Selection of steel in furnace construction

In industrial ovens, where the equipment is exposed to prolonged high temperatures and potentially aggressive substances (e.g. chemical residues from the etching of workpieces), the construction material is crucial for durability, safety and subsequent trouble-free operation. The standard choice in most cases is 304 stainless steel - it provides good resistance to temperatures of 300-400°C and to typical paint shop conditions, where moisture and fine contaminants are not chemically aggressive. It is durable, accessible and relatively cost-effective. However, if the annealing process involves workpieces fresh from the chemical bath, which bring residues of acids, chlorides or other aggressive substances into the furnace, it may be necessary to use 316-grade stainless steel. The addition of molybdenum provides it with significantly higher chemical resistance, which translates into a longer service life of the structure in harsh conditions and reduces the risk of costly failures. The choice between 304 and 316 steel is primarily a decision based on what will actually happen inside the furnace chamber. When extreme conditions are not present - 316 is an unnecessary expense. When they are - 304 will simply not perform. The choice of steel should therefore be directly related to the processing technology of the workpiece and the anticipated intensity of furnace operation - 'better' does not always mean 'more cost-effective'.