GB 13075-91 Welded Steel Cylinders Periodic Inspection and Assessments
The GB 13075-91 is a national standard for welded steel cylinders periodic inspection and assessments. The scope of GB 13075-91 covers the design and manufacture, inspection, testing, manufacturing licensing requirements and maintenance, periodic inspection and assessment of welded steel cylinders of prescribed safety quota gas, volatile gas, mixed gas and liquefied gas, which are tension filled and refillable. The criteria for periodic inspection shall be determined by the national standard for use of high-pressure cylinders.
The scope of this national standard applies to tension filled, refillable welded steel cylinders with a wall thickness of no less than 3mm, water capacity of not more than 40L, inner diameter exceeding 160mm, and the total maximum working pressure no more than 300 MPa.
The tensile strength, wall thickness, and safety ratio of welded cylinders must meet the requirements in the national standard on pressure vessels. The design, manufacture and other related process of these welded cylinders ought to comply with the requirements specified in the national standard on pressure vessels.
The conditions and cyclic work load of welded cylinders provided by the user, determined by the user, or associated with the product should be taken into account for the inspection. The condition grading of welded steel cylinders shall follow the national standard on the rules of classification, and the type of welding seam shall be inspected in accordance with the requirements of the national standard for inspection methods for pressure vessels.
Besides, welded cylinders with an internal water volume of less than 2.5L and an inner diameter of less than 160mm, and whose wall thickness is greater than or equal to 2mm are exempted from the periodic inspection requirement. However, whether or not these cylinders are fit for use must be based the actual using conditions and according to the opinion of a qualified professional.
The inspection should be split into internal and external test and periodic test and assessment. The internal examination includes examination of the inner liner and assessment of the residual volume of the cylinder body. The external examination includes examination of the external surface of the cylinder, spring locks, check valve, safety device, adsorption valve, and filler valve. The periodic test and assessment shall include a hydrostatic pressure test, a proof pressure test, a visual inspection, and an airproof test.
The internal examination must inspect inner liner of the cylinder body, the condition of the sealing material, the condition of the internal gasket, and the residual amount of the cylinder body or it’s contents. The external examination of the welded cylinder should check for deformation, pitting, corrosion, leakage, error in the welding joints and other mechanical damage, painted surfaces and safety devices.
The hydrostatic pressure test examines the material, welds, and gasket seal with enhanced security to ensure that there is no visible leakage and that the material, weld and gasket meet the design requirements. The proof pressure test is a test to verify whether the product satisfies the proof pressure set by the manufacturer. The visual inspection is conducted to check the surface area and general condition of the cylinder in order to guarantee the quality of the welding joint. The airproof test should largely be directed at those that are adversely affected by environment and air pollutants to guarantee the airproof performance of contain a certain amount of oxygen or carbon dioxide and steel cylinders.
The whole process of the periodic inspection and assessment of the welded steel cylinder should be done by a professional team, and the assessment results shall also be licensed by the technical supervision department. The approved periodic inspection and assessment results are valid for a period of two years for cylinders for the industrial use, and are valid for a year for cylinders for the medical use. Subsequent examination and assessment should be conducted when their validity period expires.
The safety and quality of the welded steel cylinder is of most importance, and the requirements in this national standard should ensure that the cylinders are in accordance with the safety and quality requirements of their use.
总结：
本文主要介绍了GB 13075-91钢质焊接气瓶定期检验与评定的内容。该国家标准覆盖了设计、制造、检验、试验、制造许可要求、维修、定期检验和评估等，适用于压力容器中指定的安全系数的负面充气、挥发性气体、混合气体和液化气的焊接钢瓶。在定期检验和评估中，应采用高压瓶使用的国家标准来确定检验标准，涉及内检、外检、定期检验和评估，包括水压试验、证明压力试验、视检、气密性试验等，整个检验和评估流程应由专业人员完成，并由技术监督部门颁发认证结果，用于工业用途的瓶子有效期为两年，用于医用的瓶子有效期为一年。
