All issues
Volume 41, Issue 3
Displaying 1-8 of 8 articles from this issue
- |<
- <
- 1
- >
- >|
-
[in Japanese]1972 Volume 41 Issue 3 Pages 254-259
Published: 1972
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSDownload PDF (4361K) -
Kunihiko Satoh, Kenji Seo, Shigenori Sone1972 Volume 41 Issue 3 Pages 260-272
Published: 1972
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSProgressive research program is undertaken to observe the mechanical behaviour in crusiform fillet welded joint under tension. Attension is forcussed, in particular, on the effect of geometry of fillet weld including its contour, size and penetration on plastic deformation and strength of welded joint. The present report explains experimentally the effect of contour of fillet weld. Model specimens, having profile of crusiform fillet welded joints, machined from a mild steel of 1.6 mm thick are used for the experiments. Strain distributions in fillet weld are measured by using the Moire method. The strain and stress distributions in fillet weld at several load levels are obtained for various fillet angle θf. Influence of the fillet angle θf and reinforcement of weld on the strength of fillet welded joint are determined.View full abstractDownload PDF (6218K) -
Fractured Positions for High and Low Cycle Fatigue TestsMasaki Watanabe, Satoshi Fujiwara1972 Volume 41 Issue 3 Pages 273-282
Published: 1972
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSThis report presents results of the fatigue test on the dissimilar welded joint (Mild Steel & AISI304 Steel) with smoothed plane test specimens.
Generally, it is well known that the accumulation of the microscopic plastic strain occurs during the fatigue test.
Then we observed the degree of the plastic deformation caused by difference of microstructures at the bonded part of the dissimilar welded joint by micro-interference method and also discussed the fractured position for each high and low cycle fatigue tests.
The results obtained from this experiment are-summarized as follows;
(1) We can sufficiently obtain the qualified behavior of plastic strain occurred at the bonded part by micro-interference method.
(2) Generally speaking, we are apt to consider that the bonded part will be, weakest. But according to our experiments fracture occurred near the center of mild steel part in case of low cycle fatigue; on the while fracture occurred at the bonded part in the case of high cycle fatigue (Photo 8).View full abstractDownload PDF (7554K) -
Isao Masumoto, Ryuichiro Ebara1972 Volume 41 Issue 3 Pages 283-290
Published: 1972
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSGilde1) has reported on the effect of epoxy-resin coating over the weld reinforcement in improving the fatifue strength of welded joints. But the reason of this effect has not been explained clearly. Authors) have experimentally showed the influence of atmospheres on the fatigue strength of steels. And it is considered that the fatigue strength improving effect of epoxy-resin coating may be attributed to the protective effect of its coating against air. Then the improving effect of coating may depend on the coating conditions and the kinds of coatings and metals. These points are experimentally studied in this report by a plate bending fatigue tests in the controlled atmosphere tank and rotating bending fatigue tests, using mild steel, 60 kg/mm2 and 80 kg/mm2 high strength steels.
The reslts obtained are as follows.
1) Improvement of fatigue strength of notched steel specimens by epoxy-resin coating is attributed to its protective effect against oxygen and/or humidity in air.
2) The most effective coating was epoxy-resin cured by poly-amid and another coatings, synthetic rubber, vinyle chloride and acrylicemulsion has little effect on improving fatigue strength.
3) An effective epoxy-resin coating has poor air peremeability, flexibility and a good adhesion for metals.
4) The coating effect by epoxy-resin is more predominant in the notched specimen than in the plain specmen. This shows that the coating delay a fatigue crack propagation rate as the same as the no oxygen atmosphere.View full abstractDownload PDF (3005K) -
Interaction between Focused Laser Beam and MetalYoshiaki Arata, Isamu Miyamoto1972 Volume 41 Issue 3 Pages 291-301
Published: 1972
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSInteraction between focused CO2 laser beam and metallic specimen was discussed based on the heat conduction theory and observation using high speed camera. The laser beam absorption characteristics under various surface conditions were analyzed from these results.
Conclusions obtained may be summerized as follows:
(1) A CO2 laser-weldability under several hundred watts was the best in titanium, zirconium, type 304 stainless steel etc., and it was the worst in silver, copper etc. When the absorptance was enhanced sufficiently, aluminium sheet was the most suitable metal for high speed welding.
(2) When melting point of the thin surface layer coated on the base metal was higher than the metal's one, the layer can remain on the surface of metal in molten state to enhance the absorptance.
(3) The absorptance of sheet metal having higher thermal diffusivity and lower melting point can be effectively enhanced by the surface treatment but depends hardly on the kind of the surface treatment.
(4) An evaporation during laser heating was violent in the case of the specimen coated with non-metallic finepowder. The reaction of the evaporation induced an appreciable convection in the liquid metal, and affected the shape of fusion isotherm in the case of low thermal diffusivity metal such as type 304 stainless steel.
(5) Under sufficient laser power, a deep penetration is obtained as well as the case of electron beam. But when the laser was excited with ac (60Hz) electric power supply, the deep penetration may be considerably suppressed.View full abstractDownload PDF (10445K) -
Isao Masumoto, Ryuichiro Ebara1972 Volume 41 Issue 3 Pages 302-307
Published: 1972
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSIt was experimentally confirmed that improvement of fatigue strength of mild and high strength steels by epoxy-resin coating of notched part is attributed to its protective effect against oxygen and/or humidity in air. Fatigue strength improving effect of epoxy-resin coating may be wonder for austenitic stainless steel, because it is considerably stable for oxygen.
Therefore the effects of atmosphere and epoxy-resin coating on the fatigue strength of 18-8 austenitic stainless steel are studied in this report. Plate bending fatigue testing machine is equiped in the atmosphere controlled chamber and rotating bending fatigue testing machine were used for these experiments.
The results obtained are as follows.
1) The S-N curve of 18-8 sautenitic stainless steel in air was almost the nearly that in dry nitrogen. Oxygen content in dry nitrogen and oxygen mixed atmosphere had no influence on a fatigue life of 18-8 austenitic stainless steel.
2) Fatigue crack propagation rate of 18-8 austenitic stainless steel in air was also the same as that in dry nitrogen.
These two points were quite different from the case of mild and high strength steels.
3) Little effect of epoxy-resin coating was recognized on fatigue strength of austenitic stainless steel collared bar specimen.
4) It can be concluded that the fatigue strength of austenitic stainless steel is not affected by oxygen and/or humidity in air at room temperature and little effect of epoxy-resin coating is expected on its fatigue strength.View full abstractDownload PDF (4328K) -
Welding in Nitrogen AtmosphereTakuro Kobayashi, Takeshi Kuwana, Ryuji Kiguchi1972 Volume 41 Issue 3 Pages 308-321
Published: 1972
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSUsing ten series of alloy steel electrode wires, mild steel was welded in a nitrogen atmosphere.
The individual influence of the alloying elements, C, Si, Mn, Nb, Mo, V, Co, Ta, W and Cu in the electrode wires on the nitrogen content of weld metals was systematically studied.
The results are summarized as follows;
1) The nitrogen content of weld metals increases with increasing the vanadium, niobium, tungsten, molybdenum, tantalum and manganese contents in electrode wires.
2) The nitrogen content of weld metals decreases with increasing the carbon and silicon contents in electrode wires.
3) Cobalt and copper have no significant influence.
4) The effects of alloying elements in electrode wires on the nitrogen content of weld metals are generally similar to their effects on the solubility of nitrogen in liquid iron alloys.
5) The influence of each alloying element on the nitrogen absorption by weld metals during are welding was estimated by analogy with thermodynamics.View full abstractDownload PDF (803K) -
Effects of alooying elements on the 0.01% C cast steelIsao Masumoto, Yoshio Kiuchi, Hironyri Ozaki1972 Volume 41 Issue 3 Pages 322-328
Published: 1972
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSIt was previously investigated that the 0.01% C cast steel containing 0.35% Si and 1.50% Mn gave excellent toughness and the same strength as rolled mild steel.
In this report, the effects of aluminium, nickel, chromium, molybdenum and boron additions on the mechanical properties of this extremely low carbon Mn-Si cast steel were additionally investigated.
The results were summerized as follows;
1) The addition of a suitable amount of nickel, chromium, molybdenum and boron can lower the energy transition temperature of the extremely low carbon cast steel.
2) Nickel, chromium and molybdenum can linearly increase the tensile strength of the extremely low carbon cast steel depending on their contents and chromium was more effective to increase strength.
3) The lowest transition temperature and the highest strength of the extremely low carbon cast steel were given by an addition of 0.44% nickel and their values were respectively -45°C and 50 kg/mm2.View full abstractDownload PDF (3897K)
- |<
- <
- 1
- >
- >|