Background technology
The domestic and international research report of relevant wire rod controlled rolling technology is more, and especially the research done in this respect of the U.S., Japan is more, and has obtained a series of patent.At home and abroad, mostly present stage is to concentrate on a certain to the controlled rolling technology of wire rod studies, like zerolling, regulate roll gap, improve pass etc.As for increasing substantially the obdurability of steel, develop the kind that adapts to demands of different, improve steel product quality, reduce production costs, the peace steel has carried out the exploitation and the trial production of Φ 8-Φ 12mm super-steel wire rod on high-speed rod-rolling mill.Through the adjustment chemical composition, and adopt controlled rolling and control process for cooling, successfully developed the HRB400 ultra-fine grain reinforcing bar wire rod of ferrite grain size below 6 μ m, and produced in batches.Hangzhou Steel Company is through 950-980 ℃ of start rolling temperature, finishing temperature 820-860 ℃ of control and roll back retardance process for cooling, manufactured experimently 20Mn2 (%:0.19-0.24C, 1.50-1.70Mn) chain is with steel Φ 8mm and Φ 12mm wire rod; The grain size of steel is the 8-10 level; Yield strength is 620-650MPa, tensile strength 835-875MPa, percentage elongation 15%-18%; Hot rolling material hardness (HB) 175-195 satisfies the requirement of standard and use.Japan, the U.S. also disclose the Rolling Production technology of multiple wire rod, mainly are to the control of open rolling in the wire rod operation of rolling, finishing temperature and the control technology of cooling procedure.
But because it is more special to be all the chemical analysis of ultra-clean low-carbon low-silicon steel wire rod of wire rod, i.e. C, Si content lower (C≤0.10%, Si≤0.05%), and P, S content extremely low (≤0.10%) make that the sex change drag is little; And rolling specs is mainly the small dimension of Φ 6.5mm and Φ 5.5mm; Rate of deformation is high; Temperature rise is very fast in the operation of rolling, and the control of wire rod specification, surface quality control all have big difficulty, adopt traditional rolling technique can't guarantee product quality; In the operation of rolling, very easily produce the problems such as useless, folding, that specification control is bad of rolling.Because resistance of deformation is low, when rolling, rolled piece exists in the pass of milling train and overcharges full phenomenon; Promptly this steel is in pass after the stressed compressing; It is expanded greater than general steel grade to the non-stress direction, thereby causes rolled piece non-stress direction distortion super large in pass, is in the situation of being full of; Thereby cause the rolled piece blemish, cause percent defective high (percent defective is at least 2.5%).In addition, though the wire rod out-of-roundness of this traditional rolling mill practice production satisfies basic demand, be controlled at below the 0.46mm, along with the client more and more wants the requirement of ultra-clean low-carbon low-silicon steel wire rod, the control of its out-of-roundness is also hoped as much as possible little.
Summary of the invention
The objective of the invention is provides the ultra-clean low-carbon low-silicon steel wire rod controlled rolling process that a kind of technology is simple, easy and simple to handle, percent defective is low in order to solve the problems of the technologies described above.
Technical scheme of the present invention comprise with steel billet through roughing, in roll with finish rolling after weave silk, collect volume, check, warehouse-in again; Accomplish the operation of rolling; Said rolling heating-up temperature is 950-1000 ℃; Start rolling temperature is at 880-930 ℃, and said finish rolling comprises preparatory finish rolling and finish rolling, and the last 4 road roll gap of control finishing mill are followed successively by: 2.3-2.35mm, 1.42-1.47mm, 1.55-1.60mm, 1.1-1.15mm.
The last twice roll gap of control pre-finishing mill is followed successively by 3.45-3.5mm, 2.35-2.40mm.
Resistance of deformation and suitable the amplify roll gap of the present invention through suitably improving steel avoided the generation of blemish, reduces rolling waste product, improves wire rod specification precision.Adopt and reduce rolling heating and start rolling temperature, adjust the method for preparatory finish rolling, finishing groove (being roll gap), greatly improved the rolling quality of ultra-clean low-carbon low-silicon steel, obtained good effect.Heating and temperature control is at 950-1000 ℃, and start rolling temperature is controlled at 880-930 ℃, guarantee steel roughing, in roll the district and have the certain deformation drag, avoid roughing, in roll the district because the soft then fold defect that causes of steel; Because high speed wire rolling process deformation velocity is fast, be the intensification operation of rolling again, the temperature of steel raises once again in the finish rolling process; Resistance of deformation reduces, and is rolling by former pass, is prone to cause pass to cross and is full of; In the follow-up operation of rolling, produce fold defect, and influence the control of final rolling specs, suitably transfer big roll gap this moment; Can avoid pass to cross and be full of phenomenon, avoid defective to produce, and make specification control better.Therefore the roll gap of the part frame of part mm finishing mill unit is adjusted, the more former rules of part frame roll gap of pre-finishing mill group are transferred big 0.05~0.10mm; The more former rules of the roll gap of finishing mill are transferred big 0.10~0.15mm; The last two passage roll gap that are pre-finishing mill are followed successively by 3.45-3.5mm, 2.35-2.40mm, and the last 4 passage roll gap of finishing mill are followed successively by: 2.3-2.35mm, 1.42-1.47mm, 1.55-1.60mm, 1.1-1.15mm.Thereby effectively avoided preparatory finish rolling, finish rolling partly produce folding, roll useless phenomenon, and improved the specification control accuracy.Compare with original production process, adopt this technology after, the rolling percent defective of ultra-clean low-carbon low-silicon steel wire rod reduces to 0 by 2.5%, out-of-roundness drops to 0.32mm by 0.46mm.
Production method of the present invention has following advantage:
1; Employing is rolled temperature control and is cooperated interference controlled rolling technology, can avoid the appearance of waste product in the operation of rolling fully, significantly improves the ultra-clean low-carbon low-silicon steel wire rod quality; Percent defective reduces to 0 by 2.5%; Out-of-roundness by 0.46mm drop to 0.32mm, maximum allowance is dropped to below the 0.19mm by 0.32mm, has satisfied the requirement of client to the high-quality ultra-clean low-carbon low-silicon steel wire rod, is specially adapted to the ultra-clean low-carbon low-silicon steel wire rod that rolling specs is Φ 6.5mm and Φ 5.5mm.
2, need not to increase new equipment, and technological process is changed not quite, need not increase investment, can improve the problem that exists in the present ultra-clean low-carbon low-silicon steel wire rod production, produce high-quality product, be that enterprise creates economic benefit.Compare with the low-carbon low-silicon steel wire rod that former technology is produced, can improve lumber recovery 0.81%, by producing 100000 tons of calculating of low-carbon low-silicon steel wire rod per year, a year wound is imitated and can be reached 3,200,000 yuan.
2, technology of the present invention is not only applicable to the control technology of ultra-clean low-carbon low-silicon steel wire rod, also can be applied to other mild steel series products production.
The specific embodiment
The rolling situation of the ultra clean welding steel H08AT that produces with Wuhan Iron & Steel (Group) Corp. below is that example specifically describes process of the present invention.
Ultra clean welding steel H08AT main component is (percentage by weight): C≤0.10%, Si≤0.05%, Mn0.30~0.60%, P≤0.006%, S≤0.003%, and C, Si, P, S content are low, and rolling specs is Φ 6.5mm.
Comparative example: the former rolling mill practice of ultra clean welding steel H08AT wire rod.
1, the steel billet heating furnace of packing into is heated, the soaking zone temperature is controlled at 1020-1070 ℃.
2, tapping be rolled (amount to 27 passages, wherein the 1-11 passage be roughing with in roll, the 12-17 passage is preparatory finish rolling, 18-27 is finish rolling), actual start rolling temperature is 950-1020 ℃.
3, the pre-finishing mill roller gap does not adjust (like table 1) by the rolling schedule regulation.
4, the finishing mill roller gap does not adjust (like table 2) by the rolling schedule regulation.
5, rolling after through weaving silk, collect volume, warehouse-in is accomplished the operation of rolling.
Table 1 pre-finishing mill roller gap original program table
Table 2 finishing mill roller gap original program table
The rolling mill practice of the present invention of ultra clean welding steel H08AT wire rod.
Embodiment 1:
1, at first the steel billet heating furnace of packing into is heated, the soaking zone temperature is controlled at 950-970 ℃.
2, tapping is rolled, and actual start rolling temperature is 880-900 ℃.
3, the last twice roller gap of preparatory finish rolling is transferred big 0.1mm, promptly 16 passages are adjusted into 3.5mm, and 17 passages are adjusted into 2.4mm.
4, the last 4 road roller gaps of finishing mill are transferred big 0.15mm, adjusted roll gap such as table 3.
5, rolling after through weaving silk, collect volume, warehouse-in is accomplished the operation of rolling.
Table 3 finishing mill roller gap program list
Embodiment 2:
1, at first the steel billet heating furnace of packing into is heated, the soaking zone temperature is controlled at 960-980 ℃.
2, tapping is rolled, and actual start rolling temperature is 890-910 ℃.
3, with embodiment 1.
4, with embodiment 1.
5, rolling after through weaving silk, collect volume, warehouse-in is accomplished the operation of rolling.
Embodiment 3:
1, at first the steel billet heating furnace of packing into is heated, the soaking zone temperature is controlled at 980-1000 ℃.
2, tapping is rolled, and actual start rolling temperature is 910-930 ℃.
3, with embodiment 1.
4, with embodiment 1.
5, through weaving silk, collect volume, the warehouse-in completion operation of rolling.
Embodiment 4:
1, at first the steel billet heating furnace of packing into is heated, the soaking zone temperature is controlled at 950-970 ℃.
2, tapping is rolled, and actual start rolling temperature is 880-900 ℃.
3, the last twice roller gap of preparatory finish rolling is transferred big 0.05mm, promptly 16 passages are adjusted into 3.45mm, and 17 passages are adjusted into 2.35mm.
4, the last 4 road roller gaps of finishing mill are transferred big 0.10mm, adjusted roll gap such as table 4.
5, through weaving silk, collect volume, the warehouse-in completion operation of rolling.
Table 4 finishing mill roller gap program list
Embodiment 5:
1, at first the steel billet heating furnace of packing into is heated, the soaking zone temperature is controlled at 960-980 ℃.
2, tapping is rolled, and actual start rolling temperature is 890-910 ℃.
3, with example 4.
4, with example 4.
5, through weaving silk, collect volume, the warehouse-in completion operation of rolling.
Embodiment 6:
1, at first the steel billet heating furnace of packing into is heated, the soaking zone temperature is controlled at 980-1000 ℃.
2, tapping is rolled, and actual start rolling temperature is 910-930 ℃.
3, the last twice roller gap of preparatory finish rolling is transferred big 0.08mm, promptly 16 passages are adjusted into 3.48mm, and 17 passages are adjusted into 2.38mm.
4, the last 4 road roller gaps of finishing mill are transferred big 0.12mm, adjusted roll gap such as table 5.
5, through weaving silk, collect volume, the warehouse-in completion operation of rolling.
Table 5 finishing mill roller gap program list
Adopt the interference controlled rolling process as shown in table 6 with the product quality contrast situation that adopts former explained hereafter H08AT wire rod.
The product quality situation that table 6 interference controlled rolling process is produced