Strong & Tough Steel Welds M. Murugananth, H. K. D. H. Bhadeshia E. Keehan, H. O. Andr₫n L. Karlsson.

Slides:

Advertisements

Similar presentations

Ferrous Metallurgy: The Chemistry and Structure of Iron and Steel

Advertisements

Changing the Properties of Steels

Heat Treatment of Steel

HEAT TREATMENT OF STEEL

Nitriding Team Nitriding

MatSE 259 Exam 1 Review Session 1.Exam structure – 25 questions, 1 mark each 2.Do NOT forget to write your student I.D. on the answer sheet 3.Exams are.

Heat Treatment of metals

Chemical composition and heat treatments

Welding Metallurgy 2. Lesson Objectives When you finish this lesson you will understand: The various region of the weld where liquid does not form Mechanisms.

Group 2 Steels: Medium Carbon Alloy Steels (0.25 – 0.55 %C)

Welding Metallurgy 2.

University of Cambridge Department of Materials Science and Metallurgy

Neural Networks

Phase transformations Fe 3 C (cementite) L  (austenite)  +L+L  + Fe 3 C  L+Fe 3 C  C o, wt% C 1148°C T(°C)

S. Terashima and H. K. D. H. Bhadeshia

Performance of Neural Networks. Brief explanation of neural networks Four classes of innovations based on neural networks Are papers on neural networks.

Traveling Speed (mm s-1)

H. Roelofs, S.Hasler, L. Chabbi, U. Urlau, Swiss Steel AG

University of Cambridge Stéphane Forsik 5 th June 2006 Neural network: A set of four case studies.

CARBON STEEL Microstructure & Mechanical properties

Materials for fusion power plants Stéphane Forsik - Phase Transformations and Complex Properties Group FUSION POWER PLANT.

Predicting the Microstructure and Properties of Steel Welds.

Neural Networks in Design and Manufacture.

UPPER BAINITE (High Temperature) LOWER BAINITE (Low Temperature) Carbon supersaturated plate Carbon diffusion into austenite Carbon diffusion into austenite.

Dominique Carrouge Houston February 2002 Phase Transformation Group H. K. D. H. Bhadeshia MCAS Technology Group Dr. P. Woollin.

Efficient Generation of Electricity

Understanding Transformations in Copper Bearing Low Carbon Steels Teruhisa Okumura Department of Materials Science and Metallurgy University of Cambridge.

Welding Procedures and Type IV Cracking Tendency - an Experimental Study J.A. Francis School of Materials University of Manchester V. Mazur Manufacturing.

The Effect of Restoration Process on the Mechanical Behavior of Ultrafine Grain Size Nb-Ti Steel Processed by Warm Rolling and Sub and Intercritical Annealing.

Tribo-Mechanical Evaluations of HIPed Thermal Spray Cermet Coatings V. StoicaHeriot-Watt University, UK Rehan Ahmed Heriot Watt University, UK T. ItsukaichiFujimi.

RG1 University of Chemical Technology and Metallurgy Department of Materials Science Microstructure and Mechanical Properties of Austempered Ductile Cast.

- heating on at required temperature - dwell at temperature - cooling

Precipitation, microstructure and mechanical properties of maraging steels Wei SHA Professor of Materials Science

Annealing, Normalizing, and Quenching of Metals

B. Titanium-based Alloys Titanium is hcp at room temperature – and transform to the bcc structure on heating to 883 o C. Alloying elements are added to.

Surface hardening.

HEAT TREATMENT OF STEEL

Contents Background Strain-based design concept Stress-strain curve

Group 3 Steels: Eutectoid Composition Steels Steels with carbon contents just below the eutectoid to the eutectoid composition (0.6 – 0.8 C) are used.

Department of Microstructure Physics and Metal Forming Düsseldorf, Germany C. Herrera, D. Ponge, D. Raabe Microstructure and deformation mechanisms of.

Chapter 10: Phase Transformations

Dual Phase Steels Producing a new high strength steels without reducing the formability or increasing costs.

Innovative Martensite-Free Precipitation Hardened Tool Steel Composites with Improved Fracture Toughness Waleed Elghazaly (1), Omyma Elkady (2), Saied.

The “Quenching and Partitioning” Process: Background and Recent Progress Fernando Rizzo Seminar Cambridge,

Microstructures and Mechanical Properties

Materials Engineering

What are stainless steels?

IT Phsae transformation of metals

H. Khorsand, S. M. Habibi, M. Arjomandi, H. Kafash

The Consequence of Element Alloying.

Nanocrystalline Materials

Neural Network Analysis

Fe Ru 6d 2s Os Hs.

Group 3 Steels: Eutectoid Composition Steels

Microstructure & Property

Group 2 Steels: Medium Carbon Alloy Steels (0.25 – 0.55 %C)

Fundamentals and Applications of Bainitic Steels

Bulk Nanocrystalline Steel Phase Transformations and Complex Properties Group Transformation to bainite at temperatures.

Complex Weldment Properties: Trends in Predictive Power

Transformation Plasticity in Steel Welds

Carbide Precipitation in Steel Weld Metals

S. B. Singh1 and H. K. D. H. Bhadeshia2

Heat Treatment of Steels

Bengal Engineering & Science University

Heat Treatment of Metals

Silicon-Rich Bainitic

Heat Treatment of Steels

910 °C Austenite (g) a+g g + cementite ferrite 723 °C Temperature / °C

Prepared By: Mr. Prashant S. Kshirsagar (Sr.Manager-QA dept.)

Presentation transcript:

Strong & Tough Steel Welds M. Murugananth, H. K. D. H. Bhadeshia E. Keehan, H. O. Andr₫n L. Karlsson

10  m Transition Cleavage Flow stress Temperature Stress

General perception: nickel improves cleavage resistance of ferrite Fe-0.05C-2Mn-3Ni wt% Yield strength 850 MPa Charpy toughness 60 J at -60 o C Weld A: Fe -0.03C-2Mn-7Ni Weld B: Fe -0.03C-2Mn-9Ni

A B A = 790 MPa B = 840 MPa

Weld A: Fe -0.03C-2Mn-7Ni Weld B: Fe -0.03C-2Mn-9Ni Conclusion: Nickel has not improved toughness Different approach needed !

Neural network created 3300 experimental data 22 variables chemical composition, heat treatment, welding conditions test temperature Charpy UTS

Weld A: Fe -0.03C-2Mn-7Ni Weld B: Fe -0.03C-2Mn-9Ni Weld C: Fe -0.03C-0.6Mn-7Ni

How to find the reason ? -Study temperature dependence of strength. -Retained austenite measurements. -Hardness testing. -Measure transformation temperatures.

Temperature Dependence Study Trends remain same. Also not able to compare toughness at same strength Idea was to compare toughness at same strength But...

Retained Austenite Not a significant change in volume % to explain large difference in toughness.

Vickers Hardness Measurement Observation Large scatter in hardness values along depth of the weld C but not in weld A. Why large scatter ? A offset offset distance 5 mm from weld centerline

Reason for scatter in hardness.. Dilatometric measurements revealed the difference in Ac 1, as expected. Though, difference in Ac 1 is less, it is enough to cause a change in temper effects of reheated zones in a multi-pass weld. Low Mn = High Ac 1 High Mn = Low Ac 1

Mechanism of Toughness Improvement Lower Ac 1 means reaustenitising and transforming back to fresh hard martensite. Higher Ac 1 means tempering of already formed martensite. Tempering of substrate layers gives a combination of soft and hard final microstructure than a uniformly hard final microstructure.

Assessment of Microstructure H m =V  ' H  ' + V o H o

Future Work and Anticipation Ø Tempering kinetics of welds A and C may differ. Would be investigated. Ø Charpy sample spans many layers of the weld. Hence, homogenisation weld C should change the toughness.

Conclusion  Nickel does not necessarily improve toughness under all circumstances  A well trained neural network model can predict any complex relationship.  Transformation temperature, Ac 1, has a marked effect on toughness of multipass welds.

M

M

M

M