scholarly journals Effect of Quenching Strategy and Nb-Mo Additions on Phase Transformations and Quenchability of High-Strength Boron Steels

JOM ◽  
2021 ◽  
Author(s):  
Irati Zurutuza ◽  
Nerea Isasti ◽  
Eric Detemple ◽  
Volker Schwinn ◽  
Hardy Mohrbacher ◽  
...  
Keyword(s):  
High Strength ◽  
Thick Plates ◽  
Direct Quenching ◽  
Martensitic Microstructure ◽  
High Cooling Rates ◽  
Hot Rolled ◽  
Boron Steels ◽  
Cct Diagrams ◽  
Rolled Plates ◽  
Mo Additions

AbstractThe application of direct quenching after hot rolling of plates is being employed in the production of ultra-high-strength hot rolled plates. When heavy gauge plates are produced, the complexity involve in achieving high cooling rates in the plate core is increased and the formation of undesirable soft phases within martensite is common. In the current paper, both direct quenching and conventional quenching (DQ and CQ) processing routes were reproduced by dilatometry tests and continuous cooling transformation (CCT) diagrams were built for four different high-strength boron steels. The results indicate that the addition of Mo and Nb-Mo suppresses the ferritic region and considerably shifts the CCT diagram to lower transformation temperatures. The combination of DQ strategy and the Mo-alloying concept provides the best option to ensure hardenability and the formation of a fully martensitic microstructure, and to avoid the presence of soft phases in the center of thick plates.

Application of Quenching-Partitioning-Tempering Process in Hot Rolled Plate Fabrication

2010 ◽  
Vol 654-656 ◽  
pp. 82-85 ◽  
Author(s):  
Shu Zhou ◽  
Ying Wang ◽  
Nai Lu Chen ◽  
Yong Hua Rong ◽  
Jian Feng Gu
Keyword(s):  
Mechanical Properties ◽  
Retained Austenite ◽  
High Strength Steels ◽  
High Strength ◽  
Significant Fraction ◽  
Rolled Plate ◽  
Quenching And Partitioning ◽  
Good Ductility ◽  
Hot Rolled ◽  
Rolled Plates

The quenching-partitioning-tempering (Q-P-T) process, based on the quenching and partitioning (Q&P) treatment, has been proposed for producing high strength steels containing significant fraction of film-like retained austenite and controlled amount of fine martensite laths. In this study, a set of Q-P-T processes for C-Mn-Si-Ni-Nb hot rolled plates are designed and realized. The steels with Q-P-T processes present a combination of high strength and relatively good ductility. The origin of such mechanical properties is revealed by microstructure characterization.

scholarly journals Investigation on High Strength Hot-rolled Plates by Quenching-partitioning-tempering Process Suitable for Engineering

2011 ◽  
Vol 51 (10) ◽  
pp. 1688-1695 ◽  
Author(s):  
Shu Zhou ◽  
Ke Zhang ◽  
Nailu Chen ◽  
Jianfeng Gu ◽  
Yonghua Rong
Keyword(s):  
High Strength ◽  
Hot Rolled ◽  
Rolled Plates ◽  
Tempering Process

Structure and properties of high strength low alloyed cold-resistant steel after reheat and direct quenching with tempering

2020 ◽  
pp. 7-19
Author(s):  
O. V. Sych ◽  
E. I. Khlusova ◽  
E. A. Yashina ◽  
E. V. Svyatysheva ◽  
E. A. Vasilyeva
Keyword(s):  
High Temperature ◽  
High Strength ◽  
Optical Metallography ◽  
Resistant Steel ◽  
Structure And Properties ◽  
Direct Quenching ◽  
The Impact ◽  
Rolled Plates ◽  
Reheat Quenching ◽  
Rolling Heat

The paper shows comparative investigations of structure of rolled plates from low alloyed coldresistant steel 08CrNi2MoCuNb with guaranteed yield strength 750 MPa after traditional reheat quenching and quenching from rolling heat (direct quenching) with subsequent high temperature tempering. The research is carried out by means of optical metallography, SEM and TEM. The peculiarities of parameters of bainitemartensite structure, which influence the strength level in initial (quenched) state, are revealed. Also, the impact of tempering on structure and properties of rolled plates after reheat and direct quenching is shown. 

scholarly journals Mechanical Properties of Direct-Quenched Ultra-High-Strength Steel Alloyed with Molybdenum and Niobium

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 350 ◽  
Author(s):  
Jaakko Hannula ◽  
David Porter ◽  
Antti Kaijalainen ◽  
Mahesh Somani ◽  
Jukka Kömi
Keyword(s):  
Mechanical Properties ◽  
High Strength ◽  
Steel Plates ◽  
High Yield ◽  
Direct Quenching ◽  
Finish Rolling ◽  
Martensitic Microstructure ◽  
Ultra High Strength Steel ◽  
Thick Steel ◽  
Rolling Temperatures

The direct quenching process is an energy- and resource-efficient process for making high-strength structural steels with good toughness, weldability, and bendability. This paper presents the results of an investigation into the effect of molybdenum and niobium on the microstructures and mechanical properties of laboratory rolled and direct-quenched 11 mm thick steel plates containing 0.16 wt.% C. Three of the studied compositions were niobium-free, having molybdenum contents of 0 wt.%, 0.25 wt.%, and 0.5 wt.%. In addition, a composition containing 0.25 wt.% molybdenum and 0.04 wt.% niobium was studied. Prior to direct quenching, finish rolling temperatures (FRTs) of about 800 °C and 900 °C were used to obtain different levels of austenite pancaking. The final direct-quenched microstructures were martensitic and yield strengths varied in the range of 766–1119 MPa. Mo and Nb additions led to a refined martensitic microstructure that resulted in a good combination of strength and toughness. Furthermore, Mo and Nb alloying significantly reduced the amount of strain-induced ferrite in the microstructure at lower FRTs (800 °C). The steel with 0.5 wt.% Mo exhibited a high yield strength of 1119 MPa combined with very low 28 J transition temperature of −95 °C in the as-quenched condition. Improved mechanical properties of Mo and Mo–Nb steels can be attributed to the improved boron protection. Also, the crystallographic texture of the investigated steels showed that Nb and Nb–Mo alloying increased the amount of {112}<131> and {554}<225> texture components. The 0Mo steel also contained the texture components of {110}<110> and {011}<100>, which can be considered to be detrimental for impact toughness properties.

scholarly journals Production of Directly Quenched High-Strength Hot-Rolled Strip Steels - Influence of Rolling and Cooling Conditions on Mechanical Properties and Flatness

2016 ◽  
Vol 854 ◽  
pp. 29-34
Author(s):  
Joachim Schöttler ◽  
Thorsten Maiwald ◽  
Gunnar Linke
Keyword(s):  
Mechanical Properties ◽  
High Strength ◽  
Cost Effective ◽  
Rolled Strip ◽  
Coiling Temperature ◽  
Hot Rolled Strip ◽  
Direct Quenching ◽  
Cooling Conditions ◽  
Plant Trials ◽  
Hot Rolled

The production of hot-rolled sheets of high-strength and wear-resistant special structural steels by direct quenching from the rolling heat is a cost effective and energy-saving alternative to traditional production via downstream quenching the previously cut-to-length plates. Reaching the required strength and toughness parameters in combination with best flatness of the sheets requires strict compliance with the pre-set rolling and cooling conditions over the entire strip width. Using two high-strength low-alloyed steels, plant trials have been carried out to study the effect of the cooling conditions and the coiling temperature on mechanical properties, impact toughness and flatness of cut-to-length sheets made of hot-rolled strip. The results showed that by applying optimized cooling pattern and low coiling temperatures, high-strength steel sheets with outstanding mechanical properties and good flatness can be produced.

Microstructure, Properties and Design of Direct Quenched Structural Steels

2014 ◽  
Vol 783-786 ◽  
pp. 246-251 ◽  
Author(s):  
Pasi Suikkanen ◽  
J.I. Kömi
Keyword(s):  
High Performance ◽  
High Strength ◽  
Structural Steels ◽  
Rolled Strip ◽  
Physical Metallurgy ◽  
Paper Briefly ◽  
Design Rules ◽  
Hot Rolled Strip ◽  
Direct Quenching ◽  
Hot Rolled

Direct quenching (DQ) is one of the latest process routes in production of ultra-high strength, high performance steels and Ruukki one of the pioneering companies in the utilization of direct quenching. Ruukki has applied direct quenching for the production of ultra-high-strength structural steels in the form of hot-rolled strip and plate. The paper briefly summarizes the physical metallurgy fundamental of direct steels and shows some selected examples of the microstructures and properties of steels produced by direct quenching. In addition, a brief review on the usability properties and design rules of ultra-high strength structural steels is made.

scholarly journals The Effects of Finish Rolling Temperature and Niobium Microalloying on the Microstructure and Properties of a Direct Quenched High-Strength Steel

2017 ◽  
Vol 62 (2) ◽  
pp. 619-626 ◽  
Author(s):  
A. Kaijalainen ◽  
N. Vähäkuopus ◽  
M. Somani ◽  
S. Mehtonen ◽  
D. Porter ◽  
...  
Keyword(s):  
High Strength ◽  
Rolling Temperature ◽  
Rolled Strip ◽  
Low Carbon ◽  
Finish Rolling Temperature ◽  
Niobium Microalloying ◽  
Finish Rolling ◽  
Nb Microalloying ◽  
Hot Rolled ◽  
Cct Diagrams

AbstractThis paper comprehends the effects of finish rolling temperature (FRT) and Nb-microalloying on the microstructural evolution and resultant properties of a low carbon direct quenched steel in the yield strength category of ≥900 MPa. Results indicate that a decrease in FRT close to Ar3temperature significantly influenced the microstructure following phase transformation, especially at the subsurface (~50-400 μm) of the rolled strip. On decreasing the FRT, the subsurface microstructure revealed a fine mixture of ferrite and bainite obviously as a result of strain-induced transformation, whereas the structure at the centreline remained essentially martensitic. Further, Nb-microalloying promoted the formation of ferrite and bainite even at higher FRTs, thus influencing the mechanical properties. The microstructures of the hot-rolled strips were further corroborated with the aid of CCT diagrams.

TENFORM XF450

Alloy Digest ◽  
2007 ◽  
Vol 56 (1) ◽  
Keyword(s):  
Physical Properties ◽  
Tensile Properties ◽  
Alloy Steel ◽  
High Strength ◽  
Bend Strength ◽  
Low Alloy Steel ◽  
Hot Rolled

Abstract The high strength of Tenform XF450, a hot-rolled high-strength low-alloy steel, allows the user to increase the strength of a finished component or to reduce the thickness. The steel is used in the construction and the automotive industries. This datasheet provides information on composition, physical properties, tensile properties. and bend strength. It also includes information on forming. Filing Code: CS-148. Producer or source: Hille & Mueller, USA Inc. See also Alloy Digest CS-173, November 2012.

STRENX SECTION 900

Alloy Digest ◽  
2017 ◽  
Vol 66 (7) ◽  
Keyword(s):  
Fracture Toughness ◽  
High Strength ◽  
Bend Strength ◽  
Bend Channel ◽  
Cold Formed Steel ◽  
The Common ◽  
Hot Rolled ◽  
Common Shape ◽  
Minimum Yield ◽  
Steel Section

Abstract Strenx Section 900 is a cold-formed steel section made of hot-rolled, high-strength steel with a minimum yield strength of 900 MPa (131 ksi). Its high strength combined with naturally stiff form enables construction of stronger and lighter structures. The common shape is a U-bend channel. This datasheet provides information on composition, physical properties, tensile properties, and bend strength as well as fracture toughness. It also includes information on forming, machining, and joining. Filing Code: SA-792. Producer or source: SSAB Swedish Steel Inc..

Sign in / Sign up

Export Citation Format

Share Document