Three Generations Micro-Allying Steel Processing: Thirty Years of Successive Work at CMRDI

2020 ◽  
Vol 835 ◽  
pp. 324-334
Author(s):  
Maha El-Meligy ◽  
Taher El-Bitar
Keyword(s):  
Mechanical Properties ◽  
Temper Embrittlement ◽  
Steel Plates ◽  
Alloying Elements ◽  
Recrystallization Temperature ◽  
Low Carbon ◽  
Alloying Element ◽  
Hot Strip ◽  
Steel Processing ◽  
Steel Grades

The present article presents cumulative works, which were carried out in the field of micro-alloying steel processing at Central Metallurgical R&D Institute (CMRDI) and/or full scale trials in collaboration with the Egyptian steel industry.It was agreed upon defining three main generations of processing micro-alloying steel. The 1stgeneration starts officially on 1975 and continues up to 1995, where it deals with using Ti and V as micro-alloying elements for steel long products. On the year 1985, Central Metallurgical R&D Institute (CMRDI) succeeded to implement of HSLA V-micro-alloyed rebar steel grades at Delta steel mills instead of conventional rebar grades.The 2nd generation was starting on late 1995 and continued to 2005. It was dealing mainly with low carbon content steel (0.04-0.08 %) for flat products (plate and sheet). The most successfully used micro-alloying element was Nb. Beside its precipitate forming effect, Nb is working as substitution solid solution strengthener. Moreover, it raises the recrystallization temperature (Tr). Mainly, micro-alloyed flat steels were developed to fulfill the requirements of the American Petroleum Institute (API) specifications 5L- Product Specification Levels (PSL1) and (PSL2) for manufacturing oil and natural gas pipelines. Meanwhile, a newly born Compact Slab Processing (CSP)-hot strip direct rolling technology was created. On years 2002, the metal forming department in CMRDI succeeded to implement controlled rolling of hot strip Nb-steel sheet at the Compact Slab Process (CSP) Machine in Alexandria National Iron and Steel (ANSDK) Company. Controlled hot rolling schedules were used and followed by early and late cooling at the run out table (ROT). Both contracts were fruitfully succeeded to introduce the API X52 grade at ANSDK Company, followed by X60, and X70 steel grades at Ezz Flat Steel (EFS) Company. The essential mechanical properties of the processed API steel sheets were matched with the API 5L-PSL2 specifications.The 3rd generation was initially developed after 2005 and continued up to day. It deals with micro-alloying with special functional elements like Boron (B). Boron was favored as a micro-alloying element for bilateral effects. Boron carbide (B4C) precipitates are the hardest after diamond, which would be reflected on raising the mechanical properties of the steel. Moreover, Boron was favorably used because it delays the temper embrittlement phenomena. On year 2014, the National for Military Industrialization authority requested from CMRDI to collaborate with Military Factory 100 to develop a technology package for processing armor steel plates. Trials were started with a 3rd generation B-micro-alloyed steel alloy. Many other alloying elements were used beside Boron to develop extra high strength 6.0 mm thickness plates. Finish hot rolled plates were then subjected to a subsequent water quenching from 900 °C and followed by tempering at 250 °C for 20 min. Representation 50X50 cm2 steel plates were successfully passed after 3 bullets in front and 3 bullets rear shooting.

The Influence of Ti/N Ratio on the Effective Boron and Mechanical Properties of Low Carbon Boron Alloyed Bainitic Steel

2014 ◽  
Vol 496-500 ◽  
pp. 392-395 ◽  
Author(s):  
Tao Zhang ◽  
Hua Xing Hou ◽  
Jun Ping Chen
Keyword(s):  
Mechanical Properties ◽  
Steel Plate ◽  
Steel Plates ◽  
Bainitic Steel ◽  
Low Carbon ◽  
Obvious Effect ◽  
Ti Content

The influence of Ti/N ratio on the effective boron and mechanical properties was investigated by analyzing data from low carbon boron alloyed bainitic steel plates. The result shows Ti/N ratio varies with effective boron value. Less than 50% effective boron was obtained when Ti/N ratio is below 3.3, nearly 90% effective boron is obtained when ratio Ti/N is more than 4; Adding enough Titanium is an effective and economic way to improve qualified ratio of bainitic steel plate. The Ti content between 0.010% and 0.030% does not have obvious effect on the toughness of the bainitic steel;

scholarly journals Computer Model STAN 2000 and its Use in Practice of Steels Hot Rolling on Mill 2000 of Severstal

2016 ◽  
Vol 854 ◽  
pp. 183-189 ◽  
Author(s):  
Alexey Ogoltcov ◽  
Dmitry Sokolov ◽  
Semen Sokolov ◽  
Alexander Vasilyev
Keyword(s):  
Mechanical Properties ◽  
Computer Model ◽  
Hot Rolling ◽  
Relative Elongation ◽  
Integral Model ◽  
Accelerated Cooling ◽  
Chemical Compositions ◽  
Hot Strip ◽  
Steel Grades ◽  
Strip Production

An integral computer model/program STAN 2000 for simulation of steels hot rolling on mill 2000 of SEVERSTAL was developed. The capacity of the model includes, for example, the following features:‒ control of power parameters and prediction of hot strip temperature for a given rolling and accelerated cooling regimes;‒ follow-up of the evolution of steel microstructure at all stages of strip production and prediction of ultimate mechanical properties (yield stress, ultimate tensile stress and relative elongation);‒ optimization of rolling regimes for existing steel grades and developing them for a new ones.The STAN 2000 program is written in С++ programming language and can work on all modern Microsoft Windows family operating systems. The program has a well-designed and user-friendly interface facilitating its practical use.The integral model was calibrated using an extensive data base on rolling regimes and forces, measured temperatures and final mechanical properties for a number of steel grades rolled on mill 2000 of SEVERSTAL with chemical compositions covering the following ranges of alloying elements content (mass.%): С(≤0.65); Mn(≤2.0); Si(≤1.0); Cr(≤0.9); Ni(≤0.6); Cu(≤0.5); Mo(≤0.4); Nb(≤0.05); V(≤0.065); Ti(≤0.06); B(≤0.003).Some results of calculations performed with STAN 2000 program for temperatures, rolling forces and mechanical properties are presented and compared with experimental data. Some examples of the program utilization in hot strip production on mill 2000 of SEVERSTAL are presented and discussed.

scholarly journals Reaction of Unalloyed and Cr-Mo Alloyed Steels with Nitrogen from the Sintering Atmosphere

2016 ◽  
Vol 16 (2) ◽  
pp. 86-98
Author(s):  
Magdalena Dlapka ◽  
Christian Gierl-Mayer ◽  
Raquel de Oro Calderon ◽  
Herbert Danninger ◽  
Sven Bengtsson ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Critical Temperature ◽  
Structural Steels ◽  
Low Alloy Steel ◽  
Alloying Element ◽  
Sintering Atmosphere ◽  
High Affinity ◽  
Different Temperatures ◽  
Steel Grades ◽  
The Subject

Abstract Nitrogen is usually regarded as an inert sintering atmosphere for PM steels; however, this cannot be taken for granted in particular for steels alloyed with nitride forming elements. Among those elements, chromium has become more and more important as an alloying element in sintered low alloy structural steels in the last decade due to the moderate alloying cost and the excellent mechanical properties obtainable, in particular when sinter hardening is applied. The high affinity of Cr to oxygen and the possible ways to overcome related problems have been the subject of numerous studies, while the fact that chromium is also a fairly strong nitride forming element has largely been neglected at least for low alloy steel grades, although frequently used materials like steels from Cr and Cr-Mo prealloyed powders are commonly sintered in atmospheres consisting mainly of nitrogen. In the present study, nitrogen pickup during sintering at different temperatures and for varying times has been studied for Cr-Mo prealloyed steel grades as well as for unalloyed carbon steel. Also the effect of the cooling rate and its influence on the properties, of the microstructure and the composition have been investigated. It showed that the main nitrogen uptake occurs not during isothermal sintering but rather during cooling. It could be demonstrated that a critical temperature range exists within which the investigated CrM-based steel is particularly sensitive to nitrogen pickup.

scholarly journals The Relation between the Alloying Elements and the Mechanical Properties of Low-carbon Low-alloy Bainite

1972 ◽  
Vol 58 (13) ◽  
pp. 1877-1892
Author(s):  
Tatsuro KUNITAKE ◽  
Fukunaga TERASAKI ◽  
Yasuya OHMORI
Keyword(s):  
Mechanical Properties ◽  
Alloying Elements ◽  
Low Carbon

scholarly journals Boron Steel: An Alternative for Costlier Nickel and Molybdenum Alloyed Steel for Transmission Gears

2010 ◽  
Vol 8 (1) ◽  
pp. 12 ◽  
Author(s):  
A. Verma ◽  
K. Gopinath ◽  
B. Sarkar
Keyword(s):  
Mechanical Properties ◽  
Precipitation Hardening ◽  
Carbon Steels ◽  
Alloyed Steel ◽  
Alloying Elements ◽  
Boron Steel ◽  
Low Carbon ◽  
Low Carbon Steels

 Case Carburized (CC) low carbon steels containing Ni, Cr and Mo alloying elements are widely used for transmission gears in automobile, as it possesses desired mechanical properties. In order to cut cost and save scarce materials like Ni and Mo for strategic applications, steel alloyed with Boron has been developed, which gives properties comparable to Ni-Cr-Mo alloyed steel. In the process of steel development, care was taken to ensure precipitation of boron which results in precipitation hardening. The characterization of the developed boron steel had exhibited properties comparable to Ni-Cr-Mo alloyed steel and superior to conventional boron steel. 

Effect of Tempering on Bendability and Impact Property of Hot Rolled Low-Carbon Martensitic Steel

2018 ◽  
Vol 941 ◽  
pp. 474-479
Author(s):  
Sung Il Kim ◽  
Seok Jong Seo ◽  
In Shik Suh
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Impact Property ◽  
Alloying Elements ◽  
Bending Test ◽  
Low Carbon ◽  
Martensitic Steels ◽  
Tempering Temperature ◽  
Impact Properties ◽  
The Impact

We examined the effects of tempering process and alloying elements on the microstucture, tensile properties, bendability and impact property of direct quenched (DQ), and re-austenitizing and quenched (RQ) low-carbon martensitic steels. For this purpose, four low carbon martensitic steels (Fe-0.07C-1.8Mn-Cr-Nb-Ti-B) were selected. We have investigated the effects of tempering temperature and alloying elements of chromium (Cr), titanium (Ti) and niobium (Nb) on mechanical properties and microstructures. Mechanical properties and microstructures were analyzed as well using tensile test, V-bending test, charpy V-notched impact test and electron microscopy for DQ, DQ and tempered (DQ-T), RQ and RQ and tempered (RQ-T) low-carbon martensitic steels. It has been found that the as-quenched microstructures of the DQ and RQ specimens were fully martensitic structure. Prior austenite grain size and effective grain size after quenching were larger in the case of RQ steel. In both cases, tempering made the needle-shaped carbides. It is shown that the strength decreased when the tempering temperature increased. The strengths of the DQ and DQ-T steels were 30~50MPa higher than those of the RQ and RQ-T steels. Despite the higher strength of the DQ and DQ-T states, both had similar impact properties with the RQ and RQ-T states. However, the impact properties of the Nb added RQ and RQ-T steels with fine martensite morphology exhibited higher than those of DQ and DQ-T steels.

Mechanical Properties of Dendritic and Inter-Dendritic Regions in As-Cast Medium-Carbon Steel

2014 ◽  
Vol 894 ◽  
pp. 104-109
Author(s):  
Masoud Al-Gahtani ◽  
Rian Dippenaar
Keyword(s):  
Mechanical Properties ◽  
Carbon Steel ◽  
Hot Rolling ◽  
Nucleation And Growth ◽  
Medium Carbon Steel ◽  
Alloying Elements ◽  
Alloying Element ◽  
Solute Content ◽  
Medium Carbon ◽  
Segregation Of Alloying Elements

During solidification of steel, dendrite nucleation and growth leads to the segregation of alloying elements in the inter-dendritic regions. The dendrite arms are low in carbon while alloying elements segregate to the inter-dendritic regions. During subsequent hot-rolling, this variation in alloying element content leads to the formation of regions of high and low solute content, which in turn, leads to the formation of microstructural banding during heat treatment. In the present study, the respective mechanical properties of these dendritic and inter-dendritic regions were studied in medium carbon steel in order to investigate the rotation of dendrites during hot rolling.

scholarly journals MICROSTRUCTURE AND MECHANICAL PROPERTIES OF STEELS FOR SHAPED CHARGE LINERS AND PRELIMINARY ASSESSMENT OF THE EFFECTIVENESS OF EXPERIMENTAL SHAPED CHARGES INTENDED FOR USE IN THE MINING INDUSTRY

2021 ◽  
Vol 73 (2) ◽  
pp. 2-12
Author(s):  
Jarosław MARCISZ ◽  
Artur ŻAK ◽  
Jerzy STĘPIEŃ ◽  
Marek BURDEK ◽  
Tymoteusz TOMCZAK ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Steel Wire ◽  
Mining Industry ◽  
Cold Drawing ◽  
Low Carbon ◽  
Microstructure And Mechanical Properties ◽  
Concrete Blocks ◽  
Microstructure Examination ◽  
Steel Grades ◽  
Unalloyed Steel

The paper presents the results of investigation of the microstructure and mechanical properties of Fe-based materials designed for the manufacture of semi-spherical liners for experimental shaped charges. The tests were carried out on material samples taken from two semi-finished products, i.e. a rod for the manufacture of charge liners with a diameter of 50 mm using machining, and sheets for the manufacture of liners with a diameter of 100 mm using cold drawing. Microstructure examination was also carried out on a test specimen obtained using the additive method (3D-WAAM), made of low-carbon unalloyed steel wire. Firing tests on concrete blocks were carried out in order to quantify the effects of drilling at the Experimental Mine Barbara. The scope of the tests consisted of firing at cylindrical concrete blocks using projectiles containing 50 mm diameter liners made of Fe-based alloys. Based on the results of the laboratory material, two experimental steel grades were selected for further testing. Plates made of the selected steels will be used to manufacture charge liners with a diameter of 100 mm.

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