Converter Refractory Hot Patching Machine: A Key Equipment for Ensuring Efficient Operation of Iron and Steel Smelting

In the core link of iron and steel smelting, the converter is a key equipment for steelmaking. The integrity of its furnace lining refractory materials directly determines the service life, production efficiency and steelmaking quality of the converter. However, under the harsh working conditions of high temperature, high-speed slag scouring and chemical reactions, the furnace lining refractories of the converter are prone to wear problems such as erosion and spalling. To solve this pain point, the converter refractory hot patching machine has emerged as the times require. With its efficient and accurate refractory repair capability, it has become a core equipment for extending the service life of the converter and reducing production costs, and occupies an indispensable position in modern iron and steel enterprises.

I. Working Principle of Converter Refractory Hot Patching Machine: "Precision Repair Technology" at High Temperature

• Material Preparation Stage: According to the material and damage degree of the converter furnace lining, select the suitable refractory powder, and carry out accurate measurement and transportation through the feeding system of the equipment to ensure the stable composition and accurate proportion of the patching material.

• High-Temperature Heating Stage: Use fuel combustion (such as mixed combustion of natural gas, propane and oxygen) or arc heating to generate a high-temperature heat source of 1500-2000℃. When the refractory material passes through the heat source area, it is quickly heated to a semi-molten state to form "hot-melt particles" with good fluidity and adhesiveness.

• High-Speed Spraying and Bonding Stage: Use high-pressure air or nitrogen as the carrier gas to spray the hot-melt refractory particles at high speed to the damaged part of the converter furnace lining. When the particles hit the surface of the furnace lining, they can not only fill the pits and cracks on the surface, but also undergo physical fusion and chemical reaction with the original refractory under the action of high temperature to form a repair layer with high bonding strength and strong erosion resistance.

II. Core Components and Technical Features: "Hardcore Support" for High Efficiency and Stability

1. Analysis of Core Components

• Patching Gun System: As the "execution end" of the equipment, the structural design of the patching gun directly affects the patching effect. Modern patching guns mostly adopt double-layer or multi-layer sleeve structure. The inner layer transports refractory materials, and the outer layer transports fuel and combustion-supporting agent (or carrier gas). The gun head is equipped with a special mixed combustion chamber to ensure full combustion of fuel and uniform mixing with refractory materials. At the same time, the adjustable nozzle is used to control the spraying angle (usually 15°-20°) and spraying range to realize accurate repair of different parts of the furnace lining.

• Feeding System: It is responsible for stably and uniformly transporting refractory materials to the patching gun to avoid voids or thickness deviations in the repair layer caused by uneven material supply.

• Heat Source Supply System: It provides a stable high-temperature heat source for patching. The mainstream technologies are divided into "combustion type" and "arc type". The combustion heat source uses clean energy such as natural gas and propane as fuel, and generates high temperature after mixed combustion with oxygen, which has the characteristics of fast heating speed and easy temperature control. The arc heat source generates arc heating through electrode discharge, which is suitable for scenarios with higher requirements on the melting degree of refractory materials. The two heat sources can be flexibly selected according to the type of refractory materials and production needs.

2. Key Technical Features

• High Efficiency: The single patching operation time is short, and the repair can be completed during the interval of converter steelmaking without long-term furnace shutdown, which greatly reduces the shutdown time of the converter and ensures the continuity of steelmaking production. According to statistics, the service life of the furnace lining of the converter equipped with a hot patching machine can be extended by 30%-50%, and the number of furnace lining replacements per year can be reduced by 2-3 times, significantly improving the production efficiency.

• Accuracy: Through the adjustable patching gun and automatic control system, the accurate control of the thickness of the repair layer can be realized (error ≤ ±2mm), avoiding the waste of refractory materials. At the same time, the flexible adjustment of the spraying angle and range can cover the "vulnerable areas" of the converter furnace lining (such as the furnace mouth, the side wall of the molten pool and the vicinity of the tapping hole), and solve the problem of high wear in a targeted manner.

• Durability: The core components of the equipment are made of special materials with high temperature resistance and wear resistance, which can work for a long time in a high temperature environment above 1800℃, reducing the frequency of component replacement and lowering the equipment maintenance cost.

III. Application Scenarios and Industry Value: "Life Guardian" of Iron and Steel Production

• Daily Maintenance and Repair: After the converter completes the smelting of one furnace of steel, the furnace lining will have slight wear due to the scouring of high-temperature slag. At this time, the "immediate repair" is carried out by the hot patching machine, which can avoid the accumulation of wear, maintain the integrity of the furnace lining, and ensure the temperature stability and molten steel quality in the subsequent steelmaking process.

• Medium-Term Emergency Repair: When the converter furnace lining has local serious erosion or cracks, if it is not repaired in time, it may lead to the leakage of the furnace lining and cause safety accidents. The hot patching machine can quickly carry out "reinforcement repair" on the damaged part, avoid the converter from shutting down for maintenance in advance, and reduce economic losses.

• Extension of the End of Furnace Campaign: At the end of the converter furnace campaign (the cycle from the commissioning of the new furnace lining to the replacement), the overall wear of the furnace lining is relatively large. At this time, multiple large-area repairs are carried out by the hot patching machine, which can extend the furnace campaign cycle by 1-2 months, gain more production time for the enterprise, and reduce the cost of furnace lining replacement (the cost of one converter furnace lining replacement can reach millions of yuan).

• Cost Reduction and Efficiency Improvement: Extend the service life of the converter furnace lining, reduce the number of furnace lining replacements and shutdown time, and at the same time reduce the consumption of refractory materials (the utilization rate of refractory materials for patching repair is more than 30% higher than that of overall replacement).

• Improvement of Steel Quality: The integrity of the furnace lining directly affects the temperature and composition stability of molten steel. By maintaining the uniformity of the furnace lining with the hot patching machine, the mixing of impurities caused by the erosion of the furnace lining can be reduced, the composition fluctuation of molten steel can be reduced, and the qualification rate of steel products can be improved (especially crucial for the production of high-quality special steel).

• Safety Guarantee: Repair the damage of the furnace lining in time, avoid safety accidents such as molten steel leakage and explosion caused by the leakage of the furnace lining, and provide a strong guarantee for the safe production of the steelmaking workshop.

Conclusion