How to select the most economical and rational materials for pressure vessels?

Choosing the right materials for pressure vessels is crucial for both economic efficiency and safety. The following guidelines outline how to select materials that strike a balance between cost-effectiveness and suitability for the intended use.

1.General Principles for Economical and Rational Material Selection

Thickness Less than 8mm: When the required thickness is less than 8mm, carbon steel is usually the preferred material over low-alloy steel, except for multilayered vessels.

2.Stiffness vs. Strength: For applications focused on structural integrity and stiffness, carbon steel is preferred. For strength-focused designs, materials should be selected based on pressure, temperature, and media, with options likeASTM A36 or SA516 Gr.70.

3.Stainless Steel: If the required thickness of stainless steel exceeds 16mm, alternatives such as cladding, composites, or weld overlays should be considered.

4.Temperature Considerations: Stainless steel should generally not be used for designs where the temperature is less than or equal to 500°C. For temperatures below 350°C, pearlitic heat-resistant steel is not recommended.

5.Minimizing Material Variety: Reducing the number of different steel types and specifications used in the design can help minimize costs.

pressure vessels

Guidelines for Material Selection

The following principles provide a framework for choosing appropriate steel types for different applications:

1.Carbon Steel: Suitable for low- and medium-pressure vessels where the media is not highly corrosive and the wall thickness is moderate. It can also be used for non-pressure components or where wall thickness is determined by structural or rigidity factors.

2.Low-Alloy Steel: Used in environments with low corrosion and for thicker vessels (≥8mm).

3.Pearlitic Heat-Resistant Steel: Ideal for high-temperature environments with hydrogen or hydrogen sulfide corrosion, or for pressure vessels operating between 350°C and 575°C.

4.Austenitic Stainless Steel: Appropriate for highly corrosive environments, preventing iron ion contamination, or where the design temperature exceeds 500°C or falls below -100°C. When austenitic stainless steel is used in environments prone to intergranular corrosion, temperature limits must be considered:

(1)Low-carbon, non-stabilized austenitic stainless steel: ≤300°C.

(2)Ultra-low-carbon austenitic stainless steel with ≤3% molybdenum: ≤350°C.

(3)Ultra-low-carbon austenitic stainless steel with >3% molybdenum: ≤400°C.

(4)Low-carbon stabilized austenitic stainless steel: ≤400°C.

5.Non-Stabilized Austenitic Stainless Steel: If the material contains more than 0.03% carbon and lacks stabilizing elements such as titanium or niobium, it should not be used in environments where intergranular corrosion could occur if the material has undergone heat treatment or welding at temperatures exceeding 300°C.

By following these material selection guidelines, pressure vessel designs can achieve the right balance between cost-effectiveness and performance, ensuring safety, durability, and compliance with industry standards.