How to choose a conveyor chain for metallurgical processes?

The selection of conveyor chains for metallurgical processes is a critical decision that directly affects production efficiency and maintenance costs. High temperatures, abrasive materials, and continuous loads place specific demands on chain materials and construction. The correct choice can double the service life, while an incorrect material leads to rapid wear and production downtime.

Many maintenance managers wonder why conveyor chains wear out faster than expected or why more expensive solutions are worthwhile in the long run. Forged conveyor chains offer a solution to these challenges when designed and manufactured according to the requirements of metallurgical processes.

What are conveyor chains for metallurgical processes?

Conveyor chains for metallurgical processes are specially made conveyor solutions designed to withstand the extreme conditions of the steel industry, smelters, and metal processing. They operate at temperatures of 300–400°C and can withstand continuous abrasive loading.

These chains differ from standard industrial chains in their material selection and construction. Metallurgical applications typically use forged boron steel link chains, which maintain their strength and wear resistance at high temperatures. The chains must withstand falling accretions, hot dust, and continuous mechanical stress.

Typical applications include conveyors for waste heat boilers, slag conveyors for smelters, and material conveyors for gas cooling boilers. In these applications, the chain is often the only moving part, making its reliability vital for production continuity.

Korkeat lämpötilat vaikuttavat kuljetinketjun valintaan siten, että ne voivat heikentää materiaalin lujuutta, aiheuttaa lämpölaajenemista ja vaikuttaa voiteluaineiden tehokkuuteen.

High temperatures significantly reduce the tensile strength and surface hardness of steel, necessitating specific material choices and structural solutions. Above 250°C, standard manganese steel rapidly loses its mechanical properties.

The effect of temperature on chain material is exponential. As the temperature rises from 200°C to 400°C, the tensile strength of ordinary steel can drop by up to 40 percent. Simultaneously, the surface hardness decreases, accelerating wear in abrasive environments.

Boron steel retains its properties better at high temperatures. Test results show that the surface hardness of a boron steel link is 30 percent higher than that of manganese steel at room temperature, and at high temperatures the difference increases to as much as 70 percent. This explains why boron steel chains often last twice as long in metallurgical applications.

Temperature control is as important as material selection. If the internal temperature of the conveyor drops below the acid dew point, sulfuric acid will form, accelerating corrosion. The optimal operating temperature range is 250–400°C, where the chain's mechanical properties and corrosion resistance are in balance.

What is the difference between stainless steel and regular steel cable in metallurgical applications?

Stainless steel offers better corrosion resistance, but plain boron steel is mechanically stronger and more wear-resistant in metallurgical applications. The choice depends on the primary challenges of the process: chemical or mechanical stress.

The main advantage of stainless steel is its ability to resist chemical corrosion. In processes where acidic gases or moisture are present, stainless steel maintains its surface integrity for longer. However, it does not withstand mechanical wear as well as hardened boron steel.

The standard boron steel chain, in turn, offers considerably higher surface hardness and a tougher structure. The main challenge in metallurgical processes is often abrasive wear and impact loads, where the mechanical properties of boron steel are crucial. Boron steel also hardens throughout during heat treatment, making it more uniform across its entire cross-section.

In terms of cost-effectiveness, boron steel is usually the winner. Although stainless steel may fare better in corrosion resistance, its weaker wear resistance often leads to a shorter overall service life. Boron steel's higher surface hardness compensates for its susceptibility to corrosion in metallurgical applications where mechanical stress is the dominant factor.

How to choose the right conveyor chain for a metallurgical process load?

The selection of the correct conveyor chain is based on a comprehensive assessment of operating temperature, material properties, load, and environmental conditions. The most critical factors are the continuous operating temperature, the abrasiveness of the material being conveyed, and shock loads.

Defining the temperature range

The first step is to determine the actual operating temperature range. If the continuous operating temperature is below 200°C, a traditional 142V manganese steel chain may suffice. For temperatures above 250°C, a 216W boron steel chain is recommended, which can withstand continuous loads of 300–400°C.

Temperature variations are as important as the average temperature. Rapid temperature changes cause thermal stresses, which can lead to cracking. Boron steel withstands thermal shock better than manganese steel, due to its more uniform through-hardening.

Load analysis

In load analysis, both continuous tensile loads and random impact loads are assessed. In metallurgical processes, the chain often experiences additional loads from falling accretions or uneven material feed. The nominal breaking strength of the 216W chain is 750 kN, which is 44 per cent higher than the 520 kN of the 142V chain.

Transport speed affects wear exponentially. Doubling the speed can quadruple the wear. Therefore, the slowest possible transport speed that meets production requirements is recommended.

Consideration of environmental factors

Particle size control is critical for chain longevity. Large agglomerates can cause permanent deformation of the chain links. Structural protection and material pre-treatment significantly extend the chain's service life.

In a corrosive environment, it is important to ensure that the internal temperature of the conveyor remains above the acid dew point. Careful insulation and temperature control prevent the formation of sulfuric acid and associated corrosion.

The choice of chain is not merely a material question, but an optimisation of the entire system. Special chains Metallurgical processes offer the best combination of lifespan, reliability, and cost-effectiveness when designed according to actual operating conditions. Contact us You can consult with our experts, and together we will assess the solution that best suits your process.