ジルカロイ-2 合金の可変雰囲気溶接に関する研究

概要

論文の詳細を見る
Mechanical and corrosion resistance properties were investigated of welded joints of Zircaloy-2 sheets, 1 and 2mm thick, which were welded in a controlled atmosphere welding chamber filled with either pure argon or impure argon mixed with an impurity gas of air, nitrogen, oxygen or hydrogen. Characteristics of welded joints which welded in pure and impure argon atmospheres, namely, hardness, microstructure, tensile and bending properties and corrosion resistance against high temperature high pressure water were studied and the following conclusions were obtained; (1) Weld metal was the most hardened zone in welded joint because its microstructure consisted of α'+α structure. The heat-affected zone was more hardened than base metal. (2) Tensile strength of weld metal was stronger than that of base metal at each temperature in the range of room temperature up to 500℃. Thus tensile fracture of welded joint occured in base metal. (3) Rupture strengths at 1000 hr. of weld metal and base metal at 316℃ were about 19kg/(mm)^2 and 16.5kg/(mm)^2,respectively. (4) Corrosion resistance of welded joint against high temperature high pressure water was better than that of base metal when was pickled after welding. (5) It is recommended for zircaloy-2 to pickle (HF 5%+HNO_3 45%+H_2O 50%, at room temperature for 30 sec) after welding for high temprature high pressure corrosion test. (6) The effects of impurity gases in argon atmosphere on mechanical and corrosive properties of weld metal are as follows (shown in Table 2) : (a) More than 5×(10)^2∿(10)^3ppm (vol.) of air, N_2 gas and (10)^3∿5×(10)^3ppm of O_2 gas embrittled the mechanical properties, and hardness of the weld metal. However, H_2 did not change the hardness and tensile strength although more than (10)^2∿5×(10)^3ppm it enbrittled the weld metal. (b) More than 7×(10)^2ppm of air and (10)^2ppm of N_2,O_2 and H_2 gas if specimens would not be pickled after welding decreased greatly the corrosion resistance against high temperature high pressure water. On the contrary, if specimens would be pickled after welding, up to (10)^4ppm of air, 5×(10)^3ppm of N_2,(10)^4∿(10)^5ppm of O_2 and H_2 gas did not decrease corrosion resistance. (7) As far as the controlled atmosphere welding is concerned, it seems to be necessary for reactor purposes to use on initial vacuum less than (10)^<-1>mmHg and filling with high pure grade (99.99% up) argon to one atmosphere and to pickle (HF 5%+HNO_3 45%+H_2O 50%) the specimens after welding.
社団法人溶接学会の論文
1961-08-25

ジルカロイ-2 合金の可変雰囲気溶接に関する研究

スポンサーリンク

概要

著者

関連論文

スポンサーリンク