What is the difference between boron steel and manganese steel in chains?

The choice of material for conveyor chains largely determines how well the chain withstands demanding industrial conditions. Especially in metal industry and smelter processes, where temperatures can reach up to 400 degrees Celsius and wear is severe, the properties of the chain material determine the reliability of the entire conveyor system. Maintenance managers often encounter situations where chains wear out faster than expected, leading to production downtime and extra costs.

Boron steel and manganese steel are two of the most common chain materials, but their properties and suitability differ significantly. By understanding the key differences between these materials, you can make an informed choice that ensures optimal chain performance for your specific process. Discover our forged link conveyor chains and find a solution that will withstand even the most demanding conditions.

What is the difference between boron steel and manganese steel?

Boron steel and manganese steel differ in their chemical composition, heat treatment properties, and mechanical properties. Boron steel (27MnCrB5) contains boron, which improves the hardenability and hardness of the steel, whereas manganese steel (20MnCr5) is based on an alloy of manganese and chromium.

The key difference is seen in heat treatment, i.e. hardening. Boron steel behaves differently from manganese steel during hardening: it is not just hardened on the surface, but is almost through-hardened. This makes boron steel linkages tougher and particularly durable against wear. Manganese steel, on the other hand, is mainly hardened on the surface, which limits its hardness at deeper levels.

Temperature resistance is another significant difference. Boron steel retains its mechanical properties at elevated operating temperatures better than manganese steel. In practice, this means that boron steel chains will function reliably at temperatures up to 400°C, whereas the recommended maximum temperature for manganese steel chains is approximately 200°C.

Why do boron steel chains have better wear resistance?

Boron steel chains are more resistant to wear thanks to their higher surface hardness, more uniform hardness distribution and better temperature resistance. According to test results, the surface hardness of a boron steel link at room temperature is approximately 30 % higher than that of a manganese steel link, and at high temperatures the difference increases to as much as 70 per cent.

Through-hardening is a key factor in the superior wear resistance of boron steel. Whilst manganese steel is hardened mainly on its surface, boron steel is hardened across almost its entire cross-section. This means that the hardness of a boron steel chain link does not change significantly as a result of surface wear, but remains on average around 30 % higher than that of a manganese steel chain link.

At high temperatures, the difference becomes even more pronounced. While the tensile strength and surface hardness of steel decrease as temperature rises, boron steel retains its properties better. This is particularly important in foundry and metalworking processes where chains are subjected to constant tensile load and high temperatures.

When is a manganese steel chain a better choice?

Manganese steel chain is a better choice for lighter applications where the operating temperature remains below 200°C and the wear stress is moderate. Manganese chain, i.e. a conveyor chain made of 20MnCr5 steel, works excellently under these conditions and is a cost-effective solution.

Manganese steel is well-suited for processes where significant temperature challenges are not present and the current service life is sufficient. If the material being transported is not particularly abrasive and does not contain large build-ups, a manganese steel chain can offer adequate performance at a considerably lower investment cost.

Typical applications for manganese steel chains include processes where the temperature remains stable and relatively low, the material being conveyed is uniform, and the particle size is controlled. Under these conditions, the properties of manganese steel chain are quite sufficient, and the additional benefits provided by boron steel chain may not necessarily be required.

How to choose the right chain material for a conveyor application?

The correct chain material is selected by evaluating the operating temperature, the characteristics of the material being conveyed, the wear stress, and the required service life. In the temperature range of 250–400 °C and under demanding conveying conditions, boron steel is the recommended choice, whereas manganese steel may suffice in more moderate conditions.

The first factor to consider is operating temperature. If the process continuously experiences temperatures above 200°C, a boron steel chain is practically the only durable option. An environment that is too hot will weaken the chain's properties by reducing tensile strength and surface hardness, making material selection critical.

The properties of the material being transported have a decisive impact on the material choice. Abrasive materials, large lumps and impact loads require the superior wear properties of boron steel. If the material being transported contains large and irregular lumps, which can cause thermal shock and deformation in the chains, a boron steel chain is clearly the better choice.

The lifetime requirements dictate the final choice. Typically, boron steel chains have achieved at least double the lifespan compared to commonly used manganese chains. If it is critical for the process to minimise maintenance downtime and maximise chain life, a boron steel chain is justifiable as an investment, despite the higher acquisition costs.

When selecting a chain, it is also important to consider the overall picture: thermal expansion, insulation, load distribution, and chain protection all crucially affect the actual service life of the chain. Material selection alone does not resolve everything; the chain is part of the entire conveyor system. Contact us And let's discuss which chain material is best suited for your specific process and how the whole system can work optimally in the long term.