Microstructure and Mechanical Properties of M50 Steel by Combining Cold Rolling with Austempering

Abstract

The microstructure and mechanical properties of M50 steel subjected to combining cold rolling (CR) with austempering are investigated. The microstructure is characterized using X-ray diffraction and scanning and transmission electron microscopy. The mechanical properties are measured using the uniaxial tensile and Charpy impact tests. It is observed that an excellent combination of ultimate tensile strength (2536 MPa) and impact toughness (128 J) was achieved by combining austempering with CR; of which the ultimate tensile strength increased by 10% compared with traditional martensite quenching-tempering (Q-T) specimen and the impact absorbed energy exhibited 2.3 times of that in Q-T specimen. The observation of the microstructure indicates that CR obviously refines the thickness of bainite sheaves, which is favorable for the formation of ultrafine equiaxed ferrite during tempering.

Research Progress on the Wear Resistance of Key Components in Agricultural Machinery

“…M50 bearing steel is a high-performance specialty steel frequently used to fabricate high-speed rotating mechanical components such as bearings, gears, and drive shafts in agricultural machinery [38]. Mukhopadhyay et al [39] used abrasive testing equipment (ASTM G 65-85) and applied 13 kg load to carry out wear test on M50 bearing steel before and after quenching treatment.…”

Tensile Test Coupled with an EBSD Study of a GH4169 Ring Rolled Product

“…Only one slip system activation was realized by the twin hinder effect on th ranked 2nd slip system, thus this part of the grain rotated heavily as illustrated in th EBSD map in Figure 9h. The part where two slip systems are activated rotates towards [ 11], while the rest rotates towards [011]. The different rotation extent between G3 and G may derives from higher content of secondary phase and surrounding twin configura tions in G3.…”

“…Interestingly, in Figure 8a, G1_1 grain and G1_2 grain with close (S M − S S )/S M (10.94% and 10.82%, respectively) reveal different activation behaviors. The G1_1 grain activated the (111) slip plane (blue line), and a shallow trace (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11) developed at the left end of the grain. With no other traces found, the G1_2 grain shows a (−111) slip plane activated (in green).…”

“…Numerous attempts have been conducted to optimize the ring rolling parameters [9]. The flow behavior and microstructure evolution during hot ring rolling are the main research focus [10,11]. By controlling radial flow of metal during hot ring rolling, the reasonable fibrous macrostructure was obtained, and thus improved the mechanical properties [7].…”

“…By controlling radial flow of metal during hot ring rolling, the reasonable fibrous macrostructure was obtained, and thus improved the mechanical properties [7]. The microstructure evolution during hot ring rolling was investigated using finite element simulation and analyzed in terms of both simulations and experiments [10][11][12][13]. Based on the simulation results, many appropriate methods and rolling parameters have been developed to meet the demands of high-performance component [14,15].…”