Tailoring Mechanical Properties of a Low Carbon Cu-Containing Structural Steel by Two-Step Intercritical Heat Treatment

2019 ◽  
Vol 25 (6) ◽  
pp. 1477-1487 ◽  
Author(s):  
Xiaohui Xi ◽  
Jinliang Wang ◽  
Liqing Chen ◽  
Zhaodong Wang
2013 ◽  
Vol 559 ◽  
pp. 427-435 ◽  
Author(s):  
Jingwei Zhao ◽  
Jeong Hun Lee ◽  
Yong Woo Kim ◽  
Zhengyi Jiang ◽  
Chong Soo Lee

Author(s):  
Sang-Seop Lim ◽  
Chung-Gil Kang

With increasing oil consumption, we have to find more oil resources in the deep sea. The extreme working condition of the deep sea requires high toughness and high strength values at low temperatures. Academic institutions limited the chemical composition of the requested casting steel to meet their requirements of fracture toughness and weldability. Thus, the carbon content was set approximately 0.10% based on classification societies which required specific mechanical properties of strength, elongation, reduction area and impact energy (−40°C). In this study, we find the optimal heat treatment condition of low carbon steel (0.10%C) to obtain the desired mechanical properties at low temperature (−40°C) according to different quenching parameters (heating times) and tempering parameters (heating temperatures, cooling methods).


10.30544/293 ◽  
2017 ◽  
Vol 23 (2) ◽  
pp. 143-152
Author(s):  
Mohammad Davari ◽  
Mehdi Mansouri Hasan Abadi

In the present study, the effect of intercritical heat treatment temperature on the tensile properties and work hardening behavior of ferritic-martensitic dual-phase steel have been investigated utilizing tensile test, microhardness measurement and microscopic observation. Plain carbon steel sheet with a thickness of 2 mm was heat treated at 760, 780, 800, 820 and 840 °C intercritical temperatures. The results showed that martensite volume fraction (Vm) increases from 32 to 81%with increasing temperature from 760 to 840 °C. The mechanical properties of samples were examined by tensile and microhardness tests. The results revealed that yield strength was increased linearly with the increase in Vm, but the ultimate strength was increased up to 55% Vm and then decreased afterward. Analyzing the work hardening behavior in term of Hollomon equation showed that in samples with less than 55% Vm, the work hardening took place in one stage and the work hardening exponent increased with increasing Vm. More than one stage was observed in the work hardening behavior when Vm was increased. The results of microhardness test showed that microhardness of the martensite is decreased by increase in heat treatment temperature while the ferrite microhardness is nearly constant for all heat-treated samples.


2021 ◽  
Vol 2133 (1) ◽  
pp. 012046
Author(s):  
Lei Chu

Abstract With the rapid development of materials, metal materials are used less and less, but at this stage, metal materials are still widely used, and iron and steel materials are the most widely used. Cracks often appear in the process of metal material processing and use, and these cracks will have a certain impact on the use of metal materials. The existence of microcracks will affect the mechanical properties of materials to some extent, but in most cases, the mechanical properties of materials will be greatly reduced, and in serious cases, metal materials will break directly in the process of use or processing. The crack healing process needed after the emergence of cracks can effectively change this situation, but so far, the research on metal crack healing is still not perfect. In this paper, taking the internal crack of low carbon steel as the object, the recovery of mechanical properties of low carbon steel by cyclic phase transformation heat treatment was studied. The results show that with the increase of the healing area, the microhardness of the area after crack healing also increases, and the tensile strength of the specimen also increases after the healing. When the healing area is similar, increasing the healing time and temperature will result in grain coarsening, resulting in the decrease of microhardness and tensile strength in the crack healing zone.


Author(s):  
S. A. Golosienko ◽  
N. A. Minyakin ◽  
V. V. Ryabov ◽  
T. G. Semicheva ◽  
E. I. Khlusova

The work covers the effect of niobium, as well as niobium and vanadium together, on mechanical properties of high-strength chromium-nickel-molybdenum steel after thermal improvement (heat treatment). The mechanical properties of steels are determined after applying various tempering temperatures (from 580 to 660°C), durations of tempering (from 1 to 16 hours), and also after quenching from rolling heat and furnace heat with subsequent tempering. It is shown that after quenching and tempering in the temperature range 580– 660°C, simultaneous microalloying by niobium and vanadium, compared to microalloying by niobium alone, increases the yield strength but in significantly decreases toughness and ductility. Quenching from rolling heat increases strength while maintaining high toughness and the increase in strength is most noticeable for steel microalloyed only by niobium.


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