Questions about the corrosion requirements in GB/T 150.4?
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GB/T 150.4-2011 specifies as follows: 8.5 For stainless steel and composite steel plate containers with corrosion resistance requirements for their surfaces before and after heat treatment, the contaminants and harmful substances on the surface of the stainless steel must be removed prior to heat treatment. After heat treatment in accordance with the requirements of the design documents, the components made from such materials also need to undergo pickling and passivation treatments. Regarding this regulation, the standard practice is to require pickling and passivation whenever stainless steel is involved. Question: 1: Should the corrosion resistance requirements here be determined by the equipment specialists on their own, or should the process specialists handle it? 2: What are the situations we encounter with containers made of stainless steel and composite steel plates that have no corrosion resistance requirements? In my understanding, for pressure vessels made of stainless steel due to hygiene requirements, it is possible to opt out of acid washing and passivation treatments.
1: The determination of corrosion resistance requirements should be made jointly by the equipment team and the process team. The equipment specialty can put forward specific requirements based on the types of media and environmental conditions that may cause corrosion to the containers during use ； The process engineering team can, based on the actual conditions, develop appropriate anti-corrosion measures to ensure that the corrosion resistance of the containers meets the required standards. 2: Containers made of stainless steel or composite steel plates that do not require corrosion resistance refer to those in which the medium inside the container does not have a significant corrosive effect on the container material, or in cases where the container does not need to be used for an extended period of time, it is not necessary to carry out acid washing or passivation treatments. However, in applications with high hygiene requirements, even if the medium does not have a significant corrosive effect on the container itself, acid washing and passivation treatments are still necessary to ensure the cleanliness and corrosion resistance of the container surface. .
This post was last edited by wanlirn on 2023-5-18 at 14:45. Besides being used for applications that require heat resistance, stainless steel must also be corrosion-resistant, which is easy to determine; it relates to hygiene requirements. For example, in food processing equipment, pickling and passivation are certainly required as well