On the dominant mechanism of irradiation embrittlement of reactor pressure vessel steels

The circumstances under which steels exhibit intergranular fracture can be classified into four general categories: (1) owing to the presence of certain secondary phases at the grain boundaries; (2) owing to thermal treatments which cause impurity segregation to the grain boundaries without the precipitation of an observable second phase; (3) owing to the action of certain environments; and (4) owing to a combination of stress and high temperatures. In this paper each of these categories and their effects on material properties are reviewed. How the chemical composition of the grain boundary influences and induces intergranular cracking is discussed in detail for all four cases.

Intergranularfailure in steel: the role of grain-boundary composition

Irradiation effects on structural alloys for nuclear reactor applications : a symposium sponsored by the American Society for Testing and Materials, Toronto, Ontario, Canada, 29 June -1 July 1970

Hardening mechanisms and impact toughening of a high-strength steel containing low Ni and Cu additions

Solute interaction effects on grain boundary segregation in ternary alloys

Effects of Copper and Phosphorus on Temper Embrittlement of Mn–Mo–Ni Low Alloy Steel (ASTM A533–B)

供試材はTable 1に 示す化学組成を 有す る4種 類の 鋼でいずれ も50kg高 周波炉で溶製 し,熱 間鍛造,熱 間 圧延に より,17mm厚 とした.各 鋼 とも焼戻脆性の チ ェ ックのため,と くに微量非金属元素に留意 してあ る. 試料の標準熱処理は850°C,lhr焼 入れ,670°C,30 min焼 戻 し(水冷)で ある.な おオーステナイ ト粒度Gγ は各試料 ともASTM No 6.0~6.5で あつた.時 効処理 と して300,400,500,600°C の各温度で10,100お よび1000hr保 持後水冷 した. 以上 の各熱処理後,1mmVノ ッチ ・サブサイズ ・シ ヤル ピー試験片 を作製 し衝撃試験を行 なつた.ま た走査 型電顕による破面観察 およびオージ ェ電子分析 もあわせ て 行 なつた.オ ージェ電子分析に ついては-140°C, 3×10-8 Torr.の 条件にて 試験片を 破断 し,た だちにそ の破面 を分析 した.

Nobuharu Kusunoki

Papers

Effects of Copper and Phosphorus on Temper Embrittlement of Mn–Mo–Ni Low Alloy Steel (ASTM A533–B)

Temper-Aging Embrittlement of Copper Bearing A533B Steel