Microstructure and Mechanical Properties of 0.15C-1.5Mn-0.3Si Steel Treated by Quenching and Partitioning Process

2014 ◽  
Vol 1063 ◽  
pp. 69-72
Author(s):  
Cai Nian Jing ◽  
Ji Chao Fan ◽  
Shu Bo Xu ◽  
Yi Sheng Zhang

In this paper, the microstructure and mechanical properties of 0.15C-1.5Mn-0.3Si steels after quenching and partitioning (Q&P) process was studied. The microstructure of experimental steels was characterized by optical microscope (OM), scan electron microscope (SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD), and mechanical properties were performed through uni-axial tensile tests. The microstructure evolution during Q&P process was also discussed together with mechanical properties. The investigated steels show excellent strength and ductility product of 10.76GPa% with retained austenite content of 11.08%. The microstructure mainly consists of lath martensite and retained austenite at room temperature, which promotes persistent work hardening during deformation.

2011 ◽  
Vol 399-401 ◽  
pp. 259-263 ◽  
Author(s):  
Xue Min Wang ◽  
Pei Zhu Li

With the aid of optical microscope, transmission electron microscope, scanning electron microscope, the processing and chemical composition on the microstructure and mechanical properties of low alloy wear resistance steels have been investigated. The results show that by multi-alloying design and TMCP processing the low alloy wear resistance steels has good synthetic properties. The lath martensite, multi phase microstructure composed of bainite and retained austenite film could be obtained after direct quenching. The lath martensite with retained austenite shows better wear resistance than bainite. Under the two bodies abrasive wear condition the characteristics of worn surface reveals that the main wear mechanism is micro-cutting.


2021 ◽  
Vol 118 (6) ◽  
pp. 601
Author(s):  
Chunhui Jin ◽  
Honglin Zhou ◽  
Yuan Lai ◽  
Bei Li ◽  
Kewei Zhang ◽  
...  

The influence of aging temperature on microstructure and mechanical properties of Cr15Ni5 precipitation hardening stainless steel (15-5 PH stainless steel) were investigated at aging temperature range of 440–610 °C. The tensile properties at ambient temperature of the 15-5 PH stainless steel processed by different aging temperatures were tested, and the microstructural features were further analyzed utilizing optical microscope (OM), transmission electron microscope (TEM), electron backscatter diffraction (EBSD) as well as X-ray diffraction (XRD), respectively. Results indicated the strength of the 15-5 PH stainless steel was firstly decreased with increment of aging temperature from 440 to 540 °C, and then increased with the increment of aging temperature from 540 to 610 °C. The strength and ductility were well matched at aging temperature 470 °C, and the yield strength, tensile strength as well as elongation were determined to be 1170 MPa, 1240 MPa and 24%, respectively. The microstructures concerning to different aging temperatures were overall confirmed to be lath martensite. The strengthening mechanisms induced by dislocation density and the second phase precipitation of Cu-enriched metallic compound under different aging temperatures were determined to be the predominant strengthening mechanisms controlling the variation trend of mechanical properties corresponding to different aging temperatures with respect to 15-5 PH stainless steel.


2021 ◽  
Vol 55 (2) ◽  
pp. 269-275
Author(s):  
Cainian Jing ◽  
Qiteng Lei ◽  
Tao Lin ◽  
Daomin Ye ◽  
Cong Wu ◽  
...  

In this paper, the TRIP590 steel was used for C-Mn partitioning. The influence of C-Mn partitioning on the microstructure and mechanical properties of the steel was studied. SEM, EPMA, XRD and tensile tests were used to characterize the microstructure of the tested steel, calculate the content of retained austenite, and analyze the enrichment of C atoms and Mn atoms and mechanical properties. The results show that there was a lot of lath martensite and scattered ferrite in the microstructures of the Q&P steel and C-Mn partitioning steel. After C-Mn partitioning, the content of ferrite was increased. The enrichment of C and Mn in the C-Mn partitioning steel was relatively apparent, and the concentration of the atoms in the center of martensite was significantly higher than at the boundary between martensite and ferrite. Mn-rich areas were also C-rich areas. Compared with the Q&P steel, the C-Mn partitioning steel had a larger amount of retained austenite, higher elongation and PSE.


Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1306
Author(s):  
Gong-Ting Zhang ◽  
Na-Qiong Zhu ◽  
Bo-Wei Sun ◽  
Zheng-Zhi Zhao ◽  
Zhi-Wang Zheng ◽  
...  

Three C-Si-Mn Q&P steels with different V addition after one-step and two-step quenching and partitioning (Q&P) processes were investigated by means of optical microstructure observation, X-ray diffraction (XRD) measurement, transmission electron microscopy (TEM) characterization and particle size distribution (PSD) analysis. The effect of V addition on strength and ductility of the steels was elucidated by comparative analysis on the microstructure and mechanical properties as functions of partitioning time and temperature. For one-step Q&P treatment, the mechanical properties were mainly controlled by the tempering behavior of martensite during partitioning. V addition was helpful to mitigate the deterioration of mechanical properties by precipitation strengthening and grain refinement strengthening. For two-step Q&P treatment, the satisfying plasticity was attributed to the transformation-induced plasticity (TRIP) effect of retained austenite maintaining the high work hardening rate at high strain regime. The higher volume fraction of retained austenite with high stability resulted from the refined microstructure and the promoted carbon partitioning for the steel with 0.16 wt% V addition. However, the carbon consumption due to the formation of VC carbides led to the strength reduction of tempered martensite.


Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 795 ◽  
Author(s):  
Cheng Zhang ◽  
Shouxin Wang ◽  
Hanxue Qiao ◽  
Zejun Chen ◽  
Taiqian Mo ◽  
...  

In this study, the traditional hot rolling to fabricate Al/Ti laminated metal composites (LMCs) was improved by using a pre-rolling diffusion process. The effect of the pre-rolling diffusion on microstructure and mechanical properties of Al/Ti LMCs were investigated by various methods, such as optical microscope (OM), scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and tensile tests. The results show that, with increasing diffusion temperature, the thickness in diffusion layer was increased and the mechanical properties of LMCs were improved obviously, which was attributed to the optimized interfacial structure after diffusion process. In addition, the formation of TiAl3 intermetallic compounds (IMCs) was detected in the bonding interface, which played an important role in improving the mechanical properties for Al/Ti LMCs. The predicted results of stress-strain curves from rule of mixture (ROM) indicated that, there existed an extra interfacial strengthening in Al/Ti LMCs beside the mechanical properties provided by the contribution of constituent layers. The pre-rolling diffusion process is effective for the optimization of interfacial structure and improvement of mechanical properties in Al/Ti LMCs.


2010 ◽  
Vol 667-669 ◽  
pp. 863-866
Author(s):  
Xin Zhao ◽  
Xiao Ling Yang

Steel plates with lath martensite microstructure were rolled up to 68% reduction at 673 K and then annealed at 473-973 K. The microstructure evolution was studied by using an optical microscope and a transmission electron microscopy. And the properties were investigated by using tensile tests and hardness tests. Results show that ultrafine grains + nano-carbides are obtained in the steel plates. The specimen annealed at 823 K has a good combination of strength and ductility. The tensile strength and total elongation are 1028 MPa and 7.2%, respectively. And the hardness is 338 Hv.


2014 ◽  
Vol 629 ◽  
pp. 456-460 ◽  
Author(s):  
S. Rasool Mohideen ◽  
Ahmad Zaidi Ahmad Mujahid ◽  
Abdullah Shohaimi ◽  
S. Ravi

Materials are subjected to low temperatures either intentionally as in the case of cryogenic fuels or non-intentionally as in the case of aerospace environment and are observed to undergo changes in their properties. Microstructural changes are the premier indications of changes in the properties of materials. This paper investigates the effect of cryogenic temperature on the microstructure of low alloy steel weldments. The weldments were subjected to liquid nitrogen temperature of 77K and the microstructures were analyzed using optical microscope and transmission electron Microscope. A distinct change in the microstructure was observed which would reason out the changes in the mechanical properties of weldments.


2012 ◽  
Vol 562-564 ◽  
pp. 39-42
Author(s):  
Hang Su ◽  
Xi Qing Zhao ◽  
Tao Pan ◽  
Xiao Rong Lei ◽  
Qing Feng Wang

Microstructure and mechanical properties in QT-Treated 9Ni steel were investigated. The detail microstructures were observed by optical microscope (OM) and transmission electron microscope (TEM). The volume fraction of austenite was estimated by XRD. Tensile test at room temperature and Charpy-V-Notch (CVN) impact test at -196°C were carried out. The results showed that the microstructure of QT-treated 9%Ni steel was composed of tempered martensite and reversed austenite. The brittle cementite was absorbed gradually by the increasing reversed austenite as the tempering temperature increased. The optimum tempering temperature range was 560°C~580°C. The reversed austenite could improve the cryogenic toughness of 9Ni steel through the combination of the scavenging effect and the TRIP effect.


2012 ◽  
Vol 531-532 ◽  
pp. 596-599
Author(s):  
Kai Zhang ◽  
Shang Wen Lu ◽  
Yao Hui Ou ◽  
Xiao Dong Wang ◽  
Ning Zhong

The recently developed “quenching and partitioning” heat treatment and “quenching-partitioning-tempering” heat treatment are novel processing technologies, which are designed for achieving advanced high strength steels (AHSS) with combination of high strength and adequate ductility. In present study, a medium carbon steel containing Nb was subjected to the Q-P-T process, and both the microstructure and mechanical properties was studied. The experimental results show that the Nb-microalloyed steel demonstrates high tensile strength and relatively high elongation. The microstructure of the steel was investigated in terms of scanning electron microscope and transmission electron microscope, and the results indicate that the Q-P-T steel consist of fine martensite laths with dispersive carbide precipitates and the film-like interlath retained austenite. The orientation relationships between martensite and retained austenite is as well-known Kurdjurmov-Sachs relationship and Nishiyama-Wasserman relationship.


2011 ◽  
Vol 233-235 ◽  
pp. 1009-1013
Author(s):  
Cai Zhao ◽  
Di Tang

The mechanical properties of Low Carbon Si-Mn Q&P steel are strongly affected by the conditions of heat treatment. Microstructures and mechanical properties of Low Carbon Si-Mn Q&P steel at different partitioning temperature and holding time was investigated. The microstructure was analysed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It is shown that the microstructure of Q&P steel is carbon-depleted lath martensite and carbon enriched retained austenite. The retained austenite appear film-type between the laths. Higher partitioning temperature and longer partitioning time can obtain more retained austenite. It is shown that with increasing partitioning time ultimate tensile strength decreases, while elongation increases obviously. Carbon-enriched metastable retained austenite is considered beneficial because the TRIP phenomenon during deformation can contribute to formability and energy absorption.


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