scholarly journals Effects of Start and Finish Cooling Temperatures on Microstructure and Mechanical Properties of Low-Carbon High-Strength and Low-Yield Ratio Bainitic Steels

2013 ◽  
Vol 45 (4) ◽  
pp. 2004-2013 ◽  
Author(s):  
Hyo Kyung Sung ◽  
Sunghak Lee ◽  
Sang Yong Shin
Keyword(s):  
Mechanical Properties ◽  
High Strength ◽  
Yield Ratio ◽  
Low Carbon ◽  
Microstructure And Mechanical Properties ◽  
Bainitic Steels

Electron Microscope studies of the microstructures in as-quenched and aged HSLA-100 production steels and correlation with mechanical properties

1991 ◽  
Vol 49 ◽  
pp. 582-583
Author(s):  
A.G. Fox ◽  
V.R. Mattes ◽  
S. Mikalac ◽  
M.G. Vassilaros
Keyword(s):  
Mechanical Properties ◽  
High Strength ◽  
Low Carbon ◽  
Austenite Grain Size ◽  
Solid Solution Strengthening ◽  
Austenite Grain ◽  
Microstructure And Mechanical Properties ◽  
Hsla Steels ◽  
Carbonitride Precipitation ◽  
Strength And Toughness

Because of their excellent weldability, high strength low alloy (HSLA) ultra low carbon bainitic (ULCB) steels are finding increasing applications in ship and submarine construction. In order to achieve the required strength and toughness in ULCB HSLA steels it is necessary to control chemical composition and thermo-mechanical processing very carefully so that the desired microstructure and mechanical properties can be achieved. For instance HSLA 100 ULCB steel (nominal yield strength 100 ksi) used by the U.S. Navy in shipbuilding applications can derive its strength and toughness from the following sources:- (1) solid solution strengthening (2) small prior austenite grain size derived from niobium carbonitride precipitation at austenite grain boundaries (3) dislocation substructure and (4) from copper precipitates (in aged alloys). The object of the present work is to correlate the microstructure and mechanical properties of production batches of HSLA 100 in the quenched and aged conditions. Because many of the salient features of these microstructures are submicron in size it was found necessary to use SEM and TEM.

Effect of Tempering Temperature on the Microstructure and Mechanical Properties of a 0.1C Steel with High Strength and Low Yield Ratio

2012 ◽  
Vol 535-537 ◽  
pp. 601-604
Author(s):  
Wen Hao Zhou ◽  
Hui Guo ◽  
Cheng Jia Shang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Yield Strength ◽  
Major Change ◽  
Total Elongation ◽  
Yield Ratio ◽  
High Yield ◽  
Low Carbon ◽  
Tempering Temperature ◽  
Microstructure And Mechanical Properties

The influence of tempering temperature on the microstructure and mechanical properties of low carbon low alloy steel was investigated. The results show that tempering temperature has considerable influence on both yield strength and tensile strength. With the increase in tempering temperature, the yield strength increases first and then decreases after it reaches the highest point at 600°C with a strength of 843MPa, while the tensile strength decreases fastly from 550°C to 650°C and keeps stable after increasing drastically at 720°C. The yield ratio is about 0.60 except at 600°C and 650°C with a high yield ratio of 0.90, while the total elongation has little change. It is concluded that the major change of mechanical properties after tempering has a connection with the decomposition of M/A(martensite/austenite) islands, the recovery of dislocations and the precipitation of alloy elements.

scholarly journals Microstructure and Mechanical Properties of Low-Carbon High-Strength Steel Fabricated by Wire and Arc Additive Manufacturing

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 216
Author(s):  
Laibo Sun ◽  
Fengchun Jiang ◽  
Ruisheng Huang ◽  
Ding Yuan ◽  
Chunhuan Guo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
High Strength Steel ◽  
High Strength ◽  
Taylor Factor ◽  
Image Correlation ◽  
Experimental Fact ◽  
Fracture Mechanisms ◽  
Low Carbon ◽  
Microstructure And Mechanical Properties

Wire and arc additive manufacturing (WAAM) is a novel technique for fabricating large and complex components applied in the manufacturing industry. In this study, a low-carbon high-strength steel component deposited by WAAM for use in ship building was obtained. Its microstructure and mechanical properties as well as fracture mechanisms were investigated. The results showed that the microstructure consisted of an equiaxed zone, columnar zone, and inter-layer zone, while the phases formed in different parts of the deposited component were different due to various thermal cycles and cooling rates. The microhardness of the bottom and top varied from 290 HV to 260 HV, caused by temperature gradients and an inhomogeneous microstructure. Additionally, the tensile properties in transversal and longitudinal orientations show anisotropy characteristics, which was further investigated using a digital image correlation (DIC) method. This experimental fact indicated that the longitudinal tensile property has an inferior performance and tends to cause stress concentrations in the inter-layer areas due to the inclusion of more inter-layer zones. Furthermore, electron backscattered diffraction (EBSD) was applied to analyze the difference in Taylor factor between the inter-layer area and deposited area. The standard deviation of the Taylor factor in the inter-layer area was determined to be 0.907, which was larger than that in the deposited area (0.865), indicating nonuniform deformation and local stress concentration occurred in inter-layer area. Finally, as observed from the fracture morphology on the fractured surface of the sample, anisotropy was also approved by the comparison of the transversal and longitudinal tensile specimens.

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