CN115927968A - 400 MPa-level coating-free hot-rolled wire rod and round rod and rolling process thereof - Google Patents
400 MPa-level coating-free hot-rolled wire rod and round rod and rolling process thereof Download PDFInfo
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- CN115927968A CN115927968A CN202211658126.9A CN202211658126A CN115927968A CN 115927968 A CN115927968 A CN 115927968A CN 202211658126 A CN202211658126 A CN 202211658126A CN 115927968 A CN115927968 A CN 115927968A
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- 238000005096 rolling process Methods 0.000 title claims abstract description 33
- 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
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 11
- 239000000126 substance Substances 0.000 claims abstract description 11
- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 8
- 239000012535 impurity Substances 0.000 claims abstract description 7
- 238000010438 heat treatment Methods 0.000 claims description 35
- 238000000034 method Methods 0.000 claims description 14
- 238000001816 cooling Methods 0.000 claims description 13
- 238000004321 preservation Methods 0.000 claims description 7
- 229910001566 austenite Inorganic materials 0.000 claims description 4
- 238000002791 soaking Methods 0.000 claims description 4
- 238000010583 slow cooling Methods 0.000 claims description 3
- 238000001953 recrystallisation Methods 0.000 claims description 2
- 238000012545 processing Methods 0.000 abstract description 11
- 238000004519 manufacturing process Methods 0.000 abstract description 5
- 238000013461 design Methods 0.000 abstract description 3
- 230000007797 corrosion Effects 0.000 description 13
- 238000005260 corrosion Methods 0.000 description 13
- 239000010949 copper Substances 0.000 description 12
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 9
- 230000000052 comparative effect Effects 0.000 description 9
- 239000011593 sulfur Substances 0.000 description 9
- 239000011651 chromium Substances 0.000 description 8
- 239000010955 niobium Substances 0.000 description 7
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 6
- 229910000870 Weathering steel Inorganic materials 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 229910052758 niobium Inorganic materials 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
- 229910052804 chromium Inorganic materials 0.000 description 5
- 229910052802 copper Inorganic materials 0.000 description 5
- 230000009286 beneficial effect Effects 0.000 description 4
- 239000011572 manganese Substances 0.000 description 4
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 3
- 229910045601 alloy Inorganic materials 0.000 description 3
- 239000000956 alloy Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 3
- 239000011574 phosphorus Substances 0.000 description 3
- 238000005728 strengthening Methods 0.000 description 3
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 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
- 229910052748 manganese Inorganic materials 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 238000004513 sizing Methods 0.000 description 2
- 238000005482 strain hardening Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 229910001563 bainite Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000010962 carbon steel Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method 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
- 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
- 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
- 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 a round bar, which comprise the following chemical components in percentage by mass: c:0.02 to 0.10wt%, si: < 0.25wt%, mn: less than 0.4wt%, P less than 0.03wt%, S less than 0.02wt%, cu:0.1 to 1.0wt%, cr: 1.0-4.5 wt%, cr/Cu = 5-11, and the balance of Fe and inevitable impurities; and microalloying, wherein the chemical components of the microalloying steel further comprise Nb: 0.015-0.035 wt%, V:0.04 to 0.07wt%, nb/V =1/3 to 2/3; the invention provides a coating-free hot-rolled wire rod and a round bar of 400MPa and a rolling process thereof, which meet the requirements of coating-free direct exposure of downstream users and maintenance-free of a whole life cycle, and greatly reduce the production investment cost; in addition, the invention has excellent steel toughness through reasonable component design and matching with a steel rolling process, can meet various cold processing requirements of hot rolled wire rods and round bars, and greatly expands the application scene of weathering resistant steel.
Description
Technical Field
The invention belongs to the technical field of metallurgy, and particularly relates to a coating-free hot-rolled wire rod and a round rod of 400MPa and a rolling process thereof.
Background
With the advance of the aim of 'double carbon', the weathering steel with coating-free and long service life is becoming the development hotspot of current green steel products; at present, most of the weather-resistant steel produced at home and abroad is plates, due to completely different deep processing flows and application scenes of wire rods, round rods and plates, the difference of product structure and performance requirements is large, and hot rolled wire rods and round steel for weather-resistant steel structures with more continuous rolling passes, high structure performance requirements and large cold processing deformation are rarely reported at home.
CN115110006A discloses a weathering steel with high corrosion resistance and a preparation method thereof, the weathering steel comprises the following chemical components by mass percent: c:0.05 to 0.12%, si:0.20 to 0.60%, mn:0.30 to 0.60%, P:0.07 to 0.15%, S: less than or equal to 0.015 percent, cu:0.25 to 0.55%, ni: less than or equal to 0.20 percent, cr:0.30 to 0.60%, and the balance of Fe and inevitable impurities, wherein the relative corrosion rate of atmospheric corrosion resistance is 40% or less of that of Q345B. In order to ensure the corrosion resistance of steel, a certain amount of weather-resistant elements such as P, cu, cr and the like are added into the steel, but the relative corrosion rate is below 40 percent, so that the coating-free requirement cannot be met, and the cold working performance of the steel is inevitably deteriorated due to the addition of P, so that the steel is unfavorable for deep processing of wire rods and round bars.
CN114959483A discloses a weathering steel for moisture-heat-resistant high-salinity marine atmospheric environment and a production method thereof, wherein the weathering steel comprises the following components in percentage by mass: c:0.02% -0.06%, si:0.17% -0.37%, mn:0.8% -1.2%, P: less than or equal to 0.012 percent, S: less than or equal to 0.005 percent, cu:0.8% -1.2%, cr:0.2% -0.4%, ni:1.5% -2%, mo: 0.1-0.25%, ti:0.01 to 0.03 percent, sn:0.05 to 0.2 percent of the total weight of the alloy, and the balance of Fe and inevitable impurities. The invention ensures that the steel plate has excellent economy and corrosion resistance by adding a large amount of noble metal Ni and matching with certain weather-resistant elements, but the invention has higher cost and is not suitable for cold processing of wire rods and round bars, and is only a conventional weather-resistant plate.
The wire rod and the round bar are usually subjected to deep processing of a plurality of working procedures (such as cold drawing, stranding, rolling and the like), the application scene of the wire rod and the round bar is greatly different from the plate, the coating-free weathering steel is developed in the plate more mature at present, but no relevant report is found in the field of the wire rod and the round bar. According to the application scene requirements of the wire rod and the round bar, how to design the coating-free hot-rolled wire rod and the round bar with the 400MPa level and the rolling process thereof from comprehensive consideration of chemical components and the rolling process so as to meet the requirement of upgrading galvanized materials into coating-free weather-resistant materials in multiple industries, and the technical problem to be solved is urgent.
Disclosure of Invention
The invention aims to provide a 400 MPa-grade coating-free weather-resistant hot-rolled wire rod and a round rod and a rolling process thereof, which have excellent strength and 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 and over 25 years of bare use.
In order to achieve the purpose, the technical scheme is as follows:
a400 MPa-grade coating-free hot-rolled wire rod and round bar comprises the following chemical components in percentage by mass:
c:0.02 to 0.10wt%, si: < 0.25wt%, mn: less than 0.4wt%, P less than 0.03wt%, S less than 0.02wt%, cu:0.1 to 1.0wt%, cr:1.0 to 4.5wt%, cr/Cu =5 to 11, and the balance Fe and unavoidable impurities.
According to the scheme, C:0.04 to 0.08wt%, si: < 0.25wt%, mn: less than 0.4wt%, P less than 0.03wt%, S less than 0.02wt%, cu:0.3 to 0.7wt%, cr:2.0 to 3.0wt%, cr/Cu =6 to 10, and the balance Fe and inevitable 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%, V: 0.04-0.07 wt%, nb/V = 1/3-2/3.
The rolling process of the coating-free hot-rolled wire rod and the round rod with the pressure of 400MPa comprises the following steps:
heating a steel billet; comprises a preheating section, a heating section and a soaking section;
rolling; low-temperature controlled rolling is adopted, and austenite non-recrystallization rolling is adopted in the whole process;
controlling cold; cooling the wire rod by adopting a stelmor process; the round bar is subjected to heat preservation and slow cooling by an upper cooling bed.
According to the scheme, the billet in the billet heating process is a small square billet or a rectangular billet, and the section is 140-220 mm multiplied by 140-220 mm; the heating temperature of the preheating section is less than or equal to 600 ℃, and the heating time is 15-20 min; the heating section is divided into a heating section 1 and a heating section 2, 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 sizing temperature is 840 +/-10 ℃ and the finishing temperature is 850 +/-10 ℃.
According to the scheme, in the controlled cooling process, the wire rod is cooled by adopting a stelmor 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 increased by 3 percent (extremely poor) relative to the speed of the former group of roller ways; the air volume of the 13 groups of fans is 210000m 3 And h, opening the No. 1-No. 2 fan by 5-25%, opening the heat preservation cover, ensuring the temperature of the No. 2 fan to be 700 +/-20 ℃, completely closing the No. 3-No. 13 fan, closing the heat preservation cover, and ensuring the temperature of the No. 13 fan to be more than 350 ℃.
According to the scheme, in the controlled cooling process, the temperature of the cooling bed on the round bar is more than 850 ℃, the round bar is slowly cooled by adopting a heat-insulating cover, and the temperature of the round bar out of the heat-insulating cover is more than 600 ℃.
Compared with the prior art, the invention has the following beneficial effects:
the invention provides a coating-free hot-rolled wire rod and a round bar of 400MPa and a rolling process thereof, which meet the requirements of direct coating-free direct exposure of downstream users and maintenance-free requirement of a whole life cycle, and greatly reduce the production investment cost; in addition, the invention has excellent steel toughness through reasonable component design and matching with a steel rolling process, can meet various cold processing requirements of hot rolled wire rods and round bars, and greatly expands the application scene of weathering resistant steel.
Detailed Description
The following examples further illustrate the technical solutions of the present invention, but should not be construed as limiting the scope of the present invention.
In a specific embodiment, C: the carbon has the most obvious influence on the strength and plasticity of the wire rod, the strength of the wire rod is continuously improved and the plasticity is rapidly reduced along with the increase of the carbon content, and the carbon content also influences the drawability of a final finished product. Comprehensively, the carbon content of the invention is 0.02-0.10 wt%.
Si: the silicon element is beneficial to corrosion resistance and can obviously improve the elastic limit of the drawn steel wire, but the overhigh content of the Si increases the brittleness of ferrite and is not beneficial to cold heading processing. Taken together, the silicon content of the invention is < 0.25wt%.
Mn: manganese is combined with sulfur to generate MnS, so that the harm of sulfur is reduced, pearlite can be refined, and the strength of the steel wire is improved; however, mn tends to segregate in steel, which causes non-uniformity of structure and properties, and too high Mn content also increases production cost. Comprehensively, the manganese content of the invention is less than 0.4wt%.
P: phosphorus is one of the most effective alloy elements for improving the atmospheric corrosion resistance of steel, can be uniformly dissolved in the steel, is beneficial to forming a compact protective film on the surface of the steel, so that the interior of the steel is not corroded by the atmosphere, and has the best corrosion resistance when w (P) =0.08% -0.15% in the steel generally; however, in the case of industrial wire rods requiring deep cold working, phosphorus is liable to cause cold embrittlement, which has a great influence on the quality of steel, particularly cold workability, and therefore, strict control is required. Comprehensively, the phosphorus content P of the invention is less than 0.03wt%.
S: the sulfur belongs to harmful elements in the steel, the sulfur is easy to generate hot brittleness, 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 percent, the weather resistance of the carbon steel can be greatly improved. Comprehensively, the sulfur content S of the invention is less than 0.02wt%.
Cu: copper is a common alloy additive element for producing corrosion-resistant steel materials, cu is a metal element with a low chemical reaction speed, the strength of steel can be improved by adding Cu, and if the content of Cu is too high, the low-temperature toughness of the steel can be directly influenced. It is worth noting that the effect of copper on counteracting the deleterious effects of sulfur in steel is significant, and its effect is characterized by the higher the sulfur content in steel, the more pronounced the relative effect of copper on reducing the corrosion rate. This is because copper forms insoluble sulfides with sulfur. Comprehensively, the copper content of the invention is 0.1-1.0 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, improve the passivation capability of the steel and reduce the growth speed of a rust layer. However, chromium greatly increases the hardenability of steel, and excessive chromium causes formation of abnormal structures such as bainite and martensite in steel, which is disadvantageous in cold workability of steel. Comprehensively, the chromium content of the invention is 1.0-4.5 wt%.
Cr/Cu: and the weather-resistant elements of copper and chromium have a synergistic strengthening effect, and the Cr/Cu = 5-11 based on the most economic cost.
Nb, V: niobium and vanadium are common microalloy strengthening elements, austenite grains can be prevented from growing, reheated austenite grains are refined, uniformity of structure and performance is improved, production cost is obviously improved by adding excessive niobium and vanadium, and the Nb and V composite microalloy strengthening effect is superior to that of a single element. Comprehensively, the contents of niobium and vanadium are respectively 0.015-0.035 wt% and 0.04-0.07 wt%, and Nb/V = 1/3-2/3.
The chemical compositions of the examples of the invention and the comparative examples are shown in Table 1; the heating process parameters of each example and comparative example are shown in Table 2; the process parameters of the rolling process of each example and comparative example are shown in Table 3; the cooling control process parameters for each example and comparative example are shown in table 4. The test effects (toughness, cold heading property, weather resistance) of each example and comparative example are shown in Table 5.
TABLE 1 chemical composition
TABLE 2 heating Process parameters
TABLE 3 Rolling Process parameters
| Item | The temperature of finish rolling is lowered | Reducing 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 results
As can be seen from Table 5, although the comparative steel grade can meet the requirement of 400MPa, the cold heading is cracked, the relative corrosion rate is more than or equal to 60 percent, and the requirements of hot-rolled wire rods, deep processing of round rods and coating-free coating cannot be met; the coating-free hot-rolled wire rod and round bar with the strength of 400MPa and the rolling process thereof have excellent strength and toughness, the surface shrinkage rate of the wire rod and round bar reaches more than or equal to 70 percent, the relative corrosion rate of the wire rod and round bar is less than or equal to 25 percent, the cold workability is excellent, and the coating-free and direct-naked requirements of users can be met.
Claims (8)
1. A400 MPa-grade coating-free hot-rolled wire rod and round bar are characterized by comprising the following chemical components in percentage by mass:
c:0.02 to 0.10wt%, si: < 0.25wt%, mn: less than 0.4wt%, P less than 0.03wt%, S less than 0.02wt%, cu:0.1 to 1.0wt%, cr:1.0 to 4.5wt%, cr/Cu =5 to 11, and the balance Fe and unavoidable impurities.
2. The coating-free hot-rolled wire rod and round rod with the strength of 400MPa according to claim 1, wherein the chemical components are as follows by mass percent: c:0.04 to 0.08wt%, si: < 0.25wt%, mn: less than 0.4wt%, P less than 0.03wt%, S less than 0.02wt%, cu:0.3 to 0.7wt%, cr:2.0 to 3.0wt%, cr/Cu =6 to 10, and the balance Fe and inevitable impurities.
3. The coating-free hot-rolled wire rod and round rod with the strength of 400MPa according to claim 1, wherein the coating-free hot-rolled wire rod and the round rod are microalloyed, and the chemical components of the coating-free hot-rolled wire rod and the round rod in percentage by mass further comprise Nb:0.015 to 0.035wt%, V: 0.04-0.07 wt%, nb/V = 1/3-2/3.
4. The rolling process of the 400 MPa-level coating-free hot rolled wire rod and round bar, which is disclosed by claim 1, is characterized by comprising the following steps of:
heating a steel billet; comprises a preheating section, a heating section and a soaking section;
rolling; low-temperature controlled rolling is adopted, and austenite non-recrystallization rolling is adopted in the whole process;
controlling cold; cooling the wire rod by adopting a stelmor process; the round bar is subjected to heat preservation and slow cooling by an upper cooling bed.
5. The rolling process of 400 MPa-level coating-free hot-rolled wire rods and round rods according to claim 4, wherein the billet in the billet heating process is a small square billet or a rectangular billet with a cross section of (140-220 mm) × (140-220 mm); the heating temperature of the preheating section is less than or equal to 600 ℃, and the heating time is 15-20 min; the heating section is divided into a heating section 1 and a heating section 2, 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.
6. The rolling process of 400 MPa-level coating-free hot-rolled wire rods and round bars according to claim 4, characterized in that the finish rolling temperature in the rolling process is 830 +/-10 ℃, the diameter reducing temperature is 840 +/-10 ℃ and the finish rolling temperature is 850 +/-10 ℃.
7. The rolling process of the 400 MPa-level coating-free hot rolled wire rod and the round bar according to claim 4, wherein in the controlled cooling process, the wire rod is cooled by a stelmor 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 increased by 3 percent (extremely poor) relative to the speed of the former group of roller ways; the air volume of the 13 groups of fans is 210000m 3 And h, opening the 1# to 2# fan by 5-25 percent, opening the heat preservation cover to ensure that the temperature of the 2# fan is 700 +/-20 ℃, completely closing the 3# to 13# fan and closing the heat preservation cover to ensure that the 13# fan is dischargedThe blower temperature is more than 350 ℃.
8. The rolling process of 400 MPa-grade coating-free hot-rolled wire rods and round bars according to claim 4, characterized in that in the controlled cooling process, the temperature of a cooling bed on the round bars is more than 850 ℃, a heat-preservation cover is adopted for slow cooling, and the temperature of the cooling cover is more than 600 ℃.
Priority Applications (2)
| 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 |
Applications Claiming Priority (1)
| 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 |
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| Publication Number | Publication Date |
|---|---|
| CN115927968A true CN115927968A (en) | 2023-04-07 |
| CN115927968B CN115927968B (en) | 2024-05-14 |
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|---|---|---|---|
| CN202211658126.9A Active CN115927968B (en) | 2022-12-22 | 2022-12-22 | 400 MPa-level coating-free hot rolled wire rod, round bar and rolling process thereof |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN115927968B (en) |
| WO (1) | WO2024130968A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024130968A1 (en) * | 2022-12-22 | 2024-06-27 | 武汉钢铁有限公司 | 400 mpa-grade coating-free hot-rolled wire rod and round rod, and rolling process therefor |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030098104A1 (en) * | 2000-04-04 | 2003-05-29 | Kiichiro Tsuchida | Hot rolled wire or steel bar for machine structural use capable of dispensing with annealing, and method for producing the same |
| 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 |
Family Cites Families (4)
| 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 |
| 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 |
| CN112375995B (en) * | 2021-01-15 | 2021-05-07 | 江苏省沙钢钢铁研究院有限公司 | 400 MPa-grade 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 |
-
2022
- 2022-12-22 CN CN202211658126.9A patent/CN115927968B/en active Active
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2023
- 2023-05-31 WO PCT/CN2023/097478 patent/WO2024130968A1/en unknown
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030098104A1 (en) * | 2000-04-04 | 2003-05-29 | Kiichiro Tsuchida | Hot rolled wire or steel bar for machine structural use capable of dispensing with annealing, and method for producing the same |
| 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 |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024130968A1 (en) * | 2022-12-22 | 2024-06-27 | 武汉钢铁有限公司 | 400 mpa-grade coating-free hot-rolled wire rod and round rod, and rolling process therefor |
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| Publication number | Publication date |
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| CN115927968B (en) | 2024-05-14 |
| WO2024130968A1 (en) | 2024-06-27 |
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