If you work in the steel industry, you may be familiar with the push steel heating furnace. This type of furnace is used to heat up steel billets, slabs, blooms, and beam blanks before they are rolled or forged into the desired shape. Push steel heating furnaces are known for their energy efficiency and low operating costs, making them a popular choice for many steel mills.

Push steel heating furnaces are classified based on their method of heating, method of charging, movement of steel stock, and heat recovery methods. One common type of push steel heating furnace is the pusher furnace, which uses a simple mechanical system to ensure that the steel products moving through the furnace are well-aligned. This, combined with the lack of cooled elements inside the heating chamber, makes pusher furnaces highly energy-efficient and cost-effective.

If you are interested in learning more about push steel heating furnaces and how they work, continue reading to discover their benefits, classifications, and applications in the steel industry.

Fundamentals of Push Steel Heating Furnaces

A push steel heating furnace is a type of continuous heating furnace used in steel rolling mills and forging workshops to heat metal billets before rolling or forging. The furnace is called a push furnace because the billets are pushed through the furnace by a mechanical pusher.

Push steel heating furnaces can be classified based on the fuel used, temperature system and furnace type. Depending on the fuel, there are coal-fired, oil-fired, and gas-fired continuous heating furnaces. Depending on the temperature system and furnace type, there are two-stage, three-stage, intensified heating, parallel-flow, and reverse heating continuous heating furnaces. [1]

Push steel heating furnaces have a simple structure and are easy to operate. They consist of a heating chamber, a cooling chamber, and a pusher mechanism. The heating chamber is lined with refractory bricks and contains burners that provide heat to the billets. The cooling chamber is used to cool the billets after they have been heated. The pusher mechanism pushes the billets through the furnace at a controlled speed.

Push steel heating furnaces have some disadvantages. They have a low heating efficiency, which means that a lot of fuel is wasted. They also have a limited heating capacity, which means that they can only heat a certain number of billets at a time. However, some new technologies have been adopted to achieve high quality, low energy consumption, and high efficiency. [1]

In the 1960s, the walking beam furnace was invented, which overcame the disadvantages of push furnace and gradually superseded the push furnaces of steel rolling mills. However, the pusher-type heating furnaces are still used in some steel rolling mills and forging workshops because of their simple structure and ease of operation. [1]

Design and Construction

When it comes to designing and constructing a push steel heating furnace, there are several important factors to consider. In this section, we will discuss the structural components and insulation materials that are typically used in the construction of these types of furnaces.

Structural Components

The structural components of a push steel heating furnace are designed to withstand high temperatures and provide a stable platform for the furnace body. The most common structural components used in the construction of these furnaces include steel pushers, furnace bodies, and combustion systems.

Steel pushers are used to push the billets or continuous casting billets through the furnace. They come in several types, including spiral type, rack type, piston type, and crank connecting rod type. The furnace body is generally elongated and is comprised of steel-structural framing and refractory masonry. The combustion system is responsible for providing heat to the furnace and typically includes burners, fuel delivery systems, and control systems.

Insulation Materials

Insulation materials are used to prevent heat loss and ensure that the furnace operates efficiently. The most common insulation materials used in the construction of push steel heating furnaces include ceramic fibers, refractory bricks, and insulating castables.

Ceramic fibers are lightweight and have excellent thermal insulation properties, making them an ideal choice for the insulation of push steel heating furnaces. Refractory bricks are also commonly used and are made from materials such as alumina, silica, and magnesia. Insulating castables are lightweight and can be easily molded to fit the shape of the furnace.

In conclusion, designing and constructing a push steel heating furnace requires careful consideration of the structural components and insulation materials used. By choosing the right materials and components, you can ensure that your furnace operates efficiently and provides reliable performance.

Operational Mechanics

Heating Elements

Pusher-type heating furnaces are designed to heat steel billets, slabs, blooms, and beam blanks to a specified temperature range before they are rolled or forged. The heating elements in these furnaces are typically natural gas or oil-fired burners that are located at the sides of the furnace. The combustion gases from the burners are directed towards the center of the furnace, where they heat the steel products.

The burners in a pusher-type heating furnace are arranged in zones that are controlled by a computerized system. This system adjusts the fuel and air flow to each burner to maintain a consistent temperature throughout the furnace. The number of zones in a furnace depends on its size and the desired temperature range.

Temperature Control

Temperature control is critical in pusher-type heating furnaces to ensure that the steel products are heated uniformly and to the desired temperature range. The temperature is monitored by thermocouples that are located at various points in the furnace. These thermocouples send signals to the computerized control system, which adjusts the fuel and air flow to the burners to maintain the desired temperature.

The temperature range for a pusher-type heating furnace depends on the type of steel being heated and the subsequent rolling or forging process. Generally, the temperature range is between 1100°C and 1250°C. The furnace is designed to heat the steel products to the desired temperature range within a specified time period to prevent over-heating or under-heating.

In conclusion, pusher-type heating furnaces use burners to heat steel products to a specified temperature range. The temperature is controlled by a computerized system that adjusts the fuel and air flow to the burners. Temperature control is critical to ensure that the steel products are heated uniformly and to the desired temperature range.

Process and Workflow

Material Handling

In a push steel heating furnace, the material handling process is crucial to ensure that the billets, slabs, blooms, and beam blanks are well aligned and move through the furnace without any issues. The material handling system is usually simple and mechanical, and it ensures that the material moves through the furnace in a predetermined pattern. This system reduces the need for cooled elements inside the heating chamber, which makes the furnace highly energy-efficient and reduces operating costs.

Heating Cycle

The heating cycle in a push steel heating furnace is a critical process that determines the quality of the final product. The heating cycle is usually divided into three stages: preheating, soaking, and heating. In the preheating stage, the material is slowly heated to a temperature that is just below the desired temperature. This stage helps to reduce thermal shock and ensures that the material is evenly heated.

In the soaking stage, the material is held at a constant temperature for a specific amount of time. This stage allows the material to reach a uniform temperature throughout its cross-section. The soaking stage is critical to ensure that the material is evenly heated and to prevent any thermal gradients that could cause warping or cracking.

In the heating stage, the material is rapidly heated to the desired temperature. This stage is usually the shortest stage, and it requires a significant amount of energy to achieve the desired temperature. Once the material has reached the desired temperature, it is ready for further processing.

Overall, the material handling and the heating cycle are critical processes in a push steel heating furnace. These processes must be carefully monitored and controlled to ensure that the final product meets the desired specifications.

Maintenance and Safety

Routine Maintenance

To ensure that your push steel heating furnace operates efficiently and safely, it is important to conduct routine maintenance. Routine maintenance includes tasks such as cleaning, lubricating, and inspecting various components of the furnace.

Cleaning the furnace involves removing any debris or buildup that may have accumulated on the heating elements, burners, and other parts of the furnace. Lubricating the moving parts of the furnace helps to reduce friction and wear, which can lead to breakdowns and costly repairs. Inspecting the furnace allows you to identify any potential issues before they become major problems.

It is recommended to conduct routine maintenance at least once a year. However, depending on the frequency of use, you may need to conduct maintenance more frequently.

Safety Protocols

Safety is a top priority when operating a push steel heating furnace. To ensure the safety of yourself and others, it is important to follow proper safety protocols.

Before operating the furnace, make sure to read and understand the manufacturer’s instructions and safety guidelines. Always wear appropriate personal protective equipment (PPE) such as gloves, safety glasses, and a respirator when working with the furnace.

In addition, it is important to regularly inspect the furnace for any potential safety hazards such as gas leaks, faulty wiring, or other issues. If you notice any issues, stop using the furnace immediately and contact a qualified technician for repairs.

Finally, it is important to have a clear emergency plan in place in case of an accident or malfunction. Make sure all employees are trained on the emergency plan and know how to safely shut down the furnace in case of an emergency.

By following proper maintenance and safety protocols, you can ensure that your push steel heating furnace operates efficiently and safely for years to come.

Technological Advancements

Push steel heating furnaces have come a long way since their inception, with technological advancements that have made them more efficient, reliable, and user-friendly. Here are some of the key advancements that have been made in recent years.

Automation Features

One of the most significant advancements in push steel heating furnace technology has been the integration of automation features. These features allow for greater control and precision in the heating process, resulting in improved efficiency and reduced waste.

Modern push steel heating furnaces are equipped with advanced control systems that can monitor and adjust temperature, pressure, and other key variables in real-time. This allows for more precise heating and faster cycle times, resulting in higher productivity and reduced energy consumption.

Furthermore, automation features can also help to reduce the risk of operator error and improve safety in the workplace. With automated controls, operators can monitor the furnace from a safe distance and make adjustments as needed, without having to physically interact with the furnace.

Energy Efficiency

Another key area of advancement in push steel heating furnace technology has been in energy efficiency. With rising energy costs and growing concerns about the environmental impact of industrial processes, energy efficiency has become a top priority for many manufacturers.

Modern push steel heating furnaces are designed with energy efficiency in mind, with features such as improved insulation, high-efficiency burners, and waste heat recovery systems. These features help to reduce energy consumption and lower operating costs, while also reducing greenhouse gas emissions and other environmental impacts.

In addition, many push steel heating furnaces are now equipped with advanced monitoring and control systems that can optimize energy use based on real-time data. This allows for more efficient heating cycles and reduced energy waste, resulting in significant cost savings over time.

Overall, the technological advancements in push steel heating furnace technology have made them more efficient, reliable, and cost-effective than ever before. With automation features and energy efficiency improvements, manufacturers can enjoy improved productivity, reduced waste, and lower operating costs, while also reducing their environmental impact.