API standard 650 welded tanks for oil storage roofs

Preheat Treatment
Many laboratory tests have shown preheat treatment of carbon steel to 300°F-400°F to be the equivalent of the post-heat treatment at no less than 1100°F insofar as the physical properties of the weldment are concerned.40,41 Some tests have indicated a slight advantage of the post-heat treatment. Most of the tests have been made on plates 3/4 in. - 1 in. thick; results must be viewed with caution if preheating is applied appreciably beyond this thickness range. However, for all practical purposes, improvement resulting from preheating is sufficiently well established so that preheat should be considered for field fabrication of API 620 crude oil tank plates over 3/4-in. thick whenever toughness of the tank API standard 650 welded tanks for oil storage is highly desired and the thermal post-heat treatment is impractical.

The reticulated API standard 650 welded tanks for oil storage shell API 650 storage tank is an important large-span space structure with high safety. Generally, the large-scale API 650 storage tank with a diameter of 21-60 meters or a volume of more than 20000 cubic meters should adopt the reticulated shell technology, which has been widely promoted and adopted in the world and China's petrochemical industry for more than 30 years.

Unqualified welding quality of API standard 650 welded tanks for oil storage is prone to hidden dangers such as oil tank steel plate cracks and leakage. To avoid this situation as much as possible, it needs to be avoided when the oil storage tank is manufactured. Scientific and reasonable measures are adopted to control the welding quality when welding the API standard 650 welded tanks for oil storage. How to reasonably control the welding process quality of oil storage tanks?