scholarly journals Effect of Heat Treatment on Microstructure and Mechanical Properties of High-Strength Steel for in Hot Forging Products

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 768
Author(s):  
Moonseok Kang ◽  
Minha Park ◽  
Byoungkoo Kim ◽  
Hyoung Chan Kim ◽  
Jong Bae Jeon ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
High Strength Steel ◽  
Fracture Behavior ◽  
Hot Forging ◽  
Bainitic Ferrite ◽  
High Strength ◽  
Austenitizing Temperature ◽  
Microstructure And Mechanical Properties ◽  
The Difference

High-strength steel is widely used in hot forging products for application to the oil and gas industry because it has good mechanical properties under severe environment. In order to apply to the extreme environment industry requiring high temperature and high pressure, heat treatments such as austenitizing, quenching and tempering are required. The microstructure of high-strength steel after heat treatment has various microstructures such as Granular Bainite (GB), Acicular Ferrite (AF), Bainitic Ferrite (BF), and Martensite (M) depending on the heat treatment conditions and cooling rate. Especially in large forged products, the difference in microstructure occurs due to the difference in the forging ratio depending on the location and the temperature gradient according to the thickness during post-heat treatment. Therefore, this study attempted to quantitatively analyze various phases of F70 high-strength steel according to the austenitizing temperature and hot forging ratio using the existing EBSD analysis method. In addition, the correlation between microstructure and mechanical properties was investigated through various phase analysis and fracture behavior of high-strength steel. We found that various microstructures of strength steel depend on the austenitizing temperature and hot forging ratio, and influence the mechanical properties and fracture behavior.

Effect of Heat Treatment on Corrosion and Fracture Behavior of SPV50Q High Strength Steel Weldment in H2S-Containing Environment

2008 ◽  
Author(s):  
Jianqun Tang ◽  
Jian-Ming Gong ◽  
Luyang Geng ◽  
Jiang Yong
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Residual Stress ◽  
High Strength Steel ◽  
Fracture Behavior ◽  
High Strength ◽  
Optical Microscope ◽  
Welding Residual Stress ◽  
Liquefied Petroleum Gas ◽  
Steel Weldment

SPV50Q high strength steel is often used to fabricate liquefied petroleum gas (LPG) spherical tanks with larger capacity, and tanks are expected to free post weld heat treatment (PWHT) for avoiding the possible reduction in strength. Sulfide stress corrosion cracking (SSCC), however, has been found in weldment, especially the heat-affected zone (HAZ), in LPG environment contaminated by wet H2S. The failure analysis showed that the existence of welding residual stress in weldment is one of the major factors in the occurrence of cracking. Post welding heat treatment (PWHT) is a feasible method of reducing welding residual stress. Therefore, in order to investigate the effect of heat treatment on mechanical properties, corrosion and fracture behavior of SPV50Q steel weldment, the difference in mechanical properties of the weldment with and without heat treatment at 590°C for 160 min after welding was measured using tensile test and impact test. The corrosion behaviors of base metal (BM), weld metal (WM) and HAZ metal in the weldment were investigated by potentiodynamic polarization in H2S-containing solution. In the same solution, the susceptibility to environmental cracking was evaluated by slow strain rate testing (SSRT). The feature of fracture and the morphologies of cracks were observed by scanning electrode microscope (SEM) and optical microscope (OP). The results indicate that the execution of heat treatment does not greatly change the properties of SPV50Q steel weldment, which can provide technology support for the remanufacturing of the LPG tanks having suffered from SSCC by repair welding following local or integral heat treatment.

Effect of Heat Treatment on the Properties and Precipitations of High Strength Steel Plate for Construction Machinery

2014 ◽  
Vol 971-973 ◽  
pp. 240-243
Author(s):  
Tao Zhang ◽  
Hua Xing Hou ◽  
Zhao Tan
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
High Strength Steel ◽  
Steel Plate ◽  
High Strength ◽  
Quenching Temperature ◽  
Tempering Temperature ◽  
Construction Machinery ◽  
Microstructure And Mechanical Properties ◽  
Tempering Resistance

The effect of heat treatment on the microstructure and mechanical properties of High Strength steel plate Q960E for construction machinery was investigated. The result shows the quenching temperature have obvious effects on the mechanical properties, DQ can improve the toughness and the enchance tempering resistance, precipitations become more and bigger with the rise of the tempering temperature.

scholarly journals Grain Size Evolution and Mechanical Properties of Nb, V–Nb, and Ti–Nb Boron Type S1100QL Steels

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 492
Author(s):  
Jan Foder ◽  
Jaka Burja ◽  
Grega Klančnik
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Hot Forging ◽  
Size Control ◽  
High Strength ◽  
Fatigue Properties ◽  
Titanium Addition ◽  
Austenite Grain Size ◽  
Size Evolution

Titanium additions are often used for boron factor and primary austenite grain size control in boron high- and ultra-high-strength alloys. Due to the risk of formation of coarse TiN during solidification the addition of titanium is limited in respect to nitrogen. The risk of coarse nitrides working as non-metallic inclusions formed in the last solidification front can degrade fatigue properties and weldability of the final product. In the presented study three microalloying systems with minor additions were tested, two without any titanium addition, to evaluate grain size evolution and mechanical properties with pre-defined as-cast, hot forging, hot rolling, and off-line heat-treatment strategy to meet demands for S1100QL steel. Microstructure evolution from hot-forged to final martensitic microstructure was observed, continuous cooling transformation diagrams of non-deformed austenite were constructed for off-line heat treatment, and the mechanical properties of Nb and V–Nb were compared to Ti–Nb microalloying system with a limited titanium addition. Using the parameters in the laboratory environment all three micro-alloying systems can provide needed mechanical properties, especially the Ti–Nb system can be successfully replaced with V–Nb having the highest response in tensile properties and still obtaining satisfying toughness of 27 J at –40 °C using Charpy V-notch samples.

Study of processing, microstructure and mechanical properties of hot rolled ultra-high strength steel

2018 ◽  
Vol 46 (6) ◽  
pp. 535-541 ◽  
Author(s):  
Tihe Zhou ◽  
David Overby ◽  
Peter Badgley ◽  
Chris Martin-Root ◽  
Xiang Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Strength Steel ◽  
High Strength ◽  
Microstructure And Mechanical Properties ◽  
Ultra High Strength Steel ◽  
Hot Rolled

Effect of Hot Processing on Mircrostructure and Properties of Flat Billets of TA15 Titanium Alloy

2021 ◽  
Vol 1016 ◽  
pp. 906-910
Author(s):  
Xin Hua Min ◽  
Cheng Jin
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Titanium Alloy ◽  
High Temperature ◽  
Room Temperature ◽  
High Strength ◽  
Slow Cooling ◽  
Microstructure And Mechanical Properties ◽  
Ta15 Titanium Alloy ◽  
The Ideal

In this paper,effect of the different forging processes on the microstructure and mechanical properties of the flat flat billets of TA15 titanium alloy was investigated.The flat billiets of 80 mm×150 mm×L sizes of TA15 titanium alloy are produced by four different forging processes.Then the different microstrure and properties of the flat billiets were obtained by heat treatment of 800 °C~850 °C×1 h~4h.The results show that, adopting the first forging temperature at T1 °C、slow cooling and the second forging temperature at T2°C 、quick cooling, the primary αphases content is just 10%, and there are lots of thin aciculate phases on the base. This microstructure has both high strength at room temperature and high temperature, while the properties between the cross and lengthwise directions are just the same. So the hot processing of the first forging temperature at T1 °C、slow cooling and the second forging temperature at T2°C 、quick cooling is choosed as the ideal processing for production of aircraft frame parts.

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