In the instrumentation industry, the choice of stainless steel material directly affects the corrosion resistance, mechanical strength, service life and cost of the product. SUS304, SS316 and SS316L are three common types of stainless steel. This article will analyze their differences in detail and provide selection recommendations based on industry application scenarios.

1. Basic composition and core differences

SUS304 (304 stainless steel)

Composition: Based on 18% chromium (Cr) and 8% nickel (Ni), without molybdenum (Mo), and with a high carbon (C) content.

Features:

• Resistant to general corrosion (such as weak acid, atmospheric environment), but weak resistance to chloride ion corrosion.
• Excellent mechanical properties, easy to stamp, weld and process.
• Non-magnetic, low cost, it is a general-purpose stainless steel.

SS316 (316 stainless steel)

Composition: Add 2-3% molybdenum (Mo) to 304, and the nickel content is slightly higher (10-14%).

Features:

• Corrosion resistance is significantly improved, especially suitable for chloride ion environment (such as seawater, chemical media).
• Better high temperature strength, suitable for high temperature and high pressure scenarios.

SS316L (316L stainless steel)

Composition: Compared with 316, the carbon content is lower (≤0.03%), which is a low-carbon version.

Features:

• It is not easy to cause intergranular corrosion due to carbide precipitation after welding, and is suitable for complex structures that need to be welded.
• It is more stable in highly corrosive environments (such as acid and alkali solutions containing chloride ions).

2. Performance comparison and industry application

Index	SUS304	SS316	SS316L
Corrosion resistance	General environment	Chloride ion/high temperature environment	Strong corrosion/welding environment
Mechanical strength	Good	High	High (strong high temperature creep)
Processability	Easy to process, low cost	Difficult to process, high cost	Excellent welding performance
Typical applications	Conventional sensor housing	Seawater equipment, chemical instrumentation	High-precision welding instrumentation

1) Pressure transmitter

• SUS304: Suitable for dry, non-corrosive environments (such as air compression systems).
• SS316/316L: Recommended for environments containing corrosive media such as chemicals and offshore platforms. 316L is particularly suitable for welding sealing components.

2) Flow meter and level sensor

• In sewage treatment or seawater applications, SS316L’s resistance to chloride ion corrosion can extend the life of the equipment.
• The food or pharmaceutical industry needs to avoid metal contamination, and the low sensitivity of 316L is more in line with safety standards.

3. Selection suggestions and cost considerations

1) Priority for economy: SUS304 has the lowest price and is suitable for projects with limited budgets and mild environments.

2) Corrosion resistance requirements: If exposed to seawater, acid and alkali media, choose SS316 or 316L, the latter has better long-term stability after welding.

3) High temperature and high pressure scenarios: The high temperature creep strength of SS316 can meet harsh working conditions (such as steam flow meters).

4. Summary

The differences between SUS304, SS316, and SS316L are due to composition and process, which directly affect their applicable scenarios. In the field of instrumentation, comprehensive selection is required based on actual working conditions (corrosiveness, temperature, processing requirements):

• General scenarios: SUS304 is cost-effective.
• Harsh environments: SS316 or 316L is preferred, the latter pays more attention to welding safety and long-term corrosion resistance.

Through scientific material selection, product reliability can be improved and maintenance costs can be reduced, providing more suitable solutions for global customers.

Related product recommendations:

SUS304 material: Miniature sputtered thin film pressure transducer 0-100bar, digital turbine flow meter for oil measurement, Radar Level Sensor

SS316 material: Submersible water level sensor for wells

SS316L material: Submersible level sensor, food grade electromagnetic flow meter sanitary design

Please contact us for more information on material parameters or customized solutions.

Keywords：

1. Miniature sputtered thin film pressure transducer 0-100bar
2. digital turbine flow meter for oil measurement
3. Submersible water level sensor for wells
4. food grade electromagnetic flow meter sanitary design