JOURNAL OF THE JAPAN WELDING SOCIETY

Burning off Paint, Varnish and Lacker

I. Ônishi, M. Mizuno, E. Hamai, T. Masuya

1951 Volume 20 Issue 6 Pages 181-184
Published: 1951
Released on J-STAGE: June 12, 2009

DOIhttps://doi.org/10.2207/qjjws1943.20.181

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A specially designed oxy-acetylene blow-pipe of multiple tips was used to remove efficiently the paint, varnish and lacker coated on the metal surface of structures.
These coatings were burned off by the oxygen rich flame and then easily removed by scraping with the tool.
Various lackers and varnishes were easily removed. Many kinds of oil paints were removed as well, but some pigments contained -namely, ultramarine, carbon black and chrome yellow-hindered perfect burning. They are hard to remove.
Papers pasted on the wooden plate burned off quickly. If uhe surface of such plate was saturated with water, carbonization of it did not occur.

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On the Welding Operation of Tank Cars for Shipment of Liquid Chlorine

R. Kawarago, H. Niuchi

1951 Volume 20 Issue 6 Pages 184-187
Published: 1951
Released on J-STAGE: June 12, 2009

DOIhttps://doi.org/10.2207/qjjws1943.20.184

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With the development of the synthetic textile industry, the transportation of liquid chlorine has pre. sented a difficult problem.
In solution of the difficulty, we have completed special-type tank cars for carrying liquid chlorine for the first time in Japan after several investigations. Results of various tests having been satis-factory, they were put into practical'use and still remain in service without any trouble.
This is a brief report of the welding operation on the tanks of these cars.

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Some Micro-Observations of the Brittle Fractures in Mild Steel Arc Welds Containing Nitrogen

T. Kobayashi

1951 Volume 20 Issue 6 Pages 188-193
Published: 1951
Released on J-STAGE: June 12, 2009

DOIhttps://doi.org/10.2207/qjjws1943.20.188

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Charpy specimens of mild steel weld metals containing comparatively large nitride precipitates were fractured by impact bending at various temperatures within the so-called transition temperature range. The lattice distortions in the brittle fractures were surveyed by the X-iay back diffraction, method. Angular correlations among fractured edges, nitride needles and slip lines, generated by static compression independently of the rupture, were measured statistically with micro-photographs.
From these observations, the following conclusions wgre obtained:
1. The fractures, which look similarly brittle to the naked eye, actually have different degrees of lattice distortions correspondihg to the testing temperature.
2. X-ray back reflection photography is useful for comparing brittleness of these fractures.
3. Crystallographic plane of cleavage fractures could not be hastily decided to be a {001} plane, but it was ascertained to be one of {h01} planes, in which h is an integer or zero.
4 Nitrides in weld metals inhibit. plastic flow. They contribute to stress concentration and reduce the cohesive strength of ferrite crystals, thereby promoting brittle fracture.

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On Distortion Correcting of Welded Thin Plate Structures (Part 1)

Mechanism of spot heat-treatment method for distortion correcting

M. Watanabe, K. Sato, S. Minehisa, T. Yokoo

1951 Volume 20 Issue 6 Pages 194-202
Published: 1951
Released on J-STAGE: June 12, 2009

DOIhttps://doi.org/10.2207/qjjws1943.20.194

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Spot heat-treatment method is usually adopted in order to correct the distortion of welded thin steel plate structures such as shells of ships and cars. This is a method in which a part of distorted shell plates is quenched after being heated to 500°C=700°C by oxy-acetylene flame.
With the purpose of finding the most adequate operating conditions in this method, such as heating time, and diameter and pitch of heatnd zone, analysis was made of the mechanism of this methcd on the basis of our previous inveitigation* concerning weld stresses.
It was clarified that the points in and near the heated zone shrink in radial direction when quenching for correction becomes effective. The theoretical values for the radical shrinkage agreed with the measured results in the fundamental experiment as shown in Fig 12.
*) Presented at the annual meeting of Japan Institution of Naval Architects, November 1949.

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On Distortion Correcting of Welded Thin Plate Structures (Part II)

—Function of cover plate (Part I)—Thermal stress and distortion of locally heated thin curved plate

M. Watanabe, K. Sato

1951 Volume 20 Issue 6 Pages 202-209
Published: 1951
Released on J-STAGE: June 12, 2009

DOIhttps://doi.org/10.2207/qjjws1943.20.202

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Regarding thin curved plate as a part of thin spherical shell, in this report we studied elastically on thermal stress and distortion of the shell heated at the center. The heated zone of the shell puffs out perpendicular to the plate as shown in Table 4., and so this method has no effect of distortion correcting. On the other hand, by using cover plate distortion perpendicular to the shell plate can be more or less restricted. Then radial shrinkage occurs in and near the heated zone as reported in our previous paper; therefore this proves to be an effective method of controlling vertical distortion.

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[title in Japanese]

[in Japanese]

1951 Volume 20 Issue 6 Pages 209-212
Published: 1951
Released on J-STAGE: June 12, 2009

DOIhttps://doi.org/10.2207/qjjws1943.20.209

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