Additive manufacturing (AM) is a relatively new manufacturing method that can produce complex geometries and optimized shapes with less process steps. In addition to distinct microstructural features, residual stresses and their formation are also inherent to AM components. AM components require several post-processing steps before they are ready for use. To change the traditional manufacturing method to AM, comprehensive characterization is needed to verify the suitability of AM components. On very demanding corrosion atmospheres, the question is does AM lower or eliminate the risk of stress corrosion cracking (SCC) compared to welded 316L components? This work concentrates on post-processing and its influence on the microstructure and surface and subsurface residual stresses. The shot peening (SP) post-processing levelled out the residual stress differences, producing compressive residual stresses of more than −400 MPa in the AM samples and the effect exceeded an over 100 µm layer below the surface. Post-processing caused grain refinement and low-angle boundary formation on the sample surface layer and silicon carbide (SiC) residue adhesion, which should be taken into account when using the components. Immersion tests with four-point-bending in the heated 80 °C magnesium chloride solution for SCC showed no difference between AM and reference samples even after a 674 h immersion.

中文翻译：

---

增材制造的316L不锈钢样品：后处理后的微观结构，残余应力和腐蚀特性

增材制造（AM）是一种相对较新的制造方法，可以用较少的工艺步骤生产复杂的几何形状和优化的形状。除了独特的微结构特征，残余应力及其形成也是AM组件固有的。在准备使用AM组件之前，需要执行几个后处理步骤。要将传统的制造方法更改为增材制造，需要进行全面表征以验证增材制造组件的适用性。在非常苛刻的腐蚀气氛下，问题是与焊接的316L组件相比，AM是否降低或消除了应力腐蚀开裂（SCC）的风险？这项工作集中于后处理及其对微观结构以及表面和地下残余应力的影响。喷丸处理（SP）可以消除残余应力差，在AM样品中产生大于-400 MPa的压缩残余应力，其作用超过了表面以下100 µm的层。后处理会导致晶粒细化和样品表面层上的低角度边界形成以及碳化硅（SiC）残留物粘附，在使用组件时应考虑在内。在加热的80°C氯化镁溶液中对SCC进行四点弯曲的浸入测试显示，即使浸入674 h，AM和参考样品之间也没有差异。后处理会导致晶粒细化和样品表面层上的低角度边界形成以及碳化硅（SiC）残留物粘附，在使用组件时应考虑在内。在加热的80°C氯化镁溶液中对SCC进行四点弯曲的浸入测试显示，即使浸入674 h，AM和参考样品之间也没有差异。后处理会导致晶粒细化和样品表面层上的低角度边界形成以及碳化硅（SiC）残留物粘附，在使用组件时应考虑在内。在加热的80°C氯化镁溶液中对SCC进行四点弯曲的浸入测试显示，即使浸入674 h，AM和参考样品之间也没有差异。