Research Of Large High Strength Apply On Large Equipment

With the development of chemical equipment be larger, it requires the materials to high strength steel, in order to reduce its weigh and transport more conveniently.This paper analyzes the trend of large-scale petrochemical equipment's development.Based on the analysis of the cause of the crack which appeared at the bottom of reactor/cooler weld in two operational epoxy ethane glycol devices of a set of ethylene glycol equipment in a plant, we discuss the problem of large equipment which is made of high strength steel, and give some strategies to the crack in these equipments.We fix on the number of weld defects and the location of the crackles through the magnetic powder and ultrasonic testing of two epoxy ethane reactors. We find out the main reason of the cracking through analyzing the fracture specimens by Physics and Chemistry Testing.Results show:high strength steel welding line exhibited a tendency toward stress corrosion; the crack is caused by stress corrosion.It is difficult for large devices on-site repairing; we made safety determinations toward the defects according to the fracture mechanics principle. Results show:mother materials and weld satisfied the condition of leakage first then broken, because of good toughness. it won't cause broken brittle fracture failure.Finally we discuss the technical feasibility for field repair.