| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 773943 | Engineering Failure Analysis | 2014 | 10 Pages |
•We analyse the failure of a centrifugal cast roll in CA-15M steel.•Transversal fracture was initiated in its internal surface due to tensile thermal stresses.•The microstructure is embrittled and sensitized by continuous network of M23C6 carbides along the δ/α′ interfaces.•Materials selection to minimise thermal stress and thermal strain chose CB-7Cu martensitic stainless steel aged at 495 °C.
The failure analysis of a martensitic stainless steel (CA-15M) roll manufactured by centrifugal casting and used in cast glass rolling was carried out by means of traditional characterization techniques (optical metallography, SEM, EDX microanalysis, tensile testing and XRD). The roll was in the as-cast condition and its microstructure featured large proportion of δ ferrite (between 20% and 27%) in a martensitic (α′) matrix, with the δ/α′ interfaces presenting an intergranular network of M23C6 carbides. The crack propagation began in the internal surface of the roll, with δ/α′ intergranular and transgranular cleavage in the “equiaxed region” of the casting, progressing to δ/α′ intergranular ductile fracture in the “columnar” and “chilled regions”. Tensile thermal stresses in the internal surface of the roll associated with microstructural embrittlement (network of interfacial carbide and microporosities) are thought to be the main causes for the premature failure of the roll. Finally, materials selection was performed to replace the CA-15M stainless steel with another class of stainless steel for centrifugal casting.
