Microstructure and Properties of Heat-Treated 440C Martensitic Stainless Steel

Abstract

440C martensitic stainless steels are widely used because of their good mechanical properties. The mechanical properties of 440C martensitic stainless steel were evaluated after heat treatment of these materials at various types of heat treatment processes. The initial part of this investigation focused on the microstructures of these 440C steels. Microstructure evaluations from the as-received to the as-tempered condition were described. In the as-received condition, the formations of ferrite matrix and carbide particles were observed in this steel. In contrast, the precipitation of M7C3carbides and martensitic structures were present in this steel due to the rapid quenching process from the high temperature condition. After precipitation heat treatment, the Cr-rich M23C6carbides were identified within the structures. Moreover, a 30 minutes heat-treated sample shows the highest value of hardness compared to the others holding time. Finally, the tempering process had been carried out to complete the whole heat treatment process in addition to construct the secondary hardening phenomenon. It is believed that this phenomenon influenced the value of hardness of the 440C steel.

Microstructures and Mechanical Properties of Austempering SUS440 Steel Thin Plates

“…The second set underwent the same salt-bath temperature (300˝C) and different time intervals (30, 60, 90, and 120 min), and were then quenched in the water. Each austempering condition was called x˝C-y min, based on the salt-bath condition, such as 200˝C-120 min [7,8]. punch-shear process on brittleness.…”

Effect of Titanium on the Microstructure and Mechanical Properties of High-Carbon Martensitic Stainless Steel 8Cr13MoV

“…Titanium could refine the grain, increase the hardness and tensile strength, and combine with carbon to form TiC to inhibit the formation of carbides containing chromium, resulting in the dissolution of chromium in the matrix and increasing the hardenability and the quantity of martensite. 6 were large in size, and most single TiCs were granular. In sample No.…”

“…Metals 2016, 6,193 10 of 15 precipitated after being spheroidized. As shown in Figure 9b, there are no large complex carbides in sample No.…”

“…For martensitic stainless steel, carbides precipitate in the matrix through heat treatment in the final process, which can achieve secondary hardening [4][5][6]. However, high carbon content can also result in some undesired problems, especially for the HMSS.…”

The correlation between ZDDP tribofilm morphology and the microstructure of steel

“…Two kinds of residual carbides may be distinguished in 440C steel: small (< 3 mm in diameter) spherical M 23 C 6 , and larger (up to few tens in mm in diameter) carbides of irregular shape, which are usually M 7 C 3 surrounded by M 23 C 6 [29]. Both types of carbides are richer in chromium [41,42] and harder than the matrix (Figure 1). M2 is a representative of high speed steels, although it is sometimes used for bearing applications [43].…”