Microstructure Evolution of a HSLA Offshore Steel with Cooling Rates

2012 ◽  
Vol 583 ◽  
pp. 306-309
Author(s):  
Yan Tang Chen ◽  
Kai Guang Zhang ◽  
Ji Hao Cheng
Keyword(s):  
Cooling Rate ◽  
Steel Plate ◽  
Hsla Steel ◽  
High Strength ◽  
Structural Steels ◽  
Steel Making ◽  
Offshore Engineering ◽  
Hsla Steels ◽  
Rolling Experiment ◽  
Final Rolling

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.

Dual Ferrite-Martensite Treatments of an ASTM A588 HSLA Steel

1981 ◽  
Vol 39 ◽  
pp. 318-319
Author(s):  
L.J. Chen ◽  
J.R. Yang
Keyword(s):  
Yield Strength ◽  
Hsla Steel ◽  
Charpy Impact ◽  
High Strength ◽  
High Yield ◽  
The Past ◽  
Hsla Steels ◽  
Corrosion Resistance Property ◽  
Different Temperatures ◽  
Subsequent Quenching

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.

Research on Hot Stamping Technology of High Strength Medium and Heavy Steel Plate

2020 ◽  
Vol 837 ◽  
pp. 81-86 ◽  
Author(s):  
Ning Ma ◽  
Yu Jie Ma ◽  
Ye Xuan Wang ◽  
Jian Yi Ji ◽  
Yi Chun Ji ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Temperature Difference ◽  
Production Efficiency ◽  
Steel Plate ◽  
Cooling System ◽  
Hot Stamping ◽  
High Strength ◽  
Steel Plates ◽  
Large Temperature ◽  
Forming Process

An innovative study on the high strength of U shaped steel plate was carried out. Through the two different cooling systems of hot stamping die obtained the two U shaped steel plates, founding that the cooling rate of U shaped steel plate obtained by bath water cooling system in the die was significantly higher than the steel plate obtained by cooling pipe in the die system, and had a smaller temperature difference, Which is a good solution to the problem the cooling rate of blank decreases with the thickness of blank increasing and the blank had a large temperature difference for badly uniform temperature quenching. This system is also greatly shorten the quenching time and improve the production efficiency in hot forming process.

Cooling Rate Control on Cold Cracking in Welded Thick HSLA Steel Plate

2011 ◽  
Vol 689 ◽  
pp. 269-275 ◽  
Author(s):  
Winarto ◽  
Muhammad Anis ◽  
Taufiqullah
Keyword(s):  
Low Temperature ◽  
Cooling Rate ◽  
Thick Plate ◽  
Steel Plate ◽  
Hsla Steel ◽  
Welding Process ◽  
Cooling Time ◽  
Cold Cracking ◽  
Electric Heater ◽  
Cooling Media

Cold cracking phenomenon is a very significant problem on welding of steel. This phenomenon usually occurs after welding process finishes in more than 24 hours. Crack often takes place in the heat affected zone area. Generally, cold cracking is due to hydrogen diffusion during welding process, residual stress and susceptible microstructure at low temperature (below 150°C). Welding process on thick plate high strength low alloy (HSLA) steel gives a high risk to cold cracking phenomenon. The cooling rate of thick plate during welding may increase the absorbtion of heat compared to thin plate. Controlling cooling rate is the main factor on welding of thick HSLA steel plate. A single v-butt joint on HSLA and S45C by using Gas Metal Arc Welding (GMAW) has been investigated. This investigation was carried out on a 40 mm thick HSLA steel by controlling cooling rate and by using cooling media such as air, blanket and electric heater. The result shows that prevention of cold cracking can be made by controlling cooling time at low temperature (T300- T100) in order to keep the cooling time larger than the critical cooling time. The use of cooling media with electric heater can prevent the cold cracking at HSLA weldment. Crack can be found on the weldment due to the presence of stress concentration, local variation of hardness and microstructure, which may result in brittle fracture of the crack surface.

Effect of Alloying Elements on Mechanical Properties of High-Strength Low-Alloy Steel

2020 ◽  
Vol 1007 ◽  
pp. 41-46
Author(s):  
Ning Li ◽  
Wilasinee Kingkam ◽  
Zi Ming Bao ◽  
Ren Heng Han ◽  
Yao Huang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Hsla Steel ◽  
High Strength ◽  
Ultimate Tensile Stress ◽  
Vacuum Induction Furnace ◽  
Low Alloy Steels ◽  
Hsla Steels ◽  
Different Types ◽  
Calculation Results ◽  
Alloy Steels

In this study, the two types of high-strength low-alloy steels were melted and cast in a vacuum induction furnace. Phase transition temperature of HSLA steel was calculated by JMatPro software. The calculation results show that the two different types of HSLA steels which have equal phase proportions of ferrite and austenite at a temperature of approximately 820 and 800 °C in HSLA-I and HSLA-II, respectively. In addition, the effect of chemical composition on the microstructure and mechanical properties of steels were studied. The results indicate that the ultimate tensile stress value of HSLA-II samples was greater than the HSLA-I samples by about 35%, and the yield stress and breaking strength value of HSLA-II were higher than HSLA-I as well.

scholarly journals Electrochemical Determination of Hydrogen Entry to HSLA Steel during Pickling

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Jari Aromaa ◽  
Antero Pehkonen ◽  
Sönke Schmachtel ◽  
Istvan Galfi ◽  
Olof Forsén
Keyword(s):  
Hydrochloric Acid ◽  
Hsla Steel ◽  
Harmful Effect ◽  
High Strength ◽  
Steel Sample ◽  
Electrochemical Determination ◽  
Hsla Steels ◽  
Anodic Side ◽  
A Cell ◽  
The One

Pickling with hydrochloric acid is a standard method to clean steel surfaces before hot-dip galvanizing. When normal low strength steels are pickled, hydrogen formed in pickling reactions does not have any significant harmful effect on the mechanical properties of steel. However, in pickling of steels with higher strength, the penetration of hydrogen into the steel may cause severe damages. The effect of pickling of high-strength low-alloy (HSLA) steels was investigated using a cell construction based on the Devanathan-Stachurski method with modified anodic surface treatment and hydrogen production using acid. The penetration and the permeability of hydrogen were measured using an electrochemical cell with hydrochloric acid on the one side of the steel sample and a solution of NaOH on the other side. No protective coating, for example, palladium on the anodic side of the sample, is needed. The penetration rate of hydrogen into the steel and exit rate from the steel were lower for higher strength steel.

Influence of Grain Size on Corrosion Resistance of a HSLA Steel

2012 ◽  
Vol 557-559 ◽  
pp. 143-146 ◽  
Author(s):  
Yan Tang Chen ◽  
Kai Guang Zhang
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Corrosion Resistance ◽  
Mechanical Performance ◽  
Hsla Steel ◽  
High Strength ◽  
Corrosion Resistant ◽  
Hsla Steels ◽  
Mechanical Properties And Corrosion ◽  
Mn Steel

The mechanical performance, workability, weldability and corrosion resistance of structural high strength low alloy (HSLA) steels used in offshore engineering have been generally required. The effect of grain size on the corrosion resistant performance of a C-Mn structural steel has been investigated with stress on hunting a appropriate grain size to balance mechanical properties and corrosion resistant performance. The results showed that the C-Mn steel with grain size in 10～25μm scope provided expected mechanical properties and corrosion resistance.

Quantification of Vanadium Precipitates after Reheating Slab Steel by Synchrotron X-Ray Absorption Spectroscopy (XAS)

2017 ◽  
Vol 728 ◽  
pp. 20-25
Author(s):  
Audtaporn Worabut ◽  
Nirawat Thammajak ◽  
Hans Henning Dickert ◽  
Piyada Suwanpinij
Keyword(s):  
Hsla Steel ◽  
Dissolution Kinetics ◽  
High Strength ◽  
Rolling Process ◽  
Solubility Limit ◽  
Carbon Steels ◽  
Microalloyed Steels ◽  
Hsla Steels ◽  
Microalloying Elements ◽  
X Ray Absorption

High Strength Low Alloy (HSLA) steels or microalloyed steels are developed in order toimprove the strength and toughness compared with conventional carbon steels. During the reheatingprocess at 1250-1300 °C for a few hours, the furnace consumes large amount of energy, and the slabsuffers from thick oxide scale. This results in significant mass loss. The long reheating time ensuresmaximum dissolution of the microalloying elements, which must be kept to precipitate duringcooling at the end of the hot rolling process. To minimise the reheating time and save the energyconsumption, this research studied the dissolution kinetics of vanadium in HSLA steel. Vanadium isa main microalloying element added to provide higher strength mainly by precipitation hardening. Itis supposed to be dissolved readily according to the solubility limit. The samples were reheated to1200 °C and 1250 °C for 0, 10, 30, and 60 s. After that the fraction of vanadium dissolved in the solidsolution and the remaining undissolved phases of VC, CN, and V(C,N) were measured bysynchrotron XAS. As soon as the sample reaches as low temperature as 1200 °C, a large atomicfraction of 0.878 of vanadium can be dissolved in the solid solution.

High Strength Offshore Steel with Excellent Weldability

2012 ◽  
Vol 482-484 ◽  
pp. 1650-1653
Author(s):  
Yan Tang Chen ◽  
Kai Guang Zhang
Keyword(s):  
Mechanical Properties ◽  
Impact Toughness ◽  
Yield Strength ◽  
Thermal Cycle ◽  
Hsla Steel ◽  
High Strength ◽  
High Impact ◽  
Weld Thermal Cycle ◽  
Offshore Engineering ◽  
Base Steel

A new high strength low alloy (HSLA) steel in 370MPa yield strength grade with low susceptivity to weld cold cracking has been developed for offshore engineering. The microstructure feature of base steel and weld heat affected zone (HAZ) has been investigated. The systematic studies showed that the developed steel exhibited high strength(yield strength≥370MPa)、high impact toughness and excellent weldability. The complex inclusions containing fine oxides in HAZ promoted the acicular ferrite formation in weld thermal cycle and resulted in desired mechanical properties of HAZ.

scholarly journals Effects of the Primary NbC Elimination on the SSCC Resistance of a HSLA Steel for Oil Country Tubular Goods

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5301
Author(s):  
Tianyi Zeng ◽  
Shuzhan Zhang ◽  
Xianbo Shi ◽  
Wei Wang ◽  
Wei Yan ◽  
...  
Keyword(s):  
Hsla Steel ◽  
High Strength ◽  
Oil Industry ◽  
High Angle ◽  
Hsla Steels ◽  
Metallic Inclusions ◽  
Sulfide Stress ◽  
The One ◽  
Sulfide Stress Corrosion Cracking ◽  
Grade Steel

Sulfide stress corrosion cracking (SSCC) has been of particular concern in high strength low alloyed (HSLA) steels used in the oil industry, and the non-metallic inclusions are usually considered as a detrimental factor to the SSCC resistance. In the present work, continuous casting (CC) and electroslag remelting (ESR) were adopted to fabricate a 125 ksi grade steel in order to evaluate the effect of microstructure with and without primary NbC carbides (inclusions) on the SSCC resistance in the steel. It was found that ESR could remove the primary NbC carbides, and hence, slightly increase the strength without deteriorating the SSCC resistance. The elimination of primary NbC carbides caused two opposite effects on the SSCC resistance in the studied steel. On the one hand, the elimination of primary NbC carbides increased the dislocation density and the proportion of high angle boundaries (HABs), which was not good to the SSCC resistance. On the other hand, the elimination of primary NbC carbides also induced more uniform nanosized secondary NbC carbides formed during tempering, providing many irreversible hydrogen traps. These two opposite effects on SSCC resistance due to the elimination of primary NbC carbides were assumed to be offset, and thus, the SSCC resistance was not greatly improved using ESR.

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