GB 3531-1996 Low Alloy Steels for Pressure Vessels Surface Quality
GB3531-1996 is a national standard for the surface quality of low alloy steels for pressure vessels. The standard was formulated in order to unify the requirements for the surface quality of low alloy steels for pressure vessels, define the surface quality requirements in terms of thickness and tensile properties, and specify the requirements for acceptance inspection. The standards also provide guidance for strengthening non-destructive testing and flaw detection for the surface quality of the steels.
The standard specifies the surface quality requirements for low alloy steels for pressure vessels with thickness not exceeding 50mm. The standard applies to steel plates with a thickness of 3-20mm and bars with a length of 3m-12m. The surface quality of steel plates and bars, including flatness requirements, surface preparation method, outer surface and inner surface quality requirements, surface treatment requirements, requirements for acceptance inspection, techniques of non-destructive testing and flaws detection, etc.
GB3531-1996 standard requirements are as follows:
1. Flatness requirements: The steel plates must meet the requirements of flatness according to the drawing and process sheet.
2. Surface preparation method: The steel plates or bars should be cleaned strictly by a high-pressure water jet or other appropriate methods.
3. Outer surface quality requirements: The surface of the steel plates or bars must be intact and free from any physical damage such as scratches, pits, corrosion, cracks, burns, defects and other defects affecting the function.
4. Internal surface quality requirements: The inner surface of the steel plates or bars, including the inner surface of all bored holes and welds, must be smooth and free from defects that affect the performance of the steel plates.
5. Surface treatment requirements: The quality of the surface treatment of the steel plates or bars must meet the relevant requirements of GB/T 123.
6. Acceptance inspection requirements: There should be acceptance inspection to the surface quality of the steel plates or bars.
7. Non-destructive testing and flaw detection technique requirements: Appropriate techniques of non-destructive testing and flaw detection should be used to detect any potential defects on the surface of the steel plate and bars.
GB3531-1996 is an important standard for the surface quality of low alloy steels for pressure vessels. It can help the manufacturers of pressure vessel components to select the appropriate material and strengthen the quality control for the surface of the steel plates and bars, which can effectively reduce and control the production risk, and guarantee the safety of the pressure vessels.
