CN115927968B - 400 MPa-level coating-free hot rolled wire rod, round bar and rolling process thereof - Google Patents
400 MPa-level coating-free hot rolled wire rod, round bar and rolling process thereof Download PDFInfo
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- 238000005096 rolling process Methods 0.000 title claims abstract description 30
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 41
- 239000010959 steel Substances 0.000 claims abstract description 41
- 229910052717 sulfur Inorganic materials 0.000 claims abstract description 15
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 14
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 11
- 239000000126 substance Substances 0.000 claims abstract description 10
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 9
- 239000012535 impurity Substances 0.000 claims abstract description 6
- 238000010438 heat treatment Methods 0.000 claims description 35
- 238000001816 cooling Methods 0.000 claims description 14
- 238000000034 method Methods 0.000 claims description 12
- 229910052802 copper Inorganic materials 0.000 claims description 8
- 238000004321 preservation Methods 0.000 claims description 8
- 229910052758 niobium Inorganic materials 0.000 claims description 6
- 229910052748 manganese Inorganic materials 0.000 claims description 5
- 229910052720 vanadium Inorganic materials 0.000 claims description 5
- 229910001566 austenite Inorganic materials 0.000 claims description 4
- 238000002791 soaking Methods 0.000 claims description 4
- 238000004513 sizing Methods 0.000 claims description 3
- 238000010583 slow cooling Methods 0.000 claims description 3
- 238000004886 process control Methods 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 abstract description 5
- 238000005482 strain hardening Methods 0.000 abstract description 5
- 229910000870 Weathering steel Inorganic materials 0.000 abstract description 4
- 238000013461 design Methods 0.000 abstract description 3
- 229910045601 alloy Inorganic materials 0.000 abstract 1
- 239000000956 alloy Substances 0.000 abstract 1
- 239000010949 copper Substances 0.000 description 13
- 230000007797 corrosion Effects 0.000 description 13
- 238000005260 corrosion Methods 0.000 description 13
- 239000011651 chromium Substances 0.000 description 12
- 230000000052 comparative effect Effects 0.000 description 9
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 8
- 239000011593 sulfur Substances 0.000 description 8
- 239000010955 niobium Substances 0.000 description 7
- 238000012545 processing Methods 0.000 description 7
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 239000011572 manganese Substances 0.000 description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 5
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 5
- 229910052799 carbon Inorganic materials 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 239000011574 phosphorus Substances 0.000 description 3
- 238000005728 strengthening Methods 0.000 description 3
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- 238000005275 alloying Methods 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 2
- 230000008520 organization Effects 0.000 description 2
- 238000007747 plating Methods 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 2
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 229910001563 bainite Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000010962 carbon steel Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000010622 cold drawing Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 230000002939 deleterious effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 229910000734 martensite Inorganic materials 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000005272 metallurgy Methods 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 229910000510 noble metal Inorganic materials 0.000 description 1
- 238000002161 passivation Methods 0.000 description 1
- 229910001562 pearlite Inorganic materials 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 230000036632 reaction speed Effects 0.000 description 1
- 238000009987 spinning Methods 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 230000002195 synergetic effect Effects 0.000 description 1
- 150000003568 thioethers Chemical class 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- 238000005491 wire drawing Methods 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
- B21B1/16—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling wire rods, bars, merchant bars, rounds wire or material of like small cross-section
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B3/00—Rolling materials of special alloys so far as the composition of the alloy requires or permits special rolling methods or sequences ; Rolling of aluminium, copper, zinc or other non-ferrous metals
- B21B3/02—Rolling special iron alloys, e.g. stainless steel
-
- 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
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/06—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires
-
- 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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/20—Ferrous alloys, e.g. steel alloys containing chromium with copper
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
The invention discloses a 400 MPa-level coating-free hot rolled wire rod and round bar, which comprises the following chemical components in percentage by mass: c:0.02 to 0.10wt percent of Si: < 0.25wt%, mn: less than 0.4wt%, P less than 0.03wt%, S less than 0.02wt%, cu:0.1 to 1.0 weight percent of Cr:1.0 to 4.5wt%, cr/Cu=5 to 11, and the balance of Fe and unavoidable impurities; microalloying is also performed, and the chemical components of the alloy comprise Nb in percentage by mass: 0.015 to 0.035wt percent, V:0.04 to 0.07wt%, nb/v=1/3 to 2/3; the invention provides a 400 MPa-level coating-free hot rolled wire rod, a round rod and a rolling process thereof, which meet the maintenance-free requirements of direct bare coating-free downstream users and full life cycle, and greatly reduce the production investment cost; in addition, the invention has excellent steel strength and toughness through reasonable component design and matching with a steel rolling process, can meet various cold working requirements of hot rolled wire rods and round bars, and greatly expands the application scene of weathering steel.
Description
Technical Field
The invention belongs to the technical field of metallurgy, and particularly relates to a 400 MPa-level hot rolled wire rod and round rod without plating and a rolling process thereof.
Background
With the promotion of 'double carbon' targets, weather resistant steel with coating free and long service life is becoming a development hot spot of current green steel products; at present, most of weathering steel produced at home and abroad is plate material, and because of the completely different deep processing flow and application scene of wire rods, round bars and plate material, the difference of product organization and performance requirements is large, and hot rolled wire rods and round steel for weathering steel structure with more continuous rolling passes, high organization performance requirements and large cold processing deformation are reported in China.
CN115110006a discloses a weather-resistant steel with high corrosion resistance and a preparation method, wherein the chemical composition and the mass percentage of the weather-resistant steel are ：C：0.05～0.12％,Si：0.20～0.60％,Mn：0.30～0.60％,P：0.07～0.15％,S：≤0.015％,Cu：0.25～0.55％,Ni：≤0.20％,Cr：0.30～0.60％,, the balance is Fe and unavoidable impurities, and the relative corrosion rate of atmospheric corrosion resistance is below 40% of Q345B. In order to ensure the corrosion resistance of steel, the invention adds certain weather-resistant elements such as P, cu, cr and the like into the steel, but the relative corrosion rate is less than 40 percent, the coating-free requirement cannot be met, the cold working performance of the steel is necessarily deteriorated due to the addition of P, and the invention is unfavorable for the deep processing of wire rods and round bars.
CN114959483a discloses a weather-resistant steel with moisture and heat resistance and high salinity for ocean atmospheric environment and a production method thereof, wherein the weather-resistant steel comprises ：C：0.02％～0.06％,Si：0.17％～0.37％,Mn：0.8％～1.2％,P：≤0.012％,S：≤0.005％,Cu：0.8％～1.2％,Cr：0.2％～0.4％,Ni：1.5％～2％,Mo：0.1％～0.25％,Ti：0.01％～0.03％,Sn：0.05％～0.2％, mass percent of Fe and unavoidable impurities. The invention ensures that the steel plate has excellent economical efficiency and corrosion resistance by adding a large amount of noble metal Ni and matching with a certain weather-proof element, but the invention has higher cost and is not suitable for cold working of wire rods and round bars, and is only a conventional weather-proof plate.
The wire rods and round bars are often subjected to deep processing (such as cold drawing, stranding, rolling and the like) with multiple working procedures, the application scene of the wire rods and round bars has a larger gap from the plate, the current plating-free weather-resistant steel is developed in the plate more mature, and no relevant report is found in the field of the wire rods and round bars. According to the requirements of the application scenes of the wire rods and the round bars, how to design a 400 MPa-level coating-free hot rolled wire rod, a round bar and a rolling process thereof from the comprehensive consideration of chemical components and rolling processes so as to meet the requirements of a plurality of industries on upgrading galvanized materials into coating-free weather-resistant materials, and the method becomes a technical problem to be solved urgently.
Disclosure of Invention
The invention aims to provide a 400 MPa-level coating-free weather-proof hot rolled wire rod, a round rod and a rolling process thereof, which have excellent toughness, cold heading property and weather resistance (the relative corrosion rate is less than or equal to 25%), can meet the requirements of deep drawing and cold heading processing, and can meet the requirements of coating-free bare use for more than 25 years.
In order to achieve the above purpose, the following technical scheme is adopted:
a400 MPa-level coating-free hot rolled wire rod and round rod comprise the following chemical components in percentage by mass:
C:0.02 to 0.10wt percent of Si: < 0.25wt%, mn: less than 0.4wt%, P less than 0.03wt%, S less than 0.02wt%, cu:0.1 to 1.0 weight percent of Cr:1.0 to 4.5wt%, cr/Cu=5 to 11, and the balance of Fe and unavoidable impurities.
According to the scheme, C:0.04 to 0.08 weight percent of Si: < 0.25wt%, mn: less than 0.4wt%, P less than 0.03wt%, S less than 0.02wt%, cu:0.3 to 0.7 weight percent of Cr:2.0 to 3.0wt%, cr/cu=6 to 10, and the balance being Fe and unavoidable impurities.
According to the scheme, the microalloying is carried out, and the chemical components of the microalloying also comprise Nb in percentage by mass: 0.015 to 0.035wt percent, V:0.04 to 0.07wt% Nb/v=1/3 to 2/3.
The rolling process of the 400 MPa-level coating-free hot rolled wire rod and round bar comprises the following steps of:
Heating a steel billet; comprises a preheating section, a heating section and a soaking section;
rolling; adopting low-temperature controlled rolling, wherein the whole process adopts austenite unrecrystallized rolling;
Cooling control is performed; cooling the wire rod by adopting a stelmor process control; the round bar is insulated and slowly cooled by an upper cooling bed.
According to the scheme, in the billet heating process, the billet is a small square billet or a rectangular billet, and the section (140-220 mm) is x (140-220 mm); heating temperature in the preheating section is less than or equal to 600 ℃ and heating time is 15-20 min; the heating section is divided into a heating section 1 and a heating section 2, wherein the heating temperature of the heating section 1 is 600-1000 ℃, the heating time is 10-15 min, the heating temperature of the heating section 2 is 1000-1200 ℃, and the heating time is 20-30 min; the heating temperature of the soaking section is 1150-1200 ℃ and the heating time is 20-30 min.
According to the scheme, the finish rolling temperature in the rolling process is 830+/-10 ℃, the reduced sizing temperature is 840+/-10 ℃, and the finish rolling temperature is 850+/-10 ℃.
According to the scheme, in the cooling control process, the wire rod is cooled by adopting a Steyr process, the speed of a 0# roller way is 0.2-1 m/s, and the speed of the rest 8 groups of roller ways is improved by 3% relative to that of the former group of roller ways (extremely bad); the air quantity of the 13 groups of fans is 210000m 3/h, the 1# fan to the 2# fan is opened by 5% -25%, the heat preservation cover is opened, the temperature of the outlet 2# fan is 700+/-20 ℃, the 3# fan to the 13# fan is fully closed, and the heat preservation cover is closed, and the temperature of the outlet 13# fan is more than 350 ℃.
According to the scheme, in the cooling control process, the temperature of a cooling bed on a round bar is more than 850 ℃, a heat preservation cover is adopted for slow cooling, and the temperature of a heat preservation cover is more than 600 ℃.
Compared with the prior art, the invention has the following beneficial effects:
The invention provides a 400 MPa-level coating-free hot rolled wire rod, a round rod and a rolling process thereof, which meet the maintenance-free requirements of direct bare coating-free downstream users and full life cycle, and greatly reduce the production investment cost; in addition, the invention has excellent steel strength and toughness through reasonable component design and matching with a steel rolling process, can meet various cold working requirements of hot rolled wire rods and round bars, and greatly expands the application scene of weathering steel.
Detailed Description
The following examples further illustrate the technical aspects of the present invention, but are not intended to limit the scope of the present invention.
In a specific embodiment, C: the carbon has the most remarkable influence on the strength and the plasticity of the wire rod, and as the carbon content increases, the strength of the wire rod is continuously improved, the plasticity is rapidly reduced, and the carbon content also influences the drawability of a final finished product. Comprehensively, the carbon content of the invention is 0.02 to 0.10 weight percent.
Si: the silicon element is favorable for corrosion resistance and can obviously improve the elastic limit of the steel wire after drawing, but too high Si content can increase the brittleness of ferrite and is unfavorable for cold heading. In general terms, the silicon content of the invention is < 0.25% by weight.
Mn: manganese and sulfur are combined to generate MnS so as to reduce the harm of sulfur, refine pearlite and improve the strength of the steel wire; however, mn tends to drift in the steel, which causes non-uniformity in structure and properties, and too high Mn content will increase production costs. Comprehensively considering that the manganese content is less than 0.4 weight percent.
P: phosphorus is one of the most effective alloying elements for improving the atmospheric corrosion resistance of steel, and can be uniformly dissolved in the steel, so that a compact protective film is formed on the surface of the steel, the inside of the steel is not corroded by the atmosphere, and the corrosion resistance is optimal when w (P) =0.08-0.15% in the steel; however, for industrial wire rods requiring deep cold working, phosphorus tends to be cold brittle, and has a great influence on steel quality, particularly cold workability, and strict control is required for this purpose. In comprehensive consideration, the phosphorus content P of the invention is less than 0.03 weight percent.
S: sulfur belongs to harmful elements in the steel, and is easy to generate thermal embrittlement, so that the steel wire drawing and heat treatment processing conditions are further deteriorated, and if the mass fraction of residual sulfur in the steel is reduced to 0.01%, the weather resistance of the carbon steel can be greatly improved. In general terms, the sulfur content S of the invention is less than 0.02 wt.%.
Cu: copper is an alloying addition element commonly used for producing corrosion-resistant steel materials, cu is a metal element with slower chemical reaction speed, and the strength of the steel can be improved by adding Cu, but if the Cu content is too high, the low-temperature toughness of the steel can be directly affected. Notably, the effect of copper on counteracting the deleterious effects of sulfur in steel is evident, and the effect is characterized by the higher sulfur content in steel and the more pronounced the relative effect of copper on reducing corrosion rate. This is because copper forms poorly soluble sulfides with sulfur. In general, the copper content of the invention is 0.1 to 1.0 wt.%.
Cr: chromium is a main element for improving the weather resistance of steel, and can form a compact oxide film on the surface of the steel, so that the passivation capability of the steel is improved, and the growth speed of a rust layer is reduced. However, chromium can greatly improve the hardenability of the steel, and excessive chromium can cause abnormal structures such as bainite, martensite and the like to be formed in the steel, which is disadvantageous to the cold workability of the steel. Considering comprehensively, the chromium content of the invention is 1.0 to 4.5 weight percent.
Cr/Cu: the invention has synergistic strengthening effect on the weather-resistant elements copper and chromium, and Cr/Cu=5-11 based on the most economic cost.
Nb, V: niobium and vanadium are common microalloy strengthening elements, can prevent austenite grains from growing, refine and reheat the austenite grains, improve uniformity of structure and performance, but excessive addition can obviously improve production cost, and the Nb and V composite microalloy strengthening effect is superior to that of single element. Comprehensively considering that the content of niobium and vanadium is respectively 0.015-0.035 wt percent and 0.04-0.07 wt percent, and Nb/V=1/3-2/3.
The chemical compositions of the examples and comparative examples of the present invention are shown in Table 1; the heating process parameters of each example and comparative example are shown in Table 2; the rolling process parameters of each example and comparative example are shown in Table 3; the process parameters for the cooling control of each example and comparative example are shown in Table 4. The test results (toughness, cold heading property, weather resistance) of each example and comparative example are shown in Table 5.
TABLE 1 chemical compositions
TABLE 2 heating process parameters
TABLE 3 Rolling Process parameters
| Project | Entering the finish rolling temperature, DEG C | Reducing the sizing temperature, DEG C | Spinning temperature, DEG C |
| Example 1 | 825 | 845 | 840 |
| Example 2 | 840 | 835 | 855 |
| Example 3 | 830 | 840 | 850 |
| Example 4 | 840 | 835 | 855 |
| Example 5 | 825 | 840 | 845 |
| Example 6 | 830 | 830 | 860 |
| Example 7 | 825 | 845 | 855 |
| Example 8 | 840 | 850 | 850 |
| Example 9 | 835 | 845 | 860 |
| Example 10 | 835 | 840 | 855 |
| Example 11 | 830 | 845 | 850 |
| Example 12 | 835 | 840 | 855 |
| Example 13 | 835 | 845 | 840 |
| Example 14 | 830 | 840 | 840 |
| Example 15 | 840 | 850 | 855 |
| Comparative example 1 | 910 | 910 | 900 |
| Comparative example 2 | 920 | 900 | 890 |
| Comparative example 3 | 930 | 920 | 910 |
Table 4 controlled cooling process parameters
TABLE 5 test effect
As can be seen from Table 5, the comparative steel grade can meet the requirement of 400MPa, but the cold heading is cracked and the relative corrosion rate is more than or equal to 60 percent, and the requirements of hot rolled wire rods, round bars deep processing and coating-free coating cannot be met; the 400 MPa-level hot rolled wire rod, the round rod and the rolling process thereof have excellent toughness, the strength reaches 400 MPa-level, the surface shrinkage is more than or equal to 70 percent, the relative corrosion rate is less than or equal to 25 percent, and the cold workability is excellent and the requirements of users on no plating and direct bare use can be met.
Claims (2)
1. A400 MPa-level coating-free hot rolled wire rod and round rod are characterized by comprising the following chemical components in percentage by mass:
C：0.02～0.08wt%、Si：＜0.25wt%、Mn：＜0.4wt%、P＜0.03wt%、S＜0.02wt%、Cu：0.1～1.0wt%、Cr：1.0～4.5wt%、Cr/Cu=5～11、Nb：0.015～0.035wt%、V：0.04～0.07wt%、Nb/V=1/3～2/3, The balance of Fe and unavoidable impurities;
The rolling process of the 400 MPa-level coating-free hot rolled wire rod and round bar comprises the following steps of:
Heating a steel billet; comprises a preheating section, a heating section and a soaking section; in the billet heating process, the billet is a small square billet or a rectangular billet, and the section (140-220 mm) is x (140-220 mm); heating temperature in the preheating section is less than or equal to 600 ℃ and heating time is 15-20 min; the heating section is divided into a heating section 1 and a heating section 2, wherein the heating temperature of the heating section 1 is 600-1000 ℃, the heating time is 10-15 min, the heating temperature of the heating section 2 is 1000-1200 ℃, and the heating time is 20-30 min; the heating temperature of the soaking section is 1150-1200 ℃ and the heating time is 20-30 min;
rolling; adopting low-temperature controlled rolling, wherein the whole process adopts austenite unrecrystallized rolling; the finish rolling temperature in the rolling process is 830+/-10 ℃, the reduced sizing temperature is 840+/-10 ℃, and the finish rolling temperature is 850+/-10 ℃;
Cooling control is performed; cooling the wire rod by adopting a stelmor process control; the round bar is subjected to heat preservation and slow cooling by adopting an upper cooling bed; in the controlled cooling process, the wire rod is cooled by adopting a Steyr process, the speed of a 0# roller way is 0.2-1 m/s, and the speed of the rest 8 groups of roller ways is improved by 3% relative to the speed of the former group of roller ways; the air quantity of the 13 groups of fans is 210000m 3/h, the 1# fan to the 2# fan is opened by 5% -25%, the heat preservation cover is opened, the temperature of the outlet 2# fan is 700+/-20 ℃, the 3# fan to the 13# fan is fully closed, and the temperature of the outlet 13# fan is higher than 350 ℃; in the controlled cooling process, the temperature of a cooling bed on a round bar is more than 850 ℃, a heat preservation cover is adopted for slow cooling, and the temperature of a heat preservation cover is more than 600 ℃.
2. The 400 MPa-level coating-free hot rolled wire rod and round rod as claimed in claim 1, wherein the chemical components are as follows in percentage by mass: c:0.04 to 0.08 weight percent of Si: < 0.25wt%, mn: less than 0.4wt%, P less than 0.03wt%, S less than 0.02wt%, cu:0.3 to 0.7 weight percent of Cr:2.0 to 3.0wt% and Cr/cu=6 to 10.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211658126.9A CN115927968B (en) | 2022-12-22 | 2022-12-22 | 400 MPa-level coating-free hot rolled wire rod, round bar and rolling process thereof |
| PCT/CN2023/097478 WO2024130968A1 (en) | 2022-12-22 | 2023-05-31 | 400 mpa-grade coating-free hot-rolled wire rod and round rod, and rolling process therefor |
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| CN202211658126.9A CN115927968B (en) | 2022-12-22 | 2022-12-22 | 400 MPa-level coating-free hot rolled wire rod, round bar and rolling process thereof |
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| CN115927968B true CN115927968B (en) | 2024-05-14 |
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|---|---|---|---|---|
| KR20110076148A (en) * | 2009-12-29 | 2011-07-06 | 주식회사 포스코 | Hot rolled steel sheet having excellent corrosion resistance and impcat toughness and manufacturing method thereof |
| CN113025917A (en) * | 2021-02-03 | 2021-06-25 | 江阴兴澄合金材料有限公司 | Wire rod for low-strength high-plasticity annealing-free cold forging steel and manufacturing method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3506033B2 (en) * | 1999-03-09 | 2004-03-15 | 住友金属工業株式会社 | Method of manufacturing hot-rolled steel bars or wires |
| EP1281782B1 (en) * | 2000-04-04 | 2007-10-03 | Nippon Steel Corporation | Hot rolled wire or steel bar for machine structural use capable of dispensing with annealing, and method for producing the same |
| JP5194994B2 (en) * | 2008-04-25 | 2013-05-08 | 新日鐵住金株式会社 | Manufacturing method of welded structural steel with excellent high temperature strength |
| CN113186472B (en) * | 2021-01-15 | 2022-07-22 | 江苏省沙钢钢铁研究院有限公司 | Corrosion-resistant steel bar and production method thereof |
| CN115927968B (en) * | 2022-12-22 | 2024-05-14 | 武汉钢铁有限公司 | 400 MPa-level coating-free hot rolled wire rod, round bar and rolling process thereof |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20110076148A (en) * | 2009-12-29 | 2011-07-06 | 주식회사 포스코 | Hot rolled steel sheet having excellent corrosion resistance and impcat toughness and manufacturing method thereof |
| CN113025917A (en) * | 2021-02-03 | 2021-06-25 | 江阴兴澄合金材料有限公司 | Wire rod for low-strength high-plasticity annealing-free cold forging steel and manufacturing method thereof |
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| CN115927968A (en) | 2023-04-07 |
| WO2024130968A1 (en) | 2024-06-27 |
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