Refinement Practice and Control of Impurity in Pure Ca and Ba Series Compound Alloys;

Strangers is created by human being,and the pursuits of purity always want to extinguish them through assimilation strategy and discrimination strategy.

We have learned a lot from the Russian-Soviet literature,but many important distinctive characters such as purity,confessional narration,and religious complex,are neglected,and even reputed by us as negative examples.

This paper is devoted to build an upper bound on the maximum number of clear two-factor interactions in 2~(n-(n-k)) designs with resolution Ⅳ.

Improving the purity of SA675M Gr70 Steel Used for Hanger Rod of Boiler Drum;

It has proved that 75 t LF also presents good ability of deoxidation and desulphurezation,which improved the purity of stainless steel with the addition of bottom argon blowing.

It is shown that high grade pipe steel can be produced with the three refining processes, but the purity and cleanness of the steel produced with LF-RH process are higher; the functions of different refining instruments are distinct, but they are affected effected by up and down working procedures because of the conjunction and restriction of the quantity and composition .

The effects of varying rare-earth content on cleanness, undercooling and grain size of 40CrMnSi alloy steel have been investigated by using metallographic microscope, scan electron microscope, temperature recorder, etc.

The relationships of cleanness, undercooling and grain size of low carbon steel have been investigated by using of vacuum glass encasement levitation melting.

During developing, the chemical composition and cleanness of steel can be controlled by UHP(EBT)+LF/.