Adopting the advanced infrared imaging technology, the slag content of the molten steel in the process of converter/electric furnace discharging is detected in real time, the synchronous image is given with sound and light alarm, and the furnace lifting or slag blocking system are automatically controlled to provide the high-quality molten steel with little or no slag for the next process. When using the slag blocking linkage, according to the angle of the converter and the time of discharging, the slag blocking plug is automatically put in, so as to reduce the slag flowing into the ladle and further improve the purity of the steel.

Alarm accuracy	≥99%
Image acquisition speed	30or50fps
Image processing time	＜20ms
Distance between lens and converter	8m-25m
Ambient temperature	-40℃-120℃
Slag stopper hit rate ≥98% Slag blocking success rate ≥96% Average slag thickness ≤70mm	When use slag blocking linkage equipment

 

• The lens is installed in a high temperature environment, using gas cooling and purge dustproof effect is good, long service life;
•  Long-distance use of optical fiber to transmit image signals, strong anti-electromagnetic interference ability;
• The sensor is sealed and protected by a double-layer stainless steel cover. It has automatic sensor temperature control and automatic lens dust removal functions. It is suitable for harsh environments such as high temperature, dust and vibration at the steelmaking production site.
• The image is clear and smooth, and the grayscale difference between the molten steel and steel slag images is large and easy to distinguish;
•  It can distinguish the changes of cold steel, smoke and flame steel flow in the steel mouth without false alarm.
•  Full automatic control of the slag blocking putting process: (when using the slag blocking linkage)
• The installation process does not affect production, and basically no modification is made to the on-site equipment.
•  According to abnormal conditions, the slag blocking truck can respond quickly according to the change of converter angle, which can reduce accidents caused by improper operation. (When using the blocker linkage device)
• With remote diagnosis function, the system fault information status information and data are sent back every day, and remote processing can be performed according to these information to ensure the operation of the equipment.

 

• Improve the yield of molten steel

From September 20 to September 25, after being put into use in the No. 2 converter of a special steelmaking branch, 114 furnaces were continuously tracked (two of which were tapped twice), of which there were 0 leak alarms and 1 alarm about slag entrapment, The accuracy rate is 99.12%. 2#

The recovery rate of molten steel after the converter is put into use for slag detection:

1#BOF: The number of smelting furnaces is 120, and the average molten steel recovery rate is 94.5%.

2#BOF: The number of smelting furnaces is 122 furnaces with an average molten steel yield of 95.2%.

 

• Reduce the amount of phosphorus returned molten steel

Taking the phosphorus returned data analysis of the 1# and 2# converters (when slag detection is put into use) from September 20 to September 25

 

variable	Heater number	average value	Standard deviation	Lower quartile	median	Upper quartile
Phosphorus returned	1#BOF	0.003264	0.002459	0.001850	0.003050	0.004125
Phosphorus returned	1#BOF	0.001490	0.002520	-0.000300	0.001700	0.003100

 

Histogram of the amount of phosphorus returned to the converter

From the analysis of the above data, the average phosphorus returned of the 2# converter is lower than that of the 1# converter; the standard deviation of the phosphorus returned is basically close, that is, the stability of the phosphorus recovery is basically the same; the lower quartile and median of the phosphorus returned of the 2# converter And the upper quartile are lower than the phosphorus recovery of 1# converter.

 

• Reduce ladle slag thickness

Measurement method: After the converter is tapped, the ladle car is driven to the sand filling hole after the furnace, the bottom is adjusted to the wave surface without obvious tumbling state, a thin oxygen tube with a diameter of 6mm is inserted vertically into the ladle liquid surface, wait for 5~10 seconds to take out, measure

The length from position of the slag line to fuse point is recorded as slag thickness data. During the measurement, all the tapping processes of the furnace were added with 400Kg of compound slag according to the current process.

 

Steel Grade	Carbon steel	Low-alloy steel	Low-carbon steel	No distinction
Measured value before use(mm)	100	147	67	104.6
Target value(mm)	≤80mm	≤100mm	≤50mm	≤70mm
Number of samples (furnace)	176	29	118	316
Measured value after use(mm)	54.8	55.2	43.6	50.4

 

• Use slag blocking linkage control (take Russian MMK as an example)

The average thickness of the slag layer in the ladle does not exceed 70mm;

Compared with the average consumption of 2.4kg/t in previous years, the consumption of deoxidized aluminum has been reduced by 0.25kg/t;

The consumption of CM78 ferroalloy is 7018kgti lower than the average annual consumption of 21k/t

The consumption of CM78 ferroalloy is 7018kgti lower than the average annual consumption of 21k/t