Differences Between GH3030 Capillary Tube and GH3044: Which One to Choose

Both GH3030 and GH3044 are commonly used high-temperature alloy capillary tubes, and while they both belong to the nickel-based high-temperature alloy category, their composition and performance differ significantly. Here’s a detailed comparison and guidance on how to choose between them:

1. Key Differences Comparison

Composition Design Focus

• GH3030 is a typical nickel-chromium binary alloy system, with approximately 70% nickel and 20%-23% chromium. It contains small amounts of iron and titanium. The composition is primarily designed for basic high-temperature oxidation resistance, meeting standard heat-resistance requirements.

• GH3044, on the other hand, is based on the nickel-chromium system but includes an additional 15%-17% molybdenum and small amounts of tungsten. The chromium content is raised to 23%-27%. Through the synergistic effect of multiple elements, GH3044 is optimized for enhanced high-temperature strength and corrosion resistance, making it suitable for more demanding conditions.

Core Performance Indicators

• High-Temperature Resistance:
  GH3030 can withstand continuous temperatures up to 900°C, with a short-term peak temperature of around 1000°C. At high temperatures, its strength is moderate and may experience slight deformation due to stress.

  GH3044, however, can operate at continuous temperatures up to 1100°C and can briefly tolerate temperatures up to 1200°C. Its high-temperature creep strength (resistance to deformation under high temperature) is 1.5 to 2 times that of GH3030. Additionally, GH3044 shows superior resistance to corrosion from sulfur-containing, vanadium-containing, and other corrosive media, reducing the risk of oxidation skin peeling and internal corrosion.

2. Scientific Selection Guidelines

Primary Selection Criterion: Operating Temperature

• If the application operates at temperatures below 900°C, such as domestic wall-hung boiler heat conduction tubes or small industrial heating furnace thermocouple capillary tubes, GH3030 is sufficient, offering a better cost-performance ratio than GH3044.

• If the operating temperature is consistently between 900°C-1100°C, such as in aerospace engine fuel conduits or high-temperature gas conduits in metallurgy, GH3044 must be used to prevent material softening and tube leakage at high temperatures.

Consider Corrosive Medium

• For environments exposed to clean air, inert gases, or other non-corrosive media, GH3030's oxidation resistance is adequate, making it ideal for applications such as high-temperature steam tubes in food processing equipment.

• For applications in contact with corrosive media such as acidic gases in chemical reactions or sulfur compounds in power plant flue gases, GH3044, with its molybdenum and tungsten elements, forms a dense oxide layer that provides superior corrosion resistance. This makes it more suitable for chemical high-temperature reaction vessels, feed pipes, or monitoring capillary tubes in power plant boilers.

Consider the Stress Conditions

If the capillary tube is subject to low-load tasks such as temperature measurement or low-pressure flow guidance at normal or low temperatures (e.g., household water heater temperature sensors), GH3030’s strength is fully sufficient.

• For applications involving high-temperature high-pressure conditions (such as high-pressure steam transport) or vibration and shock (such as in marine engine piping), GH3044's higher strength can prevent tube deformation or rupture, ensuring safe operation of the equipment.

3. Conclusion: How to Choose?

The selection should be based on matching the material's performance to the working conditions. The key factors to consider are:

• Temperature: The material must withstand the operating temperature range.

• Corrosive Medium: Choose materials with adequate resistance to the corrosive environment.

• Mechanical Stress: Consider whether the tube will be subjected to low-load or high-load conditions.

Finally, balance the performance requirements with the cost budget to avoid wasteful over-specification or potential failures due to under-specification.

For more information on GH3030 capillary tubes, please feel free to contact Zhongxing Nickel Alloy at: 19145729409