Behaviors and Phase Analysis of Tellurium in Steel
1972 Volume 58 Issue 14 Pages 2040-2048
Details
1972 Volume 58 Issue 14 Pages 2040-2048
An attempt has been made to establish the meth od for phase analysis of Te in steel. Te is found in steel to take the forms of MnTe, iron telluride-mainly β-FeTe 0.9, and, in special case of high Te and low C contents, β-FeTe 1.9, and free Te which segregates on cooling from the γ-phase along by pearlite structure; these pre-cipitates of Te compounds (e xcept ε-FeTe1.9 unstudied) can be divided into soluble Te po rtion (MnTe) and insoluble Te portion (β-FeTe 0.9 and free Te) by 2-3N HCl dissolution at room temperature. MnTe canbe det ermined from the difference between total Te and ins oluble Te contents, and by determining Fe andTe, respectively, in the HCl insoluble residue β-FeTe 0.9 and free Te contents can be estimated supposing that any other iron compounds do not exist in the residue.
As a result of the phase analysis of Te in the specimens, the followings were clarified;
1) Te in steel exists predominantly as MnTe, and the relative content of MnTe becomes larger with increasing C content. MnTe may be dissolved by solution treat ment at 1 200°C and after water quenching reprecipitated by heating at 750°C.
2) The ratio of free Te/insol Te becomes larger with inc rease of C content.
3) The segregation of free Te occurs along by pearlite structure and this is thought to result from the difficulty of its dissolution into ferrite and cementite.
4) Loss of Te is not observed through the heat treatment up to 1 200°C
