API Std 650 unanchored tanks tack weld

Large Low-Pressure Tanks Corrosion Allowance
In cases in which the rate of corrosion is closely predictable, additional metal thickness over and above that required for the initial operating conditions shall be provided and shall be at least equal to the expected corrosion loss during the desired life of the tank.
When corrosion effects are indeterminate before the tank is designed (although they are known to be inherent to some degree in the service for which the tank is to be used), and when corrosion is incidental, localized, or variable in rate and extent, the best judgement of the API Std 650 unanchored tanks designer must be exercised in establishing reasonable maximum excess tank wall thicknesses. For all tanks that come under this classification, a minimum corrosion allowance of 1/16 in. shall be provided.

In API 650 oil storage tank, when the mixing ratio of combustible medium and air reaches a certain limit, it is easy to cause explosion. Therefore, it is necessary to add API Std 650 unanchored tanks external floating roof to open cylindrical steel API Std 650 unanchored tanks tank. At present, the external floating roof is most suitable for large-scale API 650 oil storage tank in China, ranging from 20000, 30000, 50000 cubic meters to 100000 cubic meters.

In October 19th 2018, our Malaysia customer purchased 600 Tons CCS Grade AH36 mairne steel API Std 650 unanchored tanks plates to use in their shipbuilding project .This customer is a famous shipyard company in Malaysia. Their company has the business scope of tourism, shipbuilding, transportation and so on. As a terminal manufacturer, they have strict requirements on quality for CCS Grade AH36 mairne steel plates. After visiting our steel milll, the customer is very satisfied with the quality of this batch of CCS Grade AH36 steel plates.

The specifications used in the design of large oil tanks, API Std 650 unanchored tanks mainly include American Petroleum Institute Standard API 650, Japanese Industrial Standard JIS B8501, British Industrial Standard BS2654 and Chinese National Standard GB50341 from a global perspective. The formulas used in each specification are based on the hoop stress in the membrane theory. Each specification is based on the performance characteristics of materials and the construction technology level of their respective countries to determine the allowable stresses and weld coefficients. Therefore, the calculation results of tank wall thickness of API Std 650 unanchored tanks with the same volume are sometimes quite different according to different specifications.

We should focus on the main problems to be solved and pay attention to efficiency. After receiving the user's quality objection report data, the possible causes, responsible units, compensation amount, etc. of the problem shall be judged based on experience. To have a clear service plan, to be clear about what your main problem is, what technical support is needed, these should be prepared.