CN102719641A - Method for reducing symmetrical open-grained structures of edges of low-carbon cold heading steel wire rods - Google Patents
Method for reducing symmetrical open-grained structures of edges of low-carbon cold heading steel wire rods Download PDFInfo
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- CN102719641A CN102719641A CN2012102022504A CN201210202250A CN102719641A CN 102719641 A CN102719641 A CN 102719641A CN 2012102022504 A CN2012102022504 A CN 2012102022504A CN 201210202250 A CN201210202250 A CN 201210202250A CN 102719641 A CN102719641 A CN 102719641A
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Abstract
The invention discloses a method for reducing symmetrical open-grained structures of edges of low-carbon cold heading steel wire rods and belongs to the technical field of steel rolling. The processing steps and control technical parameters include: controlling the finish rolling inlet temperature within the range of 900-950 DEG C so as to obtain small uniform austenite structures; controlling clamping force of pinch rolls to be within the range of 0.2-0.4MPa; and controlling the pinching temperature of the pinch rolls to be within the range of 860-900 DEG C. Slight deformation caused by the clamping force is reduced by controlling the pinching temperature of the pinch rolls so that great grains are generated by inducing grain boundary migration at local positions. The method has the advantages that the symmetrical open-grained structures of the hot rolled wire rod edges are obviously controlled, the symmetrical open-grained structures of the hot rolled wire rod edges are remarkably reduced, and cold heading cracking caused by the symmetrical open-grained structures of the edges during cold heading is reduced.
Description
Technical field
The invention belongs to technical field of steel rolling; A kind of method that reduces low-carbon cold heading steel wire rod limit portion symmetry open grain structure particularly is provided; Being applied to high-speed wire factory and producing low-carbon cold heading steel gren rod, is the control techniques of the symmetrical open grain structure in a kind of gren rod surface.
Background technology
Low-carbon cold heading steel gren rod mainly is used for production standard spare, in deep-processing process, need carry out cold-heading.In the cold-heading deformation process, immediate set speed, the deformation quantity of wire rod are very big.In 1/4 cold upsetting test, the wire rod girth is expanded and is original 3 times, and the tensile stress on surface is maximum, the defective of having amplified steel surface.The wire rod surface imperfection is to cause cold upsetting rimose immediate cause.The wire rod surface imperfection be formed with two aspect reasons, the one, itself brings blank; The 2nd, in the operation of rolling, produce.Causing cold upsetting rimose problem of materials usually to pay close attention to more is surface imperfection such as the ears or side handles of a utensil, scuffing, folding, crackle and hairline, and Surface Edge portion symmetry open grain structure is less to the research of cold upsetting Effect on Performance.The symmetrical open grain structure that wire rod Surface Edge portion exists causes the ununiformity of section structure, not only reduce material homogeneous deformation ability, and nonplastic compatible deformation effect has increased the probability of cold heading cracking greatly.Therefore limit portion symmetry open grain structure also is one of reason that causes cold heading cracking.
More about low-carbon cold heading steel open grain structure kind, wire rod limit portion symmetry open grain structure, nearly surperficial open grain structure, the local open grain structure in wire rod center and mixed grain structure.Outside the flash trimming portion symmetry open grain structure, local open grain structure in wire rod center and mixed grain structure often are attended by Widmannstatten structure, are exactly surperficial Widmannstatten structure in other words.Study morely about coarse-grain and Widmannstatten structure scientific research personnel, Ai Xinghui etc. propose the rate of cooling after the control wire rod is weaved silk in " fracture analysis of SWRCH22A cold heading steel wire drawing ", reduce the probability that Widmannstatten structure occurs; Liao Linlin conducts in-depth analysis to open grain structure in " exploitation of cold heading steel SWRCH22A rolling technology ", proposes to suppress through optimization process furnace technology, rolling technology, cooling control technology the method for surperficial coarse-grain and Widmannstatten structure.But do not see any report as yet about low-carbon cold heading steel limit portion symmetry open grain structure.
Summary of the invention
The object of the present invention is to provide a kind of method that reduces low-carbon cold heading steel wire rod limit portion symmetry open grain structure, solved the unmanageable problem of low-carbon cold heading steel gren rod limit portion symmetry open grain structure.Be used for the control of the symmetrical open grain structure in low-carbon cold heading steel gren rod surface.Control gren rod Surface Edge portion symmetry open grain structure through controlling in the high line production process pinch roll holding force and clamping temperature.Be suitable for optimizing and revising of high-speed wire factory production technique; On the basis of having analysed in depth the limit portion symmetry open grain structure origin cause of formation; Each process procedure of gren rod controlled rolling and controlled cooling process is proposed concrete quantified controlling, be suitable for the optimization that present high line factory produces low-carbon cold heading steel wire rod production technique.The technical parameter of process step and control is:
1, finish rolling temperature in is controlled in 900～950 ℃ of scopes, obtains the tiny and uniform austenite structure.
Final rolling temperature is that controlling board bar deformation austenite structure is crucial uniformly, if temperature is too high, causes thick austenite crystal, is easy to generate other type open grain structures such as big area coarse-grain and Widmannstatten structure in the process of cooling after rolling; If temperature is too low, occur between the part recrystallization zone rollingly, be easy to form mixed grain structure.Have only the control final rolling temperature 900～950 ℃ of temperature ranges, just can obtain comparatively evenly tiny deformation austenite structure.
2, the pinch roll holding force is controlled in 0.2～0.4MPa scope, obtains less clamping plane as far as possible.
The effect of pinch roll in the high line production process: the one, carry, guide rolled piece to get into Laying head smoothly; The 2nd, according to rolling the speed and the variation of product specification, control rolled piece portion's travelling speed end to end, spue the smoothly coil of uniformity of auxiliary Laying head; The 3rd, pinch roll cooperates reducing sizing mill and Laying head to carry out speed setting together, keeps omnidistance tension control, is the key equipment that guarantees production direct motion and Laying head works better.At present the high-speed wire factory pinch roll adopts the afterbody method of clamping more, and the setting of holding force wants suitably guarantee effective clamping rolled piece, and the too small meeting of holding force causes contact surface to skid and has an accident, and crosses conference and makes wire surface produce impression to influence surface quality even break.
3, after the finish rolling, adopt suitable water-cooling process, laying temperature is controlled at 860～900 ℃.
After the water-cooled effect first prevents the finish rolling temperature rise after the finish rolling, cause tissue abnormalities to grow up, and produce coarse-grain.It two is control laying temperatures (pinch roll pinches temperature), is controlled at 860～900 ℃, can well reduce limit portion symmetry open grain structure.Temperature is in 820～860 ℃ of scopes, and tangible red rust can appear in hot rolling rod bundle surface iron scale, influences mechanical phosphorus removal property;
4, pinch roll clamping temperature (laying temperature) is controlled in 860～900 ℃ of scopes.
Pinch roll pinches in the process at afterbody, and it is inevitable that symmetrical facet appears in the gren rod surface.Gren rod can produce less deformation quantity in the process of pinching, if it is higher to pinch temperature, interval at the comparatively high temps in non-recrystallization district, most crystal grain holds its shape constant, produces and replys.But the huge crystal grain of local appearance.Owing to give slight distortion replying the district, bring out crystal boundary in the local area and move and produce huge crystal grain.If it is lower to pinch temperature, small distortion is in the low-temperature range of non-recrystallization, and crystal grain only is elongated, and recrystallize does not take place and crystal boundary moves.Pinch roll pinches temperature (laying temperature) and only is controlled in 860～900 ℃ of scopes, could reduce limit portion symmetry open grain structure.The field control pinch roll pinches the humid test result and shows that low-carbon cold heading steel SWRCH22A gren rod pinches at 980 ℃, and wire rod limit portion symmetry open grain structure radially extends to heart location; To pinch temperature when reducing to 920 ℃, limit portion symmetry open grain structure significantly reduces; To pinch temperature when further reducing to 850 ℃, limit portion symmetry open grain structure reduces significantly, only exists in local very small amount.Under 980 ℃, 920 ℃ and 850 ℃ of temperature, pinch wire rod limit portion symmetry open grain structure and see Fig. 2, Fig. 3, Fig. 4 respectively.
The invention has the advantages that gren rod limit portion symmetry open grain structure has obtained obvious control, significantly reduced gren rod limit portion symmetry open grain structure, reduced the cold heading cracking that in the cold-heading process, causes owing to limit portion symmetry open grain structure.
Description of drawings
Fig. 1 for low-carbon cold heading steel SWRCH22A gren rod when pinching for 920 ℃, form the symmetry open grain structure macro morphology figure of limit portion.
Fig. 2 for low-carbon cold heading steel SWRCH22A gren rod when pinching for 980 ℃, form the symmetry open grain structure microscopic appearance figure of limit portion.
Fig. 3 for low-carbon cold heading steel SWRCH22A gren rod when pinching for 920 ℃, form limit portion symmetry open grain structure microcosmic microgram.
Fig. 4 for low-carbon cold heading steel SWRCH22A gren rod when pinching for 850 ℃, form limit portion symmetry open grain structure microcosmic microgram.
The specific embodiment mode
The present invention is at Shoudu Iron and Steel Co one wire rod 160mm
2Be applied in the production Φ 6.5mm SWRCH22A wire rod, obviously reduced gren rod limit portion symmetry open grain structure.
1. finish rolling temperature in is controlled at 920 ℃;
2. 1,2,4 and No. 5 water-cooled case after the unlatching finish rolling, laying temperature is controlled at 870 ℃;
3. the pinch roll holding force is controlled at 0.4MPa;
4. pinch roll clamping temperature is controlled at 870 ℃.
Claims (1)
1. method that reduces low-carbon cold heading steel wire rod limit portion symmetry open grain structure is characterized in that the technical parameter of process step and control is:
(1) finish rolling temperature in is controlled in 900～950 ℃ of scopes, obtains the tiny and uniform austenite structure;
(2) the pinch roll holding force is controlled in 0.2～0.4MPa scope;
(3) pinch roll clamping temperature is controlled in 860～900 ℃ of scopes.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012102022504A CN102719641A (en) | 2012-06-15 | 2012-06-15 | Method for reducing symmetrical open-grained structures of edges of low-carbon cold heading steel wire rods |
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| Application Number | Priority Date | Filing Date | Title |
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| CN2012102022504A CN102719641A (en) | 2012-06-15 | 2012-06-15 | Method for reducing symmetrical open-grained structures of edges of low-carbon cold heading steel wire rods |
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| CN102719641A true CN102719641A (en) | 2012-10-10 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103170510A (en) * | 2013-02-26 | 2013-06-26 | 首钢总公司 | Hot rolling method for controlling yield ratio of low-carbon cold forging steel |
| CN105032949A (en) * | 2015-07-09 | 2015-11-11 | 首钢总公司 | Clamping method for controlling circle forms of tails of high-speed wire rods |
| CN115216606A (en) * | 2022-06-15 | 2022-10-21 | 首钢集团有限公司 | Method for controlling cold deformation capacity of medium-carbon alloy cold forging steel |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1702183A (en) * | 2005-02-16 | 2005-11-30 | 安阳钢铁集团有限责任公司 | Ultra-fine grain hot-rolled steel coil with ribs and method for manufacturing the same |
| CN1745918A (en) * | 2004-09-07 | 2006-03-15 | 安阳钢铁集团有限责任公司 | Production of ultra-fine crystal hot-rolled ribbed reinforcing rob |
-
2012
- 2012-06-15 CN CN2012102022504A patent/CN102719641A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1745918A (en) * | 2004-09-07 | 2006-03-15 | 安阳钢铁集团有限责任公司 | Production of ultra-fine crystal hot-rolled ribbed reinforcing rob |
| CN1702183A (en) * | 2005-02-16 | 2005-11-30 | 安阳钢铁集团有限责任公司 | Ultra-fine grain hot-rolled steel coil with ribs and method for manufacturing the same |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103170510A (en) * | 2013-02-26 | 2013-06-26 | 首钢总公司 | Hot rolling method for controlling yield ratio of low-carbon cold forging steel |
| CN103170510B (en) * | 2013-02-26 | 2015-05-27 | 首钢总公司 | Hot rolling method for controlling yield ratio of low-carbon cold forging steel |
| CN105032949A (en) * | 2015-07-09 | 2015-11-11 | 首钢总公司 | Clamping method for controlling circle forms of tails of high-speed wire rods |
| CN105032949B (en) * | 2015-07-09 | 2017-02-01 | 首钢总公司 | Clamping method for controlling circle forms of tails of high-speed wire rods |
| CN115216606A (en) * | 2022-06-15 | 2022-10-21 | 首钢集团有限公司 | Method for controlling cold deformation capacity of medium-carbon alloy cold forging steel |
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Application publication date: 20121010 |