New low carbon structural steels hardened by aging

The principles governing the standard range of normalized steels are well established, namely improved uniformity of properties compared with steels which finish rolling at random temperatures, and the use of low carbon fine grain steels where needed to meet requirements for ease of welding, strength, and notch toughness. This paper therefore, looks at the prospects of extending the range of notch toughness guarantees at low temperatures (below — 50 °G); the achievement of resistance to lamellar tearing where stresses are applied perpendicular to plate surfaces; and the response of steels to stress relieving procedures. In practice, steels exist to meet these situations, but the ability to predict their behaviour and to understand all the physical metallurgy involved, is incomplete and warrants further study as an aid towards avoiding unforeseen problems in production or service.

Download Full-text

Improvement of Mechanical Properties and Structure Modifications of Low Carbon Steel by Inoculations with Nano-Size Silicon Nitride

Journal of Nano Research ◽

10.4028/www.scientific.net/jnanor.47.24 ◽

2017 ◽

Vol 47 ◽

pp. 24-32 ◽

Cited By ~ 3

Author(s):

Ahmed Shash ◽

Mohamed K. El-Fawkhry ◽

Sherif Ali Abd El Rahman ◽

Iman S. Elmahallawi ◽

Taha Mattar

Keyword(s):

Mechanical Properties ◽

Treatment Process ◽

Adhesive Wear ◽

Cold Deformation ◽

Low Carbon Steel ◽

Structural Steels ◽

Low Carbon ◽

Nano Size ◽

Lamellar Cementite

AISI 1020 steel is considered to be one of the most applicable structural steels, in particular in the cold drawn form. Heating of this grade of steel prior to AC1 must have been applied to spheroidize the lamellar cementite, and consequently enhances the cold formability character of the steel. Si3N4 nanoinoculation of this grade of steel has been used in this study, where it is added to the molten steel, in order to avoid the high cost long term heat treatment process prior to cold deformation process. Optical microscopy and SEM have been used to evaluate the morphology of cementite after nanoinoculation process with Si3N4. Tensile properties of nanoinoculated steels have been investigated. Finally, wear adhesive resistance of investigated samples has been evaluated. The obtained results showed a great enhancement in the mechanical properties, strength, ductility and adhesive wear resistance, as a result of the nucleation of cementite into a new spheroidal phase and grain refinement by Si3N4 inoculation and allow usage of AISI 1020 steels inoculated by nanoinoculant Si3N4 in further technological applications.

Download Full-text

Effect of grain size and carbide thickness on impact transition temperature of low carbon structural steels

Materials Science and Technology ◽

10.1179/026708301101510429 ◽

2001 ◽

Vol 17 (6) ◽

pp. 700-714 ◽

Cited By ~ 13

Author(s):

M.S. Bingley

Keyword(s):

Grain Size ◽

Transition Temperature ◽

Structural Steels ◽

Low Carbon ◽

Impact Transition Temperature

Download Full-text

Tempering of Direct Quenched Low-Alloy Ultra-High-Strength Steel, Part II – Mechanical Properties

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.922.580 ◽

2014 ◽

Vol 922 ◽

pp. 580-585 ◽

Cited By ~ 8

Author(s):

Sakari Pallaspuro ◽

Antti J. Kaijalainen ◽

Teijo Limnell ◽

David A. Porter

Keyword(s):

Tensile Testing ◽

Alloy Composition ◽

High Strength ◽

Steel Part ◽

Structural Steels ◽

Low Carbon ◽

Grain Sizes ◽

Ultra High Strength Steel ◽

Hardness Values ◽

Better Than

Direct quenched untempered ultra-high-strength structural steels can possess good toughness and weldability when based on low carbon contents. In this study, the influence of tempering at 500 °C has been investigated to evaluate the possibilities of widening the range of strengths that can be produced from one 0.1% C alloy composition. The study covered the four microstructural states presented in part I: direct quenched (DQ), reheated and quenched (RQ) and their tempered variants (DQ-T and RQ-T). In addition to tensile testing, the Charpy-V transition temperature T28J and the fracture toughness reference temperature T0 were determined for 6 mm thick specimens. The hardness of the DQ and RQ states was identical at ca. 400 HV. However, on tempering, the DQ state retained its hardness better than the RQ state with hardness values 346 HV (DQ-T) and 327 HV (RQ-T). The yield strengths of the DQ materials were ca. 100 MPa higher than those of the RQ materials both as-quenched and after tempering. Despite the higher strength of the DQ and DQ-T states, both had lower T28J temperatures than the RQ and RQ-T states mainly due to their finer effective grain sizes. The widely used correlation between the T28J and the T0 temperatures was not obeyed and the reasons for this are discussed.

Download Full-text