Haynes 230镍基合金无缝管的组织及性能

Microstructure and properties of Haynes 230 Ni-based alloy seamless tube

采用VIM+ESR+热挤压工艺制造出Haynes 230镍基合金荒管,经过两道次冷轧+固溶热处理开发出规格为Ф89 mm×12 mm的无缝管,并对其组织及性能进行了分析。结果表明:Haynes 230合金无缝管中存在较多沿纵向弥散均匀分布的细小白色析出相,主要为富W的碳化物,呈近似圆形或椭圆形均匀分布,少量呈带尖角的圆形,最大尺寸可达10μm,面积含量约为2%,此外还有少量灰色相,为富Cr的碳化物。无缝管基体为奥氏体等轴晶,且存在较多孪晶,纵向平均晶粒尺寸约为33. 35μm,晶粒度6. 5级;无缝管具有良好的拉伸性能、冲击韧性和耐晶间腐蚀性能。开发出的Haynes 230合金无缝管的化学成分、显微组织、力学性能及耐腐蚀性能满足其使用要求。

A Haynes 230 nickel-base alloy hollow billet was manufactured by VIM + ESR + hot extrusion process,and a Ф89 mm × 12 mm seamless tube was manufactured by two-pass cold rolling + solution heat treatment,and its microstructure and properties were analyzed. The experimental results show that there are many fine white precipitate phases distributed uniformly along the longitudinal direction in the seamless tube of Haynes 230 alloy. These white precipitate phases are the W-rich carbides distributed in a nearly circular or elliptical shape,a slight amount of them with sharp corners,their largest size is up to 10 μm,and their area content is about 2%. In addition,there is also a small amount of gray precipitate of Cr-rich carbide. The matrix of the seamless tube is austenitic equiaxed grains with many twins. The average grain size in the longitudinal direction is about 33. 35 μm or No. 6. 5 grade. The seamless tube has good tensile properties,impact toughness and intergranular corrosion resistance. The chemical composition, microstructure, mechanical properties and intergranular corrosion resistance of the developed Haynes 230 alloy seamless tube meet the use requirements.