TAN Wen
,
HAN Bin
,
WANG Shui-ze
,
YANG Yi
,
ZHANG Chao
,
ZHANG Yong-kun
钢铁研究学报(英文版)
Effects of chemical compositions, finish rolling temperature, isothermal temperature on runout table and coiling temperature on microstructure and mechanical properties of economical dual phase steel produced on CSP line were investigated. Experimental results showed that martensite volume fraction could be enhanced and banding microstructure could be reduced by controlling Mn, Si contents and applying proper finish rolling temperature. Optimized processing-parameters were obtained for DP580 production on CSP line of Wuhan Iron and Steel (group) Co (WISCO) in China. Optimal microstructure and mechanical properties could be achieved when the strip was finished rolling at the range of 790 to 830 ℃, isothermally holding at 680 to 740 ℃ and coiling below 250 ℃.
关键词:
economical dual phase steel
,
mechanical property
,
banding microstructure
,
processing-parameter
M Safavi
,
S M Abbasi
,
R Mahdavi
钢铁研究学报(英文版)
The influence of 001% to 025% of Aluminum content (in mass percent) on the mechanical properties and cold workability of low thermal expansion Fe-33Ni-15Co sheets in the annealed and hot rolled condition was investigated. Addition of Al up to 015% resulted in the increase of ductility and toughness and improvement of workability. Besides, achievement of fine grain structure and increase in the amount of annealing twins caused ductility to improve. Addition of Al higher than 015% led to the increase in oxidation reaction during melting process and to refine under argon atmosphere. This caused the volume fraction of Al containing inclusions to increase and consequently the ductility and toughness to decrease.
关键词:
Fe-33Ni-15Co alloy
,
Al content
,
mechanical property
,
cold workability
ZHOU Min
,
DU Lin-xiu
,
LIU Xiang-hua
钢铁研究学报(英文版)
The variation of heat treatments including directed quenching and tempering off-line after controlled rolling (DQT) and quenching off-line and tempering off-line after controlled rolling (RQT) with microstructure and mechanical properties of a low-carbon microalloyed steel was compared and analyzed. For DQT, the quenched steel was obviously banded microstructure, with increasing tempering temperature, lath martensite coarsened, the cusp carbide precipitated at grain boundaries, the yield strength fluctuated slightly, and the fracture-separation was obvious. The impact toughness was better in the steel tempered at 500 ℃ for 1 h. In RQT, with increasing tempering temperature, lath martensite degenerated, intragranular and intergranular finer precipitations with smaller than 30 nm precipitated and grew up and were distributed dispersedly, the stripe-like carbides were distributed at grain boundaries, and the yield strength and tensile strengthen decreased obviously. The impact toughness of RQT process was much better than that of DQT process, and the comprehensive mechanical properties were better for the steel tempered at 500 ℃ for 1 h of RQT process.
关键词:
X120 pipeline steel
,
heat treatment
,
microstructure
,
mechanical property
,
fracture-separation
SONG Ren-bo
,
XIANG Jian-ying
,
HOU Dong-po
钢铁研究学报(英文版)
A comparative study on mechanical properties and microstructure of 316L austenitic stainless steel between solution treated specimen and hot rolled specimen was conducted. After a specimen was subjected to solution treatment at 1050 ℃ for 6 min, its mechanical properties were determined through tensile and hardness tests. Based on the true stress vs true strain and engineering stress vs engineering strain flow curves, the work hardening rate has been explored. The results show that the solution treated specimen has an excellent combination of strength and elongation, and that this steel is easy to work-hardening during deformation. Optical microscope, scanning electron microscope, transmission electron microscope and X-ray diffraction examinations were conducted, these reveal that twins in 316L austenitic stainless steel can be divided into suspended twin and transgranular twin which have different formation mechanisms in growth, and that the deformation induced martensite nucleated and grown in the shear band intersections can be observed, and that the fracture surfaces are mainly composed of dimples and exhibit a tough fracture character.
关键词:
316L
,
mechanical property
,
twin
,
martensite
,
fracture morphology
LIU Sheng-fa
,
CHEN Yang
,
CHEN Xin
,
MIAO Hua-ming
钢铁研究学报(英文版)
Austempered ductile iron (ADI) has several advantages of replacing cast steel and forged steel in many engineering fields. A new Mn-Cu alloyed ADI with excellent mechanical properties has been developed in order to cut the cost and enlarge the application of ADI. The helical bevel gears were made of the new-developed Mn-Cu alloyed ADI. The microstructure and mechanical properties of the standard sample were investigated by optical microscope (OM), scanning electron microscope (SEM) and performance measurement. The results showed that after a series of treatments, the mechanical properties (Rm 10074 to 1200 MPa, A 52% to 88%, HRC 32 to HRC 35, αK 70 to 120 J/cm2) of the Mn-Cu alloyed ADI standard sample could reach European standard EN1564-97/ EN-CJS-1000-5. The surface hardness after helical bevel gears meshing was significantly increased due to the formation of martensite. The bench test and traffic running testing results suggested that the new Mn-Cu alloyed ADI with ultimate life and median life respectively exceeding 30×104 and 50×104 times could replace 20CrMnTi forged steel for manufacturing the EQ140 helical bevel gears.
关键词:
ADI
,
Mn
,
mechanical property
,
helical bevel gear
MA Zheng-huan
,
ZHAO Xiang-juan
,
GE Chang-sheng
,
DING Tie-suo
,
LI Jun
,
XIAO Xue-shan
钢铁研究学报(英文版)
A new family of resource-saving, high chromium and manganese super duplex stainless steels (DSSs), with a composition in mass percent, % of Cr 0.29, Mn 0.12, Ni 2.0, Mo 1.0, and N 0.51-0.68, has been developed by examining the effect of N on the microstructure, mechanical properties and corrosion properties. The results show that these alloys have a balanced ferrite-austenite relation. The austenite volume fraction decreases with the solution treatment temperature, but it increases with an increase in N content. The increases in nitrogen enhance the ultimate tensile strength (UTS) and reduce the ductility of the material slightly. The pitting corrosion potential increases first and then decreases with an increase in nitrogen content when the amount of N arrives to 0.68%. The yield stress and ultimate tensile strength of solution-treated samples were more than 680 and 900 MPa, the elongation of experimental alloys are higher than 30%, respectively, what is more, the pitting potentials were beyond 1100 mV.
关键词:
duplex stainless steel
,
microstructure
,
mechanical property
,
pitting potential
Fatih Hayat
,
Hüseyin Uzun
钢铁研究学报(英文版)
Grade A (GA) and high strength steel DH36 ship steels possessing different chemical compositions were used, and strength properties of GA steel and DH36 steel were compared. Additionally, 4 types of dual phase (DP) steels with different martensite volume fractions (MVFs) were produced from GA steel by means of heat treatment and they were compared with other steels through conducting microstructure, microhardness, tensile and impact tests. The fracture surfaces of specimens (DH36, GA and DP steels) exposed to tensile and Charpy impact tests were investigated by scanning electron microscope. Furthermore, it was found that the specimens quenched from 800 and 900 ℃ had better strength than DH36 steel. The tensile test results indicated that the tensile strength of DP steel water quenched from 900 ℃ was 3 times that of GA steel and twice that of DH36 steel.
关键词:
Grade A ship steel
,
DH36 ship steel
,
dual phase steel
,
martensite
,
mechanical property
,
fracture
吴红艳，杜林秀，刘相华
钢铁
在热连轧生产线上采用两阶段轧制生产了09CuPTi系耐候钢，研究了轧制工艺参数对耐候钢板微观组织和力学性能的影响规律。结果表明，3种工艺试验钢的显微组织均为针状铁素体和贝氏体。当终冷温度为530℃冷却速度为25℃/s时，组织以更细小均匀的板条贝氏体为主，屈服强度及抗拉强度分别为617MPa和702MPa，韧脆性转变温度较低，具有良好的强韧性。对轧后钢板进行了耐腐蚀试验，研究了09CuPTi-Nb钢工艺B成品和参考钢在模拟工业大气环境下的腐蚀演化行为。结果表明，在腐蚀初期腐蚀速度随干湿循环次数的增加而增大，在后期腐蚀速度逐渐降低，09CuPTi-Nb钢的腐蚀速率与SPA-H钢相当，但低于Q345钢。09CuPTi-Nb钢锈层分为内外两层，内锈层致密主要由α-FeOOH和少量γ-Fe2O3组成，Q345钢锈层主要由α-FeOOH、γ-Fe2O3和Fe3O4组成。电化学试验表明，腐蚀产物促进阴极过程，抑制阳极过程。
关键词:
微观组织
,
mechanical property
,
corrosion behavior
,
structure of rust layer
,
electric polarization curve
