Causes of Wear in Refractory Castables

Causes of Wear in Refractory Castables

The causes of wear in refractory castables are varied, and are generally related to their physical and chemical properties, the service environment, and the quality of construction and maintenance. The following are the main causes of wear in refractory castables:

Mechanical Abrasion:

In high-temperature equipment such as boilers and kilns, refractory castables are frequently subjected to erosion by airflow, material flow, or molten metal.

This erosion causes particles on the castable surface to gradually detach, resulting in wear.

Thermal Stress:

Due to thermal expansion and contraction caused by temperature changes, stress is generated within the refractory castable.

These stresses can lead to cracking or spalling of the castable, especially in environments with drastic temperature changes.

Slag Erosion:

At high temperatures, refractory castables may be eroded by molten slag.

Some components in the molten slag may react chemically with the castable, leading to structural damage and performance degradation.

Gas Erosion:

Certain high-temperature gases (such as oxygen and carbon dioxide) may react with components in the refractory castable, causing gradual oxidation and wear.

Poor Construction Quality:

Improper construction of refractory castables, such as uneven mixing and insufficient compaction, can lead to internal defects like pores and cracks.

These defects reduce its strength and abrasion resistance.

Improper Maintenance:

Regular maintenance and inspection are crucial for extending the service life of refractory castables.

Failure to detect and repair cracks and worn areas in a timely manner will further exacerbate wear.

High-Temperature Environments:

High-temperature environments can cause refractory castables to thermally expand, soften, or even melt, thereby reducing their strength and abrasion resistance.

Media Flow Velocity:

High-speed flowing media (such as airflow or material flow) exert a stronger scouring effect on refractory castables, accelerating their wear.

Insufficient Abrasion Resistance:

If the selected refractory castable lacks sufficient abrasion resistance, wear will easily occur during use.

Composition and Design Issues:

If the composition of the abrasion-resistant refractory castable does not meet specifications, the stability of the abrasion-resistant material will not meet design requirements. The compressive strength, flexural strength, abrasion resistance, thermal shock stability, and reheat linear variation of abrasion-resistant castables are the main considerations.

Improper design, such as an insufficient number of anchor bolts and pull hooks, or failure to pre-treat anchor bolts as required before pouring, can also cause abrasion-resistant castables to detach.

To extend the service life of refractory castables, it is necessary to comprehensively consider the above factors and optimize and improve aspects such as material selection, construction technology, and maintenance management.