Microstructures and Properties of HAZ of JB800 Bainite Steel

2014 ◽  
Vol 670-671 ◽  
pp. 65-69
Author(s):  
Jun Sheng Sun ◽  
Hong Quan Wang
Keyword(s):  
Impact Toughness ◽  
Lower Cost ◽  
Welding Process ◽  
High Strength ◽  
Granular Bainite ◽  
Low Alloy Steels ◽  
Test Results ◽  
Bainite Steel ◽  
Alloy Steels ◽  
Allotriomorphic Ferrite

JB800 steel has grain boundary allotriomorphic ferrite and granular bainite (FGBA/BG), and it is a kind of high strength low alloy steels, which has simple produce procedure, lower cost and excelled property. The law of microstructure transformation in CGHAZ, hardness, and impact toughness in HAZ of JB800 steel were studied by means of thermal simulation. The test results show that under the general condition of welding process (t8/5=5~50s), microstructure of CGHAZ is composed of mixture microstructure of Martensite and Bainite and with the increase of cooling rate, the content of Martensite will decrease, but that of Bainite will increase; when t8/5 is 20s, CGHAZ zone have better impact toughness, which is composed of 95% Martensite and 5% Bainite. Therefore t8/5 should be controlled at about 20s to get better impact toughness.

Effect of Hot Work on Hardness and Impact Toughness of Heat Treated Low Alloy Steels

2014 ◽  
Vol 1082 ◽  
pp. 197-201
Author(s):  
Mahmoud M. Tash ◽  
Saleh A. Alkahtani ◽  
Khaled A. Abuhasel
Keyword(s):  
Impact Toughness ◽  
Hot Forging ◽  
Weight Ratio ◽  
High Strength ◽  
Extensive Study ◽  
Low Alloy Steels ◽  
Alloying Additions ◽  
Heat Treated ◽  
Alloy Steels ◽  
Effect Of Hot Rolling

The present study was undertaken to investigate the effect of hot work reduction ratio on the hardness and impact toughness of different grades of low alloy steels. The effect of hot rolling and hot forging with different reduction ratios on the hardness and impact toughness properties will be studied. An extensive study will be carried out to investigate the effect of alloying additions and TMT parameters on the hardness and impact toughness of heat-treated low alloy steels. An understanding of the combined effect of TMT and heat treatment on the hardness and impact toughness of the low alloy steels would help in selecting conditions required to achieve optimum mechanical properties and alloy high strength to weight ratio.

Effect of Nb on Microstructure Evolution of Coarse-Grained Heat-Affected Zone with Large Heat Input Welding

2011 ◽  
Vol 284-286 ◽  
pp. 1174-1179 ◽  
Author(s):  
Xue Li Tao ◽  
Kai Ming Wu ◽  
Xiang Liang Wan
Keyword(s):  
Grain Boundary ◽  
Heat Affected Zone ◽  
Heat Input ◽  
Acicular Ferrite ◽  
High Strength ◽  
Coarse Grained ◽  
Granular Bainite ◽  
Low Alloy Steels ◽  
Alloy Steels ◽  
Grain Boundary Ferrite

The effect of Nb microalloying on microstructure transformation of coarse-grained heat-affected zone of high strength low alloy steels were investigated utilizing different heat input welding simulation. For the low-Nb steel, the microstructures of coarse-grained heat-affected zone mainly consisted of acicular ferrite, bainite and grain boundary ferrite for small heat input welding; the amount of acicular ferrite decreased whereas grain boundary ferrite, polygonal ferrite and pearlite increased with increasing heat input. In constrast, for the high-Nb steel, granular bainite was the dominant microstructure. The formation of granular bainitic microstructure was associated with the solid solution of Nb, which suppressed ferrite transformation and promoted the formation of granular bainite. The hardness of coarse-grained heat-affected zone increased with increasing Nb content, and decreased with decreasing heat input, which was attributed to the microstructural change.

The Effect of Ti-Zr Deoxidation on the Mechanical Properties of High Strength Low Alloy Steels

2010 ◽  
Vol 146-147 ◽  
pp. 1878-1884 ◽  
Author(s):  
Wei Yu Lu ◽  
Ling Dong Meng ◽  
Hong Hong Wang ◽  
Dao Yuan Wang ◽  
Yong Kuan Yao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Impact Toughness ◽  
High Strength ◽  
Optical Microscope ◽  
Low Alloy Steels ◽  
X Ray ◽  
The Matrix ◽  
Alloy Steels ◽  
The Stability

The uniformity of the mechanical properties, especially elongation and impact toughness, were compared between steel A, which was deoxidized with Ti-Zr, and steel B, which was deoxidized with Al. Microstructural observations, energy dispersive X-ray spectroscopy and X-ray diffraction analyses were conducted using an optical microscope, a scanning electron microscope and a transmission electron microscope, respectively. Results showed that sub-micron and nano-sized complex oxides were obtained by the combined deoxidation of Ti-Zr. The stability of the mechanical properties of steel A was better than that of steel B. The elongation and impact toughness of steel A were enhanced relative to those of steel B. This was attributed to spheroidization and the dispersed distribution of MnS inclusions in the matrix of steel A.

Effect of Thermomechanical Treatment (TMT) on Hardness, Impact Toughness of Different Grades of Low Alloy Steels

2015 ◽  
Vol 1101 ◽  
pp. 212-216
Author(s):  
Mahmoud M. Tash ◽  
Saleh A. Alkahtani ◽  
Khaled A. Abuhasel
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Impact Toughness ◽  
Mechanical Treatment ◽  
Weight Ratio ◽  
High Strength ◽  
Extensive Study ◽  
Low Alloy Steels ◽  
Alloy Steels ◽  
Thermo Mechanical Treatment

The present study was undertaken to investigate the effect of thermo-mechanical treatment (TMT) on the mechanical behaviour of different grades of low alloy steels. The effect of hot forming (rolling) with different reduction ratios on the hardness and impact toughness properties will be studied. Correlations between different thermo-mechanical treatment parameters, hardness and impact toughness for different grades of low alloy steels were carried out. Different grades of Low alloy steels were selected for the present study. An extensive study will be carried out to investigate the effect of alloying additions and TMT parameters on the hardness and impact toughness of heat-treated low alloy steels. An understanding of the combined effect of TMT and heat treatment on the mechanical properties of the low alloy steels would help in selecting conditions required to achieve optimum mechanical properties and alloy high strength to weight ratio. The scope of the present work is therefore to study the effects of hot rolling reduction ratios on microstructure and mechanical properties of such alloys. By measuring hardness, impact toughness, strength and ductility resulting from different heat treatment following TMT, it is possible to determine which conditions yielded optimum mechanical properties and high strength to weight ratio.

scholarly journals Assessment the Partial Welding Influences on Fatigue Life of S700MC Steel Fillet Welds

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 334
Author(s):  
Jaromir Moravec ◽  
Jiri Sobotka ◽  
Iva Novakova ◽  
Sarka Bukovska
Keyword(s):  
Fatigue Life ◽  
Welded Joints ◽  
Welding Process ◽  
High Strength ◽  
Major Effect ◽  
Strength Properties ◽  
Low Alloy Steels ◽  
Grain Coarsening ◽  
Fine Grained ◽  
Alloy Steels

Fine-grained steels belonging to the HSLA group (High-Strength Low-Alloy steels) of steels are becoming increasingly popular and are used in both statically and dynamically stressed structures. Due to the method of their production, and thus also the method use to obtain the required mechanical properties, it is really necessary to limit the heat input values for these steels during welding. When applying temperature cycles, HSLA steels in highly heated heat-affected zones (HAZ) reveal intensive grain coarsening and also softening behaviour. This subsequently results in changes in both mechanical and brittle-fracture properties, and the fatigue life of welded joints. While grain coarsening and structure softening have a major effect on the change of strength properties and KCV (Charpy V-notch impact toughness) values of statically stressed welded joints, the effect of these changes on the fatigue life of cyclically stressed welded joints has not yet been quantified. The paper is therefore conceived so as to make it possible to assess and determine the percentage impact of individual aspects of the welding process on changes in their fatigue life. To be more specific, the partial effects of angular deformation, changes that occur in the HAZ of weld, and the notch effect due to weld geometry are assessed.

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