Ferritic ductile cast iron alloys having high carbon content, high silicon content, low nickel content and formed without annealing
Disclosed are methods of making ferritic ductile iron castings (60-40-18) with high toughness (6 ft.lb minimum Charpy V at −20 F and 10 ft.lb minimum Charpy V at +72 F), without adding Nickel and without annealing.
1. A cast iron alloy having:
a toughness of at least 6 ft. lb Charpy V at −20° F. and a toughness of at least 10 ft. lb Charpy V at +72° F.;
a tensile strength of at least 60,000 psi;
a yield strength of at least 40,000 psi; and
an elongation of at least 18%;
the alloy comprising:
(a) 3.30-3.85% Carbon by mass;
(b) 2.35-2.90% Silicon by mass;
(c) 0.020-0.060% nodularizing agent by mass;
(d) 0-0.40% Manganese by mass;
(e) 0-0.15% Copper by mass;
(f) 0-0.10% Chromium by mass;
(g) 0-0.050% Phosphorus by mass;
(h) 0-0.030% Sulfur by mass;
(i) 0-0.25% Nickel by mass;
(j) 0-0.10% any other incidental non-ferrous impurities by mass; and
(k) balance up to 100% of Iron;
wherein the cast iron alloy is prepared by a process comprising the steps of casting the iron alloy in a mold and cooling the cast iron alloy in the mold at a rate of no more than about 600° F./h, wherein the process does not include annealing.
2. The alloy of claim 1 , comprising 3.50-3.65% Carbon by mass.
3. The alloy of claim 1 , comprising 2.40-2.60% Silicon by mass.
4. The alloy of claim 1 , wherein the nodularizing agent is Magnesium present at a concentration of 0.025-0.045% by mass.
5. The alloy of claim 4 , comprising 0.030-0.035% Magnesium by mass.
6. The alloy of claim 1 , comprising 0.15-0.25% Manganese by mass.
7. The alloy of claim 1 , comprising 0-0.10% Copper by mass.
8. The alloy of claim 1 , comprising 0-0.020% Phosphorus by mass.
9. The alloy of claim 1 , comprising 0-0.015% Sulfur by mass.
10. The alloy of claim 1 , comprising 0-0.20% Nickel by mass.
11. The alloy of claim 1 , comprising 0-0.15% Nickel by mass.
12. The alloy of claim 1 , comprising 0-0.10% Nickel by mass.
13. The alloy of claim 1 , comprising 0-0.05% Nickel by mass.
14. A process for making a cast iron alloy, the alloy having a toughness of at least 6 ft.lb Charpy V at −20° F. and a toughness of at least 10 ft.lb Charpy V at +72° F.; the alloy having a tensile strength of at least 60,000 psi; the alloy having a yield strength of at least 40,000 psi; and the alloy having an elongation of at least 18%;
the process comprising:
(a) casting the iron alloy in a mold, the alloy comprising:
(i) 3.30-3.85% Carbon by mass;
(ii) 2.35-2.90% Silicon by mass;
(iii) 0.020-0.060% nodularizing agent by mass;
(iv) 0-0.40% Manganese by mass;
(v) 0-0.15% Copper by mass;
(vi) 0-0.10% Chromium by mass;
(vii) 0-0.050% Phosphorus by mass;
(viii) 0-0.030% Sulfur by mass;
(ix) 0-0.25% Nickel by mass;
(x) 0-0.10% any other incidental non-ferrous impurities by mass; and
(xi) balance up to 100% of Iron;
(b) cooling the cast iron alloy in the mold at a rate of no more than about 600° F./h;
wherein the process does not include annealing.
15. The process of claim 14 , comprising cooling the cast iron alloy in the mold at a rate of no more than about 500° F./h.
16. The process of claim 14 , comprising cooling the cast iron alloy in the mold at a rate of no more than about 300° F./h.
17. The process of claim 14 , wherein the alloy comprises 3.50-3.65% Carbon by mass.
18. The process of claim 14 , wherein the alloy comprises 2.40-2.60% Silicon by mass.
19. The process of claim 14 , wherein the nodularizing agent is Magnesium present at a concentration of 0.025-0.045% by mass.
20. The process of claim 19 , wherein the alloy comprises 0.030-0.035% Magnesium by mass.
21. The process of claim 14 , wherein the alloy comprises 0.15-0.25% Manganese by mass.
22. The process of claim 14 , wherein the alloy comprises 0-0.10% Copper by mass.
23. The process of claim 14 , wherein the alloy comprises 0-0.0.20% Phosphorus by mass.
24. The process of claim 14 , wherein the alloy comprises 0-0.015% Sulfur by mass.
25. The process of claim 14 , wherein the alloy comprises 0-0.20% Nickel by mass.
26. The process of claim 14 , wherein the alloy comprises 0-0.15% Nickel by mass.
27. The process of claim 14 , wherein the alloy comprises 0-0.10% Nickel by mass.
28. The process of claim 14 , wherein the alloy comprises 0-0.05% Nickel by mass.