On July 25^th, after “being in service” for 365 days and making steel 6,450 times, Steelmaking No. 1 Converter, as the first converter of Shougang Qian’an Iron & Steel Co., Ltd. to be put into production, has broken a historic steelmaking record of Shougang. The in-service combined blowing ratio of the whole converter was 100% and the in-service carbon oxygen equilibrium of the whole converter was 0.00195, reaching the international advanced level.

The carbon oxygen concentration of the whole converter is an important index to evaluate the combined blowing effect and end-point control level of the converter. Low carbon oxygen equilibrium means that the oxygen content of molten steel is low in the control level of the same end-point carbon, which can reduce alloy consumption, reduce foreign impurity in the process of deoxidation and improve the purity of molten steel.

Insist on Doing Something Repeatedly

With the increasingly fierce industrial competition and changing market demands, there are higher requirements for the quality of products and smelting cost. Shougang Qian’an Iron & Steel Co., Ltd. set up a relevant research team to deal with various “difficulties” in technical skill.

The difficulty of top and bottom combined blowing converter control is the dynamic control over the converter situation. According to the actual working conditions on the spot, the converter combined blowing team of the steelmaking operation department determined the suitable control parameters through many prior analyses and tests. Taking into consideration the obstacles affecting further progress of the combined blowing research, it worked out specific research measures and broke them one by one.

Guo Yuming is the head of the dayshift of the steelmaking operation zone of the Steelmaking Operation Department. Coming to Qian’an from Beijing in 2004, he regards converter steelmaking, which he has been involved in for 30 years, as his own “line”. He once won the title of “National Model Worker.” As one of the core members of his team, he committed: “Be conscientious. I’ll manage the converter well.”

As the bottom situation of the converter should be monitored in real-time, the “Converter Combined Blowing WeChat Group” came into being. Guo Yuming has had the habit of reading information from the “Converter Combined Blowing WeChat Group” on his cell phone at 5 a.m. and 6 p.m. every day. Every day at these times, the steelmaking worker on duty sends photos of the bottom converter to the group to determine the combined blowing condition. In over one year during the run of No. 1 Converter to restart-up, no matter what kind of day it was, Guo Yuming has never neglected this habit. Guo Yuming said with a smile: “In the past two years, I’ve made “Converter Combined Blowing” one of the top contact groups in my cell phone. I always have my cell phone with me. When I’m cooking at home, I put it in my pocket. When eating, I put it beside my bowl. The moment my cell phone sounds, it’s likely that it’s something about combined blowing.” He goes to the main control room every morning to arrange the major steel smelting technologies of the day to the steelmaking worker on duty, and summarizes the combined blowing situation of the daytime shift and smelting deployment of the night shift before going off duty.

Guo Yuming said: “I need to regulate each case in real-time. If I miss one step, a domino effect is likely to happen. We need to make the right micro-adjustments and keep the converter in its best condition every day.”

Synergistic Enhancement and Hundred-Percent Execution

According to characteristics of the converter condition, meeting the dynamic control standard is the requirement for smelting each converter of steel. The strong sense of responsibility and hundred-percent execution power of each steelmaking worker are “swords” ensuring that requirements are always met.

Regarding field operation, by optimizing the slag splashing, fettling and production rhythm and other means, the control of bottom converter and converter type is strengthened and bottom blowing and converter life are synchronized; regarding fettling, by optimizing different ways of feeding, the smallest influence of fettling on a plugged combined blowing hole can be achieved; through adjustment of the slag splashing lance position, slag splashing flow, slag splashing feeding mode, and so on. Optimizing the slag splashing control will strengthen maintenance of the weld pool, gradually improve the slag splashing converter protection effect and reduce the impact caused by the erosion of weld pool, creating conditions for combined blowing control and forming the control scheme. The converter combined blowing flow is strictly executed according to the corresponding control scheme, and the working zone should be adjusted dynamically in real-time under special circumstances.

Wang Zenghui, a steelmaking worker of C shift said with emotion: “In-service combined blowing of the whole converter brings us various benefits and great convenience during field operations. When I am on duty, I do my best to do my work well to avoid leaving any hidden dangers to the next shift, hindering the team.”

With the increasing amount of smelting, they should be more careful and especially cautious about each operation and each decision, as they have a common voice. That is, they don’t want to undermine the plan for the overall goal and hinder the team due to a mistake during their shift.

“Only by overcoming the hardest problem can we reach the highest goal”. Since the research has been carried out, the field operators of the combined blowing team are making progress by trial and error. Since the combined blowing research has been carried out, both stability of converter operation and the quality control level of branded steel greatly improved. At the same time, it also provides a strong guarantee for the quality control of high-end branded steel.

Hard Work Pays off

The Steelmaking Operation Department doesn’t fight unprepared battles. During each test, it carried out the numerical simulation and the water simulation research, tracked its actual effect and strictly observed the rule of having no influences on normal production.

In over one year, the “Converter Combined Blowing WeChat Group” has become the research team’s closest contact channel, besides calls. Here, innumerable “important rules” have been established and achieved. When combined blowing is done well, there are many benefits, such as stable converter conditions, improved quality of molten steel and reduced costs. The in-service combined blowing ratio of the whole No. 1 Converter, for the 6,543 times it has made steel, has reached 100% and last year the in-service carbon oxygen equilibrium of the whole converter reached 0.0021. To make these achievements, the research team made relentless efforts.

We must learn from previous achievements. Much experience was previously summarized as “highly valuable.” All members of the team have gained a greater implied understanding, they operate more and more expertly, and set increasingly stricter requirements. The smelting amount of 1,000 times is a small goal. They are cautious about each process and each detail and they give special instructions to important schedules and other special circumstances. Guo Yuming has a “current record” of each time of smelting, documenting its combined blowing situation. Including pictures and yellow-marked text, it showcases their perseverance and effort.

Guo Yuming said: “The current level is not the final goal, so we will continue to do well as always.”