Application of Duplex Stainless Steel Pipe in Petroleum Refining

Over the years, the purchase of duplex stainless steel pipe in the oil refining industry has been used to do the special requirements for exchangers, pipes, containers and other applications in the refining environment. Each oil company and engineering contractor lacks a complete, authoritative information, material procurement, or the same normative lack of critical details in the development of procurement specifications, so occasional problems, which can actually be done through the correct material process and Manufacturing to prevent.
To this end, API (American Petroleum Association) project working group developed a unified, complete guidance. The API Working Group has clearly defined the scope of this document to cover the most important aspects of the oil refining industry. Including alloys limited to grades containing 22% Cr and 25% Cr. This product type includes pipes, plates, forgings, fittings and delivery pipes (excluding castings).
Duplex stainless steel pipe is mainly used in the manufacture of containers, exchangers and delivery pipes in petroleum refining, but these applications are used in wet acidic (liquid water and H2S) environments, water and chlorides, hydrocarbon-containing naphthenic acids limit. The report gives a reference and explanation, the reference material provides a good list of duplex stainless steel resources.
API publications give an early history of welding problems and how to overcome the development history of nitrogen, pitting and crevice corrosion in the API 938C, chloride stress corrosion cracking (SCC), hydrogen stress cracking and sulfide Stress corrosion cracking (SSC), ammonium sulfite corrosion, naphthenic acid corrosion and 475 ℃ (885 ℉) brittleness mechanism discussed the dual - phase stainless steel corrosion resistance and various limitations;
At the same time API report in accordance with the processing (welding, cutting, etc.) made a different request. The API report also includes two summary tables for the use of duplex stainless steel in petroleum refining. The first form includes NACE's 46 applications reported by the oil refining company, sorted by device, listing parts, grades, questions and other notes. The second summary form includes 24 types of applications from the seller's information and an oil refinery, sorting out the parts, grades, temperature, pressure, tube sheet material and notes. The table lists the applications and has undergone corrosion or other failure mechanisms leading to the selection of duplex stainless steel.