CS240278B1 - Steel for orientated transformer bands - Google Patents

Abstract

formator strips containing 2.0 to 4.0% by weight of silicon, 0.02 to 0.06 percent carbon, 0.02 to 0.20% manganese, 0.004 to 0.012% nitrogen, 0.003 to 0.030% sulfur, traces up to 0.050% aluminum, the rest iron and impurities. The essence of the solution is that ratio of aluminum to nitrogen in the steel is 0.3 to 4.0.

Description

The invention relates to steel for oriented transformer belts.

The known starting steel generally contains 2.0 to 4.0 wt% silicon, 0.02 to 0.05 wt% carbon, 0.02 to 0.20 wt% manganese, 0.004 to 0.012 wt% nitrogen, 0.004 wt% 3 to 0.030% by weight of sulfur, traces of up to 0.050% by weight of aluminum and the remainder being iron and impurities.

Fine precipitates are used to control the texture-forming processes that make it possible to achieve the desired magnetic properties of the strips. The originally developed technology by N. P. Gossem used manganese sulfides for this function.

Another technological process uses aluminum nitrides to control the texturizing processes. So far this type of steel has been produced in electric arc furnaces. Silicon alloying ferro-silicon is added to the furnace, and aluminum alloying is performed in the ladle during tapping, or during pouring into the second ladle, for homogenization and refining.

A disadvantage of the prior art method is the uneven use of aluminum, which. it makes it difficult to achieve uniform magnetic properties. Further, in the prior alloying process, a significant proportion of aluminum binds to oxygen to form thermodynamically stable inclusions, which are known to significantly impair magnetic properties. The prior art alloying process did not make it possible to produce this type of steel in oxygen converters.

These disadvantages are overcome by steel for oriented transformer belts, containing by weight 2.0 to 4.0% / silicon, 0.02 to 0.05% carbon, 0.02 to 0.20% / manganese, 0.004 to 0.012 % Of nitrogen, 0.003 to 0.030% of sulfur, traces of up to 0.050% of aluminum, the remainder of the iron and the impurities according to the invention, characterized in that the ratio of aluminum to nitrogen in the steel is 0.3 to 4.0.

up to 100% by weight of ferro-silicon is added to the ladle before or during tapping of the steel from the production aggregate, the steel is homogenized with subsequent aluminum alloying to limit the oxidation of aluminum by air oxygen in such a quantity as to achieve an aluminum to nitrogen ratio of 0.3 to 4.0 .

The manufactured transformer belt of steel having a mass composition according to the invention had very good magnetic properties due to the reduction and uniform distribution of the inclusions. The steel according to the invention can be produced not only in electric arc furnaces, but also in oxygen converters, using even aluminum.

He did

Steel with a mass composition of 0.025% / carbon, 0.09% / manganese, 0.012% of sulfur and Q, Q04% of nitrogen was produced in an oxygen converter with a melting weight of 130 t. The steel was tapped into a ladle containing 0600 kg of ferro-silicon containing 03.4 wt% silicon, 0.48 wt% manganese and 1.52 wt% aluminum.

At the end of the tapping, the pelvis was covered with a protective hatch and breathing was started. steel-nitrogen. After 2 minutes of aeration, 40 kg of aluminum was added and after 8 minutes the aeration was terminated.

The steel produced had a percentage by weight of 0.035% by weight of carbon, 0.13. % manganese,. 3.05. % of silicon, 0.013% of sulfur, 0.009% of aluminum, 0.009% of nitrogen and 0.0023% of oxygen. The oriented transformer belt produced from this construction had a uniform structure and excellent magnetic properties of Pi, 7 = 1.08 W / kg, Biooo = 1.85 T.

Example 1 a d 2

Steel with a mass composition of 0.032% carbon, 0.11% manganese, 0.010% sulfur and 0.005% nitrogen was produced in an oxygen converter with a melting weight of 130 t. The steel was tapped into a ladle with prepared ferrosilicon of the same composition as in Example 1.

After tapping was complete, the pan was transferred to a vacuum station. After eight homogenization strokes, 30 kg of aluminum were added. After twenty strokes the vacuum was terminated.

The steel produced had a weight percent of 0.039% carbon, 0.15% manganese, 2.96% silicon, 0.010% sulfur, 0.005% aluminum and 0.010% nitrogen. The oriented transformer strip produced from this melt had very good magnetic properties of Pi, 7 = 1.29 W / kg, Biooo - 1.84 T.

Example · 3. In an electric arc arc of a melting weight of 50 t, a steel having a weight composition of 0.023% carbon, 0.07% manganese, 0.015% sulfur and 0.008% nitrogen was produced and tapped into a ladle with prepared ferosilicon. After tapping was completed, the steel was flushed with argon, after 1 minute of flushing, 15 kg of aluminum attached to the steel rod was added by submerging below the surface of the steel.

After a further 4 minutes, the aeration was terminated. The steel produced had a percentage by weight of 0.020% carbon, 0.10% manganese, 3.15% silicon, 0.010% sulfur, 0.004% aluminum and 0.010% nitrogen. The oriented transformer strip produced from this melt again had very good magnetic properties Pi, 7 = 1.29 W / kg and Biooo = 1.83 T.

Claims (2)

SUBJECT Steel for oriented transformer belts containing by weight 2.0 to 4.0% silicon, 0.02 to 0.06% carbon, 0.02 to 0.20% manganese, 0.004 to 0.012 OF THE INVENTION% nitrogen, 0.003 to 0.030% sulfur, traces up to 0.050% aluminum, iron residue and impurities, characterized in that the ratio of aluminum to nitrogen is 0.3 to 4.0.