Submerged Arc Welding Method Research Articles

INVESTIGATION OF THE MECHANICAL PROPERTIES OF DIFFERENT THICKNESS OF THE GRADE A SHIP PLATES JOINED BY SUBMERGED ARC WELDING

In this study, a large part of the ship used in the manufacture of three different thickness of Grade A ship plates were joined by submerged arc welding method. In order to determine the strength of welded joints to the tensile and charpy impact test were applied, as well as hardness and microstructure studies were conducted on samples. Tensile tests showed that rupture occurred in the base metal of all samples. From the results of charpy impact test, the highest charpy notch values were obtained from base metal and this is followed by HAZ and the weld metal. It was seen that all the welding parameters, weld metal hardness is higher than the HAZ and the base metal.

厚板すみ肉溶接における倒れ変形推定方法の開発

In order to manufacture I section of bridge, the fillet welding of the both sides for the web is conducted simultaneously, or conducted one side sequentially. The angular distortion will occur in the case of simultaneous welding, the leaning deformation on the flange to the first welding side will occur in the case of sequential welding for the thick plate. Compared with the angular distortion, it is difficult to correct the leaning deformation on the flange. If we can estimate the amount of the leaning deformation on the flange to first welding side, we will be able to set the flange lean to the second welding side before welding and keep the flange right angle to the web without correcting the deformation after welding. We conducted some cases of experiment and thermal elastic-plastic analysis for I section with sequential fillet welding. From the results, we developed the program for estimating the leaning deformation on the flange with tandem submerged arc welding method sequentially, and we applied to the actual bridge manufacturing. Consequently, we reduce the correcting work drastically, and achieve the cost reduction in production.

Effects of complex carbide fraction on high-temperature wear properties of hardfacing alloys reinforced with complex carbides

A correlation was made of microstructure, high-temperature wear resistance, and surface roughness in hardfacing alloys reinforced with complex carbides. The hardfacing alloys were deposited twice on a low-carbon steel substrate by a submerged arc welding method. In order to investigate the effect of complex carbides, different fractions of FeWTiC and WTiC carbide powders included inside hardfacing electrodes were employed. Hot-rolling simulation test was carried out using a high-temperature wear tester. Microstructural analysis indicated that cuboidal and rod-type complex carbides were homogeneously distributed in the bainitic matrix. As volume fraction of these complex carbides increased, hardness and wear resistance increased. The alloy reinforced with FeWTiC carbides contained more complex carbides in the harder matrix than those reinforced with WTiC carbides because of efficient melting and solidification during hardfacing, and thus showed the best wear resistance and excellent surface roughness. Hardness, wear resistance, and surface roughness of the hardfacing alloys reinforced with complex carbides were improved in comparison to high speed steel rolls because of the homogeneous distribution of hard, fine complex carbides in the bainitic matrix.

Progress in productivity and weld quality in UOE pipes by four-wire submerged arc welding.

Spurred by the growing demand for heavy wall UOE pipes with excellent toughness, recent progress by the 4-wire submerged arc welding (SAW) method is reported from the aspects of productivity and weld quality. The 4-wire SAW method is found to bring about 10-30% improvement in productivity and to result in a remarkable suppression of slag inclusion under optimized welding conditions, for example, in current pha se and current ratio. It is also confirmed that the speedup by the 4-wire SAW method does not deteriorate weld quality.Special attentions are paid on the weld quality of heavy wall pipes to meet the recent market situation. This was because there are two problems, i.e., the formation of coarse microstructures of low toughness owing to slow cooling rate and the deterioration of external bead appearance. To cope with them, firstly, the control of nitrogen, oxygen and boron contents in weld metal must be conducted. The optimum ratio between nitrogen and boron contents for excellent toughness is found to be B=0.7•[N]±15 (ppm) for [N]≤80ppm. Secondly, a fused type flux is developed, which has excellent performances in both lowering oxygen content in weld metal to 250-300ppm and suppressing the deterioration of bead appearance. Charpy V-notch Energy more than 100J at -60°C has, then been achieved based on above studies.

ボンドフラックスによるサブマージアーク溶接の研究(第7報)

The susceptibility to stress corrosion cracking in hydrogen sulfide-water system was studies on two commercial 80 kg/mm2 high strength steel plates and some weld metals. Here weld metals were prepared by submerged arc welding method using experimental bonded fluxes and commercial wires for low alloy steels. The susceptibility to cracking was tested by failure time on specimens loaded in tension and exposed to 0.5% acetic acid solution to which hydrogen sulfide was added. Furthermore a experiment on hydrogen embrittlement was conducted on commercial 80 kg/mm2 high strength steel plates. Hydrogen sulfide-water system was used in this experiment too.The test results were as follows :(1) Poor resistance of test materials to cracking is accompanied by relatively high nickel content (0-2% Ni in test meterials).(2) Lower susceptibility of annealed (600°C) weld metals was attained by increasing Molybdenium and Chromium content up to about 2%. (Test materials contain about up to 5% Cr and 2% MO)(3) The test steel plate which was relatively susceptible to cracking was seemed to be more sensitive to hydrogen embrittlement than the less susceptible one.

ボンド・フラックスによるサブマージアーク溶接の研究(5報)

In the Petro-chemical industry, various equipments operating at low tempesatures are increasing, and generally Aluminum killed steel down to -46°C and 3.5% Nikel steel down to -101°C are used as low temperature service structural materials. For these low temperature materials including their weld metals, the properties specified in the relevant clauses of ASTM A-300 are to be satisfied. Detailed reports on the properties for Aluminum killed steel and 3.5% Nikel steel materials and on those of weld metals made reports were with coated electrode arc welding was published in the past, and also reports were made for the case of MIG welding. However, there are only few papers of submerged are welding which considered as most efficient among all automatic welding methods ever applied to this type of welding work.Therefore we experimentally processed several bonded fluxes intended for the specific use in a submerged arc welding method applicable to low temperature steels, and investigated various properties, particularly impact values, of such weld metals obtained with these bonded fluxes.The results of experiment are summarized as follows ;(1) In the case of Aluminum killed steels, weld metal made with either of B+H-540 or B+H-350 combination satisfies the low temperature specification of ASTM as these have good mechanical properties and low temperature impact values.(2) In the case of submerged arc welding, the low temperature properties of weld metal are affected greatly by flux compositions. Therefore, the use of flux having characteristics of a low hydrogen type with large amount of CaCO3 content is recommended. Also, the low temperature impact values obtained on the weld metal are better for multipass weldieg with a small current than single pass welding with a large current.(3) In the case of single pass welding for Aluminum killed steels with a large current, the H-525 flux to which Fe-Al and Ni are added is preferable, and the weld metal obtained on such well generally gives a good low temperature impact values.(4) 3.5% Nickel wire and H-350 flux combination gives a good results for 3.5% Nikel weld metal. Possible low temperature impact value can be improved by a weld made with a low hydrogen type flux and small diameter rod combination in comparison to one made with large size rods, since the former tends to have a higher deposit metal temperature rise which boosts up the weld metal cleanliness than the latter.

ボンド・フラックスによるサブマージドアーク溶接の研究(4報)

In the Petro-chemical industry, various equipments operating at low tempesatures are increasing, and generally Aluminum killed steel down to -46°C and 3.5% Nikel steel down to -101°C are used as low temperature service structural materials. For these low temperature materials including their weld metals, the properties specified in the relevant clauses of ASTM A-300 are to be satisfied. Detailed reports on the properties for Aluminum killed steel and 3.5% Nikel steel materials and on those of weld metals made reports were with coated electrode arc welding was published in the past, and also reports were made for the case of MIG welding. However, there are only few papers of submerged are welding which considered as most efficient among all automatic welding methods ever applied to this type of welding work.Therefore we experimentally processed several bonded fluxes intended for the specific use in a submerged arc welding method applicable to low temperature steels, and investigated various properties, particularly impact values, of such weld metals obtained with these bonded fluxes.The results of experiment are summarized as follows ;(1) In the case of Aluminum killed steels, weld metal made with either of B+H-540 or B+H-350 combination satisfies the low temperature specification of ASTM as these have good mechanical properties and low temperature impact values.(2) In the case of submerged arc welding, the low temperature properties of weld metal are affected greatly by flux compositions. Therefore, the use of flux having characteristics of a low hydrogen type with large amount of CaCO3 content is recommended. Also, the low temperature impact values obtained on the weld metal are better for multipass weldieg with a small current than single pass welding with a large current.(3) In the case of single pass welding for Aluminum killed steels with a large current, the H-525 flux to which Fe-Al and Ni are added is preferable, and the weld metal obtained on such well generally gives a good low temperature impact values.(4) 3.5% Nickel wire and H-350 flux combination gives a good results for 3.5% Nikel weld metal. Possible low temperature impact value can be improved by a weld made with a low hydrogen type flux and small diameter rod combination in comparison to one made with large size rods, since the former tends to have a higher deposit metal temperature rise which boosts up the weld metal cleanliness than the latter.