API standard 650 larger diameter 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 standard 650 larger diameter 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.The API Std 650 standard published by the American Petroleum Institute (API) is designed to provide the petroleum industry with welded steel tanks for use in the API standard 650 larger diameter tanks storage of petroleum products and other liquid products commonly handled and stored by the various branches of the petroleum industry.In 2016. Our company offer 1200 tons API 5L GR.B hot rolled coil to Bangladesh——100 tons for 3.9*625mm, and 1100 tons for 7*683mm. It is one tender project, we get the tender at the end of 2015, and arrange the production in 2016. They required the tolerance of thickness is +0.1/-0.2mm, and width tolerance is +/-0.5mm, which is a very high requirement for coil tolerance, but our mill handling this very well. and our Q/C department witness all of the process.The seal of floating roof API standard 650 larger diameter tanks is a device used to reduce the evaporation loss of the storage liquid in the annular space between the tank wall and the outer ring plate of the floating roof. The common sealing forms include mechanical seal, elastic filling seal, lip seal and secondary seal. No matter what kind of seal, the seal must be combined with the floating roof effectively to reduce the evaporation loss of the liquid in the floating roof.Our company will accept the product quality objection registration record, pass it to the API standard 650 larger diameter tanks production unit and relevant departments, and timely coordinate the supervision of product API standard 650 larger diameter tanks quality objection. Our company coordinates the relevant department personnel to the customer unit to carry on the investigation, the processing.