MXPA97004316A - Low-alloy steel powders for hardening sinterizac - Google Patents
Low-alloy steel powders for hardening sinterizacInfo
- Publication number
- MXPA97004316A MXPA97004316A MXPA/A/1997/004316A MX9704316A MXPA97004316A MX PA97004316 A MXPA97004316 A MX PA97004316A MX 9704316 A MX9704316 A MX 9704316A MX PA97004316 A MXPA97004316 A MX PA97004316A
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- chromium
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- 239000000843 powder Substances 0.000 title claims abstract description 78
- 229910000851 Alloy steel Inorganic materials 0.000 title description 7
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims abstract description 41
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 29
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 28
- 239000001301 oxygen Substances 0.000 claims abstract description 28
- MYMOFIZGZYHOMD-UHFFFAOYSA-N oxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 claims abstract description 28
- 239000010959 steel Substances 0.000 claims abstract description 28
- 239000011651 chromium Substances 0.000 claims abstract description 25
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 23
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 23
- 239000011572 manganese Substances 0.000 claims abstract description 23
- VYZAMTAEIAYCRO-UHFFFAOYSA-N chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims abstract description 22
- PWHULOQIROXLJO-UHFFFAOYSA-N manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims abstract description 22
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 20
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 16
- ZOKXTWBITQBERF-UHFFFAOYSA-N molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims abstract description 15
- 239000011733 molybdenum Substances 0.000 claims abstract description 15
- 239000000203 mixture Substances 0.000 claims abstract description 10
- 238000004663 powder metallurgy Methods 0.000 claims abstract description 7
- 239000000956 alloy Substances 0.000 claims description 42
- 229910045601 alloy Inorganic materials 0.000 claims description 41
- OKTJSMMVPCPJKN-UHFFFAOYSA-N carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 32
- REDXJYDRNCIFBQ-UHFFFAOYSA-N aluminium(3+) Chemical class [Al+3] REDXJYDRNCIFBQ-UHFFFAOYSA-N 0.000 claims description 31
- 229910052799 carbon Inorganic materials 0.000 claims description 26
- 238000000034 method Methods 0.000 claims description 11
- CWYNVVGOOAEACU-UHFFFAOYSA-N fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 claims description 8
- 229910002804 graphite Inorganic materials 0.000 claims description 7
- 239000010439 graphite Substances 0.000 claims description 7
- 229910052802 copper Inorganic materials 0.000 claims description 6
- 239000010949 copper Substances 0.000 claims description 6
- RYGMFSIKBFXOCR-UHFFFAOYSA-N copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 6
- 239000002245 particle Substances 0.000 claims description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 6
- 238000000889 atomisation Methods 0.000 claims description 5
- 239000000314 lubricant Substances 0.000 claims description 4
- 238000010306 acid treatment Methods 0.000 claims description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims 2
- 239000008188 pellet Substances 0.000 claims 2
- 229910052742 iron Inorganic materials 0.000 claims 1
- 238000010310 metallurgical process Methods 0.000 claims 1
- 238000004519 manufacturing process Methods 0.000 abstract description 4
- 229910052751 metal Inorganic materials 0.000 abstract description 4
- 239000002184 metal Substances 0.000 abstract description 4
- 238000005245 sintering Methods 0.000 description 16
- 230000000694 effects Effects 0.000 description 15
- 238000005056 compaction Methods 0.000 description 9
- 238000005275 alloying Methods 0.000 description 6
- 238000000137 annealing Methods 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 238000005496 tempering Methods 0.000 description 4
- 230000003321 amplification Effects 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000003199 nucleic acid amplification method Methods 0.000 description 3
- 238000009770 conventional sintering Methods 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000006011 modification reaction Methods 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- KREXGRSOTUKPLX-UHFFFAOYSA-N octadecanoic acid;zinc Chemical compound [Zn].CCCCCCCCCCCCCCCCCC(O)=O.CCCCCCCCCCCCCCCCCC(O)=O KREXGRSOTUKPLX-UHFFFAOYSA-N 0.000 description 2
- 230000035939 shock Effects 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- 229910000604 Ferrochrome Inorganic materials 0.000 description 1
- 229910000616 Ferromanganese Inorganic materials 0.000 description 1
- 229910001309 Ferromolybdenum Inorganic materials 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 235000012970 cakes Nutrition 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000005242 forging Methods 0.000 description 1
- 238000005755 formation reaction Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- -1 manganese chromium Chemical compound 0.000 description 1
- 229910000734 martensite Inorganic materials 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000005272 metallurgy Methods 0.000 description 1
- 150000002739 metals Chemical group 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000020477 pH reduction Effects 0.000 description 1
- 238000009700 powder processing Methods 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 230000035882 stress Effects 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
Abstract
A steel powder consisting of a combination of purified steel and pre-alloyed manganese, chromium, molybdenum and nickel. Steel powder is used in the production of metal parts using powder metallurgy. The addition of the pre-alloyed elements results in a metallic part that has greater strength and hardness with a low oxygen content and good compressibility.
Description
LOW-ALLOY STEEL POWDERS FOR HARDENING BY SINTERIZATION
FIELD OF THE INVENTION
The present invention relates to alloying powders, in particular, to compositions of such powders useful for forming metal parts of high hardness by powder metallurgy (P / M), and to processes for making and using such compositions.
BACKGROUND OF THE INVENTION
Powder metallurgy is a process for imparting high pressure to substantially uniform, highly purified, ferrous powders to produce ferrous parts with high densities. The process is also known as "pressure forging". Sintering hardening is a P / M process in which the parts of P / M are partially or completely transformed into martensite during the cooling phase of a sintering cycle. Both in P / M and in sintering hardening, minor amounts of secondary metals are typically added to the base P / M material.
REF: 24900
improve its hardenability or hardenability. To achieve optimum hardenability or tempering, prealloying techniques are preferred for elemental additions. Manganese is added to typical commercial steels in the range of 0.25 to 1.0% to increase strength and hardenability of unalloyed carbon steels. Chromium is also commonly added to improve the hardenability or hardenability, strength and wear resistance of conventional steels. However, in steel powders for use in powder metallurgy, for example powders having an average particle size of 55 to 100 microns, the manganese and chromium contents are generally kept below 0.3% to reduce oxide formation during the annealed, "Design Criteria for the Manufacturing of Low Alloy Steel Powders" ("Projection Criteria for the Manufacture of Low Alloy Steel Powders"), Advances in Powder Metallurgy, vol. 5, 1991, pp. 45-58. Molybdenum and nickel are commonly used in low alloy P / M steel powders because their oxides are easily reduced during the annealing treatment of water sprayed powders. Molybdenum and nickel efficiently
they increase the strength and hardenability of steels, while nickel also increases the strength, toughness and fatigue resistance of steel, S.H. Avner, Introduction to Physical Metallurgy, McGraw-Hill, N.Y., 1974, pp. 349-361. These elements, however, are more expansive than manganese and chromium and are subject to large price variations which has an obvious deterioration effect on the price or value of steel powder or powder steel. Sintering hardening is an attractive technique for the fabrication of superhardness P / M parts because it itself eliminates the need for post-sintering heat treatment, thus significantly reducing processing costs. In addition, the high thermal stresses and distortion of the parts that result from the conventional instantaneous tempering or general tempering are avoided, provided that the dimensional control of the final parts is improved. Prior techniques for producing low alloy steel powders for the application of P / M include acid treatment to remove the oxide layer in US Patent No. 3,764,295 of Hoganas, and the use of high proportion of carbon (0.1 to
0. 70%) in the annealed powder in British Patent No. 1,564,737. In contrast, the present invention eliminates acid treatment or acidification while maintaining oxygen and carbon at low or lower concentrations to improve compressibility and minimize oxidation of the powder during atomization and the annealing process. Because of these parameters, the present invention is capable of producing a steel powder with high hardenability or hardenability and minimum oxygen content.
DESCRIPTION OF THE INVENTION
Therefore, it is an object of the present invention to overcome the drawbacks and disadvantages of prior art, and provide an alloy steel powder with improved hardenability to promote sintering hardening in conventional sintering furnaces. In particular, an object of the present invention is to produce a steel powder having a minimum apparent hardness of 30 HRC after sintering in conventional ovens. A further objective of the present invention is to maintain the compressibility of the powder
above 6.8g / cm3 at 6.2 tons / cma (40 tons / in3) (550 MPa). Another object of the present invention is to reduce the amount of expensive pre-alloying elements such as molybdenum and nickel while still hardening the powder. These objects and others are achieved by: An alloy powder for powder metallurgy, the alloy powder comprises particles having the particle size of 300 microns or less, preferably having an average particle size in the range of 50 to 100 microns and which comprise steel powder with not more than 0.1% by weight of carbon, more preferably less than 0.02% by weight, manganese in the range of 0.3 to 0.9% by weight, more preferably from 0.4 to 0.7% by weight , nickel in the range of 0.8 to 1.5% by weight, more preferably 1.0 to 1.2% by weight, molybdenum in the range of 0.5 to 1.30% by weight, more preferably 0.85 to 1.05% by weight, and chromium content in the range of 0.3 to 0.9% by weight, more preferably 0.4 to 0.7% by weight. Thus, by the addition of pre-alloyed molybdenum, nickel and manganese chromium in the amounts
A steel powder having the desirable properties noted above is achieved or achieved.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 illustrates the factors of multiplication or amplification of hardenability of the alloying elements. Figure 2 illustrates the effect of manganese and chromium on compaction pressure and oxygen content of the powder. Figure 3 illustrates the effect of the oxygen and carbon contents on the compaction pressure. Figure 4 illustrates the variation of the weight per unit volume of an uncooked tablet with the compaction pressure. Figure 5 illustrates the oxygen content of the powder annealed on or in apparent hardness of samples finished sintering or finished to be recovered. Figure 6 illustrates the effect of the weight of the sample or specimen in apparent hardness.
DETAILED DESCRIPTION OF THE PREFERRED MODALITIES
The invention has developed a new, pre-alloyed steel powder with improved hardenability to promote sintering hardening with lower ratios of oxide in conventional sintering furnaces. To evaluate the effect of alloying elements on sinterability of different materials, a test matrix was designed to conduct the comparative evaluation of various combinations of molybdenum, nickel, manganese and chromium concentrations in steel powders atomized with water. Following atomization and top-down or low-water processing, the experimental steel powders were mixed with graphite, copper and lubricant, pressed or compressed at 6.8 g / cm3 and sintered at 1120 ° C and rebounded or hardened 1 hour at 205 ° C. Additions of manganese and chromium were found to improve the hardenability or hardenability of low alloy steel powders.
EXPERIMENTAL PROCEDURE
Alloy elements can be used in different combinations to increase the hardenability of steels. In Figure 1, the hardening amplification or amplification factor is described in The Making, Shaping and Treating of Steel, 9a. edition, United States Steel Corporation, 1971, p. 1136, is used to illustrate the hardening effect of molybdenum, manganese, nickel and chromium concentrations. As illustrated, manganese has the most pronounced effect on hardenability followed by molybdenum, chromium and nickel. However, both molybdenum and nickel are expansive alloying elements, the present invention replaces a certain amount with manganese and chromium. However, manganese and chromium are oxidized or calcined during powder processing and consequently the compressibility and sintering properties of the resulting conglomerates deteriorate. To quantify the effects of the alloying elements on the properties of P / M steels, a series of experimental powders were prepared using an induction furnace with a capacity of 200 kg. The high purity steel was remelted with ferromanganese,
ferrochrome, ferromolybdenum and nickel to achieve the chemistry of the steel as shown in Table 1 below. TABLE 1
Ref. (1) is Atomet 4601 powder, commercial.
After atomization with water in a
Inert atmosphere (nitrogen), the powder alloys were dried, sieved, annealed and the sintered cake was pulverized and homogenized in a mixer prior to evaluation. The different powder alloys were analyzed by chemical composition and mixed with 0.8% graphite, 2% copper and 0.75% zinc stearate (in the attached tables and throughout the text, "%" and "% by weight" indicate the percentage by weight). Samples or test specimens were pressed or compressed in the form of rectangular blocks at 6.8 g / cm 3 and sintered for 25 minutes at 1120 ° C in a nitrogen / hydrogen atmosphere in a ratio of 90/10 and reverted one hour in air at 205 ° C. The transverse rupture strength was evaluated according to MPIF standard 41 while the tensile properties were determined using round machined samples according to MPIF standard 10. Finally, the shock resistance was measured according to MPIF standard 41. The standards are based on Materials Standards for Structural Parties of P / M, Metal Powder Industries Federation, 1994, pp. 14-15. Additional tests were carried out on samples
or specimens of discs of 10.16 cm (four inches) in diameter weighing 450, 895 and 1345 g to evaluate the effect of the size of the samples on the apparent hardness and microstructure. For this part of the study, mixtures containing 1.0% graphite, 2% copper and 0.75% zinc stearate were prepared from the alloys of tests 1, 3, 4 and 5 and from a commercial powder metallurgical alloy Atomet 4601 which was used as a reference. These were compressed at 6.8 g / cm3, sintered 20 minutes at 1120 ° C in an industrial sintering furnace using a cooling rate of either 0.75 ° C / s or 1.5 ° C / s in the range of 870 to 650 ° C .
RESULTS AND DISCUSSION
The chemical, physical, uncooked and sintering properties of the experimetal alloys are shown in Table 2 below. In Table 2, the parameters C, O, S, Ni, Mo, Mn, Cr, Mesh + 100, Mesh-325, Dens. Approx. and Flow refer to the alloy powder; Compaction and Resistance pressure before sintering refer to uncooked or non-sintered conglomerates prepared from the alloy powder
mixed with graphite, copper and lubricant; and the equilibrium of the parameters refers to the sintered conglomerate. The effect of manganese and chromium concentrations on compaction pressure and oxygen content is illustrated in Figure 2. To eliminate the effect of carbon content on annealed powder on compressibility, only the alloy with less than 0.01% of carbon was taken for the analysis. It was determined that the oxygen content was increased linearly with manganese and chromium contents. The same relation exists for the compaction pressure. To keep the oxygen content to less than 0.25%, the sum of manganese and chromium should be maintained at less than 1.0%. For these levels of manganese and chromium, the compaction pressure of less than 5.58 tons / cm (36 tons / in3) to 6.8 g / cm3 can be achieved. This result of compressibility is even better than that of the commercial powder Atomet 4601 which has a hardenability factor significantly lower than the experimental powder, 8.3 against more than 20 for the experimental powders. Figure 3 illustrates the effect of carbon and oxygen concentrations in the dust
annealing of the experimental powders. The compaction pressure increases with the carbon and oxygen contents of the annealed powders. To reduce the compaction pressure to low levels, less than 5.58 tons / cm2 (36 tons / in2), the carbon content must be maintained at less than 0.02%. As well, the oxygen content has to be minimized to optimize the compressibility. However, since the reduction of oxygen during the annealing of the steel powder is controlled by the amount of carbon in the furnace feeder, too low a carbon amount will not allow to reduce the oxides and thus result in a high oxygen content in the oxygen. the annealed powder and consequently a deterioration of the compressibility. On the other hand, too much or too much carbon in the annealed powder will result in a lower oxygen content but this higher carbon content will also deteriorate the compressibility. Since, both elements must be adjusted to allow oxygen reduction while maintaining the carbon content in the powder annealed to less than 0.02%. As illustrated in Figure 4, maintaining the carbon content at less than 0.02% and the oxygen content at less than 0.25%, the
Low alloy, new, exhibits a compressibility similar to commercial Atomet 4601 powder with, however, a significantly higher hardenability or hardenability. The effect of oxygen content on apparent hardness after sintering and after tempering is illustrated in Figure 5 for alloys with different hardenability or hardenability factors. The apparent hardness decreases with the oxygen content and the rate of reduction is more pronounced for alloys with lower hardenability or hardenability factors. This refers to the reaction of a portion of the graphite present in the sample or specimen with the oxygen in the powder. The reduction of oxygen by carbon results in a lower carbon content in the samples or sintered specimens. This loss of carbon affects the hardenability of the alloy and this effect is more pronounced in alloys with lower hardenability. Accordingly, in order to optimize the hardenability of the powder steel, the oxygen content of the annealed powder has to be minimized. As previously mentioned, lower oxygen contents are ensured by adequate control of the carbon content in the powder prior to annealing.
Figure 6 illustrates the effect of sample or specimen weight on apparent hardness after sintering measured in the cross section of samples or disc specimens made from rapidly cooled alloys # 1, 3, 4, 5, 5 and for a commercial FLC4608 alloy. The hardenability factor of these alloys were respectively 22, 29, 23, 30 and 8. It can be seen that for the 450 g samples, the sintered alloys without fast cooling speed respond in a similar way to the sintering hardening with values of Apparent hardness in the range of 31 to 35 HRC. However, since the weight of the sample reaches 895 g, the apparent hardness of the sample or specimen FLC4608 falls much to values in the range of 10 to 15 HRC which are at least half of those of the experimental powders. For the latter, the apparent hardness decreases linearly with the weight of the sample or specimen by approximately 1 HRC for each 100 g increment of the sample weight. It also becomes apparent that the # 5 cooled alloy rapidly shows the largest or highest apparent hardness for the 450 g sample but the difference is reduced when the weight of the samples
reaches 895 g. To maintain the apparent hardness in metallic parts, the hardenability or hardenability factor must be maintained at values of at least 22. However, to obtain a good alloy robustness for the carbon content in the sintered parts, a factor of more preferably 25, while the oxygen content is maintained at less than 0.25%.
In particular, these results are obtained by maintaining the content of both manganese and chromium in the range of 0.4 to 0.7% by weight, the nickel content in the range of 1.0 to 1.2% by weight (preferably for a ratio or proportion of Ni / Cr of 1.35: 1-2.65: 1), molybdenum in the range of 0.85 to 1.05% by weight to reduce the oxygen content below 0.25% by weight and the hardness, strength, resistance to shock while fixing the nickel content at 1.05 to 1.25% by weight, preferably to maintain a hardenability factor of more than 25. To maintain optimum compressibility, the carbon and oxygen contents of the powder, desirably remain at less than 0.02 and 0.25%, respectively . Although the present invention is illustrated with reference to certain preferred embodiments, it will be appreciated that the present invention is not limited to the specific data described herein. Those skilled in the art will readily appreciate numerous variations and modifications without the spirit and scope of the present invention, and all variations and modifications are intended to be covered by the present invention, which is defined by the following claims.
It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.
Having described the invention as above, the content of the following is claimed as property
Claims (18)
1. A prealloyed ferrous powder comprising iron and at least one alloy material selected from the group consisting of carbon, chromium and manganese, characterized in that the carbon is contained in an amount of not more than 0.1% by weight, and chromium and Manganese are contained in a total amount of at least 0.7% by weight, the ferrous powder has a particle size of not more than 300 microns and an oxygen content of not more than 0.3% by weight.
2. The alloy powder according to claim 1, characterized in that the alloy is an alloy of steel and the carbon is contained in an amount of not more than 0.02% by weight.
3. The alloy powder according to claim 1, characterized in that the alloy contains manganese in the range of 0.3 to 0.9% by weight, chromium in the range of 0.3 to 0.9% by weight, nickel in the range of 0.8 to 1.5% by weight. weight and molybdenum in the range of 0.5 to 1.30% by weight, the alloy has an average particle size of 50 to 100 microns and is produced by atomization with water without acid treatment.
4. The alloy powder according to claim 3, characterized in that the alloy is an alloy of steel and the carbon is contained in an amount of not more than 0.02% by weight.
5. The alloy powder according to claim 4, characterized in that the alloy contains manganese in the range of 0.4 to 0.7% by weight, chromium in the range of 0.4 to 0.7% by weight, nickel in the range of 0.8 to 1.2% by weight. weight and molybdenum in the range of 0.90 to 1.25% by weight.
6. The alloy powder according to any of claims 1-5, 15 or 18, characterized in that the amount of manganese, chromium, molybdenum and nickel in the range of 2.65 to 3.65% by total weight.
7. The alloy powder according to claim 4, characterized in that it has a hardenability factor of at least 22.
8. The alloy powder in accordance with claim 6, characterized in that it has a weight ratio of Ni: Cr in the range of 1.5: 1 to 2.65: 1.
9. A powder mixture according to any of claims 1-5, 15 or 18, characterized in that it also comprises lubricant and at least one of copper or graphite.
10. A powder mixture according to claim 6, characterized in that it also comprises lubricant and at least one of copper and graphite.
11. The powder mixture according to claim 7, characterized in that it achieves a component having a compressibility such that a density of at least 6.8 g / cm3 is reached at a pressure of no more than 6.2 tons / cma (40 tons / in2) .
12. The alloy powder according to claim 8, characterized in that it is produced by atomization of water under an inert atmosphere.
13. A powder metallurgical process, characterized in that it comprises the steps of: selecting a prealloyed ferrous powder according to claim 9; and compressing or concentrating the ferrous powder at a pressure of at least 3.10 tons / cm2 (20 tons / in3) to produce a conglomerate; and sinter the conglomerate or biqueta.
14. A powder metallurgy process characterized in that it comprises the steps of: selecting a prealloyed ferrous powder according to claim 10; and compressing or concentrating the ferrous powder at a pressure of at least 3.10 tons / cm3 (20 tons / in1) to produce a conglomerate; and sinterize the conglomerate.
15. The alloy powder according to claim 5, characterized in that the alloy contains nickel in the range of 0.8 to 1.0% by weight.
16. The process according to claim 13, characterized in that the conglomerate or pellet is sintered at a temperature of at least 1050 ° C.
17. The process according to claim 14, characterized in that the conglomerate or pellet is sintered at a temperature of at least 1050 ° C
18. The alloy powder according to claim 5, characterized in that the nickel is contained in the range of 0.8 to 1.0% by weight and the molybdenum is contained in the range of 0.90 to 1.1% by weight.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08662237 | 1996-06-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| MXPA97004316A true MXPA97004316A (en) | 1998-11-16 |
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