scholarly journals Morphology and Crystallography Analyses of HSLA Steels with Hardenability Enhanced by Tailored C–Ni Collocation

Metals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 32
Author(s):  
Zhipeng Liu ◽  
Yishuang Yu ◽  
Jie Yang ◽  
Zhiquan Wang ◽  
Hui Guo ◽  
...  
Keyword(s):  
Driving Force ◽  
Nickel Content ◽  
High Strength ◽  
Transformation Strain ◽  
Steel Plates ◽  
Granular Bainite ◽  
Variant Selection ◽  
High Hardenability ◽  
Hsla Steels ◽  
Lath Bainite

High hardenability is of great importance to ultra-heavy steel plates and can be achieved by tailoring the composition of steel. In this study, the continuous cooling transformation (CCT) curves of two high-strength low-alloy (HSLA) steels (0.16C-0.92Ni steel and 0.12C-1.86Ni steel) were elucidated to reveal the significance of C–Ni collocation on hardenability from the perspective of morphology and crystallography. At a low cooling rate (0.5 °C/s), the 0.12C-1.86Ni steel showed higher microhardness than 0.16C-0.92Ni steel. The microstructure in 0.16C-0.92Ni steel was mainly granular bainite with block-shaped martensite/austenite islands (M/A islands), while that in 0.12C-1.86Ni steel was typically lath bainite with film-shaped M/A islands, denoting that the 0.12C-1.86Ni steel is of higher hardenability. Moreover, the 0.12C-1.86Ni steel exhibited a higher density of block boundaries, especially V1/V2 boundaries. The higher density of block boundaries resulted from the weakened variant selection due to the larger transformation driving force and more self-accommodation of transformation strain induced by the reduced carbon and increased nickel content.

Development of Low Carbon Bainitic Cr-B Steel with High Strength and Good Toughness

2010 ◽  
Vol 146-147 ◽  
pp. 937-940
Author(s):  
Xiang Dong Huo ◽  
Zhang Guo Lin ◽  
Yu Tao Zhao ◽  
Yu Qian Li
Keyword(s):  
High Strength ◽  
Polygonal Ferrite ◽  
Steel Plates ◽  
Granular Bainite ◽  
High Yield ◽  
Low Carbon ◽  
Experimental Steel ◽  
Large Size ◽  
Final Microstructure ◽  
Lath Bainite

In order to develop low carbon bainitic Cr-B steel, experimental procedures including melting, thermal simulation study and laboratory hot rolling were adopted. The dynamic CCT diagram was established, microstructure and properties of experimental steel were also analyzed. The transformation temperature of experimental steel lies between 650～400°C and final microstructure changes fromquasi-polygonal ferrite, granular bainite to lath bainite as cooling rate increases from 0.2 to 50°C.s-1. The microstructure of steel plates, air cooled or water cooled to 530°C then air cooled, is mainly composed of granular bainite and quasi-polygonal ferrite, and the large size islands in granular bainite are responsible for the low strength and poor toughness. However, steel plate with lath bainite, water cooled to roomtemperature, boasts high yield strength (672MPa) and superior impact toughness (127J at -20°C). Therefore, it is feasible to produce low carbon bainitic Cr-B steel with high strength and good toughness through controlling cooling parameters.

Microstructure and Mechanical Properties of X80/X100 High Deformability Pipeline Steel

2011 ◽  
Vol 399-401 ◽  
pp. 139-143
Author(s):  
Dian Xiu Xia ◽  
De Liang Meng ◽  
Shou Yong An ◽  
Yong Lin Kang
Keyword(s):  
Pipeline Steel ◽  
Large Strain ◽  
High Strength ◽  
Longitudinal Direction ◽  
Granular Bainite ◽  
Dual Phase ◽  
Cooling Process ◽  
Bainite Structure ◽  
Lath Bainite ◽  
High Deformability

In the present study, X80 and X100 grade high deformability pipeline steels have been processed by using TMCP and followed two-stage cooling process. The microstructures of the X80HD (HD, high deformability) and X100HD steels were both characterized by ferrite-bainite dual phase. The grains sizes of ferrite were mostly less than 5μm and the volume fractions were about 20~25% in X80HD and 10~15% in X100HD steel. The bainite structure in X80HD steel was granular bainite (GB); while in X100HD steel large amounts of lath bainite (LB) were also formed besides GB, and bainite grains were much finer. Ferrite-bainite dual phase microstructure has large strain hardenability that resulting high strength and high deformability combination. Both the steels exhibit high strength/toughness in transverse direction and high deformability in longitudinal direction. The X100HD steel with more volume of LB and less volume of PF has higher strength but lower deformability than that of X80HD steel.

Continuous Cooling Transformation of Undeformed and Deformed High Strength Crack-Arrest Steel Plates for Large Container Ships

2019 ◽  
Vol 38 (2019) ◽  
pp. 183-191 ◽  
Author(s):  
Yongfeng Qi ◽  
Jing Li ◽  
Chengbin Shi ◽  
Qintian Zhu
Keyword(s):  
High Strength ◽  
Crack Arrest ◽  
Steel Plates ◽  
Granular Bainite ◽  
Deformation Condition ◽  
Stored Energy ◽  
Transformation Behavior ◽  
Continuous Cooling ◽  
Upper Bainite ◽  
Large Container

AbstractThe phase transformation behavior of crack-arrest steel during continuous cooling either with or without deformation at high temperatures was investigated. By carefully examining the microstructures of continuous cooled samples, we found that pearlite, quasi-polygonal ferrite (QPF), acicular ferrite (AF), granular bainite (GB), upper bainite, lath-like bainite and martensite/austenite will exist depending on cooling rates and transformation temperatures in both conditions of deformation and without deformation after austenization. The transformation curves of AF and GB moved toward the left in deformation condition in comparison with that of without deformation condition, which indicated that deformation promoted the formation of QPF and AF; meanwhile, deformation inhibited the formation of bainite. Finer bainite and the accompanying M/A could be obtained by reducing the bainite nucleation activation energy as follows: (i) increasing the undercooling by increasing the cooling rate; (ii) increasing the stored energy by deformation of the austenite.

Effect of Heat Imput on Microstructure and Toughness of High Strength Bridge Steel

2011 ◽  
Vol 194-196 ◽  
pp. 255-258
Author(s):  
Kun Ning Jia
Keyword(s):  
Grain Size ◽  
Crack Propagation ◽  
Heat Affected Zone ◽  
High Strength ◽  
Thermal Simulation ◽  
Granular Bainite ◽  
Coarse Grain ◽  
Bridge Steel ◽  
Lath Bainite

The coarse grain heat affected zone(CGHAZ) at different parameters t8/5 of high-strength bridge steel Q460q were simulated with thermal simulation machine. the microstructure of CGHAZ and the effect of granular bainite on the toughness were analyzed in this paper.The results show that: When t8/5<60s, lath bainite and granular bainite intertwine, and the quantity of strip M-A constituents in granular bainite decreased, so toughness is higher.When t8/5>60s, the quantity of eutectoid ferrite and granular bainite increased, coarse M-A constituent resulting in the grain size of effective crack propagation becoming coarser and toughness decreased significantly.

Microstructure and Mechanical Properties of ULCB Steels Affected by Advanced TMCP Technology

2011 ◽  
Vol 689 ◽  
pp. 289-295
Author(s):  
Zi Yong Hou ◽  
Yun Bo Xu ◽  
Di Wu ◽  
Wei Hua Sun ◽  
She E Hu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Strength Steel ◽  
Critical Factor ◽  
High Strength ◽  
Steel Plates ◽  
Granular Bainite ◽  
Finish Rolling ◽  
Ultra High Strength Steel ◽  
Lath Width ◽  
Hot Rolled

Good combination of high strength and high toughness has been considered as a critical factor of ultra-high strength steel plates. In this paper, a novel high strength steel plate of HSLA type containing Cu with 910MPa yield strength and 1163MPa tensile strength has been developed using an advanced TMCP (thermo-mechanical control processing) technology. The steel plates provide excellent combination of high strength, toughness and deformability. Microstructural evolution and mechanical properties of this steel during hot-working have been investigated. It is demonstrated that, at the relatively higher finish rolling temperature and cooling rate, the microstructure consists of acicular and granular bainite structures and a small amount of low bainite /martensite whose lath width is approximately 200~300nm. For the as-rolled conditions, despite the high strength and so low yield ratio, impact energy about 154J and fully ductility fracture at -90°C can still be obtained as documented for as-hot rolled plates.

LESCALLOY HP 9-4-30 VAC-ARC

Alloy Digest ◽  
1978 ◽  
Vol 27 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
High Strength Steel ◽  
Nickel Content ◽  
High Strength ◽  
Heat Treating ◽  
Steel Company ◽  
High Hardenability ◽  
Ingot Structure ◽  
High Nickel

Abstract LESCALLOY HP 9-4-30 VAC-ARC is a low-alloy, high-strength steel with a high nickel content to promote toughness. It was designated for high hardenability and good weldability. It is produced by the vacuum-consumable-electrode process to insure cleanliness and provide a preferred ingot structure. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: SA-343. Producer or source: Latrobe Steel Company.

Microstructure and mechanical properties of high strength TMCP steel hybrid disk laser-MAG welded joint

2019 ◽  
Vol 34 (01n03) ◽  
pp. 2040063
Author(s):  
Zheng Lei ◽  
Zongtao Zhu ◽  
Xiaoyi Yang ◽  
Yishuai Jiang ◽  
Hui Chen
Keyword(s):  
Fusion Zone ◽  
Heat Affected Zone ◽  
Acicular Ferrite ◽  
Welded Joint ◽  
Base Material ◽  
High Strength ◽  
Energy Criterion ◽  
Granular Bainite ◽  
Hybrid Laser Arc Welding ◽  
Lath Bainite

Hybrid laser-arc welding (HLAW) was carried out on high strength thermo-mechanical controlled process (TMCP) steel of 14 mm thickness using single-pass welding (SPW) and multi-pass welding (MPW) processes. Well-formed weld joints with good performance were successfully obtained. The results showed that the microstructure of weld was pre-eutectoid ferrite, acicular ferrite and some granular bainite. There were mainly lath bainite, granular bainite and acicular ferrite in the heat-affected zone. The grain sizes of SPW were thicker than MPW, and the bainite content of MPW was higher than SPW. The average hardness value of the fusion zone was lower than that of the Heat affected zone, but higher than that of the base material. The weld was divided into upper arc domain zone (ADZ) and lower laser domain zone (LDZ). The ADZ was harder than the LDZ. The average absorbed energy of SPW and MPW in the fusion zone at −40[Formula: see text]C was 125.5 and 92 J/cm2, respectively. The influences of microstructure on impact toughness were summarized by analyzing the hardness distribution and microstructure of the welded joint. The brittle transition temperatures of the two processes obtained by the energy criterion and the morphology criterion were close to each other.

scholarly journals A NEW GENERATION OF ARMORED STEEL PLATES

2016 ◽  
Vol 7 (2) ◽  
Author(s):  
Jure Bernetič ◽  
Borut Kosec ◽  
Gorazd Kosec ◽  
Mirko Gojić ◽  
Zijah Burzić ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Steel Plate ◽  
Shear Bands ◽  
High Strength ◽  
Steel Plates ◽  
Adiabatic Shear Bands ◽  
Hsla Steels ◽  
New Generation ◽  
Quenching And Tempering ◽  
Made In

The engineers of PROTAC d.o.o. and the biggest Slovenian steelwork ACRONI d.o.o., in cooperation with domestic and foreign institutions of science, have been designed and developed a new generation of armored steel PROTAC 500. Steel PROTAC 500 belongs to the group of high strength low alloy (HSLA) steels. It is made in steelwork ACRONI d.o.o. by the standard industrial procedures. The relevant mechanical properties of that steel are achieved by corresponding heat treatment procedure: quenching and tempering. Preliminary tests of the mechanical properties of the steel have indicated the possibility of using steel PROTAC 500 for light armored vehicles. The presented work studied the response of new generation armored steel plates PROTAC 500 to the ballistic testing with armored piercing bullets with a core of tungsten carbide, charge 7.62 mm. However, the interactions between the piercing bullets and the armored steel plate were also investigated. The most obvious and significant phenomena in penetrating of the piercing bullets Nammo AP8 in steel target PROTAC 500 are strain hardening of steels, the appearance of cracks and local failure, adiabatic shear bands (ASB) with related phase transformations, and melting as well as alloying at the interface between bullet and steel plate.

LESCALLOY 300M VAC ARC

Alloy Digest ◽  
1993 ◽  
Vol 42 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Tensile Strength ◽  
High Strength ◽  
Melting Process ◽  
Heat Treating ◽  
Pressure Vessels ◽  
Low Alloy Steel ◽  
Steel Company ◽  
High Hardenability ◽  
Ingot Structure

Abstract LESCALLOY 300M VAC ARC is a low-alloy steel with an excellent combination of high hardenability and high strength coupled with good ductility and good toughness. Its tensile strength ranges from 280,000 to 300,000 psi. It is produced by the vacuum consumable electrode melting process to provide optimum cleanliness and preferred ingot structure. Its applications include aircraft components, pressure vessels and fasteners. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness. It also includes information on forming, heat treating, machining, joining, and surface treatment. Filing Code: SA-321. Producer or source: Latrobe Steel Company. Originally published March 1976, revised February 1993.

Sign in / Sign up

Export Citation Format

Share Document