An Annotated Bibliography on the Significance, Origin and Nature of Discontinuities in Welds, 1975-1980, by C.D. Lundin and S. J. Pawel. November 1980 (14 pp) more detail...
Effect of Microfissures on Corrosion Performance and Mechanical Properties of Austenitic Stainless Steel Weld Metals C. D. Lundin and Yan Cui WRC Bulletin reports an extensive study on the effect of microfissures on the corrosion performance and mechanical properties of austenitic stainless steel weld metals. This program was sponsored by Welding Research Council Stainless and Nickel Alloys Committee. Eight different modified and commercial electrodes provided by Lincoln Electric Company, ESAB and Hobart together with the weld pads from previous programs were used in this investigation. Microfissure evaluation was performed by the Fissure Bend Test to determine the microfissure distribution and microfissure density. Pitting corrosion testing was performed in terms of CPT to evaluate the corrosion resistance of fissure-containing and fissure-free samples in ferric chloride solutions. With the increase in microfissure level a decrease in CPT is noted for both 308L and 316L materials. The corrosion performance of E308L, E316L, E308H and E316H weld deposits with and without microfissures were also evaluated by cyclic polarization testing Tensile testing of E308L and E316L weld deposits with and without microfissures was carried out. The result shows that microfissures affect the ductility of 316L and especially of 308L. There is little effect on yield or tensile strength of 316L, less effect on yield strength of 308L, but a significant effect on tensile strength of 308L. The fracture of modified E308L exhibited a flat transverse break bounded by a narrow shear lip, meanwhile modified E316L exhibited a classic cup-and cone rupture. Fatigue testing of E308L and E316L weld metal samples with and without microfissures showed that microfissures act as stress raisers in the weld metals and greatly decrease the fatigue properties of E308L and E316L weld metal samples. The fracture evaluation in SEM shows that the failure initiation site in microfissure-containing sample was from the microfissures with characteristic of hot cracking, and from secondary cracking for fissure-free samples. The creep test results revealed that modified E316H with 0 FN (fissure-containing deposits) had superior creep resistance, followed by commercial E316H and E308H; the modified 308H with 0 FN (fissure-containing) samples showed the poorest performance. Creep strength of austenitic stainless weld metals is apparently a function of ferrite. Secondary cracking caused by sigma phase (high ferrite content) is the main factor in affecting creep properties for E316H deposits, as were the microfissures for modified E308H deposits (low ferrite content). The test results for commercial E308H and E316H are consistent with the creep database for 308 and 316 welds. Ferrite Number shows a linear relationship with Larson Miller Parameter as a function of creep testing. more detail...
Interpretative Report Hardfacing and Wear Howard S. Avery and Paul C. Kamer Howard S. Avery, beginning in the 1930s, pioneered many developments in hardfacing while employed by American Brake Shoe Company, which later became ABEX Corporation. He tried to make a science of what was then, and is still sometimes today, a black art. After his retirement, he saw the need for an Interpretive Report on hardfacing and wear, and developed the first draft of what became this report. Howard passed away August 24, 1996, before he was able to finish the report. His Daughter, Ms. Byrd Avery Locktie, cared for the draft and references before and after Howard's death. The draft languished for a number of years until Paul Kammer took it up on behalf of the Welding Research Council, updated it and brought it to completion. The Welding Research Council Subcommittee on Hardfacing and Wear and the Welding Research Council High Alloys Committee have believed for many years that hardfacing is not really a black art, but rather is a science. Much of the scientific development of hardfacing alloys was done in the 1940s and 1950s, well before computers came to dominate the flow of information. These committees believed, quite rightly, that much of the before-computers information was in danger of being forgotten. The first purpose of this Interpretive Report is to provide a convenient route to the important scientific references. Users of hardfacing often obtain recommendations for hardfacing alloys from suppliers without a clear understanding of what it is that they are buying. Many times, the recommendation is along the lines of one alloy being harder than another, so it must be better; or one alloy contains more alloy elements or higher alloy content, so it must be better. Without an understanding of the mechanisms of wear and the role of microstructure, the user may be persuaded to make a hardfacing alloy selection that is less-than-optimum for the application. The second purpose of this Interpretive Report is to provide non-commercial guidance to the user of hardfacing in making a hardfacing alloy selection. more detail...
Half-Bead Temper-Bead Controlled Deposition Techniques for Improvement of Fabrication and Service Performance of Cr-Mo Steels Y. Wang, Carl D. Lundin, C.Y.P. Qiao, K. K. Khan, K. Al-Ejel, G. W. Batten WRC Bulletin 506 ? November 2005 The half-bead/temper-bead/controlled deposition repair welding techniques, which utilize the thermal cycles of the second and later weld layers to temper and refine the HAZ of the first layer, have been applied in accordance with ASME Boiler and Pressure Vessel Nuclear Code Section III for new construction since the late 1960?s and Section XI for in-service repair welding of nuclear power plant components. Thus Post Weld Heat Treatment (PWHT) may be omitted without causing degraded properties of the component; especially the base metal HAZ. The extensive ASME Nuclear Code studies of SA533 and SA508 materials clearly show the efficacy of non-PWHT technique on the C-Mn and C-Mo steels.The University of Tennessee, Knoxville (UTK) joined hands with the Ontario Hydro Company to conduct research on the Temper-Bead welding techniques employed primarily in Cr-Mo and also a low alloy steel with the Shielded Metal Arc Welding (SMAW) process. Two layer temper-bead refining techniques were applied in this study. Different temper-bead welding parameters were utilized for obtaining complete CGHAZ refinement, in terms of the energy input of first buttering layers and fill layers. The energy ratio between the second butter layer to the first layer is the controlling entity. Conventional stringer bead welds with and without PWHT were made for the purpose of comparison.This program was sponsored by the Pressure Vessel Research Council (PVRC) and spanned for a total of 4 years. The materials used in study were SA387-11 (1 1/4Cr-1/2Mo), SA387-22 (2 1/4Cr-1Mo) and A516-70. Ontario Hydro supplied the weld coupons and the examination and testing were conducted at The University of Tennessee, Knoxville (UTK). The goals of the program lay in the evaluation of the temper-bead welding techniques and thus the determination of the welding procedures pertinent to the refinement of the base metal HAZ.To evaluate the weldments, a series of tests were conducted. Hardness traverses across the weld metal through HAZ to base metal were taken, macrostructural and microstructural examination was conducted using optical light microscopy. The reheat cracking tendency of the weld HAZ for each of the three heats of material was evaluated using spiral notched transverse weld specimens with both small (0.125" dia.) and large (0.350" dia.) diameter samples. Gleeble thermal simulation was applied for evaluation of the HAZ refining procedures. HAZ Charpy V-notched impact tests were conducted for the temper-bead, conventional with/without PWHT welds, as well as for Gleeble simulated and UTK fabricated welds. Creep rupture testing of cross weld HAZ specimens was also carried out for the different procedure conditions, in which both small and large diameter samples were utilized for testing. Ontario Hydro temper-bead and conventional, UTK weave bead and conventional welds in the as-welded and PWHT conditions were tested for sensitivity to hydrogen cracking by a hydrogen charging-bend test method. Stress rupture testing of longitudinal smooth bar specimens, a new test method for the evaluation of the creep ductility in different weld regions, was developed during this investigation. A singular and straight CGHAZ produced by a weave bead welding technique and the overlapped CGHAZ induced by conventional deposition sequences made at UTK were also evaluated and compared to the Ontario Hydro weld coupons in terms of Charpy V-notched impact, large diameter creep rupture, spiral notched stress rupture and hydrogen sensitivity tests. The results showed a general superiority for the temper-bead welds over the conventional and weave bead welds, as regard to the tests conducted in the program. The Ontario Hydro welding procedures were found to achieve a high degree of CGHAZ refinement. Gleeble simulated samples showed lower properties than the actual welds. The temper-bead welding procedures can be used in practice if more attention is paid to root passes and the final layer of fill passes. more detail...
The Welding Research Council Committee on High Alloys is supporting a research project on a problem critical to the electric power industry. It is the need for laser welding repair methods for high-strength, directionally solidified, nickel-base superalloys used in turbine components. The success of a new technology will largely depend on consistently achieving the desired microstructure in the deposit zone. The project will identify the optimal laser repair welding conditions that will result in strong deposited fusion zone by systematically studying the process parameters, fusion zone solidification modes, and post repair heat treatment. Of course, a complete understanding of the strengthening mechanisms and metallurgy of this unusual class of materials is essential to solving this problem. To this end WRC has also supported documenting the state of the art with regard to the metallurgy and mechanical properties of this class of materials and components. WRC Bulletin 511, ¡§High Performance Cast £^'- Strengthened Nickel-Base Superalloys-An Interpretive Report¡¨ This Bulletin, ¡§Mechanical Properties of Cast £^'-Strengthened Nickel- Base Superalloys¡¨ completes the documention of the technical foundation. The two Bulletins enable evaluation of optimal welding procedures to assure that reliable repair and post welding heat treatment procedures are established. The Bulletins are also useful reference resources for those involved in material selection, life assessment and design optimization. ISSN: 0043-2326 ISBN: 1-58145- 525-9 Library of Congress Catalog Card Number: 85-647116 Number of Pages: 86 more detail...
Weldability of Steels, R. D. Stout more detail...
