Effects of deep cryogenic treatment on property of 3Cr13Mo1V1.5 high chromium cast iron

Effect of cryogenic treatment on the matrix structure and abrasion resistance of white cast iron subjected to destabilization treatment

The initial as-cast microstructure of a high-chromium (2.35% C, 18.23% Cr) white cast iron consisting of primary austenitic dendrites and a eutectic mixture of M7C3 carbides/austenite was extensively modified by four different heat treatments: H.T.A: destabilization (970 °C-2.5 h), H.T.B: destabilization/subcritical treatments (970 °C-2.5 h + 600 °C-13 h), H.T.C: subcritical treatment (600 °C-13 h) and H.T.D: subcritical/destabilization treatments (600 °C-13 h + 970 °C-2.5 h). H.T.A leads to martensitic structures that present considerable precipitation of cubic secondary carbide particles of M23C6 type. H.T.B produces pearlitic structures and causes further carbide precipitation and pre-existent carbide particle shape modifications. H.T.C extensively modifies the initial as-cast structure to more pearlitic morphologies accompanied with spheroidization/degradation of the M7C3 primary carbide structure. H.T.D causes extensive formation of secondary carbide particles within the primary austenitic matrix; the latter has been mainly transformed to martensite. The effect of each heat treatment on the hardness of the alloy was correlated with the attained microstructure.

Microstructural Modifications of As-Cast High-Chromium White Iron by Heat Treatment

The precipitation and transformation of secondary carbides in a high chromium cast iron

Effects of cryogenic treatment on the microstructure, and abrasion resistance of CrMnB high-chromium cast iron subjected to sub-critical treatment were investigated by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and wear test. The results show that cryogenic treatment makes the alloy present a more refined and homogeneous matrix. In the course of sub-critical treatment followed by cryogenic treatment, the amount of precipitated secondary carbide was more than that in air cooling. Cryogenic treatment can further reduce the austenite content but cannot make retained austenite transform to martensite completely. After cryogenic treatment, the hardness and abrasion resistance of CrMnB high-chromium cast iron can be improved obviously due to the precipitation of carbides, the martensite transformation, and a refined microstructure resulting from cryogenics treatment.

Jing Yan

Papers

TEM study on precipitation and transformation of secondary carbides in 16Cr–1Mo–1Cu white iron subjected to subcritical treatment

A Multifunctional Subassembly of Carbon Nanotube Paper for Stable Lithium Metal Anodes

Roles of Lithium Aluminum Titanium Phosphate in Lithium Batteries