Effects of alloying elements on microstructure, hardness, and fracture toughness of centrifugally cast high-speed steel rolls

Abstract

A study was made of the effects of alloying elements on the microstructure, hardness, and fracture toughness of centrifugally cast high-speed steel (HSS) rolls. Particular emphasis was placed on the role of hard carbides located along solidification cell boundaries and the type of the tempered martensitic matrix. Microstructural observation, X-ray diffraction analysis, hardness and fracture-toughness measurements, and fractographic observations were conducted on the rolls. The constitution and morphology of carbides observed within the intercellular boundaries varied depending upon the predominant alloying elements that comprised them. These massive carbide formations strongly influenced the bulk material hardness and fracture toughness due to their high hardness. The effects of alloying elements were analyzed on the basis of the liquidus-surface diagram which and indicated that the proper contents of the carbon equivalent (CE), tungsten equivalent, and vanadium were 1.9 to 2.0, 10 to 11, and 5 to 6 pct, respectively. The roll material, containing a small amount of intercellular carbides and lath-type tempered martensitic matrix, had excellent fracture toughness, since carbides were well spaced. Therefore, it was suggested that the optimization of alloying elements was required to achieve the homogeneous distribution of carbides.

Investigations on Heat Treatment of a High-Speed Steel Roll

“…Tempering at 793-813 K, high-carbon HSS roll presents smaller wear volume and excellent abrasion resistance. (6) The service life of high-carbon HSS rolls austenitizing at 1320-1330 K for 150-180 min and tempering at 790-800 K for 380-400 min is eight times longer than that of high-chromium white cast iron rolls used in the tensile reducing diameter mills of steel pipe.…”

“…The application of high-carbon high-speed steel (HSS) replacing high-chromium cast iron is one of the recent developments in the manufacture of rolls employed in the steel production (Ref [3][4][5][6]. Currently, many methods such as centrifugal casting (Ref 7,8), electric slag remelting (Ref 9), continuous pouring process for cladding (CPC) (Ref 10), hot isostatic pressing (Ref 11), and spray forming ( Ref 12,13), etc., have been used to fabricate the compound high-carbon HSS work roll.…”

Effects of Alloying Elements on Sticking Behavior Occurring during Hot Rolling of Modified Ferritic STS430J1L Stainless Steels

“…The matrix is mainly composed of lath-type tempered martensite. [15][16][17] Table II shows the room-and high-temperature hardness test results of the steels. The room-temperature hardness ranges from 150 to 165 VHN, and the A, B, and E steels are harder than the C and D steels.…”

Effects of Austenitizing Conditions on the Microstructure of AISI M42 High-Speed Steel

“…High-speed steels (HSS) have been widely used to make engineering cutting tools in quenched and high-temperature tempered conditions due to their high hardness, wear resistance, and favorable high-temperature properties [1][2][3]. Among them, AISI M42 HSS is one of the most popular one owing to its excellent combination of hardness and toughness.…”

“…Following quenching, they contain martensite, retained austenite, and undissolved carbides. The final microstructure after tempering, which may occur several times, mainly consists of tempered martensite and well-distributed hard carbides [1,[4][5][6]. It is known that microstructural factors like distribution of carbides, as well as characteristics of the martensitic matrix, play important roles in optimizing the properties of high-speed steel such as hardness, wear resistance, fracture toughness, and thermal-fatigue behavior.…”