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CN-116770126-B - Chip-breaking single-phase brass and preparation method thereof

CN116770126BCN 116770126 BCN116770126 BCN 116770126BCN-116770126-B

Abstract

The invention discloses a chip-breaking single-phase brass which is characterized by comprising, by weight, 64-70wt% of Cu, 0.003-0.06wt% of Pb, 0.005-0.15wt% of Ce, 0.005-0.1wt% of P, 0.01-0.15wt% of As0.01 and the balance of Zn and unavoidable impurities. The invention also discloses a preparation method of the chip-breaking single-phase brass. Compared with the prior art, the chip-breaking single-phase brass has good cutting processability.

Inventors

  • YE DONGHUANG
  • ZHENG ENQI
  • HUA CHENGWEN
  • FU JIE

Assignees

  • 宁波金田铜业(集团)股份有限公司

Dates

Publication Date
20260508
Application Date
20230621

Claims (6)

  1. 1. The chip-breaking single-phase brass is characterized by comprising, by weight, 64-70wt% of Cu, 0.003-0.06 wt% of Pb, 0.005-0.15wt% of Ce, 0.005-0.1wt% of P, 0.01-0.15wt% of As and the balance of Zn and unavoidable impurities; the process flow of the chip-breaking single-phase brass comprises smelting, horizontal continuous casting, extrusion, peeling, stretching, annealing, stretching a finished product and annealing at a low temperature; The preparation method of the chip-breaking single-phase brass comprises the following steps: 1) Smelting, namely, proportioning according to required components, smelting in a smelting furnace, wherein the smelting temperature is 950-1150 ℃, pouring the converter into a heat preservation furnace for heat preservation after all metals are molten and the tested components are qualified, and the heat preservation temperature is 1010-1130 ℃, namely the casting temperature; 2) Horizontal continuous casting: ingot casting specification phi 80-300 mm, traction time 1-7 s, traction pitch 1-10 mm, dwell time 0.1-3 s, the reverse pushing time is 0.1-3 s, the reverse pushing pitch is 0.5-4 mm, stopping time is 0.1-3 s, and sawing length of the cast ingot is 300-160 mm; 3) The extrusion temperature of the brass is determined according to the Cu content, wherein the Cu content is 64-66wt%, the extrusion temperature is 640-700 ℃, the Cu content is 66-68wt%, the extrusion temperature is 680-740 ℃, the Cu content is 68-70wt%, the extrusion temperature is 720-780 ℃, the extrusion flow number is 1-3, the extrusion ratio is 30-500, the extrusion speed is 2-18 mm/s, and the wire winding mode is wire coiling or straight strip; 4) Peeling, namely stretching an extrusion blank for one pass before peeling, wherein the processing rate is controlled to be 5-30%; 5) Stretching, namely stretching the peeled extrusion blank to a reserved base specification for 1-4 times, wherein the single-pass processing rate is controlled to be 10-25%, and the total processing rate is controlled to be 35-50%; 6) Annealing, wherein the annealing temperature is controlled to be 390-450 ℃, the time from normal temperature to the temperature is controlled to be 15-90 min, and the heat preservation time is 120-300 min after the temperature reaches the set temperature; 7) Stretching the finished product, namely controlling the processing rate to be 8-20%; 8) Low-temperature annealing, namely setting the annealing temperature at 250-300 ℃, controlling the time from normal temperature to the temperature at 20-60 min, and keeping the temperature for 120-360 min; 9) Checking and packaging; In the step 3), the extrusion billet directly enters a water seal tank for cooling after flowing out of a die, and the water temperature is not more than 40 ℃; in the step 6), the tapping cooling mode is water cooling.
  2. 2. The chip-prone single-phase brass according to claim 1, wherein the chip-prone single-phase brass has a hardness HV5 of 140-170, an elongation A50 of 12-20% and a grain size of 8-25 μm.
  3. 3. The chip-breaking single-phase brass according to claim 1, wherein the chip-breaking single-phase brass comprises a matrix phase and a second phase, the matrix phase is an alpha phase, the second phase comprises Pb 2 Ce、Cu 3 P, cuZnAs phase and is dispersed, and the area ratio of the second phase is 0.1-1.5%.
  4. 4. The chip-prone single-phase brass according to claim 3, wherein the average size of the second phase is 800nm or less.
  5. 5. The chip-breaking single-phase brass according to claim 1, wherein in the step 4), a sizing band is removed from a peeling die, and the peeling amount is controlled to be 0.10-0.30 mm.
  6. 6. The chip-breaking single-phase brass according to claim 1, wherein in the step 6), the heating time is controlled to be 15-40 min.

Description

Chip-breaking single-phase brass and preparation method thereof Technical Field The invention relates to the field of metallurgical materials, in particular to single-phase brass easy to break scraps and a preparation method thereof. Background In the process of cutting metal materials by a numerical control machine tool, the problems of close connection between tool holders and tools and chip breaking are particularly important because of the large number of tools, and the automatic circulation of the machine tool and even the normal operation of the whole automatic line can be possibly damaged as long as one of the tools is unreliable in chip breaking. Therefore, the difficulty of chip breaking is often used as an index for measuring the cutting performance of the material. When cutting, the cutting processability of the material which is easy to break chips is good, and conversely, the cutting processability is poor. For a numerical control machine tool, not only strip-shaped rolling scraps or long spiral rolling scraps are avoided, because the copper scraps with the morphology are extremely easy to wind on a workpiece and a cutter, but also excessively finely crushed copper scraps are avoided, because the copper scraps are easily embedded into important parts (such as a datum plane) of a machine tool guide rail and a cutter device, an additional protection device is needed, and a certain difficulty is brought to copper scraps removal. The C-shaped chip is a better form of chip, and does not hurt people or wind on a workpiece and a cutter. Brass is an alloy composed of Cu and Zn, and its Zn content varies widely, so its room temperature structure also varies greatly. According to the Cu-Zn binary phase diagram, the room temperature structure of the brass is three, namely the brass with Zn content below 35 percent and the microstructure at room temperature is composed of alpha phase only and is called alpha brass (single-phase brass), and the brass with Zn content in the range of 36-46 percent and the microstructure at room temperature is composed of (alpha+beta) two phases and is called (alpha+beta) brass and is also called two-phase brass. The α phase is a solid solution of Zn dissolved in Cu, and has the same crystal structure as Cu, so that the α phase is soft and has good plasticity. The single-phase brass has good strength, plasticity, conductivity, electroplate property and other properties, is suitable for processing deep-drawing parts with complex shapes, is widely applied to industries of electronics, digital mobile communication, automobiles, medical treatment, instruments and meters and the like, and can be particularly referred to an invention patent 'brass alloy and a preparation method thereof' with a patent application number of CN202210162683.5 (publication number of CN 114540662A). The alpha single-phase brass has excellent comprehensive performance, but during cutting, the alpha single-phase brass is difficult to break, and the copper scraps are hair-shaped rolling scraps or long spiral rolling scraps, so that the alpha single-phase brass is very easy to wind a cutter, and the alpha single-phase brass is difficult to use for cutting of a numerical control machine tool. Disclosure of Invention The invention aims to solve the first technical problem of providing the chip-breaking-easy single-phase brass with good machinability aiming at the current state of the art. The second technical problem to be solved by the invention is to provide a preparation method of the chip-breaking single-phase brass. The invention solves the first technical problem and adopts a technical scheme that the chip-breaking single-phase brass is characterized by comprising, by weight, 64-70wt% of Cu, 0.003-0.06 wt% of Pb, 0.005-0.15 wt% of Ce, 0.005-0.1 wt% of P, 0.01-0.15 wt% of As and the balance of Zn and unavoidable impurities. The brass has the following functions: pb has extremely low solubility in the alpha brass, the limiting solubility is only 0.03 weight percent, and when the content of Pb in the alpha brass exceeds 0.03 weight percent, the cracking phenomenon is easy to occur during hot working, when the content of Pb in the alpha brass is lower than 0.003 weight percent, pb can be completely dissolved in the alpha brass at normal temperature, and Pb cannot exist in a free state, so that the chip breaking effect cannot be realized; Ce can form Pb 2 Ce compound with Pb, can not merely dispel the hot embrittlement phenomenon of low-melting Pb, has avoided the thermal processing cracking problem after the content of alpha brass Pb exceeds 0.03wt%, pb 2 Ce is a brittle compound, can play a role of breaking chip, when the content of Pb exceeds 0.06wt%, although brass is easier to break chip, but the added Ce element can not completely dispel the hot embrittlement phenomenon of Pb; P is less in solid solution in brass, if the P content exceeds 0.005wt% in alpha brass, brittle phase Cu 3 P appears, and the pla