THE CHANGE IN THE CHEMICAL COMPOSITION AND TOUGHNESS OF API 5L-X70 WELDS BY ADDITION OF TITANIUM

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1209-1216 ◽  
Author(s):  
BEHROOZ BEIDOKHTI ◽  
AMIR HOSEIN KOUKABI ◽  
ABOLGHASEM DOLATI ◽  
PENG HE
Keyword(s):  
Grain Boundary ◽  
Weld Metal ◽  
Acicular Ferrite ◽  
Titanium Content ◽  
Weld Deposit ◽  
Steel Weld Metal ◽  
Metal Properties ◽  
Api 5L X70 Steel ◽  
The Relationship ◽  
Grain Boundary Ferrite

The objective of this work was to study the influence of titanium variations on the API 5L-X70 steel weld metal properties. The relationship between microstructure and toughness of the weld deposit was studied by means of full metallographic, longitudinal tensile and Charpy- V notch tests on the specimens cut transversely to the weld beads. The best combination of microstructure and impact properties was obtained in the range of 0.02-0.05% titanium. By further increasing of titanium content, the microstructure was changed from a mixture of acicular ferrite, grain-boundary ferrite, Widmanstätten ferrite to a mixture of acicular ferrite, grain-boundary ferrite, bainite and ferrite with M/A microconstituent. Therefore, the mode of fracture also changed from dimpled ductile to quasi-cleavage. Titanium-base inclusions improve impact toughness by increasing the formation of acicular ferrite in the microstructure. The amount of manganese in inclusions was decreased with addition of titanium to the weld metal.

scholarly journals The Use of Compressed Air for Micro-Jet Cooling After MIG Welding

2016 ◽  
Vol 61 (3) ◽  
pp. 1405-1408
Author(s):  
D. Hadryś ◽  
T. Węgrzyn ◽  
J. Piwnik ◽  
Z. Stanik ◽  
W. Tarasiuk
Keyword(s):  
Weld Metal ◽  
Acicular Ferrite ◽  
Compressed Air ◽  
Steel Weld ◽  
Low Alloy Steel ◽  
Mig Welding ◽  
Jet Cooling ◽  
Metal Deposit ◽  
Steel Weld Metal ◽  
First Time

AbstractThe material selected for this investigation was low alloy steel weld metal deposit (WMD) after MIG welding with micro-jet cooling. The present investigation was aimed as the following tasks: obtained WMD with various amount of acicular ferrite and further analyze impact toughness of WMD in terms of acicular ferrite amount in it. Weld metal deposit (WMD) was first time carried out for MIG welding with micro-jet cooling of compressed air and gas mixture of argon and air. Until that moment only argon, helium and nitrogen were tested as micro-jet gases for MIG/MAG processes. An important role in the interpretation of the results can give methods of artificial intelligence.

Designing Shielded Metal Arc Consumables for Underwater Wet Welding in Offshore Applications

1995 ◽  
Vol 117 (3) ◽  
pp. 212-220 ◽  
Author(s):  
A. Sanchez-Osio ◽  
S. Liu ◽  
D. L. Olson ◽  
S. Ibarra
Keyword(s):  
Calcium Carbonate ◽  
Weld Metal ◽  
Acicular Ferrite ◽  
Oxide Formation ◽  
Electrode Coating ◽  
Microstructural Refinement ◽  
Underwater Wet Welding ◽  
High Toughness ◽  
Porosity Reduction ◽  
Grain Boundary Ferrite

The use of underwater wet welding for offshore repairs has been limited mainly because of porosity and low toughness in the resulting welds. With appropriate consumable design, however, it is possible to reduce porosity and to enhance weld metal toughness through microstructural refinement. New titanium and boron-based consumables have been developed with which high toughness acicular ferrite (AF) can be produced in underwater wet welds. Titanium, by means of oxide formation, promoted an increase in the amount of acicular ferrite in the weld metal, while boron additions decreased the amount of grain boundary ferrite (GBF), further improving the microstructure. Porosity reduction was possible through the addition of calcium carbonate at approximately 13 wt percent in the electrode coating. However, weld metal decarburization also resulted with the addition of carbonate.

scholarly journals The coexistence of acicular ferrite and bainite in an alloy-steel weld metal

1992 ◽  
Vol 11 (22) ◽  
pp. 1547-1548 ◽  
Author(s):  
J. R. Yang ◽  
C. C. Yang ◽  
C. Y. Huang
Keyword(s):  
Weld Metal ◽  
Alloy Steel ◽  
Acicular Ferrite ◽  
Steel Weld ◽  
Steel Weld Metal

Functional forms of Equations to Predict Steel Weld Metal Properties

1998 ◽  
Vol 31 (2) ◽  
pp. 31
Author(s):  
S. Ibarra ◽  
D. L. Olson ◽  
S. Liu
Keyword(s):  
Weld Metal ◽  
Steel Weld ◽  
Steel Weld Metal ◽  
Functional Forms ◽  
Metal Properties

The coexistence of acicular ferrite and bainite in an alloy-steel weld metal

1992 ◽  
Vol 11 (16) ◽  
pp. 1145-1146 ◽  
Author(s):  
J. R. Yang ◽  
C. C. Yang ◽  
C. Y. Huang
Keyword(s):  
Weld Metal ◽  
Alloy Steel ◽  
Acicular Ferrite ◽  
Steel Weld ◽  
Steel Weld Metal

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.

The Effect of Weld Metal Manganese Content on the Microstructure, Mechanical Properties and Hot Crack Susceptibility of Helically Welded Linepipes

2008 ◽  
Author(s):  
Navid Pourkia ◽  
Pirooz Marashi ◽  
Rouzbeh Leylabi ◽  
Seyed Alireza Tabatabaei ◽  
Hadi Torshizi
Keyword(s):  
Mechanical Properties ◽  
Grain Boundary ◽  
Weld Metal ◽  
Acicular Ferrite ◽  
Microalloyed Steels ◽  
Second Phase ◽  
Optimum Level ◽  
Hot Crack ◽  
Mn Content ◽  
Crack Susceptibility

The effect of manganese addition on decreasing hot crack susceptibility of submerged arc welding in microalloyed steels is well understood, but its increment should not cause unsuitable changes in metallurgical and mechanical properties of weld metal. Therefore, since weld metal Mn content in SAW process is mainly controlled by welding wire composition, the aim of this investigation is to study the effect of wire Mn content on the microstructure, mechanical properties and hot crack susceptibility of helical linepipes weld metal. In this regard, three different wires with 0.88, 1.05 and 1.54 wt% of Mn content were selected and welding was performed in both experimental and production process condition of X70 helical linepipes. As a result, 1.26, 1.44 and 1.67 wt% of Mn in weld metal was obtained respectively. Metallographical examinations using optical and scanning electron microscopy showed that, increasing the amount of Mn in weld metal, decrease the grain size of all phases (acicular ferrite, primary ferrite and ferrite with aligned second phase). Moreover, in the expense of increasing acicular ferrite, the volume fraction of primary ferrite (mostly grain boundary ferrite) and ferrite with aligned second phase decreased. Also, the results of mechanical properties indicated that the higher the amount of Mn, the higher the strength and hardness of weld metal, but in the case of impact toughness and tensile elongation, an optimum level was observed and lower toughness in the highest Mn content weld metal is attributed to the increasing hardenability and thus formation of martensite/retained austenite islands and grain boundary carbides in coincident sites of acicular ferrite grains. Moreover, analyzes in more than 1000m helical linepipes weld metal length showed that increasing weld metal Mn content up to 1.4wt%, reduced the possibility of hot crack formation from total percentage of 0.005 to around 0.001.

Effect of Nb on Microstructure Evolution of Coarse-Grained Heat-Affected Zone with Large Heat Input Welding

2011 ◽  
Vol 284-286 ◽  
pp. 1174-1179 ◽  
Author(s):  
Xue Li Tao ◽  
Kai Ming Wu ◽  
Xiang Liang Wan
Keyword(s):  
Grain Boundary ◽  
Heat Affected Zone ◽  
Heat Input ◽  
Acicular Ferrite ◽  
High Strength ◽  
Coarse Grained ◽  
Granular Bainite ◽  
Low Alloy Steels ◽  
Alloy Steels ◽  
Grain Boundary Ferrite

The effect of Nb microalloying on microstructure transformation of coarse-grained heat-affected zone of high strength low alloy steels were investigated utilizing different heat input welding simulation. For the low-Nb steel, the microstructures of coarse-grained heat-affected zone mainly consisted of acicular ferrite, bainite and grain boundary ferrite for small heat input welding; the amount of acicular ferrite decreased whereas grain boundary ferrite, polygonal ferrite and pearlite increased with increasing heat input. In constrast, for the high-Nb steel, granular bainite was the dominant microstructure. The formation of granular bainitic microstructure was associated with the solid solution of Nb, which suppressed ferrite transformation and promoted the formation of granular bainite. The hardness of coarse-grained heat-affected zone increased with increasing Nb content, and decreased with decreasing heat input, which was attributed to the microstructural change.

Effect of Electrode Coating on Austenitic Stainless Steel Weld Metal Properties

2019 ◽  
Vol 1152 ◽  
pp. 19-30
Author(s):  
Justus Uchenna Anaele ◽  
Chijioke Peter Egole ◽  
Gaius Chukwuka Nzebuka ◽  
Anthony Nnamdi Nnodum
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Weld Metal ◽  
Steel Weld ◽  
Electrode Coating ◽  
Stainless Steel Weld ◽  
Steel Weld Metal ◽  
Stainless Steel Weld Metal ◽  
Austenitic Stainless Steel Weld ◽  
Metal Properties

The effect of electrode coating on austenitic stainless steel weld metal properties was studied. Manual metal arc welding method was used to produce the joints with the tungsten inert gas welding serving as the control. Metallographic and chemical analyses of the fusion zones of the joints were conducted. Results indicate that the weldment produced from E 308-16/12 lime-titania electrode has a higher ductility and strength of about 36% in terms of percentage elongation and 517 N/mm2respectively, compared to 26% and 18% and 475 N/mm2and 425 N/mm2respectively, obtained from weldments produced from E 308-16/10 rutile and E 308-16/12 rutile electrodes respectively. The presence of lime which is a slag former in E 308-16/12 lime-titania electrode was relevant in slowing down the cooling rate of both the weld pool and the just solidified weld metal resulting in the overall improvement of the resultant weld metal properties. It was found that the values of the strain hardening exponent were 0.379 for E 308-16 gauge 10, rutile electrode, 0.406 for E 308-16 gauge 12 rutile electrode, 0.382 for TIG welding, 0.353 for E 308–16 gauge 12, lime-titania electrode, 0.435 for E 310-16 gauge 10, rutile electrode. E 310 – 16 gauge 10, rutile electrode had the greatest strength and strain hardening coefficients of 1180 N/mm2and 0.435 respectively, and will be more amenable to cold working. Keywords: Austenitic stainless steel, microstructure, electrode coating, welding, joints.

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