封头最小成形厚度的施工图标注与计算书输入

在压力容器设计换证审查时，对施工图中封头的名义厚度和最小成形厚度标注及计算书的输入提出了质疑。对此以实例从封头的名义厚度影响许用应力及技术条件和最小成形厚度影响有效厚度及计算结果的准确性进而关系容器建造的安全可靠性进行了讨论，认为施工图设计应限定封头的名义厚度，最小成形厚度以标注为宜，而SW6数据输入应增加“成形减薄量C3”项。建议GB150的术语符号引入C3，GB／T25798应完善封头威形厚度减薄率，《压力容器定期检验规则》应监督封头制造的成形厚度减薄率，以为容器设计提供支撑。

Construction Drawing Marked and Calculation Input of the Minimum Thickness of Head

In the review of pressure vessel design certificate renewal, the nominal thickness and the minimum thickness of head labeled in the construction drawing and the calculation input are questioned. This paper discusses the influence of the nominal thickness on the allowable stress and technical conditions, the influence of the minimum forming thickness on effective thickness and the accuracy of the calculation results, and other safe reliability related questions in pressure vessel building. The construction drawing design should limit the nominal thickness of head; and the small thickness to annotation is appropriate, while the SW6 data input increase the ＂forming thinning C3＂. The term symbol GB150 into C3, GB/T25198 should improve the head forming thickness reduction ratio, ＂content regulation＂ should supervise the manufacturing forming thickness thinning rate, that design support for vessel.