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How to choose material of plate heat exchangers?

Release time:

2025-04-28

The following is a detailed analysis of common materials and their applicable scenarios:

1. Metal materials

1) Stainless steel

(1).304 stainless steel

a.Features: General-purpose austenitic stainless steel, low cost and good processing performance.

b.Applicable scenarios: Clean water, low-corrosive media (such as air conditioning systems, food industry).

c.Limitations: Not resistant to chloride ion corrosion (prone to pitting corrosion).

(2).316/316L stainless steel

a.Features: Contains molybdenum (Mo), corrosion resistance is better than 304, especially resistance to chloride ions and acidic media.

b.Applicable scenarios: Seawater, saline solutions, chemical processes (such as pharmaceuticals, petrochemicals).

(3).904L stainless steel

a.Features: High nickel and molybdenum content, resistant to strong acids (such as sulfuric acid and phosphoric acid).

b. Applicable scenarios: Highly corrosive chemical environments (but extremely expensive).

2) Titanium and titanium alloys

(1).Features:

a.Extremely resistant to chloride ions (seawater, salt water) and oxidizing acids (such as nitric acid).

b.High strength and light weight, but high cost, and need to avoid contact with fluorides.

(2).Applicable scenarios:

Seawater cooling, ships, nuclear power, titanium dioxide production, etc.

3). Nickel-based alloys (such as Hastelloy, Inconel)

(1).Hastelloy C276:

Resistant to strong acids (hydrochloric acid, sulfuric acid) and high-temperature corrosion, suitable for chemical industry and flue gas desulfurization.

(2).Inconel 625:

Resistant to high-temperature oxidation (up to 1000°C), used for high-temperature exhaust gas treatment.

4).Other metals

(1).Copper alloy: Good thermal conductivity, but susceptible to ammonia and sulfide corrosion, now less used.

(2).Aluminum: Lightweight, low cost, used in low-temperature and low-corrosion scenarios (such as automobile heat dissipation).

2. Non-metallic materials

1) .Graphite

(1).Features: Resistant to strong acids and alkalis, thermal conductivity close to that of metals, but brittle.

(2).Applicable scenarios: highly corrosive chemical processes such as hydrochloric acid and sulfuric acid.

2) .Polytetrafluoroethylene (PTFE)

(1).Features: Resistant to almost all chemicals, but poor thermal conductivity (thin plate structure needs to be designed).

(2).Applicable scenarios: high-purity pharmaceutical and semiconductor industries.

3). Composite materials

Titanium-steel composite plate: takes into account the corrosion resistance of titanium and the strength of steel to reduce costs.

3. Key factors for selection

Factors	Considerations
Corrosiveness of the medium	Chloride ions, pH value, oxidizing/reducing media (such as 316L resistant to chloride ions, titanium resistant to seawater).
Temperature/pressure	Nickel-based alloys are required for high temperatures (>150°C); material strength needs to be considered for high pressures (such as titanium is better than PTFE).
Economical efficiency	The cost of 304 stainless steel is 1/5 of that of titanium, and a balance needs to be struck between life and initial investment.
Cleaning requirements	The food/pharmaceutical industry needs to use easy-to-clean, non-polluting materials such as 316L or PTFE.
Scaling risk	Rough surfaces are prone to scaling, titanium or polished stainless steel is better.

4. Typical industry application cases

(1).Food and beverage: 316L stainless steel (resistant to lactic acid and citric acid).

(2).Seawater desalination: titanium plate (resistant to chloride ion corrosion).

(3).Chemical sulfuric acid treatment: Hastelloy C276 or graphite.

(4).HVAC: 304 stainless steel (low cost, clean water).

5. Special considerations

(1).Galvanic corrosion: avoid direct contact between dissimilar metals (such as titanium and stainless steel require insulating gaskets).

(2).Welding process: Nickel-based alloys require special welding materials, and titanium requires argon shielded welding.

By systematically analyzing the working conditions, material selection can be optimized to balance performance and cost. It is recommended to cooperate with suppliers to conduct material corrosion tests or working condition simulation tests to verify the selection.