Effect of Tempering Time on Microstructure and Mechanical Properties of SA738 Gr.B Steel

2021 ◽  
Vol 1016 ◽  
pp. 1739-1746
Author(s):  
Yan Mei Li ◽  
Shu Zhan Zhang ◽  
Zai Wei Jiang ◽  
Sheng Yu ◽  
Qi Bin Ye ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Impact Toughness ◽  
Yield Strength ◽  
Microstructure Evolution ◽  
Impact Energy ◽  
Nuclear Power ◽  
Microstructure And Mechanical Properties ◽  
The Impact ◽  
Tempering Time

The effect of tempering time on the microstructure and mechanical properties of SA738 Gr.B nuclear power steel was studied using SEM, TEM and thermodynamic software, and its precipitation and microstructure evolution during tempering were clarified. The results showed that SA738 Gr.B nuclear power steel has better comprehensive mechanical properties after tempering at 650 °C for 1h. With the extension of the tempering time, M3C transformed into M23C6 with increasing size, which affected the yield strength and impact energy. When the tempering time is 8h ~ 10h, due to the transformation of M3C to M23C6, the composition of matrix around the carbide changed, causing the temperature of Ac1 dropped, forming twin-martensite which deteriorated the impact toughness of the steel.

scholarly journals Microstructure and Mechanical Properties of Heat-Affected Zone of Repeated Welding AISI 304N Austenitic Stainless Steel by Gleeble Simulator

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 773
Author(s):  
Y.H. Guo ◽  
Li Lin ◽  
Donghui Zhang ◽  
Lili Liu ◽  
M.K. Lei
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Impact Energy ◽  
Heat Affected Zone ◽  
Ferrite Content ◽  
Equipment Safety ◽  
Microstructure And Mechanical Properties ◽  
Δ Ferrite ◽  
The Impact

Heat-affected zone (HAZ) of welding joints critical to the equipment safety service are commonly repeatedly welded in industries. Thus, the effects of repeated welding up to six times on the microstructure and mechanical properties of HAZ for AISI 304N austenitic stainless steel specimens were investigated by a Gleeble simulator. The temperature field of HAZ was measured by in situ thermocouples. The as-welded and one to five times repeated welding were assigned as-welded (AW) and repeated welding 1–5 times (RW1–RW5), respectively. The austenitic matrices with the δ-ferrite were observed in all specimens by the metallography. The δ-ferrite content was also determined using magnetic and metallography methods. The δ-ferrite had a lathy structure with a content of 0.69–3.13 vol.%. The austenitic grains were equiaxial with an average size of 41.4–47.3 μm. The ultimate tensile strength (UTS) and yield strength (YS) mainly depended on the δ-ferrite content; otherwise, the impact energy mainly depended on both the austenitic grain size and the δ-ferrite content. The UTS of the RW1–RW3 specimens was above 550 MPa following the American Society of Mechanical Engineers (ASME) standard. The impact energy of all specimens was higher than that in ASME standard at about 56 J. The repeated welding up to three times could still meet the requirements for strength and toughness of welding specifications.

scholarly journals Influence of Vanadium on the Microstructure and Mechanical Properties of Medium-Carbon Steels for Wheels

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 978 ◽  
Author(s):  
Pengfei Wang ◽  
Zhaodong Li ◽  
Guobiao Lin ◽  
Shitong Zhou ◽  
Caifu Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Impact Toughness ◽  
Grain Refinement ◽  
Carbon Steels ◽  
Precipitation Strengthening ◽  
Austenite Grain Size ◽  
Medium Carbon ◽  
Microstructure And Mechanical Properties ◽  
Medium Carbon Steels ◽  
The Impact

Steels used for high-speed train wheels require a combination of high strength, toughness, and wear resistance. In 0.54% C-0.9% Si wheel steel, the addition of 0.075 or 0.12 wt % V can refine grains and increase the ferrite content and toughness, although the influence on the microstructure and toughness is complex and poorly understood. We investigated the effect of 0.03, 0.12, and 0.23 wt % V on the microstructure and mechanical properties of medium-carbon steels (0.54% C-0.9% Si) for train wheels. As the V content increased, the precipitation strengthening increased, whereas the grain refinement initially increased, and then it remained unchanged. The increase in strength and hardness was mainly due to V(C,N) precipitation strengthening. Increasing the V content to 0.12 wt % refined the austenite grain size and pearlite block size, and increased the density of high-angle ferrite boundaries and ferrite volume fraction. The grain refinement improved the impact toughness. However, the impact toughness then reduced as the V content was increased to 0.23 wt %, because grain refinement did not further increase, whereas precipitation strengthening and ferrite hardening occurred.

Influence of Mn and Heat Treatment Technology on Microstructure and Mechanical Properties of a Low-Alloy Wear-Resistant Cast Steel Shovel Tooth

2012 ◽  
Vol 557-559 ◽  
pp. 34-37
Author(s):  
Jing Qiang Zhang ◽  
Jie Min Du ◽  
Ji Wei Guo ◽  
Shou Fan Rong ◽  
Guang Zhou Wang
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Impact Toughness ◽  
Cast Steel ◽  
Treatment Technology ◽  
Wear Resistant ◽  
Heat Treatment Technology ◽  
Microstructure And Mechanical Properties ◽  
Mn Content ◽  
The Impact

The influences of Mn and heat-treatment technology on microstructure and mechanical properties of medium-carbon-low-alloy wear-resistant cast steel were investigated. The results show that the hardness first increases and then drops down with the increase of Mn content, and the best hardness is 54HRC with Mn content 1.5%. The impact toughness first increases and then drops down with the increase of Mn content. The hardness and impact toughness first increase and then drop down with the increases of quenching temperature. The optimal impact toughness can be obtaind by quenching at 920°C and tempering at 200°C. Part of lower bainite and residual austenite and mass of tempered martensite are obtaind after tempering.

scholarly journals Microstructure Evolution and Mechanical Properties of 0.4C-Si-Mn-Cr Steel during High Temperature Deformation

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 172 ◽  
Author(s):  
Fei Zhang ◽  
Yang Yang ◽  
Quan Shan ◽  
Zulai Li ◽  
Jinfeng Bi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
High Temperature ◽  
Impact Toughness ◽  
Microstructure Evolution ◽  
Cast Steel ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Grain Sizes ◽  
The Impact

Herein, the effects of height-diameter ratios (H/D) on the microstructure evolution and mechanical properties of 0.4C-Si-Mn-Cr steel during high temperature deformation are reported. The compression experiments were performed on steel samples using Gleeble to obtain a reasonable deformation temperature, and the degree of deformation was assessed in the range of 1.5 to 2.0 H/D via forging. The forged specimens were quenched using the same heat treatment process. The hardness and impact toughness of the steel samples were tested before and after heat treatment. Grain sizes gradually increased with an increase in the compression temperature from 950 °C to 1150 °C, and the grain sizes decreased with an increase in H/D. The microstructure of the steel samples contained pearlite, bainite, martensite, and retained austenite phase. The microstructure after forging was more uniform and finer as compared to that of as-cast steel samples. The hardness and impact toughness of the steel samples were evaluated after forging; hardness first increased and then decreased with an increase in H/D, while the impact toughness continuously increased with an increase in H/D. Hence, the microstructure and properties of steel could be improved via high temperature deformation, and this was primarily related to grain refinement.

Microstructure and Mechanical Properties of Austempered High Boron Cast Iron with Modification and its Mechanism Discussion

2013 ◽  
Vol 744 ◽  
pp. 349-352
Author(s):  
Xiao Hu ◽  
Xiang Chen ◽  
Yan Xiang Li
Keyword(s):  
Mechanical Properties ◽  
Cast Iron ◽  
Impact Toughness ◽  
Cast Alloy ◽  
Grain Refining ◽  
Small Particles ◽  
Microstructure And Mechanical Properties ◽  
High Boron ◽  
Austempering Temperature ◽  
The Impact

A kind of austempered boron alloyed high silicon cast alloy was developed though modification with Ti and controlling austempering temperature, the impact toughness of which increases to 20.7 J/cm2, which is more than triple that of the previous work. The alloy with modification exhibits obvious grain refining both in matrix and boride, improved the morphology of boride into discontinuous network and small particles. The phenomenon and mechanism are discussed in the article, it proved TiC is possible to act as the nuclei of eutectic boride and Ti can be an effective modifier.

Microstructure and Mechanical Properties of Spray Deposited W9Mo3Cr4V High Speed Steel

2011 ◽  
Vol 391-392 ◽  
pp. 714-718
Author(s):  
Rui Zhou ◽  
Jian Fei Sun ◽  
Ying Jun Yang
Keyword(s):  
Mechanical Properties ◽  
Impact Toughness ◽  
High Speed ◽  
Bending Strength ◽  
Spray Deposition ◽  
High Speed Steel ◽  
Solidification Shrinkage ◽  
Microstructure And Mechanical Properties ◽  
The Matrix ◽  
The Impact

Microstructure and mechanical properties of W9Mo3Cr4V high speed steel fabricated by spray deposition have been studied. Spray deposited W9Mo3Cr4V high speed steel has a typical equiaxed structure which is finer and more homogeneous with a grain size of 20-30 micrometer compared with conventional casted counterparts. There are pores in the matrix of the deposited steel, which involve gas porosity, filling porosity and solidification shrinkage. As-deposited high speed steel is mainly composed of martensite, austenite and carbides which comprise MC carbide and M6C carbide. Mechanical properties show that the hardness and bending strength of the as-deposited steel are higher than that of the conventionally casted ones. However, impact toughness of the high speed steel is lower than that of the conventionally casted steel, which can be attributed to the existence of porosities and M6C carbides which reduce the impact toughness of high speed steels.

Microstructures and Mechanical Properties of High Strength Low Carbon Bainitic Steel

2015 ◽  
Vol 817 ◽  
pp. 257-262 ◽  
Author(s):  
Xiao Long Yang ◽  
Yun Bo Xu ◽  
Xiao Dong Tan ◽  
Yong Mei Yu ◽  
Di Wu
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Yield Strength ◽  
Impact Energy ◽  
Bainitic Steel ◽  
Cooling Temperature ◽  
Fast Cooling ◽  
Microstructures And Mechanical Properties ◽  
The Impact ◽  
Strength And Toughness

Based on TMCP and UFC technology, the microstructures and mechanical properties of 0.05% C bainitic steel were studied in this paper. The bainite morphology and precipitation within bainite lath were observed by SEM and TEM, and the mechanical properties of bainitic steel were measured by tensile and impact test. The results showed that the yield and tensile strengths of steel were 713 MPa and 891 MPa respectively, and the elongation was 15.8% with impact energy of 95J at the temperature of-20°C as the final cooling temperature in hot rolling of 550°C. For comparison, the steel obtained the yield strength of 725 MPa, tensile strength of 930 MPa and elongation of 18% as the final cooling temperature of 450°C. However, the impact energy of steel was 195J at the temperature of-20°C. While at the same final cooling temperature of 450°C, the fast cooling-holding temperature-fast cooling was applied to experimental steel with a faster cooling rate of 50°C/s, hence the steel acquired the yield strength of 845 MPa, tensile strength of 1037 MPa, and elongation of 15.5% with impact energy of 168J at the temperature of-20°C. The strength and toughness of 0.05%C bainitic steel is related to the bainite morphology and precipitation distribution. Hence, the strength and toughness can be improved by control the different cooling processes for adjusting the content of lath bainite, distribution of granular bainite and precipitation.

scholarly journals Effect of Welding Thermal Cycles on Microstructure and Mechanical Properties of Simulated Heat Affected Zone for a Weldox 1300 Ultra-High Strength Alloy Steel

2016 ◽  
Vol 61 (1) ◽  
pp. 127-132 ◽  
Author(s):  
M. St. Węglowski ◽  
M. Zeman ◽  
A. Grocholewski
Keyword(s):  
Mechanical Properties ◽  
Impact Toughness ◽  
Heat Affected Zone ◽  
High Strength Steel ◽  
High Strength ◽  
Parent Material ◽  
Cooling Time ◽  
Microstructure And Mechanical Properties ◽  
Ultra High Strength Steel ◽  
The Impact

In the present study, the investigation of weldability of ultra-high strength steel has been presented. The thermal simulated samples were used to investigate the effect of welding cooling time t8/5 on microstructure and mechanical properties of heat affected zone (HAZ) for a Weldox 1300 ultra-high strength steel. In the frame of these investigation the microstructure was studied by light and transmission electron microscopies. Mechanical properties of parent material were analysed by tensile, impact and hardness tests. In details the influence of cooling time in the range of 2,5 ÷ 300 sec. on hardness, impact toughness and microstructure of simulated HAZ was studied by using welding thermal simulation test. The microstructure of ultra-high strength steel is mainly composed of tempered martensite. The results show that the impact toughness and hardness decrease with increase of t8/5 under condition of a single thermal cycle in simulated HAZ. The increase of cooling time to 300 s causes that the microstructure consists of ferrite and bainite mixture. Lower hardness, for t8/5 ≥ 60 s indicated that low risk of cold cracking in HAZ for longer cooling time, exists.

scholarly journals Microstructure and Mechanical Properties of CrMoV Steel after Long-Term Service

2016 ◽  
Vol 61 (1) ◽  
pp. 51-54 ◽  
Author(s):  
G. Golański ◽  
I. Pietryka ◽  
J. Słania ◽  
S. Mroziński ◽  
J. Jasak
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Elevated Temperature ◽  
Yield Strength ◽  
Impact Energy ◽  
Welded Joint ◽  
Steam Pressure ◽  
Microstructure And Mechanical Properties ◽  
Bainitic Microstructure

The paper presents the results of research on the microstructure and mechanical properties of 12HMF steel after longterm service. The investigated material was taken from a pipeline with circumferential welded joint after 419 988 hours of service at the temperature of 490°C, steam pressure 8 MPa. Performed research has shown that the 12HMF steel after service was characterized by a typical microstructure for this grade of steel, that is a ferritic-bainitic microstructure without any visible advanced processes of its degradation. The investigation of mechanical properties has shown that the examined steel after service was characterized by a very low impact energy KV, and yield strength lower than the required minimum. Whilst tensile strength and yield strength determined at elevated temperature was higher and similar to the standard requirements, respectively. It has been proved that the main cause of an increase in brittleness and a decrease in yield strength of the examined steel should be seen in the segregation of phosphorus to grain boundaries and the formation of precipitate free zones near the boundaries.

The Effect of Modification and Heat Treatment on Low Chromium White Cast Iron

2011 ◽  
Vol 418-420 ◽  
pp. 1114-1117 ◽  
Author(s):  
E Liu ◽  
Feng Lan Wei ◽  
Li Chun Qiu
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Cast Iron ◽  
Impact Toughness ◽  
White Cast Iron ◽  
Microstructure And Mechanical Properties ◽  
Carbide Morphology ◽  
The Impact ◽  
Compound Modification

The effect of compound modification and various kinds of heat treatment on microstructure and mechanical properties of the low chromium white cast iron was studied.The results showed that,after modification,the carbide morphology in cast iron has been greatly improved;the annealed modified cast iron is suitable for machining;both martensitic quenching and austempering can cause the hardness and the impact toughness of modified cast iron increase greatly.

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