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Volume 46, Issue 2
Displaying 1-8 of 8 articles from this issue
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Akira Okada1977 Volume 46 Issue 2 Pages 53-61
Published: February 05, 1977
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSDownload PDF (639K) -
Yoshinori Ito, Masahiko Ikeda, Mutsuo Nakanishi, Norio Katsumoto, Yuic ...1977 Volume 46 Issue 2 Pages 62-67
Published: February 05, 1977
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSThe effects of several factors on the weld cracking susceptibility in the through-thickness direction were investigated by oblique Y-groove cracking test, Heel cracking test and Insert window type weld cracking test.
The results obtained are summarized as follows:
(1) The cracking susceptibility in the through-thickness direction increases as sulphur content and Pct value of steel plate increase.
(2) Sulphur content is thought to indicate inclusion content, and total length of inclusion increases as sulphur content increases. Therefore, spherizing of inclusion improves greatly cracking susceptibility in the through-thickness direction.
(3) The cracking susceptibility in the through-thickness direction is affected also by the diffusible hydrogen content in weld metal. For the prevention of the cracking in the through-thickness direction, it is effective to reduce the diffusible hydrogen content.
(4) New formula PL for evaluation of the cracking susceptibility in the through-thickness direction was obtained.View full abstractDownload PDF (3087K) -
Chemical Reaction in Electroslag Welding Process (Report 1)Shozaburo Nakano, Katsuomi Tamaki, Junichiro Tsuboi1977 Volume 46 Issue 2 Pages 68-75
Published: February 05, 1977
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSA few has been known on the reaction between slag and metal in ESW process except the concern of high basic or highly contained CaF2 flux, nevertheless the reaction determines the mechanical properties.
This report cosiders the effect of compositions of the electrode and the slag on oxygen, silicon and manganese content in welded or remelted metal by electroslag process.
The experiment is carried out using fluxes with a wide range of basicity in CaO-SiO2-Al2O3, CaO-MnO-Al2O3, and CaF2-SiO3-Al2O3 system.
The elements in metal deposited by electroslag process are not in equilibria with slag compositions in detail, although the solubility products calculated from the analyses agree apparently with the equilibrium values at the temperatures of 1800-2000°C.
Oxygen sources in electrosalg process are considered to be the oxidation of electrode surface by welding atmosphere, which is about 0.1 g oxygen per 100 g metals, and decomposition of oxides.
The slag oxidation ability can be well evaluated by "the Slag Stability Ss" proposed by Narita, while Mori's basicity BL is only applicable to highly SiO2 containing slag.View full abstractDownload PDF (479K) -
Apparatus & System of the Automatic WeldingShigeo Takano, Takao Yokokawa, Teruo Ikeno, Yasuaki Ichinose1977 Volume 46 Issue 2 Pages 76-82
Published: February 05, 1977
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSIn Japan, gas pressure welding is extensively used for joining concrete reinforcing bars. It is a kind of solid phase welding and is simple as well as economical for field welding of steel bars. However, as the conventional method is a manual practice, the quality of joints depends much on the working condition and workmanship of individual operators.
Therefore, in order to improve the quality and reliability of these gas pressure welded joints, experiments were performed to investigate the influence of welding conditions and welding process on the properties of joints. On the basis of the results obtained, a new system of automatic gas pressure welding has been developed. The system consists of a portable automatic gas pressure welding machine and its control devices including welding program for sequential control. In this system, welding is automatically carried out in accordance with a preset program. In a number of experiments and field weldings, joints welded by this machine proved sufficiently strong. The present part of this paper will be devoted to a description of the apparatus and the system of automatic gas pressure welding.View full abstractDownload PDF (3815K) -
Toshio Enjyo, Kenji Ikeuchi, Masahito Kanai, Toshiharu Maruyama1977 Volume 46 Issue 2 Pages 82-89
Published: February 05, 1977
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSDiffusion welding of titanium to aluminum has been performed. It is an example of the welding between dissimilar metals which form brittle intermetallic compounds in the bonding interface. In order to investigate the important factors which affect the mechanical properties of joint, the microstructure in the bonding zone was examined in detail with several metallographic methods, such as optical micrograph, Knoop hardness test, X-ray analysis and scanning electron micrograph. The results obtained are summarized as follows:
1. The joint strength increased with increasing welding temperature and time. The joints welded for more than 30 min. at 600°C were fractured at aluminum base metals on the tensile strength test.
2. The interlayer which consisted of intermetallic compound Al3Ti was formed in the bonding interface. The thickness of this interlayer increased almost linearly with welding time. The increase in the thickness did not reduce the joint strength up to 10 μm at least.
3. The oxide film on the faying surface of aluminum was considered to be the most important factor which affects the joint strength. That is, the joint strength did not increase sufficiently since the, oxide film inhibited the formation of metallic bond between the base metals.
4. The formation of metallic bond between the base metals proceeded preferentially in the regions where the oxide film was broken by the micro-asperities on the faying surface of titanium.View full abstractDownload PDF (4785K) -
Seishin Kirihara, Tsutomu Onuma, Kiyoshi Watanabe1977 Volume 46 Issue 2 Pages 89-95
Published: February 05, 1977
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSThe relationships between various weld crack test methods were discussed at the 9th Commission meeting of I.I.W. This article evaluates crack determination methods for slit groove tests, H-type restraint cracking tests, TRC tests, RRC tests and Implant tests, and discusses the intensity of restraint and restraint stress influencing crack prevention preheating temperatures. Finally the relationships between various test methods are clarified concerning cracks caused in first layer. The results are as follows:
(1) The dependence of delayed cracks on colling speed (preheating), intensity of restraint, restraint stress and stress concentration will be explained using 80 kg/mm2 high-strength steel.
(2) A nomograph was made up to clarify the relationships between the various test methods by relating the crack prevention preheating temperatures to critical restraint stress and critical intensity of stress in the first layer of 80kg/mm2 high-strength steel.View full abstractDownload PDF (446K) -
Cracking in MIG Spot Weldments and its Prevention by Utilizing Pressurized Arc AtmosphereKinsaku Nakane, Yoji Ogata1977 Volume 46 Issue 2 Pages 96-103
Published: February 05, 1977
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSIn MIG spot welding of aluminum alloys one of the the most important problems to be throughly solved is establishment of countermeasures for the high sensitivity to circular cracking in the weldments. The authors studied to clarify the cracking mechanism and to get the preventive measure for the cracking through rising the ambient pressure. The conclusions are summarized as follows:
(1) Circular cracks are intergranular hot cracks occurring in the locations wherein solidification has been delayed to the last on account of formation of finger-type fusion zone pattern and of poor heat transfer through the interface of the two welding sheets.
(2) Circular cracks are classified as the following three types: (i) overlap crack, (ii) HAZ crack, (iii) notch crack or peripheral crack at the interface.
(3) By simply but firmly pressing the nozzle of a MIG welding torch towards the surface of welding sheet without resorting to provision with any special pressure controlling chamber, pressurized arc atmosphere for MIG spot welding can be obtained.
(4) With increase in ambient pressure the fusion zone contour of weldment changes from finger-to bell-type. In accordance with this change weld cracking tends to decrease. Especially noteworthy is that overlap cracking and HAZ cracking can be wholly prevented in the ambient pressure over 3 atm's. Notch cracking is generally hard to shut out its appearance completely, however, the crack size can be minimized to micro scale.
(5) Welding at higher ambient pressure brings about no change in specific wire melting rate per ampere-second in case of lower wire feed rate of 100mm/s. At higher feed rate of 165mm/s and 215mm/s, however, higher ambient pressure gives rise to increase specific melting rate. This result contradicts the experimental data given by Salter and Nishiguchi et al.. With respect to this discrepancy short discussion is given.View full abstractDownload PDF (2304K) -
1977 Volume 46 Issue 2 Pages e1
Published: 1977
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSDownload PDF (22K)
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