Components for exhaust system, methods of manufacture thereof and articles comprising the same
Disclosed herein is a sintered composition comprising iron; about 0.05 to about 1 wt % molybdenum; about 3 to about 4.5 wt % silicon; about 0.05 to about 0.5 wt % chromium; about 0.011 to about 0.015 wt % magnesium; all weight percents being based on the total weight of the composition; the composition being devoid of carbon except for trace amounts; and wherein the composition is sintered. Disclosed herein too is a method comprising blending a powdered composition that comprises iron; about 0.05 to about 1 wt % molybdenum; about 3 to about 4.5 wt % silicon; about 0.05 to about 0.5 wt % chromium; about 0.011 to about 0.015 wt % magnesium; all weight percents being based on the total weight of the composition; the composition being devoid of carbon except for trace amounts; compacting and sintering the composition.
1. A sintered composition comprising:
iron;
about 0.05 to about 1 wt % molybdenum,
about 3 to about 4.5 wt % silicon;
about 0.05 to about 0.5 wt % chromium;
about 0.011 to about 0.015 wt % magnesium; all weight percents being based on the total weight of the composition; the composition being devoid of carbon except for trace amounts; and wherein the composition is sintered.
2. The sintered composition of claim 1 , wherein the composition is compacted.
3. The sintered composition of claim 1 , wherein the molybdenum is present in an amount of about 0.75 to about 0.95 wt %, based on the total weight of the composition.
4. The sintered composition of claim 1 , wherein the molybdenum is added in the form of powder prior to compaction and sintering; the powder consisting of only molybdenum.
5. The sintered composition of claim 1 , wherein the molybdenum is added in the form of an atomized masteralloy powder prior to compaction and sintering.
6. The sintered composition of claim 1 , wherein the silicon is present in an amount of about 3.1 to about 4.0 wt %, based on the total weight of the composition.
7. The sintered composition of claim 1 , wherein the silicon is added in the form of a powder prior to compaction and sintering; the powder consisting of only silicon.
8. The sintered composition of claim 1 , wherein the silicon is not added in the form of a ferro-silicon masteralloy.
9. The sintered composition of claim 1 , wherein the silicon has an average particle size of about 37 to about 210 micrometers.
10. The sintered composition of claim 1 , wherein the silicon has an average particle size of about 44 to about 150 micrometers.
11. The sintered composition of claim 1 , wherein the chromium is present in an amount of about 0.15 to about 0.3 wt %.
12. The sintered composition of claim 1 , wherein the chromium is added in the form of powder prior to compaction and sintering; the powder consisting of only chromium.
13. The sintered composition of claim 1 , wherein the chromium is added in the form of an atomized masteralloy powder prior to compaction and sintering.
14. The sintered composition of claim 1 , wherein the magnesium is present in an amount of about 0.011 to about 0.015 wt %.
15. The sintered composition of claim 1 , wherein the magnesium is added in the form of powder prior to compaction and sintering; the powder consisting of only magnesium.
16. The sintered composition of claim 1 , where is magnesium is added as an atomized alloyed iron-magnesium masteralloy to the sintered composition.
17. A method comprising:
blending a powdered composition that comprises:
iron;
about 0.05 to about 1 wt % molybdenum,
about 3 to about 4.5 wt % silicon;
about 0.05 to about 0.5 wt % chromium;
about 0.011 to about 0.015 wt % magnesium; all weight percents being based on the total weight of the composition; the composition being devoid of carbon except for trace amounts; the powders all having a particle size less than (−70) mesh;
press compacting the composition; and
sintering the composition.
18. The method of claim 17 , wherein the pressure employed during the press compacting is about 35 to about 55 tons per square inch and wherein the temperature during the press compacting is about 73° F. to about 170° F.
19. The method of claim 17 , wherein the sintering comprises de-lubrication, high-temperature consolidation and cooling segments.
20. The method of claim 19 , wherein the de-lubrication segment of sintering is carried out at a temperature of up to 2095° F. in an atmosphere comprising hydrogen, an oxidizing agent, and inert gases.
21. The method of claim 19 , wherein the de-lubrication is carried out in a separate thermal device.
22. The method of claim 19 , where the high-temperature consolidation segment of sintering is conducted at a temperature of about 2100° F. to about 2530° F.
23. The method of claim 19 , where the high-temperature sintering consolidation segment of sintering is conducted at a temperature of about 2350° F. to about 2450° F. for a time period of about 20 to about 90 minutes.
24. The method of claim 19 , where the high-temperature thermal consolidation segment of sintering is conducted at temperature of about 2400° F. for about 55 minutes.
25. The method of claim 19 , wherein high-temperature thermal consolidation sintering segment of composition is performed in a reducing atmosphere that is devoid of carbonaceous gases.
26. The method of claim 19 , wherein the high-temperature thermal consolidation segment of sintering is carried out in a mixture of reducing gases and inert gases at a heat rate about 175° F./minute to about 215° F./minute.
27. The method of claim 19 , wherein the high-temperature thermal consolidation segment of sintering is carried out in a reducing gas atmosphere consisting of hydrogen.
28. The method of claim 19 , wherein the cooling segment of sintering is conducted in a reducing atmosphere.
29. The method of claim 19 , wherein the cooling segment of sintering is conducted in a mixture of a reducing atmosphere and an inert atmosphere.
30. The method of claim 19 , wherein the cooling segment of sintering is conducted in a reducing atmosphere without any carbonaceous gas.
31. The method of claim 19 , wherein the cooling segment of sintering is conducted in an atmosphere that consists of hydrogen gas.
32. The method of claim 19 , wherein the cooling segment is conducted at a cooling rate of about 35° F./minute to about 65° F./minute.
33. An article manufactured from the sintered composition of claim 1 .
34. The article of claim 33 , wherein the article is an exhaust system component.
35. The article of claim 33 , wherein the article is a flange for an exhaust system.
36. The article of claim 33 , wherein article is a boss for an exhaust system.
37. The article of claim 33 , wherein the article is a turbocharger component.
38. An article manufactured by the method of claim 17 and having a composition comprising:
iron;
about 0.05 to about 1 wt % molybdenum,
about 3 to about 4.5 wt % silicon;
about 0.05 to about 0.5 wt % chromium;
about 0.011 to about 0.015 wt % magnesium; all weight percents being based on the total weight of the composition; the composition being devoid of carbon except for trace amounts.