応力改善工法で付与した圧縮残留応力の持続性評価-ショットピーニングを施した溶接継手の熱サイクル及び応力負荷による残留応力変化（第2報）
公開日:
カテゴリ: 第14回
１．はじめに
第一報では、大規模非線形構造解析手法である理想化陽解法FEMを基に、ショットピーニング（SP）時の力学挙動をモデル化した解析手法を開発し、表面近傍の圧縮残留応力等が測定値とほぼ同じであることを確認した。しかし、開発した解析手法を実機の評価に適用するためには、実機で想定される残留応力変化を解析で再現できることを確認する必要がある。そこで本報では、実機部分模擬溶接試験体を製作して、溶接→SP施工→実機を想定した熱緩和またはひずみ負荷の各々のプロセスにおける残留応力を測定し、開発したFEM解析手法の妥当性を検証するためのデータを取得した。
２．実験方法 1900/01/01 2:24:00
900 SUS316LTP S-H a SUS316L 620 STPT370-SH a STPT370 ? Table 1 SUS316L SUS316L STPT370 Y316L YNiCr-3 Fig. 1 TIG Table 1 Materials and size of welded joint made. Welded Joint Base metal Filler wire Size Same welded joint SUS316L Y316L O.D. 161.5 mm, 11.25 mmt, 195 Dissimilar welded joint SUS316L, STPT370 YNiCr-3 Y316L Fig. 1 Schematic illustration of groove shape. - 507 - O.D. 161.5 mm, 11.25 mmt, 400 Table 2 Fig. 2 2.3Table 1 Table 2 Welding condition of welded joint. 2.250 mm u SP Table 3 SP SP SP 0.265 mm Fig. 3 SP Joint Pass Current (A) Welding Voltage (V) speed (cm/min) Wire feeding speed(g/min) Same 1 10 180 10 8 6.33 1 180 10 9 12.05 Dissimilar (Y316L) 2 3 4 6 220 250 250 10 10 10 11 11 9 6.49 6.49 6.49 7 12 250 10 8 6.49 1 180 10 9 12.05 Dissimilar (YNiCr-3) 2 3 4 6 220 250 250 10 10 10 11 11 9 6.49 6.49 6.49 7 12 250 10 8 6.49 Fig. 2 Appearance of welded joint. Table 3 Shot peening condition of outer and inner surface. Equipment Impeller method Cut wire SUS304(φ0.8 mm, 0.8 mmL, Hv468) Outer Projection speed 30 m/s surface Rotation speed of stage 12 r.p.m. Projection time 280 s Coverage 200% Equipment Air method Cut wire SUS304(φ0.8 mm, 0.8 mmL, Hv468) Inner surface Projection pressure Nozzle size Projection volume 0.4 MPa φ9 mm 9.4 kg/min Rotation speed of stage 30 r.p.m. Projection time 120 s×3 - 508 - Fig. 3 Appearance of welded joint after SP. 2.3止 350 1 hr 120 /hr ￢ 0.003170 MPa 2.4 X Table 4 sin2 [1] X 1 mm ￢ 2 mm J-PARC/MLF TAKUMI U 2×2×2 mm3 2×2×12 mm3 Table 4 Measurement condition of residual stress by X-ray diffraction. Measured Material STPT370 SUS316L (Y316L) YNiCr-3 Characteristic X-ray Cr Kα Mn Kα Mn Kα Tube voltage (kV) 20 20 20 Tube Current (mA) 4 4 4 Diffraction α-Fe 211 γ-Fe 311 Ni 311 Diffraction angle 2θ(deg) 156.4 152.2 152.2 Number of X-ray incident angle ψ 9 9 9 X-ray elastic constant E/(1 ν) (GPa) 175 149 149 3.1 Fig. 4 200 MPa 50 mm D D 40 mm 200 MPa Fig. 4 Residual stress distribution on surface in as welded joint. Fig. 5 SP SP s20 mm s30 mm SP SP D -500 -600 MPa -600 -700 MPa Fig. 6 350 100 200 MPa Fig. 7 9 Fig. 7 Fig. 7 Residual stress change of outer surface by 0.07% compressive strain. Fig. 5 Residual stress distribution on surface of as peened. - 509 - Fig. 6 Residual stress change of outer surface by heat treatment at 350 °C. Fig. 8 Residual stress change of inner surface by 0.07% compressive strain. SP 100 MPa Fig. 8 Fig. 9 SP Fig. 7 100 MPa 0.07% 0.3% [2])-[5] [6] SP FEM ￢ Fig. 10 Residual stress distribution on surface in as welded 3.2 Fig. 10 Y316L YNiCr-3 SUS316L STPT370 100 MPa STPT370 200 MPa SUS316L 130 MPa Y316L YNiCr-3 SUS316L -600 -700 MPa STPT370 -300 MPa SP SUS316L joint of dissimilar welded joint. Fig. 9 Residual stress change of inner surface by 0.3% compressive strain. 350 0.3% - 510 - Fig. 11 SP 350 SP 150 300 MPa Fig. 12 YNiCr-3 SP SP 100 300 MPa 100 MPa ?1 FEM ? SP 1) 200 MPa SP SUS316L -500 -600 MPa 2) SP SUS316L -600 -700 MPa STPT370 -300 MPa (a) Filler wire: Y316L (b) Filler wire: YNiCr-3 Fig. 11 Residual stress change of outer surface by heat treatment at 350 °C. - 511 - 3) SP 350 0.3% 100 300 MPa 100 MPa ““ J-PARC MLF BL19 TAKUMI 2015P0401 (a) Stress loading history (b) Distribution of inner residual strain Fig. 12 Change of inner residual strain by stress loading. [1] X X 2002 ― JSMS-SD-5-02 [2] M M2009 CD-ROM pp.340-342. [3] WJP ?59 2010 pp.307-308. [4] 止 ““ ?7 2010 pp.568-571. [5] Vol.11 No.4 2013 pp.69-76. [6] y Vol.60 No.7 2011 pp.617-623. - 512 -“ “応力改善工法で付与した圧縮残留応力の持続性評価-ショットピーニングを施した溶接継手の熱サイクル及び応力負荷による残留応力変化（第2報）“ “西川 聡,Satoru NISHIKAWA,古川 敬,Takashi FURUKAWA,秋田 貢一,Koichi AKITA,鈴木 裕士,Hiroshi SUZUKI,諸岡 聡,Satoshi MOROOKA, ハルヨ ステファヌス,Stefanus HARJO,柴原 正和,Masakazu SHIBAHARA,生島 一樹,Kazuki IKUSHIMA,木谷 悠二,Yuji KITANI,山田 祐介,Yusuke YAMADA
第一報では、大規模非線形構造解析手法である理想化陽解法FEMを基に、ショットピーニング（SP）時の力学挙動をモデル化した解析手法を開発し、表面近傍の圧縮残留応力等が測定値とほぼ同じであることを確認した。しかし、開発した解析手法を実機の評価に適用するためには、実機で想定される残留応力変化を解析で再現できることを確認する必要がある。そこで本報では、実機部分模擬溶接試験体を製作して、溶接→SP施工→実機を想定した熱緩和またはひずみ負荷の各々のプロセスにおける残留応力を測定し、開発したFEM解析手法の妥当性を検証するためのデータを取得した。
２．実験方法 1900/01/01 2:24:00
900 SUS316LTP S-H a SUS316L 620 STPT370-SH a STPT370 ? Table 1 SUS316L SUS316L STPT370 Y316L YNiCr-3 Fig. 1 TIG Table 1 Materials and size of welded joint made. Welded Joint Base metal Filler wire Size Same welded joint SUS316L Y316L O.D. 161.5 mm, 11.25 mmt, 195 Dissimilar welded joint SUS316L, STPT370 YNiCr-3 Y316L Fig. 1 Schematic illustration of groove shape. - 507 - O.D. 161.5 mm, 11.25 mmt, 400 Table 2 Fig. 2 2.3Table 1 Table 2 Welding condition of welded joint. 2.250 mm u SP Table 3 SP SP SP 0.265 mm Fig. 3 SP Joint Pass Current (A) Welding Voltage (V) speed (cm/min) Wire feeding speed(g/min) Same 1 10 180 10 8 6.33 1 180 10 9 12.05 Dissimilar (Y316L) 2 3 4 6 220 250 250 10 10 10 11 11 9 6.49 6.49 6.49 7 12 250 10 8 6.49 1 180 10 9 12.05 Dissimilar (YNiCr-3) 2 3 4 6 220 250 250 10 10 10 11 11 9 6.49 6.49 6.49 7 12 250 10 8 6.49 Fig. 2 Appearance of welded joint. Table 3 Shot peening condition of outer and inner surface. Equipment Impeller method Cut wire SUS304(φ0.8 mm, 0.8 mmL, Hv468) Outer Projection speed 30 m/s surface Rotation speed of stage 12 r.p.m. Projection time 280 s Coverage 200% Equipment Air method Cut wire SUS304(φ0.8 mm, 0.8 mmL, Hv468) Inner surface Projection pressure Nozzle size Projection volume 0.4 MPa φ9 mm 9.4 kg/min Rotation speed of stage 30 r.p.m. Projection time 120 s×3 - 508 - Fig. 3 Appearance of welded joint after SP. 2.3止 350 1 hr 120 /hr ￢ 0.003170 MPa 2.4 X Table 4 sin2 [1] X 1 mm ￢ 2 mm J-PARC/MLF TAKUMI U 2×2×2 mm3 2×2×12 mm3 Table 4 Measurement condition of residual stress by X-ray diffraction. Measured Material STPT370 SUS316L (Y316L) YNiCr-3 Characteristic X-ray Cr Kα Mn Kα Mn Kα Tube voltage (kV) 20 20 20 Tube Current (mA) 4 4 4 Diffraction α-Fe 211 γ-Fe 311 Ni 311 Diffraction angle 2θ(deg) 156.4 152.2 152.2 Number of X-ray incident angle ψ 9 9 9 X-ray elastic constant E/(1 ν) (GPa) 175 149 149 3.1 Fig. 4 200 MPa 50 mm D D 40 mm 200 MPa Fig. 4 Residual stress distribution on surface in as welded joint. Fig. 5 SP SP s20 mm s30 mm SP SP D -500 -600 MPa -600 -700 MPa Fig. 6 350 100 200 MPa Fig. 7 9 Fig. 7 Fig. 7 Residual stress change of outer surface by 0.07% compressive strain. Fig. 5 Residual stress distribution on surface of as peened. - 509 - Fig. 6 Residual stress change of outer surface by heat treatment at 350 °C. Fig. 8 Residual stress change of inner surface by 0.07% compressive strain. SP 100 MPa Fig. 8 Fig. 9 SP Fig. 7 100 MPa 0.07% 0.3% [2])-[5] [6] SP FEM ￢ Fig. 10 Residual stress distribution on surface in as welded 3.2 Fig. 10 Y316L YNiCr-3 SUS316L STPT370 100 MPa STPT370 200 MPa SUS316L 130 MPa Y316L YNiCr-3 SUS316L -600 -700 MPa STPT370 -300 MPa SP SUS316L joint of dissimilar welded joint. Fig. 9 Residual stress change of inner surface by 0.3% compressive strain. 350 0.3% - 510 - Fig. 11 SP 350 SP 150 300 MPa Fig. 12 YNiCr-3 SP SP 100 300 MPa 100 MPa ?1 FEM ? SP 1) 200 MPa SP SUS316L -500 -600 MPa 2) SP SUS316L -600 -700 MPa STPT370 -300 MPa (a) Filler wire: Y316L (b) Filler wire: YNiCr-3 Fig. 11 Residual stress change of outer surface by heat treatment at 350 °C. - 511 - 3) SP 350 0.3% 100 300 MPa 100 MPa ““ J-PARC MLF BL19 TAKUMI 2015P0401 (a) Stress loading history (b) Distribution of inner residual strain Fig. 12 Change of inner residual strain by stress loading. [1] X X 2002 ― JSMS-SD-5-02 [2] M M2009 CD-ROM pp.340-342. [3] WJP ?59 2010 pp.307-308. [4] 止 ““ ?7 2010 pp.568-571. [5] Vol.11 No.4 2013 pp.69-76. [6] y Vol.60 No.7 2011 pp.617-623. - 512 -“ “応力改善工法で付与した圧縮残留応力の持続性評価-ショットピーニングを施した溶接継手の熱サイクル及び応力負荷による残留応力変化（第2報）“ “西川 聡,Satoru NISHIKAWA,古川 敬,Takashi FURUKAWA,秋田 貢一,Koichi AKITA,鈴木 裕士,Hiroshi SUZUKI,諸岡 聡,Satoshi MOROOKA, ハルヨ ステファヌス,Stefanus HARJO,柴原 正和,Masakazu SHIBAHARA,生島 一樹,Kazuki IKUSHIMA,木谷 悠二,Yuji KITANI,山田 祐介,Yusuke YAMADA