The introduction of graphite endows refractories the superior thermal shock resistance and slag corrosion resistance, which makes carbon-containing refractories an indispensable support for metallurgy. The existing widely used shaped carbon-containing refractories include MgO–C, Al₂O₃–C, as well as Al₂O₃–MgO–C, and Al₂O₃–ZrO₂–C. The development on carbon-containing castables has attracted recent attention. The excellent properties of carbon-containing refractories mainly contribute to the low thermal expansion, high thermal conductivity and low permeability to molten steel and slags of graphite. However, a high carbon content (about 10%–30%) in conventional carbon-containing refractories is prone to increase the carbon pick-up in steel, affecting the production of clean steel and low–carbon steel. In addition, the sensitivity of carbon to oxidation leaves numerous pores in refractories and releases CO_x gases, which accelerate the corrosion of the refractories and greenhouse effect. It is thus of great importance to develop low–carbon (i.e., <8%) and ultralow–carbon containing refractories. However, directly decreasing the use of graphite usually leads to the deterioration of the thermal shock resistance of the refractories. Therefore, more and more attention is paid to the study of thermal shock resistance of carbon-containing refractories. Expansion and optimization of thermal shock theory of refractories, improvement and modification of thermal shock resistance testing methods, and exploration and innovation of thermal shock resistance improvement methods are the inseparable directions of the research on the thermal shock resistance of carbon-containing refractories.

This review represents recent development on thermal shock theory of refractories. The theory derived from linear elastic fracture mechanics suits dense ceramics and specific refractories and strength while it cannot be used in assessing the thermal shock resistance of carbon-containing refractories with high porosities and numerous defects. The unified theory derived by Hasselman clarifies the resistance of materials to both fracture initiation and crack propagation, and the parameter R_st can determine the thermal shock resistance of refractories. Compared to the theories above, those derived from elastic-plastic fracture mechanics with a strain energy-fracture energy as the parameters determine the resistance of refractories to thermal shock more precisely for that the fracture of refractories under strain is prone to have elastic–plastic characteristics. The development of wedge splitting test achieves the specific fracture energy of refractories. The brittleness determining parameters like the characteristic crack length and the Brittleness number can be calculated.

The existing methods used in testing the thermal shock resistance of refractories mainly contain quenching test, splitting test, cyclic test and nanoindentation. Compared to the qualitive quenching method, splitting test can assess the thermal shock resistance of refractories quantitively. Furthermore, the ability of refractories resisting thermal strain and mechanical strain can be also revealed. Nanoindentation has some dispensable advantages in exhibiting the evolution of mechanical properties in micro-/nano-scales, while it still needs numerous explorations to standardise the testing schedule on refractories.

Researches on improving the thermal shock resistance of refractories mainly concentrate on matrix toughening, aggregates modification and aggregate/matrix interface designing. Nanocarbons and ceramic whiskers are commonly used as additives to strengthen and toughen the refractory matrix. Researches on modifying magnesia aggregates to improve the thermal shock resistance of MgO–C refractories are conducted, while seldomly reported in other refractories. The design of the aggregate/matrix interface can also effectively improve the thermal shock resistance of refractories, and preparing interfacial layer with a tailored structure for load transmission and crack deflection is a potential method.

The development of improving the thermal shock resistance of refractories materials is based on scientific and reliable thermal shock resistance theories combined with scientific and accurate testing methods, and thermal shock resistance enhancement methods. The research on the thermal shock resistance of carbon-containing refractories focuses on the composition/structure nano-scaling and microstructure design. However, single modification approach cannot fulfil the requirement imposed by the low–carbon containing refractories ascribe to their complex thermal shock behavior. Integration of matrix toughening, aggregates modification and aggregate/matrix interface design is assumed to exhibit some effects on improving the thermal shock resistance of refractories.

Macro-mechanical testing methods are not sensitive to the optimization of the microstructure of refractories. Nanoindentation method can test the mechanical properties of materials in micro-scales. The combination of macro-mechanical property test and micro-mechanical property test can deeply reveal the improving mechanism of the properties of refractories. There is still a long way for nanoindentation to be widely used in refractories with a high heterogeneity because of its nano-scale characteristics. It is of great importance to standardise nanoindentation test in refractories.

Numerical simulation and machine learning can verify the experimental results and predict the properties of refractories. Combining them with experiments can provide a further guidance for the microstructure design of refractories. Besides, the combination of numerical simulation and nanoindentation or fatigue test can accelerate the development of nanoindentation test standards and fatigue test standards for refractories.