A New Method for Reducing Diffusible Hydrogen in Weld Metal

2012 ◽  
Author(s):  
Susan Fiore ◽  
Steve Barhorst ◽  
Mario Amata ◽  
Joe Bundy
Keyword(s):  
Weld Metal ◽  
Raw Materials ◽  
Shielding Gas ◽  
Feeding Problems ◽  
Diffusible Hydrogen ◽  
Flux Cored Arc Welding ◽  
Hydrogen Assisted Cracking ◽  
Wire Feeding ◽  
Metal Properties ◽  
Welding Consumables

The effect of hydrogen on weld metal and weld heat-affected zones (HAZ) has been well established over many years. The potential for hydrogen-assisted cracking increases as the strength of the steel increases. High fuel costs have driven the need for lower weights in the transportation and shipbuilding industries, and increased regulations have driven the need for higher safety factors in the pipeline industry. As a result, many industries are requiring higher and higher base metal strengths. The push for higher strength steels has resulted in an increased demand for ultra-low hydrogen welding consumables and processes. Manufacturers of flux-cored arc welding (FCAW) electrodes have generally attacked the problem of weld metal hydrogen through the use of raw materials that react with hydrogen to take it out of solution, by baking the wires in-process, and by using special drawing techniques and lubricants to minimize hydrogen pick-up. Unfortunately, many of the potential solutions result in electrodes that have poor operability, wire feeding problems, and/or increased welding fume. Hobart Brothers has recently developed a method of producing very low-hydrogen weld deposits, which utilizes fluorine-containing gas compounds in the weld shielding gas. The modified shielding gas has no effect on the weld metal properties or the operation of the welding electrodes. This paper provides details of the method, along with test results that have been achieved using a number of flux- and metal-cored electrodes representing a variety of American Welding Society (AWS) classifications.

Welding of High Strength Pipelines

2004 ◽  
Author(s):  
Bill Bruce ◽  
Jose Ramirez ◽  
Matt Johnson ◽  
Robin Gordon
Keyword(s):  
Weld Metal ◽  
Charpy Impact ◽  
High Strength ◽  
Shielding Gas ◽  
Hydrogen Cracking ◽  
Mechanized Welding ◽  
Margin Of Safety ◽  
Girth Welds ◽  
Welding Consumables

This paper presents the results of a project jointly funded by PRCI and EWI to evaluate the welding of X100 pipe grades using commercially available welding consumables. The welding trials included manual, semi-automatic and mechanized welding procedures. It was found that the combination of Pulsed GMAW and ER100S-1 (using a mixed shielding gas) produced both excellent Charpy impact and CTOD performance, but could result in undermatched girth welds if the pipe significantly exceeds minimum strength requirements. Although ER120 S-1 provides an additional margin of safety in strength, which should accommodate variations in X-100 pipe properties, the toughness results were marginal at −10°C. The risk of weld metal hydrogen cracking in X100 girth welds was also investigated.

scholarly journals Engineered Weld Design: Are Composite Welds Likely in the Future?

2008 ◽  
Vol 580-582 ◽  
pp. 307-310 ◽  
Author(s):  
D.L. Olson ◽  
Young Do Park ◽  
S. Liu ◽  
J.E. Jackson ◽  
A.N. Lasseigne-Jackson ◽  
...  
Keyword(s):  
Weld Metal ◽  
Welding Process ◽  
Potential Method ◽  
Structural Features ◽  
Gas Composition ◽  
Metal Solidification ◽  
High Toughness ◽  
Low Temperature Creep ◽  
Metal Properties ◽  
Welding Consumables

Utilizing alternating welding process parameters, deposition practices, and welding consumables, particularly during multiple pass welding, it is possible to improve a variety of weld metal properties. There are available a number of phenomena occurring during welding that allow weld metal designers the ability to generate macro- and micro-structural features amenable to implementation of composite theory. These phenomena include solidification microsegregation during dendrite growth, gas-metal reactions between the selected alternating shielding gas composition and weld pool, and solidification microstructural orientation during welding. Additional methods of producing composite welds including specially designed weld compositions, weld metal solidification modification by arc pulsing, and dual wire deposition may be utilized to achieve single pass and multipass composite weld metal deposition. Composite welds are a potential method to solve challenging demands such as high-toughness at low temperature, creep strength at high temperature, and customized design for corrosion, wear, or cracking resistance.

Effect of Weld Metal Microstructure on Cold Crack Susceptibility of High Strength Weld

2008 ◽  
Vol 580-582 ◽  
pp. 13-16
Author(s):  
Hee Jin Kim ◽  
Jun Seok Seo ◽  
Jae Hak Kim ◽  
Ka Hee Kim ◽  
Jin Hyun Koh ◽  
...  
Keyword(s):  
Weld Metal ◽  
Hydrogen Content ◽  
High Strength ◽  
Cold Cracking ◽  
Diffusible Hydrogen ◽  
Fca Welding ◽  
Flux Cored Arc Welding ◽  
Metal Microstructure ◽  
Multipass Weld ◽  
Crack Susceptibility

Facing the practical difficulties in reducing the diffusible hydrogen content of fluxcontaining welding consumables like flux-cored arc welding (FCAW) wires, the present study investigated the microstructural aspect to improve the hydrogen-induced cold crack (HICC) resistance of multipass weld metal of 600MPa strength. Two FCA welding wires were prepared by controlling the Ni content to give different weld microstructure, but to have similar levels of hardness and diffusible hydrogen content. HICC susceptibility of those two consumables was evaluated by 'G-BOP test' and also by 'multi-pass weld metal cold cracking test'. As a result of this study, it was demonstrated that microstructural modification with decreased proportion of grain boundary ferrite (GF) improved cold crack resistance of weld metal. The detrimental effect of GF against HICC has also been addressed based on the characteristics of weld metal cold cracking.

Fundamental Prediction of Steel Weld Metal Properties

1991 ◽  
Vol 113 (4) ◽  
pp. 327-333
Author(s):  
S. Ibarra ◽  
D. L. Olson ◽  
S. Liu
Keyword(s):  
Weld Metal ◽  
Heat Input ◽  
Plate Thickness ◽  
Carbon Equivalent ◽  
Steel Weld Metal ◽  
Functional Forms ◽  
Metal Properties ◽  
Welding Consumables ◽  
And Behavior ◽  
Selection Of

Empirically derived expressions are commonly used to predict specific steel weldment properties. These expressions usually consider only constitutional considerations and are limited to their ability to predict the influence of the thermal experience (heat input, weld preparation, and plate thickness). Carbon equivalent and basicity index are examples of such predictive expressions. This paper reviews some of the existing expressional forms and introduces new functional forms that are based on metallurgical engineering concepts. Forms for equations which can predict weld metal properties and behavior as a function of composition are proposed. Methodology for including cooling rate in the predictive equations is also suggested. The concept of developing iso-property diagrams that allow better selection of welding consumables with variations in heat input is introduced and discussed.

Corrosion Behaviour of Unprotected Weldments in Marine Environments

CORROSION ◽  
10.5006/3824 ◽  
2021 ◽  
Author(s):  
Nicholas Senior ◽  
Lawrence Parkinson ◽  
Magdalene Matchim ◽  
Jennifer Collier ◽  
Hung-Wei Liu
Keyword(s):  
Weld Metal ◽  
Cathodic Protection ◽  
Corrosion Behaviour ◽  
Coast Guard ◽  
Metal Corrosion ◽  
Corrosion Performance ◽  
Accelerated Corrosion ◽  
Potential Safety ◽  
Protection Systems ◽  
Welding Consumables

In the absence of protective measures such as paint or cathodic protection systems, steel weldments, immersed in seawater, are expected to corrode freely. This is particularly true for the ice breakers serving the Canadian Coast Guard, where, in the course of operations, paint is scoured from the vessel hulls and cathodic protection systems were not installed. However, the weldments do not corrode uniformly. In some cases, the weld itself corrodes rapidly and requires regular replacement. At the other extreme, the heat-affected zones corrode instead—a potential safety and integrity concern. The morphology of ice breaker weldment corrosion has altered over the last few decades and this has been attributed to changes in welding consumables and processes. The current study is an investigation into the corrosion characteristics of weldments with a particular focus on the compositional differences between weld metal and hull plate steels. A method has been developed for numerically describing the corrosion of weldment regions (plate steel, heat-affected zones, weld cap passes and weld re-heated zones) arising from an accelerated corrosion test. This in turn enabled the development of an equation that predicts weldment corrosion performance based entirely on material composition. This permits selection of welding consumables that are anticipated to give good corrosion performance, avoiding the extremes of rapid weld metal corrosion and preferential heat-affected zone attack.

Evaluation of FCAW Consumables for Offshore and Arctic Structure Fabrication

1993 ◽  
Vol 115 (1) ◽  
pp. 76-82 ◽  
Author(s):  
S. R. Bala ◽  
L. Malik ◽  
J. E. M. Braid
Keyword(s):  
Weld Metal ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Inclusion Content ◽  
Ambient Temperatures ◽  
Weld Metals ◽  
Arctic Regions ◽  
Flux Cored Arc Welding ◽  
Crack Tip Opening ◽  
Cored Wires

A primary consideration in the welding of structures for service in Canadian offshore and arctic regions is the toughness of weld metals required at very low ambient temperatures (−30°C to −60°C). To assess the suitability of cored wires for applications in these environments, some currently available commercial consumables for the flux-cored arc welding (FCAW) process were evaluated. Cored wires belonging to four different categories: basic, rutile, metal-cored and innershield, were used to prepare welds with similar welding procedures. Weld metal Charpy V-notch (CVN) and crack tip opening displacement (CTOD) tests were carried out and the effect of weld metal composition, microstructure and inclusion content in the weld metal toughness was examined. The Charpy transition temperatures and the CTOD toughness results indicated that, of the 16 wires tested, there were only seven that would be suitable for critical applications.

Diffusible hydrogen management in underwater wet self-shielded flux cored arc welding

2017 ◽  
Vol 42 (38) ◽  
pp. 24532-24540 ◽  
Author(s):  
Aleksandra Świerczyńska ◽  
Dariusz Fydrych ◽  
Grzegorz Rogalski
Keyword(s):  
Arc Welding ◽  
Diffusible Hydrogen ◽  
Flux Cored Arc Welding
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