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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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Presentation on theme: "1 ASTM E28.04 Workshop Len Manning, Dofasco Affect of Proposed Changes on the Mechanical Properties of Low Carbon and HSLA Steels."— Presentation transcript:

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

2 2 Dofasco - Study Set Up Materials Used - Low C steel - 0.02 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.

3 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.

4 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

5 5 Dofasco - Low Carbon Steel N = 15 CurrentNew E8-3New E8-2Diff. YieldAverage29.3428.8428.720.62 (ksi)Stdev0.4470.4770.636 TensileAverage42.3542.6342.400.28 (ksi)Stdev0.1590.1460.149 ElongationAverage45.3144.7745.560.79 (%)Stdev1.1200.6911.077

6 6 Dofasco - HSLA Steel N = 15 CurrentNew E8-3New E8-2Diff. YieldAverage52.1751.3251.450.85 (ksi)Stdev0.6591.0401.251 TensileAverage68.8768.9868.630.35 (ksi)Stdev0.3950.4300.635 ElongationAverage27.6528.0028.040.39 (%)Stdev0.3700.3660.480

7 7 Dofasco - Low Carbon - Yield Strength - One-way ANOVA Source DF SS MS F P Factor 2 3.213 1.606 5.79 0.006 Error 42 11.658 0.278 Total 44 14.871 S = 0.5269 R-Sq = 21.60% R-Sq (adj.) = 17.87% Individual 95% CIs For Mean Based on Pooled StDev Level N Mean StDev --+---------+---------+---------+------- YS-CU 15 29.339 0.447 (--------*--------) YS-E3 15 28.839 0.477 (--------*--------) YS-E2 15 28.724 0.636 (--------*---------) --+---------+---------+---------+------- 28.50 28.80 29.10 29.40 Pooled StDev = 0.527

8 8 Dofasco - Low Carbon - Tensile Strength - One-way ANOVA Source DF SS MS F P Factor 2 0.6534 0.3267 14.14 0.000 Error 42 0.9702 0.0231 Total 44 1.6236 S = 0.1520 R-Sq = 40.25% R-Sq (adj.) = 37.40% Individual 95% CIs For Mean Based on Pooled StDev Level N Mean StDev -------+---------+---------+---------+-- TS-CU 15 42.353 0.160 (-----*------) TS-E3 15 42.629 0.146 (-----*------) TS-E2 15 42.399 0.149 (-----*------) -------+---------+---------+---------+-- 42.36 42.48 42.60 42.72 Pooled StDev = 0.152

9 9 Dofasco - Low Carbon - Elongation - One-way ANOVA Source DF SS MS F P Factor 2 4.925 2.462 2.55 0.090 Error 42 40.499 0.964 Total 44 45.424 S = 0.9820 R-Sq = 10.84% R-Sq (adj.) = 6.60% Individual 95% CIs For Mean Based on Pooled StDev Level N Mean StDev -----+---------+---------+---------+---- EL-CU 15 45.317 1.120 (---------*----------) EL-E3 15 44.767 0.691 (---------*----------) EL-E2 15 45.557 1.077 (---------*---------) -----+---------+---------+---------+---- 44.50 45.00 45.50 46.00 Pooled StDev = 0.982

10 10 Dofasco - HSLA - Yield Strength - One-way ANOVA Source DF SS MS F P Factor 2 5.94 2.97 2.89 0.068 Error 39 40.07 1.03 Total 41 46.00 S = 1.014 R-Sq = 12.91% R-Sq (adj.) = 8.44% Individual 95% CIs For Mean Based on Pooled StDev Level N Mean StDev -----+---------+---------+---------+---- YS-CU 14 52.174 0.659 (---------*----------) YS-E3 14 51.321 1.041 (----------*----------) YS-E2 14 51.446 1.251 (----------*----------) -----+---------+---------+---------+---- 51.00 51.50 52.00 52.50 Pooled StDev = 1.014

11 11 Dofasco - HSLA - Tensile Strength - One-way ANOVA Source DF SS MS F P Factor 2 0.903 0.451 1.82 0.175 Error 39 9.670 0.248 Total 41 10.573 S = 0.4980 R-Sq = 8.54% R-Sq (adj.) = 3.85% Individual 95% CIs For Mean Based on Pooled StDev Level N Mean StDev ------+---------+---------+---------+--- TS-CU 14 68.868 0.395 (----------*---------) TS-E3 14 68.982 0.430 (---------*----------) TS-E2 14 68.630 0.635 (----------*----------) ------+---------+---------+---------+--- 68.50 68.75 69.00 69.25 Pooled StDev = 0.498

12 12 Dofasco - HSLA - Elongation - One-way ANOVA Source DF SS MS F P Factor 2 1.268 0.634 3.80 0.031 Error 39 6.505 0.167 Total 41 7.772 S = 0.4084 R-Sq = 16.31% R-Sq (adj.) = 12.02% Individual 95% CIs For Mean Based on Pooled StDev Level N Mean StDev ---+---------+---------+---------+------ Elong-CU 14 27.653 0.370 (--------*--------) Elong-E3 14 27.996 0.366 (--------*--------) Elong-E2 14 28.042 0.480 (--------*--------) ---+---------+---------+---------+------ 27.50 27.75 28.00 28.25 Pooled StDev = 0.408

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

14 14 Dofasco - Average Values Against Initial Testing Speed

15 15 Dofasco - Average Values Against Final Testing Speed

16 16 Dofasco - Average Values Against Initial Testing Speed

17 17 Dofasco - Average Values Against Final Testing Speed

18 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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