Add Some RE to Make Better Tubes

Rare Earth is the general name of seventeen metal elements including lanthanide, scandium and yttrium in the chemical periodic table whose reserves are rare, non-renewable, and it is difficult to separate, purify and process. It is an important support for the manufacture of new materials and a key resource related to national defense science and technology, and is known as "universal Earth" and "industrial vitamin".   Adding rare earth elements to steel pipes can improve their plasticity, toughness, wear resistance, corrosion resistance, and physical properties can be greatly improved. Steel pipes with rare earth elements are widely used in wet hydrogen sulfide environment, high-sulfur crude oil mining and refining, shale gas mining and transportation, bearing steel and other fields.   

Since 2018, our company has received technical documents of 10(HSC) heat exchange tubes designed by Luoyang Institute of Sinopec and other units successively. However, due to different requirements on rare earth, vanadium and other elements and physical properties, it has brought troubles to the billets purchasing and manufacturing process. KANGHONG set up a "wet hydrogen sulfide corrosion resistant heat exchange tube engineering technology development” team which integrated requirements of technical files from different design institute, communicate with the upstream steel mills repeatedly about the starting point, position, amount and terminal process control of rare earth addition，requiring the reduction of harmful elements such as sulfur, phosphorus and oxygen in steel billets to ensure that rare earth plays the role of micro alloy, and signed the billet processing agreement that meets the requirements of all design documents.    KANGHONG formulated the corresponding production process according to the technical document of 10 (HSC) heat exchange tube, and strictly controlled the pickling and heat treatment process. Samples of finished steel tubes were sent to Hefei General Research Institute for sulfide stress cracking test (SSC) and hydrogen induced cracking test (HIC), and the cracking threshold value was 0.9~1.0Rp0.2.   At the same time, CLR, CTR, CSR values are lower than the requirements of the design document.   At the beginning of 2021, Shanghai Gaoqiao Petrochemical is in urgent need of a batch of 10 (HSC) heat exchange tubes for overhaul. Under the condition of sufficient raw materials, our company successfully delivered the tubes within 15 days, which won high praise from the client.   

On July 1st, 2021, new standard NB/T47019-2021 officially implemented, the new standard clearly points out that 10 (HSC) heat exchange tube should add rare earth elements (Re) to improve its corrosion resistance, which marks the rare earth elements in the field of seamless steel pipe application into the era of standardization, add some rare earth to make better "tube" , with the better in user experience , the better in the development of the enterprise,while promoting the high-quality development of seamless steel pipe industry.