CN103343283A - Production method of steel S355NL for super-thick low-temperature wind towers - Google Patents
Production method of steel S355NL for super-thick low-temperature wind towers Download PDFInfo
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- CN103343283A CN103343283A CN 201310291217 CN201310291217A CN103343283A CN 103343283 A CN103343283 A CN 103343283A CN 201310291217 CN201310291217 CN 201310291217 CN 201310291217 A CN201310291217 A CN 201310291217A CN 103343283 A CN103343283 A CN 103343283A
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Abstract
The invention relates to the field of iron and steel products, and particularly relates to a production method of steel S355NL for super-thick low-temperature wind towers. The technological process of the production method comprises the following steps of: smelting, continuous casting, heating, phosphorous removal, controlled rolling, hot rectifying, stack slow-cooling, and fire cutting until finished products are prepared; the method is characterized in that three key points including smelting composition design, low-temperature controlled rolling and post-final-rolling cooling are controlled. The thickness of a continuous casting billet is 250-300 mm. Compared with the prior art, the method disclosed by the invention has the beneficial effects that through the reasonably controlling the proportion of each alloy element in the steel and the subsequent heating and rolling processes, filed practices prove that the mechanical properties and impact properties of the steel S355NL with a thickness of 80-100 mm can meet standard requirements, and a good effect is achieved; the method has the advantages of short production process, low production cost and suitability for mass production, and the like, and can be widely applicable to thick-plate manufacturers.
Description
Technical field
The present invention relates to the steel products field, relate in particular to the production method that the thick low-temperature wind tower of a kind of spy is used steel S355NL.
Background technology
S355NL belongs to the welded fine grained structural steel of Europe superscript scope, and the singularity of this steel grade is that the requirement steel still keep good impact property when-50 ℃ of low temperature, structural part such as wind-power tower under the environment that is mainly used in extremely trembling with fear.
In recent years along with the demand of international wind-powered electricity generation industry to 80 ~ 100mm special heavy plate S355NL, domestic each slab factory is also accelerating research and development.But because the harshness of this steel grade impact performance requriements and the restriction of each producer's state of the art have restricted the duration of this steel grade to the expansion of thickness aspect.
Domestic existing slab manufacturing enterprise produces the precedent of the special thick S355NL of 80 ~ 100mm, but all is to use the continuously cast bloom of 300 above thickness.At present, the related data record of using 250mm thickness continuously cast bloom to carry out the special thick S355NL production of 80 ~ 100mm is not also arranged both at home and abroad.
Summary of the invention
The object of the present invention is to provide the thick low-temperature wind tower of a kind of spy with the production method of steel S355NL, adopt 250mm thickness continuously cast bloom to produce, satisfy this steel grade to the standard-required of mechanical property and impact property, shorten Production Flow Chart, reduce production costs.
For achieving the above object, technical scheme of the present invention is:
The thick low-temperature wind tower of a kind of spy production method of steel S355NL, its technical process comprises that smelting, continuous casting, heating, dephosphorization, controlled rolling, control cooling, heat are rectified, stacking slow cooling, fire are cut to finished product, controlled at three key points: the control cooling after the design of smelting composition, low temperature rolling and the finish to gauge, it specifically controls as follows:
1) smelt the composition design: C 0.15 ~ 0.18%, Si 0.25 ~ 0.45%, Mn 1.4 ~ 1.8%, Nb 0.20 ~ 0.40%, V 0.30 ~ 0.50%, Ti 0.40 ~ 0.50%, Ni 0.20 ~ 0.40%, P≤0.02%, S≤0.004%, all the other are iron and inevitable trace impurity;
2) low temperature rolling: continuously cast bloom is heated to 1200 ~ 1280 ℃ at process furnace, makes the abundant solid solution of alloying element to austenite matrix; By the controlled rolling of two stages, the fs employing is depressed greatly, and each pass deformation control is 15 ~ 25%, and finishing temperature is controlled more than 950 ℃; Subordinate phase start rolling temperature control is controlled at 50%-60% at 900 ~ 940 ℃, 890 ~ 850 ℃ of finishing temperatures, deformation rate;
3) cooling of the control after the finish to gauge: after the rolling end, directly enter accelerated cooling device, speed with 15 ~ 20 ℃/S is cooled to 500 ~ 550 ℃, enter stacking slow cooling behind the heat rectification machine, the stacking temperature is not less than 400 ℃, time is not less than 16 hours, and the product microtexture that finally obtains is ferrite and pearlitic mixed structure.
The thickness of described continuously cast bloom is 250 ~ 300mm, and Production Flow Chart shortening, production cost are reduced.
This steel grade has added 0.25% ~ 0.45% Si, and one of purpose is to improve the hardening capacity of steel with Mn, makes steel obtain pearlitic ability and strengthens.The solid solubility of Si in ferrite is bigger simultaneously, and energy is reinforced ferrite significantly, and its solid solution strengthening effect is better than Mn, adds the toughness that certain Si can also improve steel in the non-hardened and tempered steel.
Mn main effect in steel is solution strengthening, improves intensity and hardening capacity.But the increase of Mn content will reduce the toughness of steel, and will be unfavorable to material welding performance simultaneously.Comprehensive above 2 points are set in 1.4% ~ 1.8% with the scope of Mn.
Ni significantly improves the toughness of steel, and especially low-temperature flexibility cooperates with elements such as Si, Mn simultaneously and can postpone perlitic transformation, makes the easier acquisition perlite of steel.
Nb, Ti, V are the most frequently used micro alloying elements, more than three kinds of elements the effect of crystal boundary is reduced successively.In steel, the effect of combined microalloying is greater than the summation that adds certain element separately.Nb, Ti, these three kinds of elements of V can precipitate in austenite or ferrite because solubleness is big and diffusivity is little in austenite, so in austenite precipitation than in ferrite slowly, deformation can be accelerated precipitation process.Usually, should make in austenite precipitation reduce to minimum, keep more alloying element and wait until and precipitate in ferrite in sosoloid, this can rely on alloying to increase the little solubleness of element in austenite of closing.
Because the price of Ti is minimum in Nb, V, three kinds of alloying elements of Ti, adopt the low Nb microalloying production cost of high Ti lower, both can reach the effect of refined crystalline strengthening, can reach the purpose that reduces cost again.Take all factors into consideration above various factors.With Nb, V, three kinds of alloying element scope controls of Ti in the reasonable scope.
Compared with prior art, the invention has the beneficial effects as follows:
By ratio and the follow-up heating rolling process of reasonably controlling each alloying constituent in the steel, through field practice, mechanical property and the impact property of 80 ~ 100mm thickness S355NL that the inventive method is produced all can satisfy standard-required, obtained good effect, and advantages such as this invention has, and Production Flow Chart is short, production cost is low, suitable production in enormous quantities can be widely used in each slab manufacturer.
Description of drawings
Fig. 1 is the metallographic structure figure of the embodiment of the invention one product.
Embodiment
The invention will be further described below in conjunction with embodiment:
Embodiment 1
The thick low-temperature wind tower of a kind of spy is with the production method of steel S355NL, and its technical process comprises that smelting, continuously cast bloom, heating, dephosphorization, controlled rolling, control cooling, heat are rectified, stacking slow cooling, fire are cut to finished product, and its concrete technology controlling and process is as follows:
1) smelt composition design (wt%): C:0.17%, Si:0.30%, Mn:1.60%, Nb:0.3%, V:0.40%, Ti:0.45%, Ni:0.30%, P≤0.01%, S≤0.005%, all the other are iron and inevitable trace impurity;
During smelting, molten steel earlier behind electrosmelting, is sent into the refining of LF refining furnace, and refining process strengthens making white slag, strengthens blowing stirrings that mix that molten steel and slag are advanced in the Ar shortness of breath, handles through VD, and S is controlled below 0.005%, carries out the Ca processing simultaneously, improves inclusion morphology;
2) casting: after the empty destruction of fidelity, casting continuously cast bloom in 1545 ~ 1550 ℃ of temperature ranges, thickness of strand is at 250mm;
3) heating considers that the complete solid solubility temperature of Nb (CN) is 1100 ~ 1200 ℃, for reducing resistance to deformation and guaranteeing the effect that subsequent control is rolling, billet heating temperature is determined at 1150 ~ 1250 ℃ simultaneously;
4) dephosphorization, high pressure water hydraulic pressure is controlled at 18-22Mpa, and a de-scaling gets final product the Ex-all scale on surface;
5) low temperature rolling: continuously cast bloom is heated to 1250 ℃ at process furnace, and mill product thickness is 80mm, and by the controlled rolling of two stages, the fs employing is depressed greatly, and each pass deformation control is 15 ~ 25%, and finishing temperature is controlled at 960 ℃.Subordinate phase start rolling temperature control is controlled 60% at 920 ℃, 870 ℃ of finishing temperatures, deformation rate;
6) cooling after the finish to gauge: after the rolling end, directly enter accelerated cooling device, be cooled to 550 ℃ with 18 ℃/S, enter stacking slow cooling behind the heat rectification machine, 420 ℃ of stacking temperature, 16 hours time, the product microtexture that finally obtains is the mixed structure of ferrite+pearlitic structure, sees Fig. 1;
7) flame cutting is to finished product.
Embodiment 2
The thick low-temperature wind tower of a kind of spy is with the production method of steel S355NL, and its technical process comprises that smelting, continuously cast bloom, heating, dephosphorization, controlled rolling, control cooling, heat are rectified, stacking slow cooling, fire are cut to finished product, and its concrete technology controlling and process is as follows:
1) smelt composition design (wt%): C:0.15%, Si:0.45%, Mn:1.40%, Nb:0.3%, V:0.40%, Ti:0.45%, Ni:0.30%, P≤0.01%, S≤0.003%, all the other are iron and inevitable trace impurity;
During smelting, molten steel behind electrosmelting, is sent into the refining of LF refining furnace earlier, sends into the refining of LF refining furnace, refining process strengthens making white slag, strengthens blowing the stirring that mixes that molten steel and slag are advanced in the Ar shortness of breath, handles through VD, S control below 0.003%, is carried out Ca simultaneously and handled, improve inclusion morphology;
2) casting: after the empty destruction of fidelity, casting continuously cast bloom in 1545 ~ 1550 ℃ of temperature ranges, thickness of strand is at 255mm;
3) heating considers that the complete solid solubility temperature of Nb (CN) is 1100 ~ 1200 ℃, for reducing resistance to deformation and guaranteeing the effect that subsequent control is rolling, billet heating temperature is determined at 1150 ~ 1250 ℃ simultaneously;
4) dephosphorization, high pressure water hydraulic pressure is controlled at 18 ~ 22Mpa, and a de-scaling gets final product the Ex-all scale on surface;
5) low temperature rolling: continuously cast bloom is heated to 1260 ℃ at process furnace, and mill product thickness is 90mm, and by the controlled rolling of two stages, the fs employing is depressed greatly, and each pass deformation control is 15 ~ 25%, and finishing temperature is controlled more than 960 ℃; Subordinate phase start rolling temperature control is controlled 55% at 940 ℃, 850 ℃ of finishing temperatures, deformation rate;
6) cooling after the finish to gauge: after the rolling end, directly enter accelerated cooling device, be cooled to 530 ℃ with 20 ℃/S, enter stacking slow cooling behind the heat rectification machine, 450 ℃ of stacking temperature, 17 hours time, the product microtexture that finally obtains is ferrite+pearlitic mixed structure;
7) flame cutting is to finished product.
Embodiment 3
The thick low-temperature wind tower of a kind of spy is with the production method of steel S355NL, and its technical process comprises that smelting, continuously cast bloom, heating, dephosphorization, controlled rolling, control cooling, heat are rectified, stacking slow cooling, fire are cut to finished product, and its concrete technology controlling and process is as follows:
1) smelt composition design (wt%): C:0.18%, Si:0.40%, Mn:1.80%, Nb:0.4%, V:0.30%, Ti:0.40%, Ni:0.40%, P≤0.01%, S≤0.003%, all the other are iron and inevitable trace impurity;
During smelting, molten steel earlier behind electrosmelting, is sent into the refining of LF refining furnace, and refining process strengthens making white slag, strengthens blowing stirrings that mix that molten steel and slag are advanced in the Ar shortness of breath, handles through VD, and S is controlled below 0.003%, carries out the Ca processing simultaneously, improves inclusion morphology.
2) casting: after the empty destruction of fidelity, casting continuously cast bloom in 1545 ~ 1550 ℃ of temperature ranges, thickness of strand is at 300mm;
3) heating considers that the complete solid solubility temperature of Nb (CN) is 1100 ~ 1200 ℃, for reducing resistance to deformation and guaranteeing the effect that subsequent control is rolling, billet heating temperature is determined at 1150 ~ 1250 ℃ simultaneously;
4) dephosphorization, high pressure water hydraulic pressure is controlled at 18 ~ 22Mpa, and a de-scaling can the Ex-all scale on surface.
5) low temperature rolling: continuously cast bloom is heated to 1280 ℃ at process furnace, and mill product thickness is 100mm, and by the controlled rolling of two stages, the fs employing is depressed greatly, and each pass deformation control is 15 ~ 25%, and finishing temperature is controlled more than 955 ℃; Subordinate phase start rolling temperature control is controlled 50% at 930 ℃, 860 ℃ of finishing temperatures, deformation rate;
6) cooling after the finish to gauge: after the rolling end, directly enter accelerated cooling device, be cooled to 520 ℃ with 15 ℃/S, enter stacking slow cooling behind the heat rectification machine, 400 ℃ of stacking temperature, 16 hours time, the product microtexture that finally obtains is ferrite+pearlitic mixed structure;
7) flame cutting is to finished product.
The product object performance that above-mentioned three embodiment produce is as shown in table 1 below:
Table 1
Claims (2)
1. the thick low-temperature wind tower of a spy is with the production method of steel S355NL, its technical process comprises that smelting, continuous casting, heating, dephosphorization, controlled rolling, control cooling, heat are rectified, stacking slow cooling, fire are cut to finished product, it is characterized in that, controlled at three key points: the control cooling after the design of smelting composition, low temperature rolling and the finish to gauge, it specifically controls as follows:
1) smelt the composition design: C 0.15 ~ 0.18%, Si 0.25 ~ 0.45%, Mn 1.4 ~ 1.8%, Nb 0.20 ~ 0.40%, V 0.30 ~ 0.50%, Ti 0.40 ~ 0.50%, Ni 0.20 ~ 0.40%, P≤0.02%, S≤0.004%, all the other are iron and inevitable trace impurity;
2) low temperature rolling: continuously cast bloom is heated to 1200 ~ 1280 ℃ at process furnace; By the controlled rolling of two stages, the fs employing is depressed greatly, and each pass deformation control is 15 ~ 25%, and finishing temperature is controlled more than 950 ℃; Subordinate phase start rolling temperature control is controlled at 50%-60% at 900 ~ 940 ℃, 890 ~ 850 ℃ of finishing temperatures, deformation rate;
3) cooling of the control after the finish to gauge: after the rolling end, directly enter accelerated cooling device, speed with 15 ~ 20 ℃/S is cooled to 500 ~ 550 ℃, enter stacking slow cooling behind the heat rectification machine, the stacking temperature is not less than 400 ℃, time is not less than 16 hours, and the product microtexture that finally obtains is ferrite and pearlitic mixed structure.
2. the thick low-temperature wind tower of a kind of spy according to claim 1 is characterized in that with the production method of steel S355NL the thickness of described continuously cast bloom is 250 ~ 300mm.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103934423A (en) * | 2014-04-03 | 2014-07-23 | 莱芜钢铁集团有限公司 | Method for producing continuous casting round billet of wind power tower cylinder flange steel |
| CN106180611A (en) * | 2016-07-08 | 2016-12-07 | 江苏联峰能源装备有限公司 | It is applicable to process the continuous cast round billets production technology of ring-like forging |
| CN115106493A (en) * | 2022-06-16 | 2022-09-27 | 山西太钢不锈钢股份有限公司 | Method for improving center density of S355NL steel continuous casting billet for wind power flange |
-
2013
- 2013-07-12 CN CN 201310291217 patent/CN103343283A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103934423A (en) * | 2014-04-03 | 2014-07-23 | 莱芜钢铁集团有限公司 | Method for producing continuous casting round billet of wind power tower cylinder flange steel |
| CN103934423B (en) * | 2014-04-03 | 2016-03-30 | 莱芜钢铁集团有限公司 | A kind of method of the continuous cast round billets for the production of wind-power tower flange steel |
| CN106180611A (en) * | 2016-07-08 | 2016-12-07 | 江苏联峰能源装备有限公司 | It is applicable to process the continuous cast round billets production technology of ring-like forging |
| CN115106493A (en) * | 2022-06-16 | 2022-09-27 | 山西太钢不锈钢股份有限公司 | Method for improving center density of S355NL steel continuous casting billet for wind power flange |
| CN115106493B (en) * | 2022-06-16 | 2024-03-01 | 山西太钢不锈钢股份有限公司 | Method for improving center density of S355NL steel continuous casting blank for wind power flange |
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