Using the same method as 1 st report, the authors calculated carbon equivalents for mechanical properties of high strength basic weld deposit treated stress relief annealing.
Further the authors searched for the equations between carbon equivalent and the values of mechanical properties of weld deposits.
The results obtained in the study are follows:
Ceq^S.R(Y.P)=C+0.08 Si+0.10 Mn+0.04 Ni+0.12 Cr+0.25 Mo
Ceq^S.R(T.S)=C+0.09 Si+0.06 Mn+0.03 Ni+0.09 Cr+0.17 Mo
Ceq^S.R(EL)=C+0.14 Si+0.11 Mn+0.03 Ni+0.16 Cr+0.14 Mo
Ceq^S.R(E₀)=C+0.27 Si+0.07 Mn+0.05 Ni+0.19 Cr+0.20 Mo
Ceq^S.R(E_-40)=C+0.38 Si+0.09 Mn+0.05 Ni+0.23 Cr+0.20 Mo
Y.P (kg/mm²)=29.2+80.2 Ceq^S.R(Y.P)
T.S (kg/mm²)=26.4+147 Ceq^S.R(T.T)
EL (%)=37.1-29.1 Ceq^S.R(EL)
E₀ (kg-m/cm²)=48.1-69.2Ceq^S.R(E₀)
E_-40 (kg-m/cm²)=28.7-37.4 Ceq^S.R(E_-40)

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In the report 2, the processes of stress corrosion cracking for 18 Cr-8 Ni stainless stainless steel and its welded metal were analyzed by the method of continuous observation with microscope. Then it became cleare that the processes could be divided into two parts : "Induction period" and "Propagation period" and the lengthes of these two periods were change independently each other by the variation of stress.
In this report, we investigated above two processes of stress corrosion cracking of six kinds of austenitic stainless steels and welded metal from the points of electrochemical study and the continuous observation of the cracks by microscope.
Main results of our experiment are as follows:
1) There is a linear relation between the corrosion potential and the value of applied stress when a crack initiates.
2) The above relation can be observed in every kinds of austenitic stainless steels.

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We investigated the rotary bending fatigue strength of butt brazed naval brass specimens with Ag-P-Cu and Ag-Cu-Cd-Zn series filler metals.
Specimens are brazed by induction heating, and are tested at room temperature and 250°C.
Test results are summarized as follows :
1) Fatigue strength of brazed joints and base metal are as follows, at room temperature, Ag-P-Cu series ; 9.0 kg/mm²
Ag-Cu-Cd-Zn series ; 11.0/ kg/mm²
base metal ; 18.2 kg/mm²
at 250°C,
Ag-P-Cu series ; 7.5 kg/mm²
Ag-Cu-Cd-Zn series ; 8.0 kg/mm²
base metal ; 15.5 kg/mm²
2) Fatigue strength of brazed joints are influenced by the impact strength of filler metals and the hardness distribution of filler metal, boundary layer and base metal at brazed joints.

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For field welding of reinforcing bars, requirements for a process are as follows :
1) The operation requires no great skill ; inexperienced men can be trained easily and quickly to do the work.
2) No heavy, expensive equipment of any kind is needed.
3) All weld joint have tensile strength equal to the ultimate strength of the bar. However, the welding methods in common use have not always fulfiled the above requirements. Judging from the above fact, author has developed a new process of self-preheating thermit welding.
This process provides a high speed means for producing sound welds of uniform high quality with less expense.
In the first report, author has investigated the thermit mixtures used for this process in regard to workability of them and mechanical properties of weld.
The results are of follows ;
1) Effective factor to thermit reaction is the homogeneity of mixtures. The homogeneity of mixtures depends upon the constitution of particle size and accordingly the void ratio. The best result is obtained in about 50 percent void ratio. Moreover, the smaller the difference in particle size, the more smoothly thermit reaction goes.
2) The ratio of iron oxide/aluminum plays the most important role on soundness of steel. Al-content giving the best ratio is higher by 2 percent than stoichiometric quantity. But Al-content should be decreased according to their deoxidizing power when other deoxidizers coexist in thermit mixture.
3) The effect of alloying elemeat on mechanical properties of thermit steel is evident.
From the results, author has established a new idea for carbon equivalent applicable to thermit steel.
On the baisis of this idea, we shall obtain a thermit mixture with a desirable property.

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