Mechanical properties and microstructure of aisi 41B30 forgings in as forged and normalized condition
- 1. MECHANICAL PROPERTIES AND MICROSTRUCTURES OF AISI 41B30 FORGINGS IN AS FORGED AND NORMALIZED CONDITIONS (DUSAN MILICEVIC M.Sc.) (COMMERCIAL FORGED PRODUCTS) (CFP)
- 3. Content • Introduction • Test plan • Results • Discussion • Conclusions • Future work
- 4. Introduction • Upset forged and normalized axles • Upset forgings are forged only on one end at 4000T press at CFP. Forging temperature was 2300⁰F. CFP has induction heating coils. • Batch furnace;1650⁰F /3-5 hours, air cool
- 5. Test Plan • Goal: • To compare as forged and normalized microstructures and properties of AISI 41B30 forgings in effort to improve the quality of the axles. • Test Plan: • Two forgings; one as forged , one normalized • Specimens for mechanical and impact testing were taken from ends of the stems and near the flanges. Only specimens for microstructures were taken from flanges.
- 6. • 1F 2F 3F • 1F 2F 3F • • •1HT 2HT 3HT 1HT 2HT 3HT SAMPLES LOCATION AND DESIGNATION 1F- AS FORGED AT THE END OF STEM 2F- AS FORGED, NEAR THE FLANGE 3F- AS FORGED, FLANGE 1HT- NORMALIZED, END OF STEM 2HT –NORMALIZED NEAR THE FLANGE 3HT- NORMALIZED, FLANGE
- 7. Results • Results of chemistry , hardness, mechanical properties, impact properties and microstructure are presented.
- 8. Chemistry and Segregation C MN P S Si Cu Ni Cr V Mo Al Ti B N 0.32 1.25 0.011 0.03 0.19 0.2 0.2 0.4 0.005 0.16 0.031 0.04 3 0.001 7 0.008 7 0.3 2 0.5 4 0.01 0 0.0 1 0.2 0.1 7 0. 1 1. 05 0.00 4 0.2 3 0.03 0.0 02 0.0 0.00 65 Top row is AISI 41B30 ; bottom row is AISI 4130; red fonts represents a major difference in chemistry between two grades. C Mn P S Si Ni Cr Mo Al Ti B 0.283 1.25 0.011 0.027 0.199 0.196 0.477 0.166 0.049 0.045 0.0032 surface 1F 0.286 1.29 0.012 0.039 0.198 0.205 0.482 0.169 0.037 0.052 0.0023 midradius 1F 0.27 1.22 0.011 0.028 0.197 0.204 0.469 0.158 0.045 0.040 0.0016 core 1F 0.278 1.26 0.011 0.029 0.197 0.198 0.479 0.167 0.045 0.046 0.0030 surface 2F 0.302 1.30 0.012 0.038 0.199 0.204 0.486 0.172 0.038 0.052 0.0031 midradius 2F 0.285 1.26 0.011 0.029 0.195 0.198 0.476 0.164 0.041 0.045 0.0031 core 2F 0.302 1.24 0.011 0.030 0.203 0.196 0.496 0.168 0.067 0.044 0.0033 surface 1H 0.354 1.29 0.013 0.041 0.203 0.201 0.50 0.175 0.051 0.049 0.0035 midradius 1H 0.306 1.25 0.011 0.033 0.199 0.193 0.491 0.168 0.039 0.044 0.0028 core 1H 0.288 1.25 0.011 0.029 0.201 0.196 0.497 0.168 0.037 0.044 0.0026 surface 2H 0.279 1.27 0.011 0.033 0.198 0.196 0.496 0.169 0.034 0.045 0.0029 midradius 2H 0.281 1.23 0.010 0.029 0.197 0.194 0.488 0.164 0.038 0.040 0.0029 core 2H
- 9. Test Number Hardness HRB (HRC) -1F Hardness HRB (HRC) -2F Hardness HRB (HRC) -1HT Hardness HRB (HRC) -2HT Hardness AISI4130 1 99.1 100.0 (22 HRC) 99.3 95.1 100 (22HRC) 2 93.8 100.0 (22HRC) 97.6 97.9 100 (22 HRC) 3 98.4 102.0 (25HRC) 96.7 97.8 102 (25HRC) 4 100.7 (23HRC) 102.2 (25HRC) 100.0 (22HRC) 99.6 102 (25HRC) 5 100.8 (23HRC) 102.5 (25HRC) 99.8 99.6 102 (25HRC) 6 100.9 (23HRC) 101.3 (24HRC) 99.8 100.4 (22HRC) 102 (25HRC) 7 100.4 (23HRC) 102.7 (25HRC) 98.9 100.5 (22HRC) 102 (25HRC) 8 101.2 (24HRC) 102.3 (25HRC) 100.1 (22HRC) 101.0 (24HRC) 100 (22HRC) 9 99.7 104.6 (29HRC) 100.2 (22HRC) 101.4 (24HRC) 100 (22HRC) 10 99.7 101.6 (24HRC) 99.5 100.4 (22HRC) 100 (22HRC) 11 100.5 (23HRC) 103.9 (28HRC) 98.7 100.6 (22HRC) 100 (22HRC) 12 99.2 99.2 99.2 100.9 (22HRC) 100 (22HRC) 13 97.7 103.0 (25HRC) 98.4 100.6 (22HRC) 100 (22HRC) 14 98 101.0 (25HRC) 98.7 101.5 (24HRC) 100 (22HRC) 15 98.2 100.3 (22HRC) 98.2 99.6 100 (22HRC) 16 100.3 (23HRC) 100.2 (22HRC) 95.9 99.7 100 (22HRC) 17 98.1 99.5 99.6 99.6 100 (22HRC) 18 100.5 (23HRC) 102.0 (25HRC) 98.7 98.3 100 (22HRC) 19 97.6 99.9 99.5 100.1 (22HRC) 100 (22HRC) 20 96.5 105.0 (29HRC) 99.5 98.8 100 (22HRC) Hardness results Testing done every 1/8 " of diameter.
- 10. Mechanical Properties Tensile strength psi (MPa) Yield strength psi (MPa) Elongation (%) Reduction in area (%) Sample 118,577 (817) 90,268 (622.3) 18.3 51.31 1F longitudinal 115,125 (793.7) 80,681 (556.2) 16.36 48.6 2F longitudinal 118,774 (818.9) 89,804 (619.17) 17.61 53.21 1HT longitudinal 118,353 (817.5) 84,542 (582.9) 11.24 30.90 1HT transverse 117,061 (807.1) 84,700 (583.9) 8.11 54.33 2HT longitudinal 117,126 (807.5) 84,536 (582,8) 6.77 31.06 2HT transverse 123,000 (848,05) 76,100 (524.69) 9.05 21.4 AISI4130 as rolled longitudinal
- 11. Impact Properties ft- lb (J) ft-lb (J) ft-lb (J) Average ft-lb (J) 4 (5.43) 4 (5.43) 5 (6.77) 4 (5.43) 1F (room temperature) longitudinal 5 (6.77) 4 (5.43) 4 (5.43) 4 (5.43) 2F (room temperature) longitudinal 10 (13.55) 13 (17.6) 11 (14.9) 11 (14.9) 1HT (room temperature) longitudinal 10 (13.5) 10 (13.5) 11 (14.9) 10 (13.5) 2HT (room temperature) longitudinal 9 (12.2) 8 (10.84) 8 (10.84) 8 (10.84) AISI4130(room temperature) longitudinal 6 (8.13) 8 (10.84) 7 (9.49) 7 (9.49) AISI 4130 (room temperature) (transverse)
- 12. Microstructures in as forged and normalized condition • Top row:1F, 2F , and 3 F • Bottom row:1HT, 2HT and 3HT
- 13. Microstructural Difference AISI 41B30 AISI 4130
- 14. Discussion • Small amount ( up to 0.025%) of Boron increases hardenability of steel. As rolled and normalized AISI 41B30 have uniform hardness from surface to the core similar to standard grade. • Segregation of Boron negatively affected impact properties of normalized AISI 41B30.
- 15. Discussion -continuation • Excess amount of Titanium may increase hardenability but reduce impact properties. • Boron suppresses ferrite nucleation at grain boundaries. Presence of ferrite in normalized structure is results of slow cooling rate.
- 16. Discussion -continuation • High cooling rate suppresses Boron segregation and ferrite formation on γ grain boundaries. • Based on 2F and 2HT microstructures, cooling rate after normalizing was slower than after rolling. • .
- 17. Discussion -continuation • Axles might be induction hardened. Strong case and brittle core might not be the best engineering solution.
- 18. Conclusions • As rolled 5.5“ in diameter billet microstructure is very similar to normalized microstructure of AISI 41B30 forgings. • Normalized AISI41B30 microstructure, for axles, is in essence brittle.
- 19. Conclusions-continuation • Normalized structure may stay in the core of axles after induction hardening. • Strong case and brittle core may not be the best solution for dynamically loaded axles.
- 20. Metallurgical lab in CFP
- 21. Future Work • Evaluate as rolled +tempered Widmanstätten microstructure • Evaluate direct quenching in water from the press and self tempering
Editor's Notes
- #2: Enter speaker notes here.
- #3: CFP IS CAPABLE TO FORGE PRODUCTS FROM 8 TO 1100 POUNDS IN CARBON , ALLOY AND STAINLESS STEEL GRADES.PRODUCTION IS SUPPORTED BY STRONG ENGINEERING AND QUALITY DEPARTMENTS.
- #6: Enter speaker notes here.
- #7: 5.5 inch in diam. X 6 inch samples, 37“ overall length , flange diameter near 20"
- #9: Titanium exhibits some positive segregation in midradius location as well as aluminum. Boron exhibits the strongest positive segregation in comparison with ladle analysis.
- #10: Hardness did not differ much regardless of chemistry (standard grade or boron grade) as rolled or normalized condition.
- #11: Normalizing was reducing elongation properties in comparison with as forged properties. Elongation of normalized sample in transvers direction is the worst. As rolled properties of standard AISI 4130 are inferior to boron grade AISI 41B30.
- #12: As rolled impact properties of AISI 41B30 at room temperature were very low. Normalizing doubled the impact properties but still , impact properties were 10-11 ft-lb. Impact properties of standard grade AISI4130 in as rolled condition are better than impact properties of boron grade, in the same condition.
- #13: As forged microstructure is mostly Widmanstätten regardless of location. Normalizing did not change microstructure in stem area . Normalizing created large amount of blocky ferrite and perlite in the flange.
- #14: Left micrographs is AISI41B30 in as rolled condition, surface of the billet, right micrograph is AISI4130 in as rolled condition , surface of the billet, 2% nital , 100 X magnification ;
- #21: Thank you CFP for support