LPG storage tank forming part

Some harmful elements have exceeded the standard; ④The thickness of the head does not meet the rules. According to the JB4746 rules, the minimum thickness of the head should be greater than the nominal thickness minus the additional amount of wall thickness. A liquefied gas storage tank is ?1000, and the planned thickness is 12mm. Its head is limited by 16MnR steel plate, and its wall thickness reduction is about 1mm, which is greater than the negative error of the steel plate. It should be limited by 14mm 16MnR steel plate, and its small wall thickness meets the planning requirements.