CN101463447B - Method for producing oriented silicon steel by heating low temperature casting blank - Google Patents

Abstract

The invention discloses a method for producing orientation silicon steel by heating low a temperature slab, which is characterized in that (1) based on the existing compositions, Mn/S ranges from 2.0-3.0 by adjusting the composition proportion; (2) the liquidus temperature of the orientation silicon of different compositions is exactly figured out by thermodynamics and dynamic model; the degree of superheat in the process of pouring is strictly controlled to be less than equal to 50 DEG C; (3) molten steel is treated by an electrical pulse in a tundish. The method has the advantages and effects that only composition proportion needs to be regulated and other alloy does not need to be added, thus avoiding the cost-push of the steel-making working procedures; when in pouring, the near-liquidus temperature can be adopted and the tundish is treated by using the electrical pulse treatment; the quality and size of the Mns solid solution is controlled in a casting blank, the produced products can obviously reduce the heating-up temperature and heating-up time of the slab, substantially reduces the manufacturing cost of the hot rolling working procedures, increases lumber recovery and production efficiency. And the electromagnetic performance can reach the global requirements.

Description

A kind of method of producing oriented silicon steel by heating low temperature casting blank

Technical field

The invention belongs to metallurgical technology field, especially relate to the production method of silicon steel, specifically is a kind of method of producing oriented silicon steel by heating low temperature casting blank.

Background technology

At present, the orientation silicon steel production technology flow process is generally: blast furnace ironmaking → converter smelting → external refining → continuous casting+electromagnetic agitation → strand spraying oxygen-proof film → heating and hot rolling → normalizing (Hi-B) → once cold rolling → intermediate annealing (GO) → secondary cold-rolling (GO) → decarburizing annealing and coating MgO interleaving agent → finished product high annealing → hot-leveling stretch and anneal and coating coating insulating film → rewinding packing

All the time, people generally believe, when producing common orientation silicon steel with conventional ingredient, Mn/S is an optimum value about 3.0～3.5, and its strand must heat that (GO is 1350 ℃～1370 ℃ through high temperature under this ratio; Hi-B is 1380 ℃～1400 ℃), make in the strand＞the thick MnS solid solution (mainly being present in the equiax crystal center of strand thickness of slab direction) of 1um, in the course of hot rolling again the small and dispersed shape MnS with≤50nm separate out, to guarantee that the secondary recrystallization development is fully and obtain high magnetic.But strand can cause following shortcoming through being higher than 1350 ℃ of heating: 1) because peroxidating makes the scaling loss amount increase (3.5%～6%), higher approximately 4 times than straight carbon steel heating scaling loss amount; 2) 2FeOSiO of Xing Chenging ₂Therefore the oxide layer fusing point only is 1205 ℃, adds at high temperature and pines for the oxide layer fusing and flow to furnace bottom, and on average heating the 4000t strand will molten slag removal, heats about 8000t will overhaul, and yields poorly, and it is poor to repair the stove working condition; 3) because strand grain coarsening and spread all over grain boundary oxidation, the hot rolling band easily produces the limit and splits, the lumber recovery reduction; 4) aluminium, silicon and carbon and oxidation are closed in the blank surface, and its content reduces, and product magnetic reduces and is inhomogeneous thereupon, and the dielectric film characteristic degenerates.So a lot of enterprises all adopt low slab heating temperature to produce the method for orientation silicon steel in research.Producing the more common method of GO steel at present is, by adding crystal boundary enriched element Sb or Sn, as inhibitors of primary grain growth; By adding some alloying element (as Cu, Se etc.), generate the inhibitor (as CuS or MnSe or CuSe) of low solid solubility temperature, the common orientation silicon steel slab heating temperature is reduced.Application number is 85100664; Patent name: the method that reduces the common orientation silicon steel slab heating temperature, this patent at silicon steel product be the GO steel, by adding crystal boundary enriched element Sb or Sn, as inhibitors of primary grain growth, and the Mn in the reduction steel, S, C content, the common orientation silicon steel slab heating temperature is reduced, but add alloy steel-making cost is increased, its cooling extent is also very little on the other hand.

Application number is 98800888; Name is called: the method for producing the preferable grain orientation electric steel plate with high magnetic flux density based on low temperature slab heating, this patent at silicon steel product be the Hi-B steel, in the method, suppressing the big inhibitor of primary recrystallization grain length forms after being cold-rolled to finished product thickness, thereby make the low-temperature heat slab become possibility, its weak point is: because the interior inhibitor of steel plate seldom, substantially can not suppress growing up of primary recrystallization crystal grain, the primary recrystallization crystallite dimension is mainly controlled by temperature and time, thereby decarburizing annealing and nitridation process narrow range, the control difficulty is big; On the other hand, because nitriding is carried out after decarburizing annealing, it is the oxide layer of main component with SiO2 that surface of steel plate has formed one deck, and the uniformity of nitriding and nitriding behavior are subject to the influence of surface oxide layer.

Summary of the invention

The present invention discloses a kind of production method of producing oriented silicon steel by heating low temperature casting blank, adopt electric pulse to add the near liquidus placing and control that MnS separates out quantity and size in the strand, slab heating temperature is significantly reduced, and satisfied production conforms with the orientation silicon steel of quality requirement.

Main technical schemes is as follows:

1) control Mn/S ratio

Chemical composition of the present invention is conventional common orientation silicon steel composition: the ratio of control Mn/S, and its Mn/S is 2.0～3.0;

2) accurately calculate the liquidus temperature of heterogeneity orientation silicon steel by the thermodynamics and kinetics model, the degree of superheat≤50 in the strict control casting process ℃;

3) molten steel carries out electric pulse at Zhong Bao and handles, by control impuls voltage and pulse frequency make molten steel composition evenly, the size of the poly-partially amount of control sulphur and MnS particle, increase in the strand proportion of equiaxed grain and control the equiax crystal size.

One of key technology of orientation silicon steel production is to control the amount of separating out of the inhibitor (MnS and AlN) that small and dispersed distributes in the course of hot rolling, and Mn/S ratio has remarkable influence to the MnS amount of separating out, best Mn/S ratio can make the solid solution capacity of MnS under a certain temperature significantly increase, can be implemented under the lower temperature obtain with high temperature under equivalent, even more MnS solid solution capacity, thereby can in course of hot rolling, separate out the favourable inhibitor MnS of more small and disperseds, can the first crystal grain of more effective inhibition grow up, promote the subgrain of high orientation to grow up, Mn/S ratio of the present invention is chosen as 2.0～3.0, temperature can drop to 1000～1300 ℃ when guaranteeing the slab heating, shorten to 100～240min heat time heating time, it is tiny in order to guarantee the MnS in the strand that nearly liquid phase cast and tundish apply electric pulse, thereby can and make in the steel MnS of the solid solution state that reaches capacity in certain heat time heating time in low heating-up temperature, MnS separates out with the small and dispersed shape of 50～100nm again in the course of hot rolling, to guarantee that the secondary recrystallization development is complete and to obtain high magnetic.

The present invention adopts conventional secondary cold-rolling method to produce orientation silicon steel.

Advantage of the present invention and effect are:

Only need be adjusted to distribution ratio, need not add all the other alloys, avoid the steel making working procedure cost to increase; Adopt near liquidus temperature and tundish to adopt electric pulse to handle during casting; The product of producing can obviously reduce slab heating temperature and heat time heating time, significantly reduces hot-rolled process production cost, raising lumber recovery and production efficiency electromagnetic performance and reaches the GB requirement.

The specific embodiment

Introducing several specific embodiments below respectively describes effect of the present invention.

1) control Mn/S ratio, its Mn/S=2.0～3.0

Table 1 becomes to be grouped into and Mn/S for comparative example of the present invention and embodiment's

Table 1 embodiment of the invention composition (percentage by weight %)

Embodiment

?C

?Si

Mn/S

?P

?Als

?N

Surplus

Comparative example 1

?0.041

?3.05

3.5

?0.009

?0.0065

?0.0050

All the other are Fe and unavoidable impurities

Comparative example 2

?0.045

?3.07

3.2

?0.009

?0.0083

?0.0055

All the other are Fe and unavoidable impurities

Embodiment 1

?0.043

?3.06

2.7

?0.009

?0.0075

?0.0053

All the other are Fe and unavoidable impurities

Embodiment 2

?0.043

?3.04

2.5

?0.009

?0.0078

?0.0055

All the other are Fe and unavoidable impurities

Embodiment 3

?0.041

?3.04

2.1

?0.009

?0.0077

?0.0056

All the other are Fe and unavoidable impurities

2) accurately calculate the liquidus temperature of heterogeneity orientation silicon steel by the thermodynamics and kinetics model, the degree of superheat≤50 in the strict control casting process ℃;

3) molten steel carries out the electric pulse processing at Zhong Bao, and the pulse frequency scope is 0.1Hz～1000Hz, and the pulse voltage scope is 10V～10000V.

Adopt the embodiment of above-mentioned explained hereafter its electromagnetic performance to be tested its result such as table 2:

Table 2 experiment material electromagnetic performance

Electromagnetic performance	Mn/S	Iron loss (P 1.7，W/kg)	Magnetic strength (B 800，T)
				Comparative example 1	3.5	1.42	1.785
Comparative example 2	3.2	1.41	1.798
				The embodiment of the invention 1	2.7	1.35	1.819
The embodiment of the invention 2	2.5	1.33	1.827
				The embodiment of the invention 3	2.1	1.34	1.820
GB/T2521-1996	-	1.40	1.78

GB requires material iron loss (P1.7) to be lower than 1.40W/kg and magnetic strength (B800) should be greater than 1.78T, and the present invention reaches the GB requirement fully.

The present invention by being adjusted to distribution ratio, adopting electric pulse and near liquidus placing and improving follow-up cold rolling and annealing process, makes slab under the condition of low-temperature heat on the basis of existing composition, has produced to meet the common orientation silicon steel that GB requires.

Claims (1)

1. the method for a producing oriented silicon steel by heating low temperature casting blank, chemical composition is conventional common orientation silicon steel composition, it is characterized in that: chemical composition is C 0.043% by weight percentage, Si 3.04%, Mn/S 2.5, and P 0.009%, Als0.0078%, N0.0055%, all the other are Fe and unavoidable impurities;

1) accurately calculates the liquidus temperature of heterogeneity orientation silicon steel by the thermodynamics and kinetics model, the degree of superheat≤50 in the strict control casting process ℃;

2) molten steel carries out the electric pulse processing at Zhong Bao, and the pulse frequency scope is 0.1Hz～1000Hz, and the pulse voltage scope is 10V～10000V.