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1 ASTM E28.04 Workshop Len Manning, Dofasco Affect of Proposed Changes on the Mechanical Properties of Low Carbon and HSLA Steels

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2 Dofasco - Study Set Up Materials Used - Low C steel C, 0.30 Mn, 30ksi Yield - HSLA steel – 0.06 C, 0.65 Mn, 0.02 Cb, 50 ksi Yield Sample Prep – all tensile coupons of each material cut from one sample sheet. – E8 Sheet type specimens prepared – all pieces milled by the same operator, on the same milling center, at the same time.

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3 Dofasco - Study Set Up Sample Testing – Verification standards run before and after study pieces – All specimen measurements conducted by one operator – All tests conducted by one operator on the same day, using one test frame. – Testing using the various speeds was conducted in random order.

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4 Dofasco - Study Set Up Testing Speeds – Three test speed set ups were used 0.16/min. until 5% strain, 1.00/min. until fracture Current lab practice 0.03/min. until 5% strain, 0.9/min. until fracture New E8 – based on minimum parallel length specimen (2.25) 0.045/min. until 5% strain, 1.35/min until fracture New E8 – based on 3 parallel length specimen

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5 Dofasco - Low Carbon Steel N = 15 CurrentNew E8-3New E8-2Diff. YieldAverage (ksi)Stdev TensileAverage (ksi)Stdev ElongationAverage (%)Stdev

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6 Dofasco - HSLA Steel N = 15 CurrentNew E8-3New E8-2Diff. YieldAverage (ksi)Stdev TensileAverage (ksi)Stdev ElongationAverage (%)Stdev

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7 Dofasco - Low Carbon - Yield Strength - One-way ANOVA Source DF SS MS F P Factor Error Total S = R-Sq = 21.60% R-Sq (adj.) = 17.87% Individual 95% CIs For Mean Based on Pooled StDev Level N Mean StDev YS-CU ( * ) YS-E ( * ) YS-E ( * ) Pooled StDev = 0.527

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8 Dofasco - Low Carbon - Tensile Strength - One-way ANOVA Source DF SS MS F P Factor Error Total S = R-Sq = 40.25% R-Sq (adj.) = 37.40% Individual 95% CIs For Mean Based on Pooled StDev Level N Mean StDev TS-CU (-----*------) TS-E (-----*------) TS-E (-----*------) Pooled StDev = 0.152

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9 Dofasco - Low Carbon - Elongation - One-way ANOVA Source DF SS MS F P Factor Error Total S = R-Sq = 10.84% R-Sq (adj.) = 6.60% Individual 95% CIs For Mean Based on Pooled StDev Level N Mean StDev EL-CU ( * ) EL-E ( * ) EL-E ( * ) Pooled StDev = 0.982

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10 Dofasco - HSLA - Yield Strength - One-way ANOVA Source DF SS MS F P Factor Error Total S = R-Sq = 12.91% R-Sq (adj.) = 8.44% Individual 95% CIs For Mean Based on Pooled StDev Level N Mean StDev YS-CU ( * ) YS-E ( * ) YS-E ( * ) Pooled StDev = 1.014

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11 Dofasco - HSLA - Tensile Strength - One-way ANOVA Source DF SS MS F P Factor Error Total S = R-Sq = 8.54% R-Sq (adj.) = 3.85% Individual 95% CIs For Mean Based on Pooled StDev Level N Mean StDev TS-CU ( * ) TS-E ( * ) TS-E ( * ) Pooled StDev = 0.498

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12 Dofasco - HSLA - Elongation - One-way ANOVA Source DF SS MS F P Factor Error Total S = R-Sq = 16.31% R-Sq (adj.) = 12.02% Individual 95% CIs For Mean Based on Pooled StDev Level N Mean StDev Elong-CU ( * ) Elong-E ( * ) Elong-E ( * ) Pooled StDev = 0.408

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13 Dofasco - Practical Implications for Production Test Labs Lab Throughput, turn around time, equipment needs Product Specification Conformance checking Manufacturing Design capability

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14 Dofasco - Average Values Against Initial Testing Speed

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15 Dofasco - Average Values Against Final Testing Speed

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16 Dofasco - Average Values Against Initial Testing Speed

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17 Dofasco - Average Values Against Final Testing Speed

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18 Dofasco - Summary Some statistical differences Little practical difference for production type labs May be a significant difference based on specific situations – i.e. – Research Significant affect on test time

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