Dual Ferrite-Martensite Treatments of an ASTM A588 HSLA Steel

Author(s):  
L.J. Chen ◽  
J.R. Yang

During the past several years duplex ferrite-martensite (DFM) steels have received increasing attention for improved strength and weight applications, since they contain characteristic microstructural features that combine high strength with good formability. ASTM A588 is one of the most widely used classes of high strength low alloy (HSLA) steels. It possesses the atmospheric corrosion resistance property as well as relatively high yield strength (∼35 kg/mm2) in the normalized condition. DFM treatments has been applied to the A588 steel.The treatments consisted of initial austenitization and quenching to form 100% martensite, followed by annealing in the (α+γ) region at different temperatures and subsequent quenching. The DFM structure samples were also tempered at 200°-600°C for one hour. Phase diagram of a model steel and the schematic of treatments are shown in Figs. 1(a) and 1(b), respectively. Hardness, ultimate tensile strength, yield strength, elongation and Charpy impact values were measured for thermally treated samples.

Author(s):  
Mehdi Soltan Ali Nezhad ◽  
Sadegh Ghazvinian ◽  
Mahmoud Amirsalehi ◽  
Amir Momeni

Abstract Three steels were designed based on HSLA-100 with additional levels of Mn, Ni, Cr and Cu. The steels were prepared by controlled rolling and tempered at temperatures in range of 550–700°C. The continuous cooling time curves were shifted to longer times and lower temperatures with the increased tendency for the formation of martensite at lower cooling rates. The microstructures revealed that controlled rolling results in austenite with uniform fine grain structure. The steel with the highest amount of Mn showed the greatest strength after tempering at 750 °C. The top strength was attributed to the formation of Cu-rich particles. The steel with 1.03 wt.% Mn, tempered at 650 °C exhibited the best Charpy impact toughness at –85°C. On the other hand, the steel that contained 2.11 wt.% Mn and tempered at 700 °C showed the highest yield strength of 1 097.5 MPa (∼159 ksi) and an impact toughness of 41.6 J at –85°C.


Alloy Digest ◽  
1967 ◽  
Vol 16 (1) ◽  

Abstract Republic 50 is a high-strength low-alloy structural steel recommended where high yield strength and toughness combined with good weldability and corrosion resistance are required. This datasheet provides information on composition, physical properties, elasticity, tensile properties, and compressive, shear, and bend strength as well as fracture toughness and fatigue. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SA-205. Producer or source: Republic Steel Corporation.


2021 ◽  
Vol 13 (6) ◽  
pp. 3482
Author(s):  
Seoungho Cho ◽  
Myungkwan Lim ◽  
Changhee Lee

High-strength reinforcing bars have high yield strengths. It is possible to reduce the number of reinforcing bars placed in a building. Accordingly, as the amount of reinforcement decreases, the spacing of reinforcing bars increases, workability improves, and the construction period shortens. To evaluate the structural performance of high-strength reinforcing bars and the joint performance of high-strength threaded reinforcing bars, flexural performance tests were performed in this study on 12 beam members with the compressive strength of concrete, the yield strength of the tensile reinforcing bars, and the tensile reinforcing bar ratio as variables. The yield strengths of the tensile reinforcement and joint methods were used as variables, and joint performance tests were performed for six beam members. Based on this study, the foundation for using high-strength reinforcing bars with a design standard yield strength equal to 600 MPa was established. Accordingly, mechanical joints of high-strength threaded reinforcing bars (600 and 670 MPa) can be used. All six specimens were destroyed under more than the expected nominal strength. Lap splice caused brittle fractures because it was not reinforced in stirrup. Increases of 21% to 47% in the loads of specimens using a coupler and a lock nut were observed. Shape yield represents destruction—a section must ensure sufficient ductility after yielding. Therefore, a coupler and lock nut are effective.


1970 ◽  
Vol 92 (1) ◽  
pp. 11-16 ◽  
Author(s):  
J. M. Barsom ◽  
S. T. Rolfe

Increasing use of high-strength steels in pressure-vessel design has resulted from emphasis on decreasing the weight of pressure vessels for certain applications. To demonstrate the suitability of a 140-ksi yield strength steel for use in unwelded pressure vessels, HY-140(T)—a quenched and tempered 5Ni-Cr-Mo-V steel—was fabricated and subjected to various burst and fatigue tests, as well as to various laboratory tests. In general, results of the investigation indicated very good tensile, Charpy, Nil Ductility Transition Temperature (NDT), low-cycle fatigue, and stress-corrosion properties of HY-140(T) steels, as well as very good burst tests results, in comparison with existing high-yield strength pressure-vessel steels. The results also indicate that the HY-140(T) steel should be an excellent material for its originally designed purpose, Naval hull applications.


2012 ◽  
Vol 583 ◽  
pp. 306-309
Author(s):  
Yan Tang Chen ◽  
Kai Guang Zhang ◽  
Ji Hao Cheng

The high strength low alloy (HSLA) steels have been extensively used in offshore engineering. The appropriate microstructure of the HSLA structural steels was designedly controlled in steel making for offshore construction. The different microstructures of the steel were formed when shifted the cooling rate after final rolling. Experiment results shown that ferrite and pearlite were observed in the HSLA steel with a cooling rate less than 0.2°C/s. Bainite was formed when the cooling rate ranged from 1.0°C/s to 5.0°C/s and martensite was seen in the steel plate with a cooling rate more than 30°C/s. Generally the martensite is a prohibited product in the offshore structural steels.


1988 ◽  
Vol 110 (3) ◽  
pp. 171-176
Author(s):  
Y. Nakano ◽  
Y. Saito ◽  
K. Amano ◽  
M. Koda ◽  
Y. Sannomiya ◽  
...  

This paper describes the metallurgical approaches for producing 415MPa and 460MPa yield strength offshore structural steel plates and the mechanical properties of the steel plates and their welded joints. A thermo-mechanical control process (TMCP) was adopted to manufacture YP415MPa and YP460MPa steel plates with weldability comparable to conventional YP355MPa steel plates. The Charpy impact and CTOD tests of the steel plates and their welded joints proved to be very good.


2018 ◽  
Vol 941 ◽  
pp. 492-497
Author(s):  
Kuo Cheng Yang ◽  
J.F. Tu ◽  
L.J. Chiang ◽  
W.J. Cheng ◽  
C.Y. Huang

Recently, due to the requirements of lightweight and safety, the grade of 980MPa high-strength steel has the demand of high hole expansibility and high yield strength. Due to the large difference of hardness between the soft ferrite and hard martensite, the traditional DP980Y dual phase steel has poor hole expansibility. In order to improve the hole expansibility of DP980Y dual phase steel, the best way is to modify the microstructure into a single-phase to eliminate the large difference of hardness. In this paper, the steel of nearly full bainite microstructure with small amount of ferrite and M/A constituents was studied. Compared to the DP980Y dual phase steel, it was found that this modified steel with a single-phase microstructure has the same grade of 980MPa of tensile strength, but can achieve the demand of higher yield strength and hole-expansion ratio. This study shows reducing the amount of ferrite can increase the homogeneity of matrix with the single phase to improve the hole expansibility. In addition, the use of lower bainite transformation temperature and lower carbon content has the higher hole-expansion ratio due to the less amount of M/A constituents.


2010 ◽  
Vol 654-656 ◽  
pp. 719-722 ◽  
Author(s):  
J. Horiuchi ◽  
Hirofumi Inoue ◽  
Takayuki Takasugi

Conventional symmetric rolling enhances yield strength by forming basal texture, while asymmetric rolling can improve formability by inclining the c-axis of hcp crystal. In this study, the combination rolling consisting of symmetric and asymmetric hot rolling has been performed to simultaneously improve formability and maintain high strength of AZ31 magnesium alloy sheet. The symmetrically/asymmetrically combination hot-rolled and annealed sheet exhibits a broadened texture having double peaks with tilt angles of 0º and 40º from ND toward RD with respect to the c-axis. Correspondingly, this sheet shows relatively high yield strength of 123 MPa and large elongation of 24.7%. As for cup drawing test, the conventional warm-rolled sheet is barely formed at 175 °C, but the symmetrically/asymmetrically combination rolled sheet can be formed at temperature as low as 75 °C. These results indicate that the symmetric/asymmetric combination hot-rolling leads to a unique texture with good balance of formability and strength.


Sign in / Sign up

Export Citation Format

Share Document