Design and manufacture of composite bolts and nuts in the secondary part of electric arc furnaces by Mobarakeh Steel

According to the economic observation and quoting the public relations of Mobarakeh Steel of Isfahan, the head of the maintenance and repair technical group of the steelmaking and continuous casting area, in an interview with a steel reporter, while announcing the design and construction of composite bolts and nuts that support high current hydrogen cables in the secondary section. Arc furnaces are, he said: in the steelmaking unit, the secondary support (support) of high current hydro cables (High Current), is an all-metal structure that is installed and restrained on the concrete wall of the transformer room of each furnace and its task is to support and support the weight of transmission equipment. High current electrical energy (85 kA) is secondary from the transformer to the arc furnace.

Yousef Esmailzadeh, referring to the role of this equipment in transmitting electricity, said: “Part of the support of this equipment is always inevitably under voltage and power, and at the same time the other part of the support that is connected to the concrete wall and restrained must be without electricity.”

He further reminded: in a part of the connections of this structure, a set of electrical insulation including plate, washer, pipe and 18 sets of anti-magnetic steel bolts and nuts have been used.

In this regard, Ali Alikhani, an expert in the process of maintenance and repair of the steelmaking and continuous casting area, said: “In the part of electric arc furnaces, the problem of arching these insulators and bolts may cause downtime and significant loss of tonnage.”

Alikhani, referring to the consequences of arching insulators and bolts at each time, said: “Each time, several hundred heavy repair activities must be performed, with a large volume of scaffolding operations, to work in difficult conditions and heights, so that it is possible to start again for Furnace provided.

The expert in the process of maintenance and repair of the steelmaking and continuous casting area continued: Although some corrective measures can be eliminated by implementing corrective measures such as changing the material and dimensions of the insulation, but it was finally decided that for the first time and in the most difficult Step, to find the right answer to the question of whether it is possible to change the material of steel bolts and nuts that are under mechanical stress and load and instead use bolts made of composite, Teflon or any other material that is inherently electrically insulating?

In response to this question and explanation of the process, Abdul Rasool Norouzi, an expert in design and engineering of parts and equipment, said: “With the participation of the parts and equipment engineering unit, an experienced expert team was formed and with the support of relevant heads and district management, in the first phase.” , Information was collected on how archetypes occurred and spread. In the second phase, the technical information of the equipment, the amount of mechanical load, force and torques on the equipment and support connections were extracted. In the third phase, all necessary calculations were performed from the beginning and finally the process of making bolts and nuts made of electrical insulation based on design And the special dimensions that were prepared by the expert team, started with the help of one of the capable domestic builders.

Continuing this conversation, Mehdi Rostaghi, an expert in repairing and maintaining electric arc furnaces, referring to the processes performed, said: “After making the insulation bolts and nuts in the manufacturer and successfully testing them in the laboratory, the steel bolts and nuts were replaced and replaced with bolts and nuts.” New insulation beads were installed.

Pointing to the importance of designing and implementing such a project for the first time, Rostaghi added: “Fortunately, this project was quite satisfactory in practice, as after installing the first set of bolts on one of the furnaces and continuing this work in other furnaces, as expected.” The problem of archiving and the resulting stops were fixed.

In the end, he emphasized: It is a matter of pride that the follow-up of the Technical Office of Steel Repairs, along with the cooperation and participation of engineering units of parts and equipment, repairs and production of arc furnaces and of course the support and trust of the district management, with the help of expert team. The leap in the production of golden leaves added to the honors of Mobarakeh Steel.