scholarly journals Analysis of Internal Crack Healing Mechanism under Rolling Deformation

PLoS ONE ◽  
2014 ◽  
Vol 9 (7) ◽  
pp. e101907 ◽  
Author(s):  
Haitao Gao ◽  
Zhengrong Ai ◽  
Hailiang Yu ◽  
Hongyan Wu ◽  
Xianghua Liu
Keyword(s):  
Internal Crack ◽  
Crack Healing ◽  
Rolling Deformation

Restoration of impact properties of internal crack healing in a low carbon steel

2017 ◽  
Vol 682 ◽  
pp. 433-440 ◽  
Author(s):  
Ruishan Xin ◽  
Qingxian Ma ◽  
Dongdong Guo ◽  
Weiqi Li
Keyword(s):  
Carbon Steel ◽  
Low Carbon Steel ◽  
Internal Crack ◽  
Low Carbon ◽  
Crack Healing ◽  
Impact Properties

Research on Crack Healing in Slab during Hot Rolling

2011 ◽  
Vol 264-265 ◽  
pp. 439-444
Author(s):  
Hai Liang Yu ◽  
Xiang Hua Liu
Keyword(s):  
Tensile Testing ◽  
Rolling Mill ◽  
Testing Machine ◽  
Fracture Morphology ◽  
Internal Crack ◽  
Rolled Steel ◽  
Crack Healing ◽  
Tensile Testing Machine ◽  
Experimental Rolling ◽  
Series Of Experiments

The elongation and the strength of rolled steel are severely affected by cracks in production. Reduction of cracks is important for the improvement of slab quality. In this paper, a series of experiments on internal crack healing in slab during rolling was carried out on the experimental rolling mill. The crack shape and the fracture morphology of the crack healing zones were observed by using the scanning electron microscope, and the shear strength of crack healing zone was tested through the tensile testing machine. With increase of the reduction ratio during rolling, the crack healing degree increases.

Effect of Heat Treatment on Microstructure and Hardness of Internal Crack Healing in a Low Carbon Steel

2017 ◽  
Vol 730 ◽  
pp. 3-7 ◽  
Author(s):  
Rui Shan Xin ◽  
Qing Xian Ma ◽  
Wei Qi Li
Keyword(s):  
Heat Treatment ◽  
Carbon Steel ◽  
Testing Machine ◽  
Low Carbon Steel ◽  
Internal Crack ◽  
Low Carbon ◽  
Crack Healing ◽  
Material Source ◽  
The Matrix ◽  
Healing Temperature

The effect of heat treatment on microstructure and hardness of internal crack healing in a low carbon steel was studied. The internal cracks were produced into the samples by a drilling and compression method. The microstructure of crack healing zone was examined using optical microscopy (OM) and scanning electron microscopy (SEM). The hardness of crack healing zone was measured using a Vickers micro-hardness testing machine (FM-800). The results show that healing temperature plays a more significant role in internal crack healing than holding time. Compared as-quenched samples with as-normalized samples under the same healing parameters, it is found that cooling speed is also an important factor for internal crack healing. The migration and enrichment of iron atoms provide material source for recrystallization and grain growth of crack healing zone. The existence of micro-voids leads to the hardness of the ferrite in the crack healing zone lower than that in the matrix.

Evolution Behaviors and Mechanisms of Internal Crack Healing in Steels at Elevated Temperatures

2018 ◽  
Vol 49 (10) ◽  
pp. 4906-4917 ◽  
Author(s):  
Rui-Shan Xin ◽  
Ju Kang ◽  
Qing-Xian Ma ◽  
Shuai Ren ◽  
Hui-Long An ◽  
...  
Keyword(s):  
Elevated Temperatures ◽  
Internal Crack ◽  
Crack Healing

scholarly journals Effect of Parameters on Internal Crack Healing in 30Cr2Ni4MoV Steel for 600-Ton Ultra-Super Ingots

Metals ◽  
2017 ◽  
Vol 7 (4) ◽  
pp. 149 ◽  
Author(s):  
Ruishan Xin ◽  
Jianbin Luo ◽  
Qingxian Ma
Keyword(s):  
Internal Crack ◽  
Crack Healing

Inner Surface Migration during the Internal Crack Healing in 45 Steel

2009 ◽  
Vol 628-629 ◽  
pp. 547-552 ◽  
Author(s):  
F.Y. Meng ◽  
S.M. Nie
Keyword(s):  
Crack Surface ◽  
Internal Crack ◽  
Crack Healing ◽  
Metallic Material ◽  
Atom Diffusion ◽  
Forging Process ◽  
Surface Migration ◽  
Higher Temperature ◽  
Relationship Of ◽  
The Relationship

Many cracks can occur in heavy forging as a result of inherent defects of heavy ingot and forging process. According to the results of current research, internal crack of metallic material can heal under high temperature. In order to get to the bottom of internal crack healing in heavy forgings, some 45 steel samples containing internal crack were normalized at higher temperature than normal. The phenomena show that new ferrite grains nucleate and grow up on the crack surfaces during the crack healing, and the ferrite grains nucleation is universal but selective on crack surfaces. The relationship of atom diffusion and ferrite grain nucleation and their actions on crack surface migration will be discussed and expounded, and that proves that ferrite grain nucleation and growth will accelerate crack healing.

A New Crack Healing Kinetic Model and Application of Crack Healing Diagram

2013 ◽  
Vol 135 (5) ◽  
Author(s):  
Y. Kan ◽  
H. Liu ◽  
S. H. Zhang ◽  
L. W. Zhang ◽  
M. Cheng
Keyword(s):  
Kinetic Model ◽  
Grain Growth ◽  
Healing Time ◽  
Creep Mechanism ◽  
Internal Crack ◽  
Crack Healing ◽  
New Model ◽  
Diffusion Controlled ◽  
Power Law Creep ◽  
And Diffusion

An internal crack is a common defect which can lead to failure of the material. There are few published studies which can quantitatively predict healed fractions under given conditions such as temperature, pressure and healing time. In the current study, a new crack healing kinetic model is developed to predict the healed crack fraction under any given temperature, pressure and healing time. In contrast to previous models, this new model describes the crack surface topography as a series of semi spherical pores, and proposes a new diffusion healing mechanism involving grain growth. Plastic deformation, power law creep and diffusion controlled creep mechanism are considered in this model. A crack healing diagram for 34MnV steel is constructed with axes of healed fraction and temperature or pressure. The predictions from the new model compare well with experimental results. The results of the model indicate that the diffusion controlled creep mechanism contributes little at high temperatures because of grain growth. The critical healing time and pressure can be determined by using the crack healing diagram.

scholarly journals The Effects of Homogenizing and Quenching and Tempering Treatments on Crack Healing

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 427
Author(s):  
Yao Qiu ◽  
Ruishan Xin ◽  
Jianbin Luo ◽  
Qingxian Ma
Keyword(s):  
Heat Treatment ◽  
Treatment Method ◽  
Internal Crack ◽  
Crack Healing ◽  
Percentage Recovery ◽  
Tempering Treatment ◽  
Deformation And Heat Treatment ◽  
The Impact ◽  
Heat Treatment Method ◽  
Quenching And Tempering

After thermal deformation and heat treatment, it can be observed that there are small, newly formed grains in the crack healing zone, which indicates that the internal crack is fully healed. However, in our previous study, the impact properties of the internal healing zone could only be partially healed. In this study, the process of homogenizing treatment was adopted to achieve grain size homogeneity. The effects of homogenizing treatment and quenching and tempering treatment on crack healing were also systematically analyzed. With the same heat treatment method, SA508-3 samples, which were subjected to multi-pass deformation, had a higher percentage recovery than those that underwent uniaxial compression. The percentage recovery of the crack healing zone was significantly improved after the process of homogenizing treatment. The impact property of the crack healing zone could be fully restored after homogenizing treatment followed by quenching and tempering treatment. However, after several episodes of heating, the grain-boundary strength decreased, and the impact value was relatively low.

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