Microstructure–hardness relationship in quenched and partitioned medium-carbon and high-carbon steels containing silicon

2008 ◽  
Vol 498 (1-2) ◽  
pp. 442-456 ◽  
Author(s):  
S.S. Nayak ◽  
R. Anumolu ◽  
R.D.K. Misra ◽  
K.H. Kim ◽  
D.L. Lee
Author(s):  
F. A. Khalid ◽  
D. V. Edmonds

The austenite/pearlite growth interface in a model alloy steel (Fe-1lMn-0.8C-0.5V nominal wt%) is being studied in an attempt to characterise the morphology and mechanism of VC precipitation at the growth interface. In this alloy pearlite nodules can be grown isothermally in austenite that remains stable at room temperature thus facilitating examination of the transformation interfaces. This study presents preliminary results of thin foil TEM of the precipitation of VC at the austenite/ferrite interface, which reaction, termed interphase precipitation, occurs in a number of low- carbon HSLA and microalloyed medium- and high- carbon steels. Some observations of interphase precipitation in microalloyed low- and medium- carbon commercial steels are also reported for comparison as this reaction can be responsible for a significant increase in strength in a wide range of commercial steels.The experimental alloy was made as 50 g argon arc melts using high purity materials and homogenised. Samples were solution treated at 1300 °C for 1 hr and WQ. Specimens were then solutionised at 1300 °C for 15 min. and isothermally transformed at 620 °C for 10-18hrs. and WQ. Specimens of microalloyed commercial steels were studied in either as-rolled or as- forged conditions. Detailed procedures of thin foil preparation for TEM are given elsewhere.


2010 ◽  
Vol 638-642 ◽  
pp. 202-207 ◽  
Author(s):  
Yu Dong Zhang ◽  
Claude Esling ◽  
Xiang Zhao ◽  
Liang Zuo

In this paper, some of our recent results in phase equilibrium, microstructure, texture and precipitation resulting from the application of an external high magnetic field during diffusional phase transformation in both medium carbon and high carbon steels have been summarized Their potential engineering applications are foreseen.


2007 ◽  
Vol 539-543 ◽  
pp. 4768-4773 ◽  
Author(s):  
Yu Dong Zhang ◽  
Claude Esling ◽  
Xiang Zhao ◽  
Liang Zuo

The new phase equilibrium of Fe-C diagram under magnetic field has been theoretically calculated. Results show that the magnetic field mainly shifts the γ⁄α+γ equilibrium line and the eutectoid point to the high carbon and high temperature sides. Based on this result, an experimental setup has been launched to investigate the effect of magnetic field on austenite decomposition in medium carbon and high carbon steels. The thermodynamic and kinetic effects of the high magnetic field on proeutectoid transformation at different cooling rates have been studied. It was found that for medium carbon steels, the magnetic field increases the amount of proeutectoid ferrite and accelerates the diffusional decomposition of austenite at medium and relatively fast cooling rates (10°C/min and 46°C/min). But there is no special grain growth along the field direction. The results led to a proposal of a new rapid annealing under a high magnetic field. However, when cooling is slow (2°C/min), the magnetic field shows a strong tendency to promote the proeutectoid ferrite grains to grow along the field direction through the magnetic dipolar interaction, which leads to the formation of an elongated grain structure. Moreover, the magnetic field also exhibits influence on the austenite decomposition in hypereutectoid steel by changing the amount of secondary cementite and lamellar spacing of pearlite.


Author(s):  
F. A. Khalid ◽  
D. V. Edmonds

The austenite/pearlite growth interface in a model alloy steel (Fe-1 lMn-0.8C nominal wt%) is being investigated. In this particular alloy pearlite nodules can be grown isothermally in austenite that remains stable at room temperature, thus facilitating examination of the transformation interfaces. This study presents preliminary results of thin foil TEM of the austenite/pearlite interface, as part of a programme of aimed at studying alloy carbide precipitation reactions at this interface which can result in significant strengthening of microalloyed low- and medium- carbon steels L Similar studies of interface structure, made on a partially decomposed high- Mn austenitic alloy, have been reported recently.The experimental alloys were made as 50 g argon arc melts using high purity materials and homogenised. Samples were hot- rolled, swaged and machined to 3mm diameter rod, solution treated at 1300 °C for 1 hr and WQ. Specimens were then solutionised between 1250 °C and 1000 °C and isothermally transformed between 610 °C and 550 °C for 10-18 hr and WQ.


Alloy Digest ◽  
1996 ◽  
Vol 45 (1) ◽  

Abstract INCO WELD C Electrode is a stainless-alloy electrode especially designed for shielded-metal-arc welding of a broad range of materials, including many difficult-to-weld compositions. It can be used in stainless steels, mild and medium-carbon steels,and spring steels. This datasheet provides information on composition, hardness, and tensile properties. It also includes information on joining. Filing Code: SS-632. Producer or source: Inco Alloys International Inc.


Author(s):  
A. S. Atamashkin ◽  
E. Yu. Priymak ◽  
N. V. Firsova

The paper presents an analysis of the mechanical behavior of friction samples of welded joints from steels 30G2 (36 Mn 5) and 40 KhN (40Ni Cr 6), made by rotary friction welding (RFW). The influence of various temperature conditions of postweld tempering on the mechanical properties and deformation behavior during uniaxial tensile testing is analyzed. Vulnerabilities where crack nucleation and propagation occurred in specimens with a welded joint were identified. It was found that with this combination of steels, postweld tempering of the welded joint contributes to a decrease in the integral strength characteristics under conditions of static tension along with a significant decrease in the relative longitudinal deformation of the tested samples.


Land ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 197
Author(s):  
He Zhang ◽  
Jingyi Peng ◽  
Dahlia Yu ◽  
Lie You ◽  
Rui Wang

Low-carbon governance at the county level has been an important issue for sustainable development due to the large contributions to carbon emission. However, the experiences of carbon emission governance at the county level are lacking. This paper discusses 5 carbon emission governance zones for 1753 counties. The zoning is formed according to a differentiated zoning method based on a multi-indicator evaluation to judge if the governance had better focus and had formulated a differentiated carbon emission governance system. According to zoning results, there is 1 high-carbon governance zone, 2 medium-carbon governance zones, and 2 low-carbon zones. The extensive high-carbon governance zone and medium-carbon zones are key governance areas, in which the counties are mainly located in the northern plain areas and southeast coastal areas and have contributed 51.88% of total carbon emissions. This paper proposes differentiated governance standards for each indicator of the 5 zones. The differentiated zoning method mentioned in this paper can be applied to other governance issues of small-scale regions.


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