小形パンチ試験法を用いたオーステナイト系ステンレス鋼JN1の溶接部および熱処理材の極低温破壊評価

概要

論文の詳細を見る
Fracture characteristics of a TIG welded joint and heat treated materials of JNI, which is an austenitic stainless steel recently developed for use as a cryogenic structural material, were evaluated by the small punch (SP) testing method using miniaturized specimens at 77K and 4K. The area under the load displacement curve up to the maximum load was defined as the SP energy to evaluate the fracture characteristics of the materials in SP tests. Fracture surfaces were also observed using a scanning clectron microscope. Solution-treated JN1 steel showed ductile fracture behavior with a high SP energy value even at 4K, and serrations were observed in the load displacement curve at 4K, In the weld metal and fusion line specimens of the TIG welded joint, serrations also occured at 4K, but the fusion line specimens showed lower SP energy values than weld metal and solutiontremed JN1 steel at 77K and 4K. In addition, the fusion line specimens showed pop in behavior at 4K, that is, cracks approximately 0.1-1mm long were induced by pop-in in the vicinity of the fusion line at the early stage of loading. JN1 materials heat treated under the conditions of 650℃ 5h and 700℃ In showed similar fracture characteristics to those of the fusion line specimens at 77 K and 4 K except for the cracks induced by pop-in. With increasing temperature and time of heat treatment, SP energy decreased significantly, and the fracture surface showed a transition from ductile dimple to brittle intergranular cracking. It is shown that the SP testing method is useful for evaluating the fracture behaviors of microscopic regions such as the fusion lines of welds at cryogenic temperatures.
一般社団法人日本機械学会の論文
1997-01-25

小形パンチ試験法を用いたオーステナイト系ステンレス鋼JN1の溶接部および熱処理材の極低温破壊評価

スポンサーリンク

概要

著者

関連論文

スポンサーリンク