FZ35-70防喷器承压螺纹孔改型仿真分析

Simulation Analysis on the Modification of Pressure-Bearing Threaded Holes in the FZ35-70 Blowout Preventer

摘要: 针对FZ35-70型闸板防喷器承压螺纹孔因粘扣及腐蚀介质侵蚀而频繁报废的工程瓶颈，本研究设计了一种利用17-4PH不锈钢螺纹套进行冷处理再制造的改型修复方案。参照API 16A规范，对其进行几何建模。在此基础上，运用ANSYS软件建立了“螺栓–螺纹套–壳体”的有限元三维模型。在通过全局网格10 mm、局部细节加密至1 mm的网格独立性验证后，系统模拟了该复合结构在75 MPa额定工况下的响应规律。动态应力场演化结果表明：改型后，原先集中于壳体的螺纹根部的应力集中效应得到缓解；在75 MPa载荷下，壳体最大应力由238.79 MPa骤降至170.63 MPa，整体最大变形量也由0.18499 mm降低至0.13211 mm，异质材料界面展现出优异的力学相容性。最终结合API 16AR再制造标准，从理论与数值仿真两方面印证了该冷修复结构具备符合规范的承压安全性，为高压井控核心部件的延寿与绿色再制造提供了一条可落地的工程范式。

Abstract: To address the engineering bottleneck of frequent scrapping of the pressure-bearing threaded holes in FZ35-70 ram blowout preventers (BOPs) due to galling and corrosive media, this study proposes a remanufacturing modification scheme utilizing 17-4PH stainless steel threaded inserts subjected to cryogenic treatment. In accordance with the API 16A specification, quantitative geometric reconstruction was performed on the structural features. Subsequently, a three-dimensional nonlinear finite element model of the “bolt-threaded insert-shell” composite structure was established using the ANSYS platform. Following mesh independence verification with a global mesh size of 10 mm and locally refined details down to 1 mm, the structural response under the rated working condition of 75 MPa was systematically simulated. The dynamic stress field evolution results demonstrate that, after modification, the stress concentration effect originally concentrated at the thread roots of the shell is significantly alleviated. Under the 75 MPa load, the maximum stress in the shell drops sharply from 238.79 MPa to 170.63 MPa, and the overall maximum deformation decreases from 0.18499 mm to 0.13226 mm, indicating excellent mechanical compatibility at the dissimilar material interface. Ultimately, combined with the API 16AR remanufacturing standard, both theoretical analysis and numerical simulations verify that the cryogenically repaired structure meets the required pressure-bearing safety specifications. This provides a practical and implementable engineering paradigm for the life extension and green remanufacturing of high-pressure well control core components.