CN114606366A - Production method for improving drawing performance of steel for 70 kg-grade gas shielded welding wire - Google Patents
Production method for improving drawing performance of steel for 70 kg-grade gas shielded welding wire Download PDFInfo
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- 238000003466 welding Methods 0.000 title claims abstract description 70
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 57
- 239000010959 steel Substances 0.000 title claims abstract description 57
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 28
- 238000001816 cooling Methods 0.000 claims abstract description 76
- 238000000034 method Methods 0.000 claims abstract description 52
- 229910001563 bainite Inorganic materials 0.000 claims abstract description 31
- 238000009987 spinning Methods 0.000 claims abstract description 26
- 238000004321 preservation Methods 0.000 claims abstract description 24
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 12
- 229910052748 manganese Inorganic materials 0.000 claims description 7
- 229910052750 molybdenum Inorganic materials 0.000 claims description 7
- 229910052759 nickel Inorganic materials 0.000 claims description 7
- 229910052742 iron Inorganic materials 0.000 claims description 4
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- 239000000203 mixture Substances 0.000 claims description 3
- 239000000126 substance Substances 0.000 claims description 3
- 230000008569 process Effects 0.000 abstract description 33
- 238000000137 annealing Methods 0.000 abstract description 13
- 230000009466 transformation Effects 0.000 abstract description 12
- 238000010438 heat treatment Methods 0.000 abstract description 10
- 229910001566 austenite Inorganic materials 0.000 abstract description 5
- 230000009286 beneficial effect Effects 0.000 abstract description 2
- 238000005096 rolling process Methods 0.000 description 28
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- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
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- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/001—Heat treatment of ferrous alloys containing Ni
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/005—Heat treatment of ferrous alloys containing Mn
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/008—Heat treatment of ferrous alloys containing Si
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
- C21D9/525—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length for wire, for rods
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/08—Ferrous alloys, e.g. steel alloys containing nickel
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/002—Bainite
Abstract
The application relates to the field of wire rods for high-speed wire rod welding, in particular to a production method for improving the drawing performance of steel for a 70 kg-grade gas shield welding wire, which comprises the following steps: spinning the blank, and cooling the uncoiled coil by Stelmor to control the temperature of the uncoiled coil to obtain 70kg grade steel for the gas shielded welding wire; the stelmor cooling comprises entering a heat-preserving cover, wherein the temperature of the heat-preserving cover entering the overlap joint is 480-500 ℃, and the temperature of the heat-preserving cover entering the non-overlap joint is 430-450 ℃. After the wire rod is placed in the cover, the remaining austenite continues to perform bainite phase transformation, the phase transformation heat generated in the phase transformation process is beneficial to improving the temperature of the wire rod in the heat-preservation cover, the transformed bainite structure in the cover can be preserved at a higher temperature range, which is equivalent to performing the softening heat treatment process of an online bainite region, and finally the tempered bainite structure is obtained, so that the strength of the wire rod can be reduced to 680-750 MPa. Meanwhile, the requirement that a user who draws the subsequent gas-shielded welding wire can draw the welding wire directly without annealing can be met.
Description
Technical Field
The application relates to the field of wire rods for high-speed wire rod welding, in particular to a production method for improving the drawing performance of steel for a 70 kg-grade gas shielded welding wire. In particular to a production method for improving the drawing performance of a wire rod for a gas shielded welding wire, which contains Mn, Ni and Mo alloy elements and has a metallographic structure of full bainite.
Background
The main production process flow of the steel for the gas shielded welding wire comprises the following steps: molten iron → converter (electric furnace) smelting → LF refining → VD (RH) vacuum smelting → tundish → continuous casting slab → high-speed wire shop → heating → rough rolling → medium rolling → finish Rolling (RSM) → spinning → Steckel delayed cooling line → batch → inspection → packaging → warehousing.
The main manufacturing process of the gas shielded welding wire comprises the following steps: (annealing) → wire rod → mechanical shelling → acid cleaning → washing → drying → coarse drawing → (annealing) → fine drawing → washing copper plating → washing → polishing → rust preventive treatment → coiling of the axle → inspection → packaging → warehousing.
The wire rod with the diameter of 5.5mm or 6.5mm needs to be subjected to rough drawing to the diameter of 2.3mm, then fine drawing is carried out to the specification of a finished welding wire (the diameter is 0.8-1.6 mm), and the total reduction rate of drawing deformation reaches 92-98%. Therefore, good drawing properties (plasticity) of the wire rod are required. In order to ensure smooth drawing, annealing and softening treatment is required to be carried out before or during drawing in the manufacturing process of the high-strength welding wire according to the strength of the wire rod or the welding wire.
For the steel for the gas-shielded welding wire below 55kg grade, the metallographic structure is ferrite + pearlite + a small amount (the volume percentage content is less than 5%) of bainite or MA hard phase structure, the structure mainly comprising ferrite and pearlite is low in strength and good in plasticity, and a user can realize annealing-free direct drawing.
For the steel for the gas-shielded welding wire of 60-65 kg grade, the coil structure is a ferrite + bainite or MA structure (volume percentage content is more than 10%) dual-phase structure, the bainite or MA structure has high strength and poor plasticity, the coil strength reaches 650 plus 850MPa, and in the drawing and wire making process, due to the difference of two-phase plastic deformation capacities of ferrite and bainite, the deformation coordination capacity is insufficient, local stress concentration is easily generated at a phase interface, and microcracks are formed to become a fracture source of the welding wire drawing brittle fracture.
Patent CN201110412471.X discloses a 70kg grade annealing-free welding wire steel wire rod and a production process thereof, and the steel wire rod consists of the following components in percentage by weight: c: 0.07 to 0.1%, Mn: 1.25-1.4%, Si: 0.4-0.6%, P is less than or equal to 0.02%, S is less than or equal to 0.02%, Mo: 0.2-0-0.55%, Ni: 0.5-1.0%, Cu not more than 0.2%, Ti not more than 0.2%, Al not more than 0.1%, and the balance of Fe. The process comprises the following steps: blank inspection → billet heating → high-pressure water descaling → rough and medium rolling, pre-finish rolling → water cooling 1 area → finishing mill group → water cooling 2 area → reducing and sizing rolling → water cooling 3 area → spinning → air cooling → finishing → warehousing. The invention adopts the controlled rolling and controlled cooling process to carry out process control on the welding wire steel wire rod to obtain the F + P structure suitable for drawing, has good comprehensive mechanical property, and can avoid annealing and multi-pass drawing without wire breakage in a welding wire factory.
Patent CN201510559693.2 discloses a rolling method of a 70 kg-grade vanadium-titanium welding steel hot rolled wire rod, which controls the structure and performance of the vanadium-titanium welding steel by controlling the heating temperature, reducing the diameter inlet temperature, the wire laying temperature and the stelmor cooling process, wherein the structure mainly comprises ferrite and pearlite, the tensile strength is reduced, the elongation and the surface shrinkage are improved, the drawing performance is improved, the annealing process before drawing is omitted in the wire drawing process, and the production efficiency during drawing is improved.
However, for the steel for the 70kg grade gas-shielded welding wire with the bainite structure, the strength of the wire rod reaches 850-1000 MPa, and in order to improve the drawing performance, a user needs to perform annealing softening treatment to reduce the strength to 680-750MPa before and during drawing so as to perform smooth drawing.
Disclosure of Invention
The application provides a production method for improving the drawing performance of steel for a 70 kg-grade gas-shielded welding wire and the steel for the 70 kg-grade gas-shielded welding wire, and aims to solve the technical problem that the steel for the 70 kg-grade gas-shielded welding wire needs to be annealed in the subsequent welding wire process.
In a first aspect, the present application provides a method of producing a steel for a grade 70kg gas shielded welding wire with improved drawability, the method comprising the steps of:
spinning the blank to obtain loose rolls;
carrying out Stelmor cooling on the uncoiled coil to control the temperature of the uncoiled coil so as to obtain 70kg grade steel for the gas shielded welding wire;
the stelmor cooling comprises entering a heat-preserving cover, wherein the temperature of the heat-preserving cover entering the overlap joint is 480-500 ℃, and the temperature of the heat-preserving cover entering the non-overlap joint is 430-450 ℃.
Optionally, the spinning temperature is 800-830 ℃.
Optionally, in the stelmor cooling, the opening of the fan at the position corresponding to the heat-insulating cover is 20-50%, and the air volume of the fan is 40000-100000 m3/h。
Optionally, the cooling speed in the heat-insulating cover is 0.2-0.3 ℃/s.
Optionally, in the stelmor cooling, the speed of the roller way is 0.10-0.13 m/s.
Optionally, the roller way comprises at least 12 segments, wherein the speed of the first segment of the roller way is less than the speed of the remaining segments of the roller way.
In a second aspect, the present application provides that the chemical composition of the steel for the grade 70kg gas shielded welding wire of the first aspect comprises: and C: 0.06-0.10%, Si: 0.40-0.60%, Mn: 1.60-1.80%, P is less than or equal to 0.015%, S: 0.008-0.012%, Ni: 1.20-1.40%, Mo: 0.40-0.60%, and the balance of iron and inevitable impurities.
Optionally, the metallographic structure of the 70kg grade steel for gas shielded welding wire is a bainite structure.
Optionally, the tensile strength of the 70kg grade steel for gas-shielded welding wire is 680-750 Mpa.
Compared with the prior art, the technical scheme provided by the embodiment of the application has the following advantages:
according to the production method provided by the embodiment of the application, the loose coils are subjected to Steyr cooling, the temperature of the cover placed at the lap joint point is controlled to be reduced to 480-500 ℃ before the cover is placed, and at the moment, the transformation from austenite to bainite tissue is completed by about 60%; the non-lap joint point cover entering temperature is 430-450 ℃, the transformation process from austenite to bainite tissue is completed by about 80%, after the cover entering, the rest austenite continues to generate bainite phase transformation, the phase transformation heat generated in the phase transformation process is beneficial to improving the temperature of the wire rod in the heat-preservation cover, the bainite tissue which is transformed in the cover can be subjected to heat preservation in a higher temperature range, which is equivalent to the softening heat treatment process of an online bainite region, and finally the tempered bainite tissue is obtained, so that the strength of the wire rod can be reduced to 680-750 MPa. Meanwhile, the requirement that a user who draws the subsequent gas-shielded welding wire can directly draw the welding wire without annealing can be met.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the invention.
In order to more clearly illustrate the embodiments or technical solutions in the prior art of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious for those skilled in the art to obtain other drawings without inventive labor.
FIG. 1 is a schematic flow chart of a production method for improving the drawing performance of steel for a grade 70kg gas shielded welding wire according to an embodiment of the present application;
FIG. 2 is a temperature drop curve of a grade 70kg steel for a gas shielded welding wire provided in an embodiment of the present application;
FIG. 3 is a graph showing the relationship between the cooling rate and the structure hardness of steel for a grade 70kg gas shielded welding wire according to an embodiment of the present disclosure;
FIG. 4 is a graph illustrating a transition from continuous cooling of a 70kg grade steel for a gas shielded welding wire according to an embodiment of the present disclosure;
FIG. 5 is a metallographic structure diagram provided in example 1 of the present application;
fig. 6 is a metallographic structure diagram provided in comparative example 1.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
In a first aspect, the present application provides a method for improving the drawability of a steel for a grade 70kg gas shielded welding wire, as shown in fig. 1, the method comprising the steps of:
s1, spinning the blank to obtain a loose coil;
as an optional embodiment, the spinning temperature is 800-830 ℃.
S2, carrying out Stelmor cooling on the uncoiled coil to control the temperature of the uncoiled coil so as to obtain 70kg grade steel for the gas shielded welding wire; the stelmor cooling comprises entering a heat-preserving cover, wherein the temperature of the heat-preserving cover entering the overlap joint is 480-500 ℃, and the temperature of the heat-preserving cover entering the non-overlap joint is 430-450 ℃.
Specifically, the fan is started for fast cooling before the wire rod is placed into the cover, the temperature of the heat-preservation cover placed at the lap joint point is reduced to 480-plus 500 ℃, the temperature of the heat-preservation cover placed at the non-lap joint point is reduced to 430-450 ℃, the process scheme breaks through the conventional traditional weld wire slow cooling process mode, the temperature of the wire rod in the cover is increased by using phase change heat during bainite phase change in the heat-preservation cover after the wire rod is cooled by the fan, the wire rod is in a temperature rise-heat preservation-slow cooling process in the cover, the cooling speed in the cover reaches 0.2-0.3 ℃/s by controlling the speed of a roller way on a slow cooling line, and a temperature drop curve on the cooling line is shown in figure 2.
Specifically, stelmor controlled cooling is carried out after spinning, the wire rod falls on a roller way in a loose roll form (the length of the roller way can be about 100 meters), the roller speed can be adjusted on the roller way, air cooling can be carried out, and the cooling speed of the wire rod can be controlled by means of heat preservation of a heat preservation cover, which is also called stelmor controlled temperature loose roll cooling.
As an optional implementation mode, in the Styromo cooling, the opening degree of a fan at the position corresponding to the heat-preserving cover is 20-50%, and the air volume of the fan is 40000-100000 m3/h。
Specifically, the fan at the position corresponding to the heat-insulating cover is uncovered; the device in the stelmor cooling comprises a heat-insulating cover, a fan and a roller way. In the Stiff mole cooling process, the front four heat-insulating covers can be opened, the rest heat-insulating covers are closed, the fans at the corresponding positions of the front four heat-insulating covers are opened, the opening degree of the fans is 20-50%, and the air volume of the fans is 40000-100000 m3/h。
As an optional implementation mode, the cooling speed in the heat-preservation cover is 0.2-0.3 ℃/s.
The steel for the welding wire is an all-bainite structure even under an extremely slow cooling rate condition (0.2 ℃/s), and the conventional limit cooling rate of a Steyr delayed cooling line in a high-speed wire production workshop is 0.4 ℃/s. The hardness of the bainite structure obtained by the slower cooling speed is lower, see attached figure 3.
The reason for controlling the cooling rate in the heat-insulating cover to be 0.2-0.3 ℃/s is that the lower the hardness of the bainite structure obtained by the lower cooling rate is, as shown in fig. 3, the corresponding strength is also lower, so the lower the cooling rate is, the better the cooling rate is, of course, the equipment capacity is limited (for example, the speed of a 0.10m/s roller way is the limit of the equipment), and the lower the cooling rate is impossible. In FIG. 4, which is a continuous cooling transformation curve (CCT curve) of the steel type to which the present application is applied, two lines represent the temperatures at which the transformation of bainite (B) structure starts and ends, and as can be seen from FIG. 4, the temperatures at which the transformation of bainite starts and ends are 580 ℃ and 395 ℃ at the cooling rate of 0.2 ℃/s. In the technical field, the CCT curve of a steel grade is the basis for designing a cooling process.
As an alternative embodiment, the stelmor cooling is carried out with a roller table speed of 0.10 to 0.13 m/s.
As an alternative embodiment, the roller table comprises at least 12 segments, wherein the speed of the first segment of the roller table is lower than the speed of the remaining segments of the roller table. Specifically, the roller speed of the 1 st segment of the Stalmol cooling line is 0.10m/s, and the roller speed of the 212 th segment can be 0.11 m/s.
In the embodiment of the application, after spinning, the front 4 heat-insulating covers are uncovered on a cooling line, fans at the corresponding positions of the 4 heat-insulating covers are opened, the opening of the fans is adjusted to be 20-50% according to the seasonal environment temperature, the lap joint points are controlled to enter the covers at 500-480 ℃, all the heat-insulating covers are closed after entering the covers, and all the fans are closed. The wire drawing and wire manufacturing method has the advantages that the traditional welding wire slow cooling process scheme is broken through by means of the existing production line, the problem that a 70 kg-grade gas-shielded welding wire steel user can draw and manufacture wires only by annealing treatment is solved, the production cost of the user is greatly reduced, and the requirements of environmental protection are met.
In a second aspect, the present application provides that the chemical composition of the steel for the grade 70kg gas shielded welding wire of the first aspect comprises: and C: 0.06-0.10%, Si: 0.40-0.60%, Mn: 1.60-1.80%, P is less than or equal to 0.015%, S: 0.008-0.012%, Ni: 1.20-1.40%, Mo: 0.40-0.60%, and the balance of iron and inevitable impurities.
As an optional embodiment, the metallographic structure of the steel for the grade 70kg gas shielded welding wire is a bainite structure.
Specifically, in the prior art, for a welding wire steel wire rod of a component system only capable of obtaining an all-bainite structure, in order to improve the drawing performance, the prior art can only perform smooth drawing by reducing the strength through an annealing treatment method.
As an optional implementation mode, the tensile strength of the steel for the 70kg grade gas-shielded welding wire is 680-750 MPa.
According to the method, the problem of poor drawing performance of the steel for the 70kg grade gas shielded welding wire containing high Mn, Ni and Mo alloy elements is solved through the working procedures of high-speed wire rod factory heating furnace → rough rolling → flying shear cutting head → medium rolling → pre-finish rolling → high-speed finish rolling → water cooling → pinch, wire laying → Stelmor cooling line control temperature-dispersed coil cooling → coil collecting → wire rod inspection. The invention breaks through the traditional technological method that the high-strength welding wire steel wire rod needs annealing treatment in the drawing and wire making process, and adopts the on-line bainite tempering heat treatment technological method that the temperature rise, the heat preservation and the slow cooling are realized by utilizing the bainite phase transformation heat in the heat preservation cover after the air blower is started for fast cooling.
The process of the present invention will be described in detail below with reference to examples, comparative examples and experimental data.
Example 1
A production method for improving the drawing performance of steel for a 70 kg-grade gas shielded welding wire comprises the following chemical elements in percentage by mass: c: 0.07%, Si: 0.55%, Mn: 1.73%, P: 0.012%, S: 0.007%, Ni: 1.32%, Mo: 0.48 percent and the balance of Fe.
The embodiment provides a production method for improving the drawing performance of steel for a 70kg grade gas shielded welding wire, which comprises the following steps:
spinning the blank to obtain a loose coil;
carrying out Stelmor cooling on the uncoiled coil to control the temperature of the uncoiled coil so as to obtain 70kg grade steel for the gas shielded welding wire;
the Steinmole cooling comprises entering a heat-insulating cover, wherein the entering temperature of the lap joint point is 480-500 ℃, and the entering temperature of the non-lap joint point is 430-450 ℃.
The specific process flow is as follows: heating furnace → rough rolling → flying shear cutting head → medium rolling → pre-finish rolling → high-speed finish rolling → water cooling → pinch, spinning → temperature control loose coil cooling → coil collection → rod coil inspection, the temperature control loose coil cooling includes: spinning after finishing rolling, and controlling the spinning temperature: 800 ℃; after spinning, uncovering the front 4 heat-preservation covers on a cooling line, opening fans at the corresponding positions of the 4 heat-preservation covers, controlling the opening degree of the fans to be 20%, controlling the lap joint point to enter the covers to be 500 ℃, controlling the non-lap joint point to enter the covers to be 450 ℃, closing all the heat-preservation covers after entering the covers, and closing all the fans; the roller way speed of the stelmor cooling line at the 1 section is 0.10m/s, and the roller way speed at the 2-12 sections is 0.1 lm/s. The metallographic structure of the example was tempered bainite as shown in fig. 5. The wire rod strength is shown in table 1.
Example 2
A production method for improving the drawing performance of steel for a 70 kg-grade gas shielded welding wire comprises the following chemical elements in percentage by mass: c: 0.10%, Si: 0.45%, Mn: 1.68%, P: 0.010%, S: 0.009%, Ni: 1.28%, Mo: 0.53 percent, and the balance being Fe.
The embodiment provides a production method for improving the drawing performance of steel for a 70kg grade gas shielded welding wire, which comprises the following steps:
spinning the blank to obtain a loose coil;
carrying out Stelmor cooling on the uncoiled coil to control the temperature of the uncoiled coil so as to obtain 70kg grade steel for the gas shielded welding wire;
the stelmor cooling comprises entering a heat-preserving cover, wherein the entering temperature of the overlap joint is 480-500 ℃, and the entering temperature of the non-overlap joint is 430-450 ℃.
The specific process flow is as follows: heating furnace of high wire factory → rough rolling → flying shear cutting head → medium rolling → pre-finish rolling → high speed finish rolling → water cooling → pinch, wire laying → temperature control loose coil cooling → coil collecting → rod coil inspection. The temperature control coil-spreading cooling process comprises the following steps: spinning after finishing rolling, and controlling the spinning temperature: 820 ℃; after spinning, uncovering the front 4 heat-preservation covers on a cooling line, opening fans at the corresponding positions of the 4 heat-preservation covers, controlling the opening degree of the fans to be 30%, controlling the lapping point to enter the cover at 490 ℃, controlling the non-lapping point to enter the cover at 440 ℃, closing all the heat-preservation covers after entering the cover, and closing all the fans; the roller speed of the 1 section of the stelmor cooling line is 0.10m/s, and the roller speed of the 2-12 sections of the stelmor cooling line is 0.11 m/s. The metallographic structure of this example was the same as that of example 1. The wire rod strength is shown in table 1.
Example 3
A production method for improving the drawing performance of steel for a 70 kg-grade gas shielded welding wire comprises the following chemical elements in percentage by mass: c: 0.09%, Si: 0.50%, Mn: 1.70%, P: 0.015%, S: 0.011%, Ni: 1.25%, Mo: 0.43 percent, and the balance of Fe.
The embodiment provides a production method for improving the drawing performance of steel for a 70kg grade gas shielded welding wire, which comprises the following steps:
spinning the blank to obtain a loose coil;
carrying out Stelmor cooling on the uncoiled coil to control the temperature of the uncoiled coil so as to obtain 70kg grade steel for the gas shielded welding wire;
the stelmor cooling comprises entering a heat-preserving cover, wherein the entering temperature of the overlap joint is 480-500 ℃, and the entering temperature of the non-overlap joint is 430-450 ℃.
The specific process flow is as follows: heating furnace of high wire factory → rough rolling → flying shear cutting head → medium rolling → pre-finish rolling → high speed finish rolling → water cooling → pinch, wire laying → temperature control loose coil cooling → coil collecting → rod coil inspection. The temperature-controlled coil-unwinding cooling process comprises the following steps: spinning after finishing rolling, and controlling the spinning temperature: 830 ℃; after spinning, uncovering the front 4 heat-preservation covers on a cooling line, opening fans at the corresponding positions of the 4 heat-preservation covers, wherein the opening degree of each fan is 50%, controlling the temperature of a lap joint cover at 480 ℃, controlling the temperature of a non-lap joint cover at 430 ℃, closing all the heat-preservation covers after covering, and closing all the fans; the roller speed of the 1 section of the stelmor cooling line is 0.10m/s, and the roller speed of the 2-12 sections of the stelmor cooling line is 0.11 m/s. The metallographic structure of this example was the same as that of example 1. The wire rod strength is shown in table 1.
Comparative example 1
In the comparative example, the traditional production process is adopted, spinning is carried out after finish rolling, and the steel wire immediately enters the heat-insulating cover, so that the austenite → bainite phase change process is completed at the lowest slow cooling speed in the heat-insulating cover. The traditional process comprises the following steps: and the spinning temperature is 850-880 ℃, all fans on the cooling line are closed, the temperature of the heat-insulating cover is 700-750 ℃ after the wires are fed into the cover, the wires are air-cooled on a roller way after being discharged from the cover, and then the wires are collected. The properties of the wire rod structure obtained by the original process are shown in table 1. The metallographic structure photograph is shown in figure 6. The metallographic structure of the wire rod is bainite, the strength reaches 880 and 980MPa, and the high strength of the wire rod needs to be annealed.
Performance detection
After the coil was taken off-line, the wire rods of the comparative examples and the example groups were tested, and the samples were randomly picked off the coil and tested for mechanical properties, with the results shown in tables 1 and 2 below.
Table 1 mechanical properties were tested on randomly intercepted coupons on coils of the example set.
Table 2. random pick specimens on the coils of comparative example 1 were tested for mechanical properties.
As can be seen from the table, the embodiment group controls the lap joint to enter the cover at 500 ℃ and 480 ℃, closes all the heat preservation covers after entering the cover, closes all the fans, reduces the strength of the obtained steel for the gas-shielded welding wire to 750MPa of 680 and 980MPa of tensile strength of the comparison example group, can directly draw, does not need annealing treatment in the subsequent drawing process, depends on the existing production line, breaks through the traditional welding wire slow cooling process scheme, solves the problem that a 70 kg-grade gas-shielded welding wire steel user can draw and wire only needs annealing treatment in advance, and greatly reduces the production cost of the user
It is noted that, in this document, relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The above description is merely illustrative of particular embodiments of the invention that enable those skilled in the art to understand or practice the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (9)
1. A production method for improving the drawing performance of steel for a 70 kg-grade gas shielded welding wire is characterized by comprising the following steps:
spinning the blank to obtain a loose coil;
carrying out Stelmor cooling on the uncoiled coil to control the temperature of the uncoiled coil so as to obtain 70kg grade steel for the gas shielded welding wire; wherein the step of Steinmo cooling comprises the step of entering a heat-preservation cover, the temperature of the heat-preservation cover entering the overlap joint is 480-500 ℃, and the temperature of the heat-preservation cover entering the non-overlap joint is 430-450 ℃.
2. The method according to claim 1, wherein the spinning temperature is 800-830 ℃.
3. The method according to claim 1, wherein the opening degree of the fan at the position corresponding to the heat-preserving cover is 20-50%, and the air volume of the fan is 40000-100000 m3/h。
4. The method according to claim 1, wherein the cooling rate in the heat-insulating cover is 0.2-0.3 ℃/s.
5. The method according to claim 1, wherein in the stelmor cooling, the velocity of the roller table is 0.10-0.13 m/s.
6. Method according to claim 5, wherein the roller table comprises at least 12 segments, wherein the speed of a first segment of the roller table is lower than the speed of the remaining segments of the roller table.
7. A grade 70kg gas shield welding wire steel prepared by the method of any one of claims 1 to 6, wherein the chemical composition of the grade 70kg gas shield welding wire steel comprises the following components in percentage by mass: c: 0.06-0.10%, Si: 0.40-0.60%, Mn: 1.60-1.80%, P is less than or equal to 0.015%, S: 0.008-0.012%, Ni: 1.20-1.40%, Mo: 0.40-0.60%, and the balance of iron and inevitable impurities.
8. The steel for a grade 70kg gas shielded welding wire according to claim 7, wherein the metallographic structure of the steel for a grade 70kg gas shielded welding wire is a bainite structure.
9. The steel for the grade 70kg gas shielded welding wire as defined in claim 1, wherein the tensile strength of the steel for the grade 70kg gas shielded welding wire is 680-750 Mpa.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102560253A (en) * | 2012-03-13 | 2012-07-11 | 南京钢铁股份有限公司 | Manufacturing method of high-quality cold heading steel with uniform structure property |
| CN105132804A (en) * | 2015-09-06 | 2015-12-09 | 南京钢铁股份有限公司 | Method for rolling vanadium-titanium welding steel hot-rolled wire rod |
| CN111690801A (en) * | 2020-05-25 | 2020-09-22 | 中天钢铁集团有限公司 | Production process of alloy tool steel wire rod for obtaining full bainite structure |
| WO2021214538A1 (en) * | 2020-04-20 | 2021-10-28 | Cmc Poland Sp. Z O.O. | Method of producing steel wire rod of round cross-section and steel wire rod of round cross-section |
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- 2022-02-08 CN CN202210119603.8A patent/CN114606366A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102560253A (en) * | 2012-03-13 | 2012-07-11 | 南京钢铁股份有限公司 | Manufacturing method of high-quality cold heading steel with uniform structure property |
| CN105132804A (en) * | 2015-09-06 | 2015-12-09 | 南京钢铁股份有限公司 | Method for rolling vanadium-titanium welding steel hot-rolled wire rod |
| WO2021214538A1 (en) * | 2020-04-20 | 2021-10-28 | Cmc Poland Sp. Z O.O. | Method of producing steel wire rod of round cross-section and steel wire rod of round cross-section |
| CN111690801A (en) * | 2020-05-25 | 2020-09-22 | 中天钢铁集团有限公司 | Production process of alloy tool steel wire rod for obtaining full bainite structure |
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