What are stainless steel heat exchanger tubes?

Stainless steel heat exchanger tube is generally used for boiler, heat exchanger, condenser, standards are A249 welded tube and A213 seamless tube, 304 / 304L, 316 / 316L, 310S, 2205, S31803 stainless steel grades, annealing pickling or bright annealing condition.

In applications like food manufacturing and pharmaceuticals manufacturing, in which the working environment or liquids prohibit the usage of typical heat exchanger components, stainless steel heat exchangers become necessary.

Corrosive environment Shell and Tube heat exchangers made of 304 & 316 stainless steel can be made to fit a range of technological, medicinal, and petrochemical industries.

While aluminum heat exchangers are generally lighter and possess excellent thermal conductivity, carbon steel thermal exchangers are more costly but seem to be a significantly better investment over the long term because of their longevity and tolerance to corrosion.

Austenitic stainless steel heat exchanger tube, with good corrosion and oxidation resistance, but its use in the process will still appear brittle fracture situation, what is the reason?

  1. Brittleness

The so-called brittleness refers to the steel and other engineering components in the toughness, plasticity index value is low, brittle failure is often no signs, the harm is often catastrophic, just like the stainless steel heat exchanger tube, once the brittle fracture, it is easy to cause heat exchanger internal leakage, and even serious will also cause huge economic losses to the enterprise, so we should pay attention to its use in the daily use of stainless steel heat exchanger tube, try to avoid the brittle fracture of stainless steel heat exchanger tube.

2. Stainless steel heat exchanger tube brittle fracture, mostly caused by the stress corrosion of Cl- and H2S. To be more specific, it is.

(1) Stress is certain to have, the effective stress that produces stress corrosion is tensile stress, it is the superposition of engineering stress, residual stress and assembly stress, residual stress in the production process of stainless steel heat exchanger tube and assembly process will be generated, in many cases, only residual stress is sufficient to produce stress corrosion; stress corrosion also has to stress concentration source, stainless steel heat exchanger tube in the assembly and use process are likely to form micro-cracks, bruises, and scratches, these are stress corrosion stress concentration source.

(2) A very small amount of Cl- (Cl- the content of more than 25mg/L), it can make austenitic stainless steel heat exchanger tube stress corrosion, cracking, Cl- on austenitic stainless steel heat exchanger tube stress corrosion, the first is in the stress concentration site pitting corrosion, along the grain boundary or penetration of the crystal to the internal penetration, when penetration to a certain depth, under the action of tensile stress, brittle fracture; in addition, H2S on Austenitic stainless steel heat exchanger tube stress corrosion is more hazardous than seawater, the stress corrosion mechanism is generated at high temperatures FeS and the role of wet air to produce even more sulfuric acid, easy to make austenitic stainless steel welding heat affected zone intergranular stress corrosion fracture.

3. It is worth noting that the brittle fracture related to the stainless steel heat exchanger tube, may also be the heat treatment of stainless steel heat exchanger tube, especially in some cases, in a certain tempering temperature interval, toughness indicators with the tempering temperature change curve there is a trough, showing the phenomenon of brittleness; Therefore, Dong Yan company production of stainless steel heat exchanger tube using a reasonable selection of materials and strict heat treatment process, in order to inhibit and prevent the generation of tempering brittleness, so as to ensure the heat transfer work of stainless steel heat exchanger tube.

Are stainless steel heat exchangers better?

Being suitable with simple, fresh water and not requiring the application of system regulators, a heat exchanger pool stainless steel is extremely useful. This implies that a ss heat exchanger only needs occasional upkeep to maintain its good shape.Additionally, it is important to realize that the efficiency of stainless-steel changes with the quantity of chromium it possesses. This indicates that it will be a less efficient heat exchanger except if the stainless steel has good quality.Although stainless steel claims superior quality, aluminum may be more affordable to produce, making it a preferred option for many boiler firms.