Oxide dispersion-strengthened alloy (ODS), lead-free and free-cutting brass and producing method thereof

Abstract

Oxide dispersion-strengthened alloy (ODS), lead-free and free-cutting brass and producing method thereof. The mass percent of components in the brass are: 52.0%-90.0% of copper, 0.001%-0.99% of phosphorus, 0.15%-0.70% of tin, 0.25%-3.0% of manganese, 0.15%-0.90% of aluminum, 0.10%-1.5% of nickel, 0.191%-0.90% of oxygen, and 0.06%-0.80% of carbon, the ratio of aluminum to oxygen not exceeding 27:24, with the balance being zinc and inevitable impurities, wherein lead is not more than 0.08%. The brass is produced by a powder metallurgy method: brass powder, copper oxide powder, and graphite micro powder are mixed evenly; 0.001%-1.5% of a forming agent is added and mixed evenly with the mixture; and then molded by compression, and sintering are performed before post-treatment.

Claims

1. Oxide dispersion-strengthened alloy (ODS) and free-cutting brass, wherein the mass percent of components in the brass are: 52.0%-90.0% of copper, 0.001%-0.99% of phosphorus, 0.15%-0.70% of tin, 0.25%-3.0% of manganese, 0.15%-0.90% of aluminum, 0.10%-1.5% of nickel, 0.191%-0.90% of oxygen and 0.06%-0.80% of carbon, and the ratio of aluminum to oxygen not exceeding 27:24, with the balance being zinc and inevitable impurities, wherein lead is not more than 0.08%.

2. The oxide dispersion-strengthened alloy (ODS) and free-cutting brass of claim 1, wherein the mass percent of components in the brass are: 54.0%-80.0% of copper, 0.01%-0.79% of phosphorus, 0.15%-0.60% of tin, 0.30%-2.0% of manganese, 0.16%-0.80% of aluminum, 0.12%-1.3% of nickel, 0.20%-0.75% of oxygen, and 0.08%-0.70% of carbon, the ratio of aluminum to oxygen not exceeding 27:24, with the balance being zinc and inevitable impurities, wherein lead is not more than 0.07%.

3. The oxide dispersion-strengthened alloy (ODS) and free-cutting brass of claim 2, wherein the mass percent of components in the brass are: 56.0%-70.0% of copper, 0.01%-0.49% of phosphorus, 0.20%-0.55% of tin, 0.35%-1.5% of manganese, 0.17%-0.70% of aluminum, 0.15%-1.0% of nickel, 0.20%-0.65% of oxygen, and 0.10%-0.60% of carbon, the ratio of aluminum to oxygen not exceeding 27:24, with the balance being zinc and inevitable impurities, wherein lead is not more than 0.06%.

4. The oxide dispersion-strengthened alloy (ODS) and free-cutting brass of claim 3, wherein the mass percent of components in the brass are: 57.0%-68.0% of copper, 0.01%-0.29% of phosphorus, 0.25%-0.50% of tin, 0.40%-1.0% of manganese, 0.18%-0.60% of aluminum, 0.15%-0.6% of nickel, 0.20%-0.59% of oxygen, and 0.15%-0.50% of carbon, the ratio of aluminum to oxygen not exceeding 27:24, with the balance being zinc and inevitable impurities, wherein lead is not more than 0.06%.

5. The oxide dispersion-strengthened alloy (ODS) and free-cutting brass of claim 4, wherein the mass percent of components in the brass are: 57.0%-63.0% of copper, 0.01%-0.10% of phosphorus, 0.30%-0.50% of tin, 0.50%-0.80% of manganese, 0.20%-0.50% of aluminum, 0.20%-0.50% of nickel, 0.22%-0.50% of oxygen, and 0.20%-0.30% of carbon, the ratio of aluminum to oxygen not exceeding 27:24, with the balance being zinc and inevitable impurities, wherein lead is not more than 0.05%.

6. A producing method of the oxide dispersion-strengthened alloy (ODS) and free-cutting brass of claim 1, comprising: A) Cu, Sn, Mn, P, Zn and Al are melted sequentially, then distributed uniformly, then the alloy elements are made into brass powder using water or gas atomization; B) nickel powder, brass powder, copper oxide powder are mixed with graphite micro powder with a particle size of less than 10 m, then the forming agent is added by 0.001%-1.5% to above mixture and is mixed for 0.4-5 h to make the powders uniformly distributed; C) the uniformly mixed powders are molded by compression, then sintered with the following sintering process: the said mixed powders are heated from room temperature to the sintering temperature of 680-780 C. with heating time of 1-5 h and heat preservation time of 30-180 minutes, the forming agent is removed, where the sintering atmosphere is a reducing atmosphere or an inert atmosphere; D) the sintered brass obtained by above step is treated by cold re-press at 500-800 MPa, or by cold-forge at 200-400 MPa, and then re-sintered with the following resintering process: the alloy are heated from room temperature to the re-sintering temperature of 820-870 C. with heating time of 1-3 h and heat preservation time of 30-180 minutes, where the sintering atmosphere is a reducing atmosphere or an inert atmosphere; E) the re-sintered brass is thermally treated at the temperature of 680-870 C.

7. The producing method of claim 6, wherein the forming agent is paraffin powder or stearate powder; and the stearate powder is one of zinc stearate powder, lithium stearate powder, sodium stearate powder, magnesium stearate powder, aluminum stearate powder, potassium stearate powder and calcium stearate powder.

8. The producing method of claim 6, wherein the step E) is conducted by hot die forging, hot extrusion or hot-rolling.

Description

(1) BRIEF DESCRIPTION OF THE DRAWINGS

(2) FIG. 1 shows a chemical component list (weight percentage content) of brass powder prepared in embodiments 1-33;

(3) FIGS. 2A and 2B show a list of weight percentage content of various powder in embodiments 1-33, wherein the amount of copper oxide powder is actual needed amount after oxygen contained in the brass powder is subtracted;

(4) FIGS. 3A and 3B show a producing process parameter list of brass in embodiments 1-33, wherein - indicates that the process is not executed;

(5) FIGS. 4A and 4B are performance lists of the brass in embodiments 1-33;

(6) FIG. 5 shows an ingredient and performance list of brass in a contrast example.

EMBODIMENTS OF THE INVENTION

Detailed Description of the Embodiments

(7) The mass fractions of elements in the brass powder are as follows: 56.0% of copper, 0.11% of phosphorus, 0.20% of tin, 0.50% of manganese, 0.19% of aluminum, and the balance of zinc and unavoidable impurities. The mass fractions of various powder are as follows: the content of graphite micro powder is 0.10%; the content of nickel powder is 0.13%; the content of externally added lithium stearate is 0.5%; the content of oxygen in the brass powder is 0.18%; the content of copper oxide powder is 0.10%; and the balance is the above brass powder. The mixing time of powders is 4.0 h, compressing is performed after the mixing is accomplished, and sintering is performed in a sintering furnace after compressing, wherein the sintering process is as follows: the mixed powders are heated from the room temperature to the sintering temperature of 680 C. for 5.0 h, then held at the temperature for 180 min, the forming agent is removed, the sintering atmosphere being an inert atmosphere, and cooling to the room temperature by water after the sintering is accomplished. The sintered brass rod is re-pressed at a pressure of 500 MPa, and then is re-sintered, wherein the re-sintering process is as follows: the alloy are heated from the room temperature to a sintering temperature of 820 C. for 3.0 h, then held at the temperature for 120 min, the sintering atmosphere being the inert atmosphere. The re-sintered brass is hot extruded at 800 C. The extruded rod is sampled to prepare a tensile strength sample, a cutting performance sample, a dezincification corrosion resistance sample and an ammonia fume stress corrosion sample. The experimental results show that the cutting ability is equivalent to 95% of the lead-brass. The tensile strength is 605.0 MPa, the yield strength is 272.9 MPa, and the average thickness of dezincification layer is 183.1 um, the maximum thickness of dezincification layer is 301.7 m, and no crack is generated after ammonia fume for 16 hours.

Embodiment 2-Embodiment 33

(8) The chemical component (mass percent content) list of the brass powder prepared in embodiments 1-33 is shown in FIG. 1, and the mass percent content list of various powder added in the preparation process of the brass in the embodiments 1-33 is shown in FIGS. 2A and 2B. In all of the embodiments, the forming agent is paraffin powder unless otherwise specified.

(9) The producing process parameter list of the brass in the embodiments 1-33 is shown in figures.

(10) After the completion of the embodiments, the hot extruded rod is sampled to prepare a tensile strength sample, a cutting performance sample, a dezincification corrosion resistance sample and an ammonia fume stress corrosion sample. A hardness test sample and a friction and wear sample are taken from the hot extruded copper-tin alloy-based brass rod, and then hardness tests and friction and wear tests are respectively performed to obtain the performance of the alloy. The performance list of the brass in the embodiments 1-33 is shown in FIGS. 4A and 4B.

(11) A component and performance list of brass in a contrast example is shown in FIG. 5.