Innovation and Application of Key Techniques for Mini-flow Production of Martensitic Stainless Steel Oil Well Pipe

The conventional manufacturing process for martensitic stainless steel pipe involves forging the cast ingot， and then turning the forged ingot into pipe via hot-piercing. Such process has disadvantages as easily causing defective fold，low qualification rate，long flow process and high cost，etc. Described here in the essay is a new mini-flow process for the martensitic stainless steel oil well pipe，i.e.，CC billet + hot-extrusion. And serial trail manufacture and inspections of the said pipe are made. Relevant practice demonstrates that the said martensitic stainless steel pipe has good surface quality and its as-cast structure is adequately crushed；and after being quenched and tempered，the pipe possesses such advantages as homogeneous microstructure，fine grain，and mechanical properties like strength，elongation，hardness and impact energy which are all up to applicable requirements a specified under Standards API Spec 5CT—2018 and ISO 13680： 2020.