Production method for reducing and fining the high-carbon chromium bearing steel D-type impurity

Abstract

The production process with reduced and fined type-D inclusion in high-carbon chromium bearing steel features the four-step metallurgical process including initial smelting of steel liquid in electric furnace, refining in bottom blowing Ar LF ladle furnace, deairing in VD vacuum furnace, and die casting or continuous casting. By means of the comprehensive deoxidation process including pre-deoxidation of aluminum deposition of the steel from electric furnace, deoxidation with Fe-Si powder diffusion slag in LF site and vacuum carbon deoxidation in VD site; and the new refining process including high alkalinity slag desulfurization in LF site, adoption of low alkalinity slag in the VD site and reducing free CaO inside slag, the present invention reaches the aims of reducing and fining type-D inclusion.

Description

technical field [0001] The invention relates to a control method for bearing steel inclusions in the metallurgical industry, in particular to a production method for controlling (reducing and refining) the D-type inclusions of high-carbon chromium bearing steel. Background technique [0002] The cleanliness of high-carbon chromium bearing steel and the fatigue life of the bearing (the main damage form of the bearing is fatigue spalling, and the inclusions in the steel are the main cause of fatigue spalling. The fatigue life of the bearing is generally determined by the shape and size of the inclusions in the steel , Quantity and uniformity of distribution.) are closely related. In recent years, with the rapid development of the economy, bearing production and use departments require the production of bearing steel with higher purity to meet the needs of lightweight bearings and longer life. [0003] For a long time, metallurgists have always regarded the oxygen content as a...

AI Technical Summary

Problems solved by technology

), so far, no bearing steel manufacturer in my country has been fully recognized by the world-famous bearing manufacturer Sweden SKF (SKF company D33-1 bearing steel standard, common 3S steel grade and high-level Grade 3 steel of the same variety In the No. 1, the classification of inclusions of type D in bearing steel is clearly stipulated, which not only expands the scope of classification of inclusion properties to ellipsoidal oxides, titanium nitrides and sulfides with length / width ≤ 5; Class and size limit requirements: 3S requires D fine ≤ 1.0, D coarse ≤ 1.0; Grade 3 requires D fine ≤ 1.0, D coarse ≤ 0.5, Dmax ≤ 27μm, Dmax ≤ 27μm is equal to Ds ≤ 1.0)