The Influence of Oxide Inclusion on the Refinement of Bainite and Toughness in HAZ for Low Carbon Steels

2013 ◽  
Vol 651 ◽  
pp. 163-167
Author(s):  
Shu Rui Li ◽  
Xue Min Wang ◽  
Xin Lai He
Keyword(s):  
Mechanical Properties ◽  
Acicular Ferrite ◽  
Oxide Inclusion ◽  
Optical Microscope ◽  
Carbon Steels ◽  
Low Carbon ◽  
Low Carbon Steels ◽  
The Core ◽  
Ti Oxides ◽  
Bainitic Steels

The influence of Ti oxide on the toughness of heat affected zone for low carbon bainitic steels has been investigated. The optical microscope, SEM and TEM were used to analyze the composition, size and distribution of the inclusions, and the microstructure and mechanical properties after welding thermal simulation were also investigated. The effect of Ti oxide inclusion on the transformation of acicular ferrite has also been studied. The results show that after the melting with Ti dioxide technique the inclusion is complex, in the core is Ti oxides about 1-3 micron and around it is MnS. It has been found the acicular ferrite can nucleate at the inclusions and the Ti oxide inclusion will promote the nucleation of acicular ferrite, and the acicular ferrite will block the growth of bainite. Therefore by introducing the Ti oxide in the steels the microstructure of HAZ could be refined markedly therefore the toughness of HAZ can be improved evidently.

The Influence of Oxide Inclusion on Austenite Grain Size and Heat Affected Zone Toughness for Low Carbon Steels

2012 ◽  
Vol 715-716 ◽  
pp. 617-622 ◽  
Author(s):  
Wei Shu ◽  
Xue Min Wang ◽  
Cheng Jia Shang ◽  
Xin Lai He
Keyword(s):  
Grain Size ◽  
Heat Affected Zone ◽  
Acicular Ferrite ◽  
Oxide Inclusion ◽  
Thermal Simulation ◽  
Carbon Steels ◽  
Low Carbon ◽  
Austenite Grain Size ◽  
Low Carbon Steels ◽  
Austenite Grain

The low carbon steels were smelted with special oxide introduction technique and the HAZ properties has been studied with thermal simulation. The optical microscope, SEM and TEM were used to analyze the composition, size and distribution of the inclusions, and the mechanical properties after thermal simulation were also investigated. The influence of oxide inclusions on the austenite grain size was also studied. The results show that after the smelting the inclusion is complex, in the core is Ti oxides about 1-3 micron and around it is MnS. When the reheat temperature is below 1000, the size of austenite grain is the same for experimental steel and base steel. However, when the reheat temperature is over than 1100, the size of austenite grains in experimental steel is one third of that in base steels. After thermal simulation, with thet8/5increasing the toughness of HAZ decreased. The austnite grain size also increased. The microstructure is composed of intergranular ferrite and intragranular acicular ferrite. Therefore by introducing the fine oxide inclusion to the steel the austenite grain was refined and during the phase transformation the acicular ferrite formed at inclusions at first. These two factors are the main causes to improve the toughness of heat affected zone for steels produced by oxide metallurgy technique.

The Oxide Inclusion and Heat-Affected-Zone Toughness of Low Carbon Steels

2010 ◽  
Vol 654-656 ◽  
pp. 358-361 ◽  
Author(s):  
Wei Shu ◽  
Xue Min Wang ◽  
Shu Rui Li ◽  
Xin Lai He
Keyword(s):  
Heat Affected Zone ◽  
Prior Austenite ◽  
Oxide Inclusion ◽  
Optical Microscope ◽  
Carbon Steels ◽  
Cooling Time ◽  
Low Carbon ◽  
Low Carbon Steels ◽  
Austenite Grain ◽  
Prior Austenite Grain

The relationship between the oxide inclusions and the Heat-affected-zone (HAZ) toughness of microalloying steels has been investigated. The low carbon steels are smelted with special oxide introduction technique and the properties of HAZ has been studied with thermo-simulation. The optical microscope and SEM were used to analyze the size, composition and distribution of the inclusions, the mechanical properties after thermo-simulation was also analyzed. The results show that the inclusions in steel are mainly Ti and Al oxide with MnS, these complex inclusions are well distributed and the size is less than 3 micron. Microstructure of HAZ consists of intragranular acicular ferrite (IAF), intergranular ferrite and small amount of lath bainite while the cooling time during the phase formation is short. After the thermo simulation with the cooling time between 800°C and 500°C (t8/5) increasing the toughness of HAZ decreased and the size of prior austenite grain increased. Inclusions which located near the prior austenite grain boundary couldn’t induce the nucleation of IAF, only the ones inside the prior austenite grain can promote IAF’s growth.

scholarly journals Battery on Carburization ST 37 Steel

2021 ◽  
Vol 3 (2) ◽  
pp. 109-114
Author(s):  
Melya Dyanasari Sebayang
Keyword(s):  
Mechanical Properties ◽  
Carbon Content ◽  
Grain Boundaries ◽  
Surface Hardening ◽  
Carbon Steels ◽  
Low Carbon ◽  
Low Carbon Steels ◽  
The Core ◽  
Hardening Process

A surface hardening process by adding carbon to its surface without changing the core properties of the material is called the carburization process. This process is carried out at the austenite temperature so that the carbon can diffuse into the phase. This process can only be done on low carbon steels with a content of below 0.25%. This research uses ST 37 steel which is a low content steel with a carbon content of 0.18%. This type of steel is surface hardened with a carburizing temperature of 850°C for a long lasting time of 1 hour, then it is carried out under moderate cooling with outside air media. This research produces a carburizing method with carbon battery media that easily breaks down into steel, which occurs in carbon batteries at temperatures below 723°C. And change its mechanical properties from the comparison of the initial mechanical properties of the specimen. Carburizing with battery rock media is more efficient at temperatures below 723°C. Because of at temperatures below austenite or below the carburizing temperature of carbon from the batteries, it can absorb the surface of the steel even though the amount is still very small. Because the temperature is below the austenite temperature, the absorbed carbons cannot diffuse as happened in the carburization process, but the absorbed carbons can bind the grain boundaries so that they change their hardness by 4%. The microstructure in the research that occurs in this process has nothing to change its phase because the temperature does not reach the austenite temperature.

scholarly journals Mechanical Properties of Nb-containing Low-carbon Steels Produced by Direct Rolling

1988 ◽  
Vol 74 (12) ◽  
pp. 2323-2329 ◽  
Author(s):  
Masahiko ODA ◽  
Hiroshi KUBO ◽  
Osamu AKISUE ◽  
Kichi NAKAZAWA
Keyword(s):  
Mechanical Properties ◽  
Carbon Steels ◽  
Low Carbon ◽  
Low Carbon Steels ◽  
Direct Rolling

Deformation, Mechanical Properties, and Fracture of Quenched and Tempered Carbon Steels

2015 ◽  
pp. 405-437
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Ductile Fracture ◽  
Carbon Steels ◽  
Low Carbon ◽  
Tempering Temperature ◽  
Medium Carbon ◽  
Low Carbon Steels ◽  
Deformation Properties ◽  
Medium Carbon Steels

Abstract Steels with martensitic and tempered martensitic microstructures, though sometimes perceived as brittle, exhibit plasticity and ductile fracture behavior under certain conditions. This chapter describes the alloying and tempering conditions that produce a ductile form of martensite in low-carbon steels. It also discusses the effect of tempering temperature on the mechanical behavior and deformation properties of medium-carbon steels.

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