CN103484716A - Lead-free free-cutting magnesium brass and manufacturing method thereof - Google Patents
Lead-free free-cutting magnesium brass and manufacturing method thereof Download PDFInfo
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- CN103484716A CN103484716A CN201310448821.7A CN201310448821A CN103484716A CN 103484716 A CN103484716 A CN 103484716A CN 201310448821 A CN201310448821 A CN 201310448821A CN 103484716 A CN103484716 A CN 103484716A
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Abstract
The invention discloses a lead-free free-cutting magnesium brass and a manufacturing method thereof. The lead-free free-cutting magnesium brass comprises the following components in percentage by mass: 57-68% of Cu, 3.9-5.0% of Mg, 0.3-0.9% of tin and the balance of Zn and unavoidable impurities, wherein the percentage of Pb is less than or equal to 0.05%. The lead-free free-cutting magnesium brass is manufactured by uniformly mixing brass powder and forming agent powder, pressing, molding, sintering, re-pressing and re-sintering according to a powder metallurgy method. The lead-free free-cutting magnesium brass does not contain lead, cadmium, mercury, arsenic, chrome, bismuth, antimony, beryllium and other elements; no pollution is generated during the production process; the lead-free free-cutting magnesium brass has the advantages of relatively high strength and excellent cutting performance, excellent hot-forging performance, high dezincification resistance, high ammonia smoking resistance, excellent polishing performance and excellent electroplating performance, and is applicable to the industries of water heating, ironware, car and the like.
Description
Technical field
?the present invention relates to a kind of metallic substance and manufacturing technology thereof, particularly non-leaded easily-cutting brass and manufacture method thereof.
The background technology leaded brass has good cold and hot working performance, fabulous cutting ability, can meet the machining requirement of different shape component.Leaded brass once was widely applied to the fields such as domestic water supply system, electronics, automobile and machinofacture by universally acknowledged for a kind of important underlying metal material.Because leaded brass is widely used, discarded leaded brass spare and accessory parts quantity is a lot, wherein only has and is recovered on a small quantity utilization, and a lot of smallclothes are used as rubbish and abandon.Discarded leaded brass contacts with soil, and its contained lead, under the long term of rainwater and atmosphere, enters soil, thus contaminated soil and water source.When discarded leaded brass is taken as waste incineration, plumbous steam distributes among atmosphere, and human body is produced to greatly harm, thereby its application is subject to strict restriction day by day.Lead neither solid solution, in copper, does not form intermetallic compound with copper yet, but is present in crystal boundary with the form of simple substance microparticle.Lead under the effect of the impurity in tap water and ion etc. in Winn bronze is slowly separated out with the form of ion, and existing Winn bronze is difficult to meet the requirement of environmental protection act.In order to reduce plumbous deleterious effect, the scientific research personnel has carried out systematic research to the mechanism of corrosion of brass and interpolation element to the corrosive effects of brass with regard to tap water, and taked many kinds of measures, as add the corrosion resisting property that the alloying elements such as a small amount of tin, nickel improve leaded brass, or certain thickness dissoluble lead is dissolved and removes resistant metals such as then on the surface of deleading, covering again chromium or take other method to suppress plumbous leaching etc.Owing to existing all the time lead in matrix brass, so these methods can't fundamentally be eliminated plumbous deleterious effect.If the long-term effect consideration gone out from the immersion scorification, above method all allows the people worry very much.The lead element of usining improves brass cutting ability leaded brass as a kind of principal element, under the regulation of environmental protection act, has to progressively exit historical stage.
No matter from environmental law Laws & Regulations both domestic and external, or, from the angle of Technological Economy, the improvement that leaded brass is patched up again, without large value, has only and develops unleaded novel brass.People have the process of a long-term accumulation to the research of metal, alloy, compound, quite abundant to the understanding of its characteristic.The elements such as bismuth, antimony, magnesium, phosphorus, silicon, sulphur, calcium, tellurium, selenium join the improvement to its cutting ability in brass and have obtained common recognition, have a large amount of patents open both at home and abroad.It must be noted that, with easy cutting leaded brass, compare, processing characteristics, use properties and the cost of at present all non-leaded easily-cutting brass, as: the processing performance such as cold and hot working performance, machinability or anti dezincification character energy, anti-ammonia smoke the use propertieies such as performance and have more or less some problems, and its over-all properties is compared gap with leaded brass also larger.Using bismuth metal when improving the principal element of cutting ability, and due to the price of bismuth, the brass of high bi content can't be accepted in market.Although the cutting ability of low bi content brass is also relatively good, compares with leaded brass and also have larger gap.On the other hand, bismuth ion is not also very clear and definite on the impact of HUMAN HEALTH so far, and the size of its side effect there is no final conclusion, also is unwilling to accept bismuth brass in some countries and regions.The finiteness of bismuth resource, also being doomed it can not be as main substitute element plumbous in easy cutting leaded brass.Bismuth can make brass produce fragility, the pressure machining characteristics of severe exacerbation brass, particularly hot workability, and its reclaimed materials even can endanger whole copper processing industry, and this can seriously reduce its recovery value, unfavorable to the marketing of bismuth-containing free-cutting brass.Antimony is human body to be had to the element of micro-poison, and its stripping concentration in water is subject to very strict restriction, and it allows that leaching concentration is also more much lower than plumbous.Although the cutting ability of Stibium Brass is also better, its use also is very restricted.The hot workability of antimony is also not ideal; The price of antimony is not cheap yet, unfavorable to its marketing yet.Magnesium can obviously improve the cutting ability of brass, but magnesium is the element of very easy scaling loss, and the smelting furnace of continuous caster is all the large stove in ton usually, for enhancing productivity, adopts continuous charging to draw continuously ingot.This contacts and the process of continuous oxidation scaling loss magnesium in process of production always with atmosphere in one, the ingot blank Mg content difference of pulling out in the different moment.This content to magnesium in brass is controlled and is brought very large challenge, and also very unfavorable to the stable control of its product performance, manufacturer particularly client can't expect to the performance of the finished product, also just can not accept.Phosphorus adds in brass and is conducive to improve its cutting ability, but falls low-alloyed plasticity simultaneously, and during low-pressure casting, the alloy hot cracking tendency increases.This is very restricted the addition of phosphorus in brass, also makes the use of phosphorus brass be very limited.Due to tin, tellurium, selenium price Gao Mao, one-ton brass and be difficult to extensively promote in market containing tellurium, selenium brass.Tin is also very limited to the effect that improves the brass cutting ability.Silicon brass is because copper content is high, and density is higher, price, and the market share is little.The fusing point of sulphur is only 113 ℃, and also only 445 ℃ of boiling points are easy to enter surrounding environment and become source of pollution in the production process of brass, and more and more stricter today at environmental regulation, the pollution-free of its production is also a difficult problem, and this is also totally unfavorable to its application.In actual development, engineering technical personnel adopt the method for alloying element diversification mostly, the multiple alloying element that cutting ability is had to improved action of compound interpolation in brass.But facts have proved, add the multiple method of improving the cutting ability element also unsatisfactory, on the one hand, due to the interaction between element, some meetings reduce the effect of improving cutting ability mutually.On the other hand, after adding Determination of multiple metal elements, can produce the effect of alloy strengthening, the intensity of brass, hardness all be improved, at press working and the machinability that to a certain degree also can reduce brass.And add-on rare, your element too much also can make the cost of brass improve, also unfavorable to the marketing application.Processing performance and the use properties of utilizing the stack of multiple element to improve brass also have significant limitation.
Vehicles Collected from Market is in the urgent need to a kind of new non-leaded easily-cutting brass, and the processing performance of the existing excellence of this brass, as machining, forge hot, polishing and plating performance, has again good use properties to smoke performance as high intensity, anti-dezincify, anti-ammonia.The present invention considers just this demand and develops.
summary of the invention
The purpose of this invention is to provide a kind of high performance non-leaded easily-cutting brass and manufacture method thereof.The composition of magnesium brass is: copper 57%-68%, and magnesium 3.9%-5.0%, tin 0.3%-0.9%, surplus is zinc and inevitable impurity, wherein plumbous≤0.05%.
The preferred component of magnesium brass is: copper 58%-65%, and magnesium 4.0%-4.9%, tin 0.4%-0.8%, surplus is zinc and inevitable impurity, wherein plumbous≤0.05%.
Further, the composition of magnesium brass is: copper 59%-63%, and magnesium 4.2%-4.7%, tin 0.5%-0.7%, surplus is zinc and inevitable impurity, wherein plumbous≤0.05%.
Cutting Lead-free Brass Containing Magnesium technical process of the present invention is as follows:
After the copper fusing, copper melts is warming up to and is no more than 1180 ℃, then add successively tin, zinc; Heat up after tin, zinc fusing, when being warming up to when 2 flame appears in melt, heating power is dropped to 0; After the standing 2-10 of melt minute, again heat up and be pressed into successively in melt by MAG block; Drag for slag after the fusing of all magnesium, dragged for slag after atomization immediately dust;
The magnesium brass powder that atomization is prepared mixes with additional binder powder 0.5%-1.5% batching, and mixing time 0.4-5h, be evenly distributed to guarantee binder powder and magnesium brass powder;
By the powder pressing forming that mixes, sintering then, sintering process is: start to be heated to sintering temperature 620-720 ℃ from room temperature, heat-up time 1-5h, fully Material removal agent, soaking time 30-120min, sintering atmosphere is reducing atmosphere or inert atmosphere;
By the cold multiple pressure of the pressure of 500-800MPa for the magnesium brass after sintering, perhaps on the punch press of drift rapid movement, use the cold die forging of pressure of 200-400MPa, then resintering, resintering technique is: from room temperature, start to be heated to sintering temperature 770-820 ℃, heat-up time 1-3h, soaking time 30-120min, sintering atmosphere is reducing atmosphere or inert atmosphere;
Brass after repressing and re-sintering is carried out to hot-work, and hot worked temperature is 700-820 ℃.
Described hot-work is hot closed-die forging or hot extrusion.
Described binder is paraffin powder or stearate powder.
Described stearate powder is lithium stearate, sodium stearate, potassium stearate, calcium stearate or Zinic stearas powder.
Prepare tensile test piece, cutting ability sample, anti-Dezincification corrosion sample and ammonia from the extruded rod sampling and smoke the stress corrosion sample.
Plumbous solubleness in copper melts is larger, but the solid solubility of lead is almost nil in room temperature copper.During the leaded brass melt solidifying, lead is distributed on the brass crystal boundary with fine spherical or subsphaeroidal particle form disperse.Lead has crisp and soft characteristics, and plumbous fusing point only has 327.5 ℃, when leaded brass is carried out to machining, the heat of friction of generation can make plumbous particle further softening, when leaded brass is cut, the cavity one by one that the plumbous particle of these disperses is equivalent to exist in brass, stress is easily concentrated at this, produces so-called " notched effect ", thereby causes smear metal to be easy in this fracture.In addition, at cutter head, with the part that contacts of smear metal, because the machining work done is converted into heat, make plumbous instant melting, also contribute to change the shape of smear metal, and play the effect of lubricated cutter, can make tool bit abrasion reduce to minimum.Therefore, plumbous change Chip Shape, cracked smear metal, minimizing bonding and seam and the raising cutting speed of playing a part in the cutting process of free-cutting brass material, can greatly improve the efficiency of machining, and the work-ing life of increase cutter, reduce the roughness of finished surface, make finished surface smooth smooth.Plumbous characteristic and the existence in easily cutting leaded brass thereof have conclusive effect to its cutting ability.Added magnesium, tin in brass of the present invention, can interact between they and matrix element copper, zinc, the generation intermetallic compound.These intermetallic compound particles have crisp, softer characteristics, have the feature tiny, disperse that distributes.The combination of these intermetallic compound particles and matrix is a kind of metallurgical binding, and interface is coherence or half coherence, and intensity is high.The existence of these intermetallic compound particles in brass is equivalent in brass exist hole, and stress is easily concentrated at this, produces so-called " notched effect ", thereby causes smear metal to be easy in this fracture.These intermetallic compound particles when the brass machining and the plumbous particle in brass same behavioral characteristic is arranged, this makes brass of the present invention have excellent machinability.Because the activity of magnesium is high, oxidization burning loss is fast, the time contacted with atmosphere containing the magnesium melt is longer, and its oxidization burning loss is more, and its machining ability is reduction very soon also.The time that minimizing magnesium contacts with atmosphere is most important, and particularly, in large-scale industrialization is produced, the oxidization burning loss that reduces magnesium just can guarantee the machining ability of brass.Manufacture method of the present invention is on the one hand by reducing the oxidization burning loss that has farthest reduced magnesium duration of contact of magnesium brass melt and atmosphere, by closing of powder, criticizes on the other hand and follow-up sintering process has fully guaranteed being uniformly distributed of magnesium in brass.This guaranteed large-scale industrialization produce in the Composition Control of magnesium in magnesium brass, also just can guarantee to produce in batches homogeneity and the stability of product composition, microstructure and property.
Advantage of the present invention: Cutting Lead-free Brass Containing Magnesium have excellent processing performance as the performances such as excellent machining, forge hot and good use properties as higher intensity, anti-dezincify, anti-ammonia smoke, polishing and plating performance.During magnesium brass of the present invention batch production, have product composition, microstructure and property consistence, stablize.Brass after repressing and re-sintering has the hot workabilitys such as good forge hot, hot extrusion.Excellent cutting performance, the intensity of hot extrusion brass are high.Press ISO6509:1981 " mensuration of the anti-Dezincification corrosion performance of the corrosion-brass of metal and alloy ", the anti dezincification character of hot extrusion brass can be excellent, by GB/T10567.2-2007 " copper and the copper alloy processing material unrelieved stress method of inspection: ammonia smokes test method(s) ", but ammonia concn is 14%, the longest anti-the smoking of brass reaches 16 hours and there is no crackle.The brass composition is simple, the elements such as component is not leaded, cadmium, mercury, arsenic, beryllium, chromium, bismuth, antimony, and production process is pollution-free.Brass can meet the strict demand that the water heating bathroom industry leaches harmful elements such as antimony fully.
Embodiment
Embodiment 1:
In brass, the massfraction of each element is respectively: copper 57.0%, and magnesium 5.0%, tin 0.7%, surplus is zinc and inevitable impurity; Each element drags for slag, powder by atomization immediately after melting successively; The additional binder paraffin powder that is 1.5% with content by the magnesium brass powder mixes; The powder batch mixing adopts V-type blender (not putting ball), mixing time 4.0h, batch mixing is i.e. compacting after finishing, and puts into the sintering oven sintering after having suppressed, and sintering process is: from room temperature, start to be heated to sintering temperature, heat-up time 5.0h, fully Material removal agent, 620 ℃ of sintering temperatures, soaking time 100min, sintering atmosphere is inert atmosphere, the complete rear water flowing cool to room temperature of sintering.Round brass rod after sintering is pressed again with the pressure of 500MPa, resintering then, resintering technique is: start to be heated to 800 ℃ of sintering temperatures from room temperature, heat-up time 3.0h, soaking time 120min, sintering atmosphere is inert atmosphere.By the brass after resintering 820 ℃ of hot extrusions.Prepare tensile test piece, cutting ability sample, anti-Dezincification corrosion sample and ammonia from the extruded rod sampling and smoke the stress corrosion sample.The experimental result discovery, the cutting power of magnesium brass is equivalent to 88% of leaded brass.Tensile strength is 499.0MPa, yield strength 269.5MPa, and average Dezincification corrosion layer thickness 172.2 μ m, maximum dezincify layer thickness 299.9 μ m, ammonia does not ftracture after smoking 16 hours.
In all embodiment, the chemical composition of magnesium brass and additional binder powder percentage composition are in Table 1, and in all embodiment, magnesium brass sintered and aftertreatment technology parameter are in Table 2, and in all embodiment, the performance of magnesium brass is in Table 3.
The chemical composition of magnesium brass and additional binder powder percentage composition in all embodiment of table 1
Magnesium brass sintered and aftertreatment technology parameter in all embodiment of table 2
-mean that this technique do not carry out
The performance of magnesium brass in all embodiment of table 3
| Embodiment | Be equivalent to leaded brass cutting ability/% | Tensile strength/MPa | Yield strength/MPa | Average dezincify layer thickness/μ m | Maximum dezincify layer thickness/μ m | Ammonia smokes not cracking time/h |
| 1 | 88 | 499.0 | 269.5 | 172.2 | 299.9 | 16 |
| 2 | 81 | 524.0 | 280.7 | 148.4 | 268.6 | 16 |
| 3 | 83 | 474.1 | 253.8 | 173.7 | 308.1 | 16 |
| 4 | 84 | 454.1 | 239.5 | 162.6 | 291.5 | 16 |
| 5 | 85 | 514.0 | 278.4 | 152.3 | 280.4 | 16 |
| 6 | 88 | 504.0 | 268.9 | 124.5 | 229.2 | 16 |
| 7 | 85 | 359.3 | 181.2 | 177.3 | 311.8 | 16 |
| 8 | 85 | 349.3 | 166.1 | 182.5 | 313.7 | 16 |
| 9 | 83 | 479.2 | 265.3 | 161.1 | 288.3 | 16 |
| 10 | 84 | 503.9 | 272.1 | 168.8 | 299.8 | 16 |
| 11 | 85 | 488.7 | 251.2 | 154.9 | 281.6 | 16 |
| 12 | 85 | 479.4 | 248.2 | 151.0 | 274.9 | 16 |
| 13 | 83 | 474.5 | 244.9 | 148.4 | 275.2 | 16 |
| 14 | 86 | 449.3 | 217.1 | 158.0 | 277.6 | 16 |
| 15 | 85 | 389.6 | 193.7 | 176.9 | 309.1 | 16 |
| 16 | 87 | 379.9 | 169.5 | 182.1 | 319.5 | 8 |
Claims (7)
1. a Cutting Lead-free Brass Containing Magnesium, it is characterized in that: the quality percentage composition of magnesium brass is copper 57%-68%, magnesium 3.9%-5.0%, tin 0.3%-0.9%, surplus is zinc and inevitable impurity, wherein plumbous≤0.05%.
2. weigh 1 described Cutting Lead-free Brass Containing Magnesium according to claim, it is characterized in that: the quality percentage composition of magnesium brass is copper 58%-65%, magnesium 4.0%-4.9%, and tin 0.4%-0.8%, surplus is zinc and inevitable impurity, wherein plumbous≤0.05%.
3. weigh 2 described Cutting Lead-free Brass Containing Magnesiums according to claim, it is characterized in that: the quality percentage composition of magnesium brass is copper 59%-63%, magnesium 4.2%-4.7%, and tin 0.5%-0.7%, surplus is zinc and inevitable impurity, wherein plumbous≤0.05%.
4. according to the described Cutting Lead-free Brass Containing Magnesium manufacture method of claim power 1,2 or 3 any one, it is characterized in that: after the copper fusing, copper melts is warming up to and is no more than 1180 ℃, then add successively tin, zinc; Heat up after tin, zinc fusing, when being warming up to when 2 flame appears in melt, heating power is dropped to 0; After the standing 2-10 of melt minute, again heat up and be pressed into successively in melt by MAG block; Drag for slag after the fusing of all magnesium, dragged for slag after atomization immediately dust;
The magnesium brass powder that atomization is prepared mixes with additional binder powder 0.5%-1.5% batching, and mixing time 0.4-5h, guarantee that binder powder and magnesium brass powder are evenly distributed;
By the powder pressing forming that mixes, sintering then, sintering process is: start to be heated to sintering temperature 620-720 ℃ from room temperature, heat-up time 1-5h, fully Material removal agent, soaking time 30-120min, sintering atmosphere is reducing atmosphere or inert atmosphere;
By the cold multiple pressure of the pressure of 500-800MPa for the magnesium brass after sintering, perhaps on the punch press of drift rapid movement, use the cold die forging of pressure of 200-400MPa, then resintering, resintering technique is: from room temperature, start to be heated to sintering temperature 770-820 ℃, heat-up time 1-3h, soaking time 30-120min, sintering atmosphere is reducing atmosphere or inert atmosphere;
Magnesium brass after repressing and re-sintering is carried out to hot-work, and hot worked temperature is 700-820 ℃.
5. weigh 4 described Cutting Lead-free Brass Containing Magnesium manufacture method according to claim, it is characterized in that: described hot-work is hot closed-die forging or hot extrusion.
6. weigh 4 described Cutting Lead-free Brass Containing Magnesium manufacture method according to claim, it is characterized in that: described binder is paraffin powder or stearate powder.
7. weigh 6 described Cutting Lead-free Brass Containing Magnesium manufacture method according to claim, it is characterized in that: described stearate powder is lithium stearate, sodium stearate, potassium stearate, calcium stearate or Zinic stearas powder.
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Citations (3)
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| CN101215653A (en) * | 2008-01-02 | 2008-07-09 | 中南大学 | Leadless free-cutting magnesium graphite brass |
| CA2639394A1 (en) * | 2008-06-11 | 2009-01-12 | Xiamen Lota International Co., Ltd. | Tin-free lead-free free-cutting magnesium brass alloy and its manufacturing method |
| CN103243233A (en) * | 2013-04-24 | 2013-08-14 | 梁亮 | Production process of lead-free cutting-easy magnesium brass rod |
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2013
- 2013-09-28 CN CN201310448821.7A patent/CN103484716A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101215653A (en) * | 2008-01-02 | 2008-07-09 | 中南大学 | Leadless free-cutting magnesium graphite brass |
| CA2639394A1 (en) * | 2008-06-11 | 2009-01-12 | Xiamen Lota International Co., Ltd. | Tin-free lead-free free-cutting magnesium brass alloy and its manufacturing method |
| CN103243233A (en) * | 2013-04-24 | 2013-08-14 | 梁亮 | Production process of lead-free cutting-easy magnesium brass rod |
Non-Patent Citations (2)
| Title |
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| 刘彦: "《微量元素Sn对含Bi、Mg无铅易切削黄铜组织与性能的影响》", 《中南大学硕士学位论文》, 31 October 2011 (2011-10-31), pages 48 - 57 * |
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Application publication date: 20140101 |