CN1718770A - Post rolling fast cooling-production technology of high strength ribbed reinforced bar - Google Patents
Post rolling fast cooling-production technology of high strength ribbed reinforced bar Download PDFInfo
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- CN1718770A CN1718770A CN 200510046823 CN200510046823A CN1718770A CN 1718770 A CN1718770 A CN 1718770A CN 200510046823 CN200510046823 CN 200510046823 CN 200510046823 A CN200510046823 A CN 200510046823A CN 1718770 A CN1718770 A CN 1718770A
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Abstract
An ultrahigh-speed cooling technology for the rolled high-strength ribbed steel bar includes hot rolling and afterheat treating. For said afterheat treating, the rolled steel bar is quickly cooled to 480-720 deg.C within 1 second to quickly convert its austenite structure to the ferrite/ pearlite structure with the grain fineness of class 11-12. It is suitable for rolling high-quality steel bar.
Description
Technical field
The invention belongs to by heat-treating the technical field that changes the concrete reinforcement physicals again after the distortion.
Background technology
The Steel Concrete hot rolled ribbed steel bar is one of rolling shapes of China's output maximum.By State Standard of the People's Republic of China's (abbreviation GB), its trade mark is made of the yield-point minimum value (MPa) of HRB and these trade mark steel.HRB is the first letter of hot rolled ribbed steel bar (Hot rolled Ribbed Bars) english abbreviation, total HRB335, HRB400 and three trades mark of HRB500.Because the development of modernization, market has reached more than 7,000 ten thousand tons to its ultimate production in 2004 to the demand sustainable growth of Ribbed Bar, is Japan and several times of U.S.'s output same period.Increasing rapidly of China's output of steel caused inadequate resource, and this causes cost of material to go up, and then causes the price of steel product fierceness to raise up again.The way that solves can only be that country in 2005 " the steel industry development policies " the 8th put into effect is pointed: require to put forth effort to improve the steel service efficiency, the development high strength ribbed reinforced bar then is one of the most effective way.
The common technology that China produces high strength ribbed reinforced bar at present is to adopt V, Nb and Ti to make Analysis of Trace Alloy Steel.Because output rapidly increases, also make V, critical shortage appears in the Nb resource provisioning, compares with 2002 in 2005, and the price of master alloys such as vanadium iron and ferro-niobium has risen 8-10 times, and is difficult to buy.From total reserves and the ultimate production of world wide V, if the high strength ribbed reinforced bar of China continues to adopt V microalloying technology, all supply falls short of demand for global V.Nb China also will rely on from external import, therefore as will making the development of the Iron And Steel Industry of China suffer from resource bottleneck with microalloying technology development high strength ribbed reinforced bar.
Abroad, particularly American-European each producer, immediate quenching technology is generally adopted in the production of its high strength ribbed reinforced bar.This technology is to utilize waste heat to quench-the self-tempering processing after the Ribbed Bar hot rolling, makes reinforcing bar obtain surface tempering martensite or tempered sorbite tissue; Simultaneously, reinforcing bar heart portion also since when quenching speed of cooling very fast, ferrite is less in the tissue, perlite is more, thereby the intensity of reinforcing bar is increased.And China user to the evaluation with the product performance of this explained hereafter is: the weldability variation of its steel, and the ratio (abbreviation strong flexor ratio) of tensile strength and yield-point is low, low-temperature impact toughness descends, and obviously its earthquake resisting performance is relatively poor for such reinforcing bar.China, Japan and Korea S are in together on the multiple area of earthquake, and national standard and Japan and Korea S. are close still, and be higher than American-European to the requirement of strong flexor ratio, thereby immediate quenching technology also is not suitable for promoting in China.
Summary of the invention
Consider the singularity that China's development high strength ribbed reinforced bar is produced, hope is on the basis of existing straight carbon steel and 20MnSi steel, control the microstructure in the steel, the performance that structure is produced product with raising by changing heat treatment mode, thus the target that realizes producing super hot rolled ribbed steel bar.
The present invention proposes a kind of post rolling fast cooling-production technology of high strength ribbed reinforced bar, comprise the Heat Treatment after reinforcing bar hot rolling and the hot rolling, it is characterized in that: adopt supper-fast cooling technology during Heat Treatment after hot rolling, with speed of cooling greater than 700 ℃/second, make reinforcing bar be chilled to 480～720 ℃ from 1020 ℃～1150 ℃ ends, allowing austenite crystal in the reinforcing bar, unlikely to grow up and be transformed into grain fineness number rapidly be 11～12 grades of (ASTM microcosmic grain size number) tiny ferrite/pearlitic structures.
The principle of producing high strength ribbed reinforced bar with ultra fast cooling technology of the present invention is: during reinforcing bar (bar) hot rolling, make wherein austenite structure bear repeatedly strong deformation at the recrystallize warm area through the high speed tandem rolling, thereby utilize operation of rolling dynamic recrystallization strengthening mechanism to form the very little austenite recrystallization crystal grain of uniform grain-size.The reinforcement that above-mentioned austenite is imposed two-forty is cooled off, and austenite is cooled to rapidly carry out " freezing " of hot rolling work hardening near the transformation temperature in very short time.Thereby the austenite crystal that has suppressed effectively before the phase transformation is grown up.Tiny austenite crystal changes the ferrite/pearlitic structure of crystal grain modest size under air cooling condition subsequently.
Key problem in technology of the present invention is:
(1) to lack cooling time.To the Ribbed Bar of the following specification of diameter of phi 22mm, cooling time should be less than 0.4 second; The Ribbed Bar of the above specification of Φ 22mm, cooling time should be less than 0.8 second.
(2) rate of cooling wants fast.Its cooling rate should be greater than 700 ℃/second.
(3) strict control final cooling temperature.When rolled piece during at cold bed, should guarantee near recrystallization temperature, avoid rebar surface to form the Q-tempering tissue.
Adopt method of the present invention can reach following several objects, that is: (1) is the hot rolled ribbed steel bar that raw material can roll out the GB HRB335 trade mark with the general carbon steel; (2) but be raw material hot rolling production GB HRB400 with the 20MnSi steel, day mark (JIS) SD390 and English mark (BSI) Gr460 trade mark hot rolled ribbed steel bar; (3) in 20MnSi or 20Mn steel, add micro-V, Nb or Ti, can roll out GB HRB500 trade mark hot rolled ribbed steel bar.
Use supper-fast cooling technology of the present invention to produce high strength ribbed reinforced bar, its technology has following advantage:
(1) keeps continuous mill high-speed rolling, the advantage of highly efficient and productive rate and the characteristics of small dimension splitting rolling.To rolling operation do not do to change, processing parameter do not give change, and the power of motor and the milling train intensity of existing rolling equipment are not had special requirement yet.
(2) adopt supper-fast cooling technology, reduced cooling time,, can solve the insufficient problem of cold bed area, improve output in the face of the production line of bar realistic situation of domestic actual output apparently higher than designed capacity.
(3) because supper-fast cooling has reduced the surface oxidation of reinforcing bar on cold bed, the more conventional continuous rolling process of the surface of reinforcing bar and rust resistance is significantly improved.Temperature when having reduced the rolled piece bundling, the product that its stress ageging is produced less than common process usually.
(4) can not add the trade mark and the every performance index that microalloy element can improve reinforcing bar, reduce production cost effectively.
(5) its total length of special use cooling line that adopts particular design is less than 13 meters, and facility investment is little.
In a word, applying of production high strength ribbed reinforced bar technology of the present invention has the characteristics of " four not two raisings ", and " four are not " is 1) need not transform primary device; 2) do not reduce operating efficiency; 3) not low temperature rolling; 4) without immediate quenching." two improve " is 1) raising output; 2) improve the quality of products.
Embodiment
Below in conjunction with specific embodiment content of the present invention is made further additional and explanation.
Embodiment 1: with the HRB335 reinforcing bar of normal carbon steel rolling Φ 14mm
The employing chemical ingredients is 0.20%C, 0.45%Si, and 0.75%Mn, the straight carbon steel of 0.030%P and 0.043%S is made raw material, and with 18 fully continuous type milling trains, wherein the roughing unit is 6,6 of middle milling train groups, finishing train is used 6, rolling 1 passage of every rolling mill.Blank is the 150mm square billet, 1080 ℃ of start rolling temperatures, and through rolling, rolled piece about 1050 ℃, adopts two splitting rollings in the temperature in finish rolling exit.
Rolled piece enters into water cooler subsequently and cools off, and water cooler is made up of 7 joints, and the joint number of adjusting the water cooler unlatching according to product specification is 3 joints.The roll speed of finisher is 15.0m/s, with 0.5 second moment by water cooler, rolled piece is about 720 ℃ in cooler outlet place temperature.Water cooler of the present invention has very high cooling power, and its rate of cooling realizes the supper-fast cooling of rolled piece greater than 700 ℃/s.
Rolled piece arrives cold bed, and temperature core is higher because surface temperature is relatively low, the surface occurs to return thermal phenomenon, and hot temperature is returned about 810 ℃ in the surface.Rolled piece moves on cold bed subsequently, and temperature reduces gradually, until the cool to room temperature state.
Every performance index to Ribbed Bar under room temperature state are tested, its unit elongation is 29%, yield strength is 405MPa, and tensile strength is 545MPa, and strong flexor ratio is 1.34, crooked its surperficial flawless of check, through the tissue check, the grain fineness number of its limit portion is 12.1 grades, and the grain fineness number of heart portion is 11.4 grades, crystal grain has obtained sufficient refinement, and metallographic structure is lamellar pearlite+ferrite.The result shows that every performance index of product satisfy the performance requriements of standard GB 1499-1998 " Steel Concrete hot rolled ribbed steel bar " to HR335 trade mark reinforcing bar comprehensively.
The HRB400 reinforcing bar of embodiment 2:20MnSi steel rolling Φ 25mm
Adopt the 20MnSi steel to make raw material, chemical composition of steel is 0.18～0.23%C, 0.45～0.65%Si, 1.2～1.58%Mn, P and S content＜0.045%.Adopt the fully continuous type milling train, use 14 altogether.Wherein the roughing unit is 6,6 of middle milling train groups, and finishing train is used 2, rolling 1 passage of every rolling mill.Blank is the 150mm square billet, 1100 ℃ of start rolling temperatures, through rolling, rolled piece in the temperature in finish rolling exit about 10.50 ℃.
Rolled piece enters into water cooler subsequently and cools off, and water cooler is made up of 7 joints, and the joint number of adjusting the water cooler unlatching according to product specification is 4 joints.The roll speed of finisher is 14.5m/s, with 0.8 second time by water cooler, rolled piece is about 650 ℃ in cooler outlet place temperature.Water cooler of the present invention has very high cooling power, and its rate of cooling realizes the supper-fast cooling of rolled piece greater than 800 ℃/s.
Rolled piece arrives cold bed, and temperature core is higher because surface temperature is relatively low, the surface occurs to return thermal phenomenon, and hot temperature is returned about 850 ℃ in the surface.Rolled piece moves on cold bed subsequently, and temperature reduces gradually, until the cool to room temperature state.
Every performance index to Ribbed Bar under room temperature state are tested, and its unit elongation is 22～27%, and yield strength is 430～480MPa, and tensile strength is 580～640MPa, and strong flexor ratio is 1.31～1.40, crooked its surperficial flawless of check.The result shows that every performance index of product satisfy the performance requriements of standard GB 1499-1998 " Steel Concrete hot rolled ribbed steel bar " to the reinforcing bar of the HRB400 trade mark comprehensively.
Embodiment 3: with the HRB500 reinforcing bar of 20MnSiV steel rolling Φ 16mm
The employing chemical ingredients is 0.22～0.24%C, 0.50～0.80%Si, 1.3～1.58%Mn, P and S content＜0.040%.0.05 the 20MnSiV of～0.06%V makes raw material, adopts the fully continuous type milling train, uses 16 altogether.Wherein the roughing unit is 6,6 of middle milling train groups, and finishing train is used 4, rolling 1 passage of every rolling mill.Blank is the 170mm square billet, 1070 ℃ of start rolling temperatures, through rolling, rolled piece in the temperature in finish rolling exit about 1050 ℃.
Rolled piece enters into water cooler subsequently and cools off, and water cooler is made up of 7 joints, and the joint number of adjusting the water cooler unlatching according to product specification is 4 joints.The roll speed of finisher is 14.0m/s, with 0.5 second time by water cooler, rolled piece is about 645 ℃ in cooler outlet place temperature.Water cooler of the present invention has very high cooling power, and its rate of cooling realizes the supper-fast cooling of rolled piece greater than 800 ℃/s.
Rolled piece arrives cold bed, and temperature core is higher because surface temperature is relatively low, the surface occurs to return thermal phenomenon, and hot temperature is returned about 826 ℃ in the surface.Rolled piece moves on cold bed subsequently, and temperature reduces gradually, until the cool to room temperature state.
Every performance index to Ribbed Bar under room temperature state are tested, and its unit elongation is 20～24%, and yield strength is 525～535MPa, and tensile strength is 645～660MPa, and strong flexor ratio is 1.28～1.35, crooked its surperficial flawless of check.The result shows that every performance index of product satisfy the performance requriements of standard GB 1499-1998 " Steel Concrete hot rolled ribbed steel bar " to HRB500 trade mark reinforcing bar comprehensively.
Embodiment 4: day mark (JIS) the outlet reinforcing bar SD390 that adopts 20MnSi steel rolling Φ 20mm
The employing chemical ingredients is 0.20%C, 0.55%Si, and 1.28%Mn, the 20MnS of P and S content＜0.040% makes raw material, adopts the fully continuous type milling train, uses 16 altogether.Wherein the roughing unit is 6,6 of middle milling train groups, and finishing train is used 4, rolling 1 passage of every rolling mill.Blank is the 150mm square billet, 1085 ℃ of start rolling temperatures, through rolling, rolled piece in the temperature in finish rolling exit about 1049 ℃.
Rolled piece enters into water cooler subsequently and cools off, and water cooler is made up of 7 joints, and the joint number of adjusting the water cooler unlatching according to product specification is 5 joints.The roll speed of finisher is 13.5m/s, with 0.5 second time by water cooler, rolled piece is about 685 ℃ in cooler outlet place temperature.Water cooler of the present invention has very high cooling power, and its rate of cooling realizes the supper-fast cooling of rolled piece greater than 800 ℃/s.
Rolled piece arrives cold bed, and temperature core is higher because surface temperature is relatively low, the surface occurs to return thermal phenomenon, and hot temperature is returned about 835 ℃ in the surface.Rolled piece moves on cold bed subsequently, and temperature reduces gradually, until the cool to room temperature state.
Every performance index to Ribbed Bar under room temperature state are tested, and its unit elongation is 25～31%, and yield strength is 435MPa, and tensile strength is 590MPa, and strong flexor ratio is 1.35, crooked its surperficial flawless of check.The result shows that every performance index of product satisfy the performance requriements of Nippon Standard JIS to SD390 outlet day marker tape rib steel muscle.
Embodiment 5: adopt the English of 20MnSi steel rolling Φ 18mm to mark mouthful (BSI) reinforcing bar Gr460
The employing chemical ingredients is 0.19～0.23%C, 0.48～0.62%Si, and 1.25～1.55%Mn, the 20MnSi of P and S content＜0.035% makes raw material, adopts the fully continuous type milling train, uses 16 altogether.Wherein the roughing unit is 6,6 of middle milling train groups, and finishing train is used 4, rolling 1 passage of every rolling mill.Blank is the 150mm square billet, 1100 ℃ of start rolling temperatures, through rolling, rolled piece in the temperature in finish rolling exit about 1040 ℃.
Rolled piece enters into water cooler subsequently and cools off, and water cooler is made up of 7 joints, and the joint number of adjusting the water cooler unlatching according to product specification is 5 joints.The roll speed of finisher is 13.2m/s, with 0.5 second time by water cooler, rolled piece is about 480 ℃ in cooler outlet place temperature.Water cooler of the present invention has very high cooling power, and its rate of cooling realizes the supper-fast cooling of rolled piece greater than 800 ℃/s.
Rolled piece arrives cold bed, and temperature core is higher because surface temperature is relatively low, the surface occurs to return thermal phenomenon, and hot temperature is returned about 634 ℃ in the surface.Rolled piece moves on cold bed subsequently, and temperature reduces gradually, until the cool to room temperature state.
Every performance index to Ribbed Bar under room temperature state are tested, its unit elongation is 22～25%, yield strength is 505～520MPa, tensile strength is 655～670MPa, strong flexor ratio is 1.28～1.35, the top layer is a tempered martensite, and heart portion is perlite+ferrite, crooked its surperficial flawless of check.The result shows that every performance index of product satisfy the corresponding requirement of the Gr460 trade mark among British Standard (BSI) BS4449.
Claims (3)
1, a kind of high strength ribbed reinforced bar rolls back ultra-high speed cooling-production technology, comprise the Heat Treatment after reinforcing bar hot rolling and the hot rolling, it is characterized in that: adopt supper-fast cooling technology during Heat Treatment after hot rolling, in 1 second, reinforcing bar is chilled to 480～720 ℃ eventually, make the austenite structure of reinforcing bar change the ferrite/pearlitic structure of 11～12 grades of grain fineness numbers rapidly into greater than 700 ℃/second rate of cooling.
2, roll back ultra-high speed cooling-production technology by the described high strength ribbed reinforced bar of claim 1, it is characterized in that the said reinforcing bar that makes is chilled to 480～720 ℃ in 1 second, should be the reinforcing bar of cooling time below Φ 22mm less than 0.4 second.
3, roll back ultra-high speed cooling-production technology by the described high strength ribbed reinforced bar of claim 1, it is characterized in that the said reinforcing bar that makes is chilled to 480～720 ℃ in 1 second, should be the reinforcing bar of cooling time more than Φ 22mm less than 0.8 second.
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| Application Number | Priority Date | Filing Date | Title |
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| CNB2005100468239A CN1327008C (en) | 2005-07-07 | 2005-07-07 | Post rolling fast cooling-production technology of high strength ribbed reinforced bar |
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| CNB2005100468239A CN1327008C (en) | 2005-07-07 | 2005-07-07 | Post rolling fast cooling-production technology of high strength ribbed reinforced bar |
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| CN1718770A true CN1718770A (en) | 2006-01-11 |
| CN1327008C CN1327008C (en) | 2007-07-18 |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102505805A (en) * | 2011-11-22 | 2012-06-20 | 江苏国建新材料股份有限公司 | Mixed reinforcement high-strength reinforced concrete component |
| CN103212575A (en) * | 2013-03-18 | 2013-07-24 | 甘肃酒钢集团宏兴钢铁股份有限公司 | Method for eliminating wave warp after through water cooling of hot rolled ribbed steel bar |
| CN103667871A (en) * | 2013-11-12 | 2014-03-26 | 山东西王特钢有限公司 | Processing technology for mantle fiber-free deformed steel bar |
| CN106048153A (en) * | 2016-07-20 | 2016-10-26 | 柳州科尔特锻造机械有限公司 | Rapid heat treatment technology for alloy steel |
| CN111378824A (en) * | 2020-05-14 | 2020-07-07 | 东北大学 | Hot processing technology of 51CrV4 hypoeutectoid fine blanking steel |
| WO2022003194A1 (en) * | 2020-07-03 | 2022-01-06 | Danieli & C. Officine Meccaniche S.P.A. | A process for manufacturing compact coils of ultra-fine grained, martensite-free steel bars |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| DE3431008C2 (en) * | 1984-08-23 | 1986-10-16 | Dyckerhoff & Widmann AG, 8000 München | Heat treatment of hot rolled bars or wires |
| JPS6179730A (en) * | 1984-09-28 | 1986-04-23 | Kawasaki Steel Corp | Manufacture of high-tension hot-rolled steel sheet having composite structure |
| CN85100647A (en) * | 1985-04-01 | 1986-07-30 | 鞍山钢铁公司 | The controlled cooling reinforcing bar that contains trace amount of titanium |
| JPH0754102A (en) * | 1993-08-10 | 1995-02-28 | Sumitomo Electric Ind Ltd | Pc steel wire or steel bar excellent in straightness and heading property |
| CN1045623C (en) * | 1996-06-20 | 1999-10-13 | 汤铁琴 | Bluing and low-carbon martensite heat treatment of high strength building steel bar |
| CN1108387C (en) * | 2000-07-06 | 2003-05-14 | 钢铁研究总院 | Method for producing low carbon steel twisted steel |
| JP4691855B2 (en) * | 2001-08-17 | 2011-06-01 | Ｊｆｅスチール株式会社 | High yield ratio type high-tensile hot-rolled steel sheet excellent in corrosion resistance, elongation and stretch flangeability, and method for producing the same |
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2005
- 2005-07-07 CN CNB2005100468239A patent/CN1327008C/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102505805A (en) * | 2011-11-22 | 2012-06-20 | 江苏国建新材料股份有限公司 | Mixed reinforcement high-strength reinforced concrete component |
| CN103212575A (en) * | 2013-03-18 | 2013-07-24 | 甘肃酒钢集团宏兴钢铁股份有限公司 | Method for eliminating wave warp after through water cooling of hot rolled ribbed steel bar |
| CN103212575B (en) * | 2013-03-18 | 2016-08-24 | 甘肃酒钢集团宏兴钢铁股份有限公司 | A kind of eliminate the method for wave bending after hot rolled ribbed bars Water cooling |
| CN103667871A (en) * | 2013-11-12 | 2014-03-26 | 山东西王特钢有限公司 | Processing technology for mantle fiber-free deformed steel bar |
| CN106048153A (en) * | 2016-07-20 | 2016-10-26 | 柳州科尔特锻造机械有限公司 | Rapid heat treatment technology for alloy steel |
| CN111378824A (en) * | 2020-05-14 | 2020-07-07 | 东北大学 | Hot processing technology of 51CrV4 hypoeutectoid fine blanking steel |
| WO2022003194A1 (en) * | 2020-07-03 | 2022-01-06 | Danieli & C. Officine Meccaniche S.P.A. | A process for manufacturing compact coils of ultra-fine grained, martensite-free steel bars |
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