Regarding the issue of temper embrittlement in high-temperature heat treatment?

It may not have directly answered the question; defined as follows: If low-alloy steel is exposed to temperatures between 371°C and 565°C (700°F to 1050°F) for an extended period of time, temper embrittlement will occur. This type of embrittlement causes the material to lose its toughness. This embrittlement issue is not apparent at operating temperatures, but it becomes evident at ambient temperatures, leading to brittle fracture of the material. As the usage time within the embrittlement range increases, the likelihood of brittle fracture in low-alloy equipment rises. Some refinery units may have been in use for a considerable length of time, and the components they contain are prone to brittle fracture during startup and shutdown. The 2-1/4 Cr-1 Mo alloy, which is widely used in hydroprocessing units and hydrocracking units, is particularly prone to brittle fracture due to its use at high temperatures. In extreme cases, variations in the embrittlement temperature as high as 93°C (200°F) have been observed. For example, even though steel is fully ductile at operating temperatures, during periods when the equipment is shut down, as the temperature drops, it rapidly enters a brittle range. Whether there is an impact load or not, any existing cracks or defects will increase the severity of the problem. Limiting the equipment pressure to 25% of the design value before the equipment temperature exceeds the embrittlement temperature can slow down embrittlement caused by tempering in older equipment. The brittleness caused by tempering is also reversible; by heating the steel to temperatures above 593°C to 648°C (1100°F to 1200°F) and then cooling it to room temperature, its brittleness can be removed. If the equipment is once again within the embrittlement temperature range, it is expected that the steel will become brittle again. By limiting the levels of residual elements such as tin, phosphorus, arsenic, manganese, and silicon, it is possible to reduce the susceptibility of new equipment to embrittlement due to tempering. On the 1st floor, you can decide for yourself how to handle such matters