a finished product after inspection and packaging.

[0026] The material is subjected to overall heat treatment (quenching + tempering) and sampling according to the standard requirements, and mechanical property tests are carried out. The tensile strength of the material is 780MPa; the yield strength is 600MPa; the elongation after fracture is 21%; the cross-sectional shrinkage is 67%; the V-notch impact test performance of the original material at -20℃ is 90J. The performance requirements of the M4 grade anchor chain material in GB / 549-2017 "Electric Welding Anchor Chain" are: tensile strength ≥770MPa; yield strength ≥490MPa; elongation after fracture ≥12%; cross-sectional shrinkage ≥50%; the V-notch impact test performance of the original material at -20℃ is ≥45J.

[0027] The material properties meet the performance requirements of M4 grade anchor chain materials in GB / 549-2017 "Electric Welded Anchor Chain". Example

[0028] The weight proportions of various raw materials in an M4 grade round steel for anchor chain are: C: 0.34 part, Si: 0.40 part, Mn: 1.85 part, Cr: 0.30 part, P: 0.030 part, S: 0.025 part, Al: 0.045 part, Cu: 0.25 part, Ni: 0.25 part, Ti: 0.025 part, Nb: 0.05 part, V: 0.10 part, Fe: 96.3 parts.

[0029] The preparation method is: S1. BOF smelting removes impurities to form qualified primary molten steel; the BOF smelting adopts a BOF basic oxygen converter, adds a slag-making agent, introduces oxygen for smelting, removes impurities in the molten steel, and uses a deoxidizer, silicon manganese, ferromanganese, ferrosilicon, ferrochrome, lime, and refined slag for deoxidation and alloying after the BOF furnace to form qualified primary molten steel.

[0030] S2 and LF refining adopts LF ladle refining furnace. By electrifying and heating the electrodes, the alloy and slag added by BOF are fully melted to fully alloy the molten steel. After the slag is melted, it completely covers the surface of the ladle to form qualified components and remove impurities in the steel.

[0031] The specific steps of LF refining are: 1. Introduce argon gas into the LF furnace, stir it thoroughly, and mix the molten steel components; 2. Add deoxidizing materials such as aluminum particles, SiCa, and SiC in small batches and multiple times to diffuse deoxidize the slag surface; 3. Form white slag through slag surface diffusion deoxidation, and keep the white slag for 20-40 minutes, thereby deoxidizing and adsorbing inclusions; 4. Use silicon manganese, ferrosilicon, ferrochrome and other alloys to micro-alloy the molten steel and adjust the molten steel composition so that the main components of the molten steel meet the requirements; 5. The soft argon blowing operation keeps the ladle slag surface slightly moving for 15-30 minutes to promote the full floating of inclusions and improve the cleanliness of the molten steel.

[0032] S3, continuous casting, using a full-arc continuous casting machine, the molten steel is cast into continuous casting billets, the billets are slowly cooled, inspected and judged to become qualified billets.

[0033] The specific steps of continuous casting are: 1. Use R10m full-arc continuous casting machine, adopt integral water nozzle, protect pouring throughout the continuous casting process, and control molten steel absorption and secondary oxidation; 2. Control cooling water, tundish superheat and billet drawing speed during continuous casting to produce continuous casting billets with different cross-sections of 150*150, 165*225, 200*200, and 280*320; 3. The billets are slowly cooled, inspected and judged to become qualified billets.

[0034] S4. Use a rolling mill to roll the ingot. The rolling process uses a walking beam heating furnace for sufficient heating and high-temperature diffusion. The steel is kept warm in a soaking section at 1130-1180℃ for 30-60min. After the steel is discharged from the heating furnace, high-pressure water is used to remove scale. There is no iron oxide scale on the surface of the ingot. Several horizontal and vertical alternating short stress rolling mills and KOCKS sizing mills are used. After initial rolling, intermediate rolling, finishing rolling, sawing and slow cooling, the size accuracy of the round steel is controlled within 0~+0.2mm. The starting rolling temperature, final rolling temperature, sawing temperature and slow cooling temperature are also controlled to ensure that the round steel has good surface quality and structure.

[0035] S6. Finishing the round steel into finished products. Finishing is to straighten and chamfer the round steel after slow cooling, and perform ultrasonic and magnetic leakage testing to ensure that the round steel has no defects. The round steel is finally formed into a finished product after inspection and packaging.

[0036] The material is subjected to overall heat treatment (quenching + tempering) and sampling according to the standard requirements, and mechanical property tests are carried out. The tensile strength of the material is 850MPa; the yield strength is 720MPa; the elongation after fracture is 16%; the cross-sectional shrinkage is 55%; the V-notch impact test performance of the original material at -20℃ is 110J. The performance requirements of the M4 grade anchor chain material in GB / 549-2017 "Electric Welding Anchor Chain" are: tensile strength ≥770MPa; yield strength ≥490MPa; elongation after fracture ≥12%; cross-sectional shrinkage ≥50%; the V-notch impact test performance of the original material at -20℃ is ≥45J.

[0037] The material properties meet the performance requirements of M4 grade anchor chain materials in GB / 549-2017 "Electric Welded Anchor Chain". Example

[0038] The weight proportions of various raw materials in a round steel for M4 grade anchor chain are: C: 0.31 parts, Si: 0.30 parts, Mn: 1.68 parts, Cr: 0.10 parts, Al: 0.030 parts, Ti: 0.020 parts, and Fe: 97.5 parts.

[0039] The preparation method is: S1. BOF smelting removes impurities to form qualified primary molten steel; the BOF smelting adopts a BOF basic oxygen converter, adds a slag-making agent, introduces oxygen for smelting, removes impurities in the molten steel, and uses a deoxidizer, silicon manganese, ferromanganese, ferrosilicon, ferrochrome, lime, and refined slag for deoxidation and alloying after the BOF furnace to form qualified primary molten steel.

[0040] S2 and LF refining adopts LF ladle refining furnace. By electrifying and heating the electrodes, the alloy and slag added by BOF are fully melted to fully alloy the molten steel. After the slag is melted, it completely covers the surface of the ladle to form qualified components and remove impurities in the steel.

[0041] The specific steps of LF refining are: 1. Introduce argon gas into the LF furnace, stir it thoroughly, and mix the molten steel components; 2. Add deoxidizing materials such as aluminum particles, SiCa, and SiC in small batches and multiple times to diffuse deoxidize the slag surface; 3. Form white slag through slag surface diffusion deoxidation, and keep the white slag for 20-40 minutes, thereby deoxidizing and adsorbing inclusions; 4. Use silicon manganese, ferrosilicon, ferrochrome and other alloys to micro-alloy the molten steel and adjust the molten steel composition so that the main components of the molten steel meet the requirements; 5. The soft argon blowing operation keeps the ladle slag surface slightly moving for 15-30 minutes to promote the full floating of inclusions and improve the cleanliness of the molten steel.

[0042] S3, continuous casting, using a full-arc continuous casting machine, the molten steel is cast into continuous casting billets, the billets are slowly cooled, inspected and judged to become qualified billets.

[0043] The specific steps of continuous casting are: 1. Use R10m full-arc continuous casting machine, adopt integral water nozzle, protect pouring throughout the continuous casting process, and control molten steel absorption and secondary oxidation; 2. Control cooling water, tundish superheat and billet drawing speed during continuous casting to produce continuous casting billets with different cross-sections of 150*150, 165*225, 200*200, and 280*320; 3. The billets are slowly cooled, inspected and judged to become qualified billets.

[0044] S4. Use a rolling mill to roll the ingot. The rolling process uses a walking beam heating furnace for sufficient heating and high-temperature diffusion. The steel is kept warm in a soaking section at 1130-1180℃ for 30-60min. After the steel is discharged from the heating furnace, high-pressure water is used to remove scale. There is no iron oxide scale on the surface of the ingot. Several horizontal and vertical alternating short stress rolling mills and KOCKS sizing mills are used. After initial rolling, intermediate rolling, finishing rolling, sawing and slow cooling, the size accuracy of the round steel is controlled within 0~+0.2mm. The starting rolling temperature, final rolling temperature, sawing temperature and slow cooling temperature are also controlled to ensure that the round steel has good surface quality and structure.

[0045] S6. Finishing the round steel into finished products. Finishing is to straighten and chamfer the round steel after slow cooling, and perform ultrasonic and magnetic leakage testing to ensure that the round steel has no defects. The round steel is finally formed into a finished product after inspection and packaging.

[0046] The material was subjected to overall heat treatment (quenching + tempering) and sampling according to the standard requirements, and mechanical property tests were carried out. The tensile strength of the material was 810MPa; the yield strength was 680MPa; the elongation after fracture was 19MPa; the cross-sectional shrinkage was 64%; the V-notch impact test performance of the original material at -20℃ was 100J. The performance requirements of the M4 grade anchor chain material in GB / 549-2017 "Electric Welding Anchor Chain" are as follows: tensile strength ≥770MPa; yield strength ≥490MPa; elongation after fracture ≥12%; cross-sectional shrinkage ≥50%; the V-notch impact test performance of the original material at -20℃ was ≥45J.

[0047] The material properties meet the performance requirements of M4 grade anchor chain materials in GB / 549-2017 "Electric Welded Anchor Chain".

Claims

1. A round steel for anchor chain, characterized in that: The weight proportions of various raw materials in the round steel are: C: 0.29-0.34 parts, Si: 0.20-0.40 parts, Mn: 1.60-1.85 parts, Cr: 0.05-0.30 parts, P: 0-0.030 parts, S: 0-0.025 parts, Al: 0.025-0.045 parts, Cu: 0-0.25 parts, Ni: 0-0.25 parts, Ti: 0.015-0.025 parts, Nb: 0-0.05 parts, V: 0-0.10 parts, Fe: 96.3-97.9 parts.

2. A round steel for anchor chain, characterized in that: The C: 0.29 parts, Si: 0.20 parts, Mn: 1.60 parts, Cr: 0.05 parts, Al: 0.025 parts, Ti: 0.015 parts, and Fe: 97.9 parts.

3. A round steel for anchor chain, characterized in that: The C: 0.34 parts, Si: 0.40 parts, Mn: 1.85 parts, Cr: 0.30 parts, P: 0.030 parts, S: 0.025 parts, Al: 0.045 parts, Cu: 0.25 parts, Ni: 0.25 parts, Ti: 0.025 parts, Nb: 0.05 parts, V: 0.10 parts, Fe: 96.3 parts.

4. A round steel for anchor chain, characterized in that: The C: 0.31 parts, Si: 0.30 parts, Mn: 1.68 parts, Cr: 0.10 parts, Al: 0.030 parts, Ti: 0.020 parts, and Fe: 97.5 parts.

5. A method for producing round steel for anchor chain according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1, BOF furnace smelts molten iron and scrap steel to remove impurities and form qualified primary molten steel; S2, LF refining uses LF ladle refining furnace, through the electrode power, temperature rise, add deoxidation material, alloy and slag, make the molten steel fully deoxidized, alloyed, slag after melting completely cover the ladle surface, remove the inclusions in the molten steel; S3, using a full arc continuous casting machine to cast molten steel into continuous casting billets, the billets are slowly cooled, inspected and judged to become qualified billets; S4, fully heating the ingot with a heating furnace; S5, rolling the ingot by a rolling mill; S6. The round steel formed by rolling is finished by finishing.

6. The method for producing round steel for anchor chain according to claim 5, characterized in that: The BOF smelting adopts a BOF basic oxygen converter, adds a slag-making agent, introduces oxygen for smelting, removes impurities in the molten steel, and uses a deoxidizer, silicon manganese, ferromanganese, ferrosilicon, ferrochrome, lime, and refined slag for deoxidation and alloying after the BOF furnace to form qualified primary molten steel.

7. The method for producing round steel for anchor chain according to claim 5, characterized in that: The steps of LF refining are:

1. Introduce argon into the LF furnace, stir it thoroughly, and mix the molten steel components; 2. Add deoxidizing materials such as aluminum particles, SiCa, and SiC for multiple times to diffuse deoxidize the slag surface; 3. Form white slag through diffusion deoxidation on the slag surface, and keep the white slag for 20-40 minutes, thereby deoxidizing and adsorbing inclusions; 4. Use silicon-manganese, ferromanganese, ferrosilicon, and ferrochrome alloys to micro-alloy the molten steel and adjust the molten steel composition so that the main components of the molten steel meet the requirements; 5. The soft argon blowing operation keeps the ladle slag surface slightly moving for 15-30 minutes to promote the full floating of inclusions and improve the cleanliness of the molten steel.

8. The method for producing round steel for anchor chain according to claim 5, characterized in that: The steps of continuous casting are:

1. Use R10m full-arc continuous casting machine with integral water nozzle to protect the pouring during the whole continuous casting process and control the air absorption and secondary oxidation of molten steel; 2. Control the cooling water, tundish superheat and billet drawing speed during the continuous casting process to produce continuous casting billets with different cross-sections of 150*150, 165*225, 200*200, and 280*320; 3. After slow cooling, inspection and judgment, the billet becomes a qualified billet.

9. The method for producing round steel for anchor chain according to claim 5, characterized in that: The steel rolling adopts a walking beam heating furnace for sufficient heating and high-temperature diffusion, and is kept warm in a soaking section at 1130-1180°C for 30-60 minutes. After the steel is discharged from the heating furnace, high-pressure water is used for descaling, and there is no oxide scale on the surface of the billet. Several horizontal and vertical alternating short stress rolling mills and KOCKS sizing rolling mills are used. After initial rolling, intermediate rolling, finishing rolling, sawing and slow cooling, the size accuracy of the round steel is controlled to be 0~+0.2mm, and the starting rolling temperature, final rolling temperature, sawing temperature and slow cooling temperature are controlled to ensure that the round steel has good surface quality and structure.

10. The method for producing round steel for anchor chain according to claim 5, characterized in that: The finishing is to straighten and chamfer the round steel after slow cooling, and perform ultrasonic and magnetic leakage detection to ensure that the round steel is defect-free. The round steel is finally formed into a finished product after inspection and packaging.

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