Quality Control for Tube for Fabrication of High-strength Crane Gib Arm

Elaborated in the paper are the features of quality control for the tube for fabrication of histrength crane gib arm. Quality of the molten steel is ensured by means of properly-controlled quality of the scrape steel charge, and employing the full-process foam slag melting technique for the EAF process;property consistency of the steel is obtained with such techniques as sufficient desulfurization by forming hi-basic white slag, and tight control of the chemical element contents during the refining process;the steel cleanness is ensured by degassing and inclusion-removal with VD process;for the continuous casting process, Ar-shielding is used, while the inclusions in the steel are drawn out by the basic covering flux;the good macrostructure and satisfactory surface quality of the billets are ensured by well-controlled matching of the superheat level with the strand-withdrawing speed, and the appropriate first and secondary cooling systems. The crane gib arm as made of the tube is up to relevant customer requirements.