The issue of minimum thickness for pressure vessels

Scientific name: Minimum forming thickness – the minimum thickness required after forming the compressed component to meet the design specifications.

The minimum thickness of a pressure vessel refers to the smallest safe thickness of the vessel wall, that is, the minimum wall thickness capable of withstanding internal pressure without failing or rupturing. This is to ensure that the container can withstand the stresses caused by internal pressure during operation without experiencing accidents. To determine the minimum thickness of a pressure vessel, the following factors need to be considered: 1. Internal pressure: The pressure inside the vessel is determined based on design requirements or operating conditions. 2. Material strength: Depending on the material selected, determine or test its strength properties. 3. Safety factor: Determine an appropriate safety factor in accordance with design specifications and industry standards. 4. Container shape and structure: Consider factors such as the container’s shape, structure, and loading method. Generally, the thin-walled theory or stress analysis can be used to calculate the minimum thickness of pressure vessels. The thin-wall theory is based on the geometric shape and stress conditions of the container, and calculates the minimum wall thickness using principles such as stress equilibrium and strain energy equilibrium. Stress analysis involves calculating the stress distribution within the container using numerical simulation or analytical methods, in order to determine the minimum wall thickness. It should be noted, however, that the design of pressure vessels also requires consideration of other factors such as welds, cracks, corrosion, and wear. Therefore, in practical design, it is also necessary to take these factors into comprehensive consideration and conduct the required checks and verifications to ensure the safety and reliability of the container. Please note that the design of pressure vessels involves highly specialized and complex areas of knowledge. It is recommended that you consult professional engineers or agencies when designing or selecting pressure vessels to ensure the rationality and safety of the design. .

Minimum thickness and minimum formability thickness are not the same concept. The minimum thickness is a value determined to ensure that the container does not deform during manufacturing, transportation, lifting, and other processes; it represents the minimum thickness required based on considerations of stiffness. According to GB/T150, for carbon steel and low-alloy steel containers, this thickness should be no less than 3 mm after the container has been formed, excluding any corrosion allowance, while for high-alloy steel containers it should generally be no less than 2 mm.

We generally indicate the nominal thickness of the sheet material plus the (minimum forming thickness requirement)

No, no – the minimum thickness and the design thickness are two completely different concepts. When using Q345R material, the minimum thickness, without taking into account corrosion allowance or negative tolerances, is 3 mm (this value is independent of pressure). However, the design thickness depends on pressure and is determined through calculations

I agree with you; minimum thickness and minimum formability thickness are not the same concept! One is the minimum thickness after molding, excluding the corrosion allowance; the minimum molding thickness is the smallest thickness required to meet the design specifications (including the corrosion allowance)

This post was last edited by Douwan on 2023-6-30 10:23. No, that’s not right; they are two different concepts

The determination of the minimum thickness of pressure vessels should take into account the effects of factors such as manufacturing, transportation, and installation.