Structure and Properties of Laser-Welded Joints from High-Strength Steels

2014 ◽  
Vol 682 ◽  
pp. 240-245 ◽  
Author(s):  
O. Berdnikova ◽  
V. Sydorets ◽  
T. Alekseienko
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Phase Composition ◽  
Welded Joints ◽  
High Strength Steel ◽  
Crack Nucleation ◽  
High Strength Steels ◽  
High Strength ◽  
Structure And Properties ◽  
Welding Zone

Presented are the results of investigations of peculiarities of structure formation and phase composition in a metal of laser-welded joints from high-strength steel 14KhGN2MDAFB. The analytical evaluations of strengthening along a welding zone and crack nucleation stresses in the places of stress concentrators determined using the experimental data that a structure being formed provides for uniform level of mechanical properties and crack resistance of the welded joints.

Laser and Hybrid Laser-Arc Welding of High Strength Steel N-A-XTRA-70

2016 ◽  
Vol 870 ◽  
pp. 630-635 ◽  
Author(s):  
O. Berdnikova ◽  
V. Pozniakov ◽  
O. Bushma
Keyword(s):  
Mechanical Properties ◽  
Welded Joints ◽  
High Strength Steel ◽  
Arc Welding ◽  
High Strength Steels ◽  
High Strength ◽  
Point Of View ◽  
Flow Sheet ◽  
Hybrid Laser Arc Welding ◽  
Fine Grain

The advantages of laser and hybrid laser-arc welding in production of welded structures from high strength steels are increase of efficiency due to rise of the welding rate by order; significant (3 – 5 times) decrease of heat input; reduction of weld size; receiving of fine grain structures in the welds and the heat affected zone increasing strength of the joint and reducing susceptibility to crack formation. Research of the peculiarities of laser and hybrid processes, their effect on weld formation, revealing the advantages and eliminating the disadvantages of laser and arc constituents of the heat sources are currently the main problems for the production engineers and researchers. Therefore, the aim of the investigation lies in determination of the effect of process mode parameters of the hybrid laser-arc and laser welding in high-strength steel welding on formation of the structure of the welded joint metal as well as the analysis of effect of this structure on their mechanical properties. The investigation was focused on the high-strength steel N-A-XTRA-70 which is widely used in European Union countries for manufacture of critical structures of different designations. A laboratory bench was developed for experiments. It was used for carrying out investigation on the process flow sheet which provided location of a consumable electrode arc at some distance ahead of a laser beam during welding proceeding. The laser irradiation source was Nd:YAG-laser DY 044 of ROFIN company (Germany). For the first time the results of carried investigations allowed determining the process modes of laser and hybrid laser-arc welding for producing quality and sound welded joints of the high-strength steel from the point of view of the structure formation and metal phase composition providing high indices of mechanical properties and crack resistance of the welded joints.

Influence of low-temperature tempering on structure and properties of welded joints of high-strength steel 30Kh2N2MF

2020 ◽  
Vol 2020 (6) ◽  
pp. 20-26
Author(s):  
O.A. Gaivoronskyi ◽  
◽  
V.D. Poznyakov ◽  
O.M. Berdnikova ◽  
T.O. Alekseenko ◽  
...  
Keyword(s):  
Low Temperature ◽  
Welded Joints ◽  
High Strength Steel ◽  
High Strength ◽  
Structure And Properties

Development of High-Strength Steel Plates for Low-Temperature Use

1988 ◽  
Vol 110 (3) ◽  
pp. 171-176
Author(s):  
Y. Nakano ◽  
Y. Saito ◽  
K. Amano ◽  
M. Koda ◽  
Y. Sannomiya ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Yield Strength ◽  
Structural Steel ◽  
Welded Joints ◽  
High Strength Steel ◽  
Control Process ◽  
Charpy Impact ◽  
High Strength ◽  
Steel Plates

This paper describes the metallurgical approaches for producing 415MPa and 460MPa yield strength offshore structural steel plates and the mechanical properties of the steel plates and their welded joints. A thermo-mechanical control process (TMCP) was adopted to manufacture YP415MPa and YP460MPa steel plates with weldability comparable to conventional YP355MPa steel plates. The Charpy impact and CTOD tests of the steel plates and their welded joints proved to be very good.

scholarly journals The Assessment of Selected Properties of Welded Joints in High-Strength Steels

2020 ◽  
pp. 73-79
Author(s):  
Lechosław Tuz
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Welded Joints ◽  
Heat Input ◽  
Structural Changes ◽  
High Strength Steels ◽  
High Strength ◽  
High Quality ◽  
Treatment Processes ◽  
Welding Processes

The use of technologically advanced structural materials entails the necessity of adjusting typical welding processes to special requirements resulting from the limited weldability of certain material groups. Difficulties obtaining high-quality joints may be the consequence of deteriorated mechanical properties and structural changes in materials (beyond requirements of related standards). One of the aforementioned materials is steel characterised by a guaranteed yield point of 1300 MPa, where high strength is obtained through the addition of slight amounts of carbide-forming elements and the application of complex heat treatment processes. A heat input during welding may worsen the aforesaid properties not only in the weld but also in the adjacent material. The tests discussed in the article revealed that the crucial area was that heated below a temperature of 600°C, where the hardness of the material decreased from approximately 520 HV to 330 HV.

scholarly journals Post-fire mechanical properties of high strength steels

2018 ◽  
Author(s):  
Ben Young ◽  
Hai-Ting Li
Keyword(s):  
Mechanical Properties ◽  
Experimental Investigation ◽  
Ambient Temperature ◽  
High Strength Steel ◽  
Elevated Temperatures ◽  
Weight Ratio ◽  
High Strength Steels ◽  
High Strength ◽  
Predictive Equations ◽  
Retention Factors

High strength steels are becoming increasingly attractive for structural and architectural applications due to their superior strength-to-weight ratio which could lead to lighter and elegant structures. The stiffness and strength of high strength steels may reduce after exposure to fire. The post-fire mechanical properties of high strength steels have a crucial role in evaluating the residual strengths of these materials. This paper presents an experimental investigation on post-fire mechanical properties of cold-formed high strength steels. A series of tensile coupon tests has been carried out. The coupon specimens were extracted from cold-formed square hollow sections with nominal yield stresses of 700 and 900 MPa at ambient temperature. The specimens were exposed to various elevated temperatures ranged from 200 to 1000 °C and then cooled down to ambient temperature before tested to failure. Stress-strain curves were obtained and the mechanical properties, namely, Young’s modulus, yield stress (0.2% proof stress) and ultimate strength, of the cold-formed high strength steel materials after exposure to elevated temperatures were derived. The post-fire retention factors that obtained from the experimental investigation were compared with existing predictive equations in the literature. New predictive equations are proposed to determine the residual mechanical properties of high strength steels after exposure to fire. It is shown that the proposed predictive equations are suitable for both cold-formed and hot-rolled high strength steel materials with nominal yield stresses ranged from 690 to 960 MPa.

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