Inductively supported laser beam welding of high and ultra high strength steel grades

2008 ◽  
Author(s):  
Katrin Harley ◽  
Heinz Haferkamp ◽  
Andreas Ostendorf ◽  
Dirk Herzog ◽  
Peter Kallage
Keyword(s):  
Laser Beam ◽  
High Strength Steel ◽  
Laser Beam Welding ◽  
High Strength ◽  
Ultra High Strength Steel ◽  
Steel Grades

Hydrogen Charging of High Strength Steel Specimens and Physical Simulation of Cold Cracking under Laser Beam Welding Conditions

2012 ◽  
Vol 706-709 ◽  
pp. 1391-1396
Author(s):  
Ossama Dreibati ◽  
R. Ossenbrink ◽  
Vesselin Michailov
Keyword(s):  
Laser Beam ◽  
High Strength Steel ◽  
Physical Simulation ◽  
Laser Beam Welding ◽  
High Strength ◽  
Cold Cracking ◽  
Tension Stress ◽  
Pure Hydrogen ◽  
Diffusible Hydrogen ◽  
Hydrogen Charging

Cold cracks occur during the cooling down of welded joint at low temperatures or later at room temperature after the end of welding. It is associated with the formation of brittle microstructures as martensite in the presence of diffusible hydrogen as well as of tension stresses. By using an enhanced Simulation-und Testing Center Gleeble 3500, a procedure for physical simulation of cold cracking under laser beam welding conditions is suggested. The approach reproduces combinations of the cold crack main parameters, a brittle microstructure, tension stress and high local hydrogen concentration under welding conditions which induce a cold crack. A specimen geometry and technique were developed to enable the gaseous hydrogen charging from pure hydrogen atmosphere. The amount of charged hydrogen can be adjusted through varying the charging parameters like temperature, gas pressure and charging time. The hydrogen charging technique and the cold crack testing procedure were proven with high strength steel specimens.

scholarly journals Characterization of Temperature Fields in Laser Beam Welded Hollow-Cylindrical Cold Crack Samples from High Strength Steel 100Cr6

2021 ◽  
Author(s):  
Eric Wasilewski ◽  
Nikolay Doynov ◽  
Ralf Ossenbrink ◽  
Vesselin Michailov
Keyword(s):  
Laser Beam ◽  
High Strength Steel ◽  
Unit Length ◽  
Laser Beam Welding ◽  
High Strength ◽  
Temperature Fields ◽  
Deep Penetration ◽  
Heating Rates ◽  
Hydrogen Distribution ◽  
Cooling Rates

Abstract This work presents a comparative study of thermal conditions that occur during laser beam welding of high strength steel 100Cr6 that often leads to a loss of technological strength and may conditionally produce cold cracks. The results from both experiments and thermal-metallurgical FE-simulations indicate that the type of heat coupling changes significantly when welding with different process parameters, e.g., in the transition between conduction and deep penetration welding. Further, the simulations show that as a result of the high welding speeds and reduced energy per unit length, extremely high heating rates of up to 2x104 K s-1 (set A) resp. 4x105 K s-1 (set B) occur in the material. Both welds thus concern a range of values for which conventional Time-Temperature-Austenitization (TTA) diagrams are not currently defined, so that the material models can only be calibrated using general assumptions. This noted change in energy per unit length and welding speeds causes significantly steep temperature gradients with a slope of approximately 5x103 K mm-1 and strong drops in the heating and cooling rates, particularly in the heat affected zone near the weld metal. This means that even short distances along the length present a staggering difference in relation to the temperature peaks. The temperature cycles also show very different cooling rates for the respective parameter sets, although in both cases they are well below a cooling time t8/5 of one second, so that the phase transformation always leads to the formation of martensite. The results from this study are intended to be used for further detailed experimental and numerical investigation of microstructure, hydrogen distribution, and stress-strain development at different restrain conditions.

scholarly journals Distortion and Residual Stress Generated by Laser Beam Welding of High Strength Steel

2010 ◽  
Vol 28 (3) ◽  
pp. 281-287 ◽  
Author(s):  
You-Chul KIM ◽  
Mikihito HIROHATA ◽  
Yusuke HAGEYAMA ◽  
Koutarou INOSE
Keyword(s):  
Residual Stress ◽  
Laser Beam ◽  
High Strength Steel ◽  
Laser Beam Welding ◽  
High Strength

Laser beam welding of aluminum to Al-base coated high-strength steel 22MnB5

2015 ◽  
Vol 217 ◽  
pp. 88-95 ◽  
Author(s):  
M. Windmann ◽  
A. Röttger ◽  
H. Kügler ◽  
W. Theisen ◽  
F. Vollertsen
Keyword(s):  
Laser Beam ◽  
High Strength Steel ◽  
Laser Beam Welding ◽  
High Strength

scholarly journals Prediction of the Shear Tension Strength of Resistance Spot Welded Thin Steel Sheets from High- to Ultrahigh Strength Range

2021 ◽  
Author(s):  
Kornél Májlinger ◽  
Levente T. Katula ◽  
Balázs Varbai
Keyword(s):  
High Strength Steel ◽  
Welding Process ◽  
High Strength ◽  
Professional Literature ◽  
Resistance Spot ◽  
Base Materials ◽  
Ultra High Strength Steel ◽  
Steel Grades ◽  
Steel Joints ◽  
Tension Strength

The tensile strength of newly developed ultra-high strength steel grades is now above 1800 MPa, and even new steel grades are currently in development. One typical welding process to join thin steels sheets is resistance spot welding (RSW). Some standardized and not standardized formulas predict the minimal shear tension strength (STS) of RSWed joints, but those formulas are less and less accurate with the higher base materials strength. Therefore, in our current research, we investigated a significant amount of STS data of the professional literature and our own experiments and recommended a new formula to predict the STS of RSWed high strength steel joints. The proposed correlation gives a better prediction than the other formulas, not only in the ultra-high strength steel range but also in the lower steel strength domain.

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