CN1039923C

CN1039923C - High strength soft solder lead-base alloy

Info

Publication number: CN1039923C
Application number: CN95105290A
Authority: CN
Inventors: 李志平
Original assignee: KUNMING NOBLE METAL INST CHINA NONFERROUS METAL INDUSTRY GENERAL Co
Current assignee: Sino Platinum Metals Co Ltd
Priority date: 1995-05-16
Filing date: 1995-05-16
Publication date: 1998-09-23
Anticipated expiration: 2015-05-16
Also published as: CN1120595A

Abstract

The present invention relates to a high strength soft solder plumbum-base alloy, which is characterized in that the alloy has the components by weight of 8 to 15.5 of Sn, 11 to 16 of Sb, 0.5 to 2.5 of Cu, 0.5 to 2.0 of Ag, 0.01 to 0.5 of P or Re, and balance of Pb. The alloy of the present invention has the advantages of low melting temperature (240 to 254 DEG C) and high intensity (sigma b is larger than or equal to 245MPa, and tau b is larger than or equal to 190MPa); the alloy does not have toxic elements of Cd and As. The alloy of the present invention is suitable for the soldering of steel cables of middle-tonnage and large-tonnage truck cranes.

Description

High strength soft solder lead-base alloy

The present invention relates to lead 2-base alloy, particularly high strength soldering lead 2-base alloy is used for brazed copper and alloy thereof, and mother metals such as steel, stainless steel are in being used in particular for, the soldering of large-tonnage truck-mounted crane wireline.

In recent years, countries such as Japan, Germany in, extensively adopted the wireline adapter soldering tech on the large-tonnage truck-mounted crane.For strengthening the intensity of brazed joint, most of producers adopt brazing, because brazing (the solder temperature of fusion is more than 450 ℃) obtains higher strength of joint than soldering (the solder temperature of fusion is below 450 ℃).The shortcoming of brazing is that brazing temperature is too high, causes that easily crystallization crystal grain is thick, then used soldering, and the low (σ of the strength of joint of soldering _b=～70MPa, τ _b=～50MPa), the wireline in can not welding, on the large-tonnage truck-mounted crane.High strength soft solder (the DIN3092-72 standard of Germany invention, its composition (weight %) is Sn9～11, Sb9～11, Cd1.7～2.5, Cu0.3～0.7, As0.3～0.7, Pb surplus) but in the soldering, the wireline of large-tonnage truck-mounted crane, but this solder contains poisonous Elements C d and As, can damage HUMAN HEALTH and contaminate environment.Day disclosure is speciallyyed permit flat 3-204194 and is disclosed the good slicker solder base alloy of a kind of thermal fatigue property, and its main component is (weight %): Sn1～60, Sb0.01～10, Pb surplus; In addition, on above-mentioned alloying constituent basis, also can add Cu, Ni, Au, Ag, Pt, Pd, Mg, Ca, Li, La, Ce, Cd, Co, Cr, Fe, Mn, Se, Te, one or more in the Zr element, content 0.07～7%.But this solder mainly is heat-resistant anti-fatigue and the creep-resistant property that improves alloy, does not have the data such as temperature of fusion, working temperature and tensile strength of solder, and this solder is mainly used in the electronic component welding.

The objective of the invention is to overcome the above-mentioned shortcoming that prior art exists, propose a kind of low melting temperature (240～254 ℃), high strength (σ that does not contain poisonous Elements C d and As _b〉=245MPa, τ _b〉=190MPa) lead 2-base alloy solder is used for, the soldering of the wireline of large-tonnage truck-mounted crane.

Technical scheme of the present invention is, changes alloying constituent, and feature of the present invention is: alloying constituent (weight %) is Sn8～15.5, Sb11～16, Cu0.5～2.5, Ag0.5～2, P or Re0.01～0.5, Pb surplus.

In engineering, intensity index is (as σ _b, τ _b) representing the resistivity of metallic substance to certain deformation process.Therefore, all factors that increase the Metallic Solids resistance to deformation all can make the intensity of material raise, in lead 2-base alloy of the present invention, add Sn, can generate intermetallics SnSb hard point, Sn can be dissolved among the Pb again, increase the Metallic Solids resistance to deformation, make matrix strengthening, thereby improve hardness of alloy and wear resistance; Simultaneously, also can improve the solidity to corrosion of solder behind the adding tin and improve the adhesive capacity of alloy steel.Less than 8%, the intermetallics of generation is few as tin content, can not reach predetermined effect; Greater than 15.5%, then solder intensity reduces as tin content.Add alloying element Sb, can reduce the surface tension of solder, improve the intensity and the creep-resistant property of solder.If Sb content is less than 11%, the Metallic Solids resistance to deformation reduces; Be higher than 16% as Sb content, then will generate β-SnSb phase, its proportion is lower than the proportion of matrix metal Pb, produces gravity segregation, makes the solder embrittlement, and wettability and solidity to corrosion reduce.Add 0.5～2.5% Cu in alloy, easy and Sn forms white needles thing (or asterisk) Cu6Sn5, prevents the SnSb come-up, reduces the segregation of solder alloy, increases creep resisting ability, thus the hardness of raising solder.If it is few that Cu content, generates the Cu6Sn5 amount less than 0.5%, hardness is low; If the Cu6Sn5 amount that Cu content greater than 2.5%, then generates too much, the flowability that is directed at solder reduces, and welding property is poor, and fusing point raises, the solder embrittlement.Add 0.5～2% Ag in alloy, can improve processibility and plasticity, improve the tensile strength of solder, solidity to corrosion and wettability reduce the solder fusing point, reduce surface oxidation.If the content of Ag less than 0.5%, can not reach desired effects; If Ag content is greater than 2%, then the solder cost raises, and is difficult to widespread use, popularization.Addition element P or Re in alloy of the present invention can improve the resistance of oxidation and the flowability of solder, make finished surface smooth; Re also can generate intermetallics with Sn, can play the effect of solution strengthening effect and crystal grain thinning in matrix.If the content of P or Re does not reach desired effects less than 0.01%; If P or Re content greater than 0.5% then strengthen the partially poly-degree of Sn on the copper crystal boundary, make the solder embrittlement, be difficult to process.Compare with prior art, the present invention has following advantage:

1. do not contain poisonous Elements C d and As, improved production atmosphere, reduced environmental pollution;

2. alloy melting temperature of the present invention low (240～254 ℃), intensity height (σ _b〉=245MPa, τ _b〉=190MPa).

Fig. 1 is the joint form synoptic diagram with solder brazing filler metal one wireline of the present invention, and (1) is wireline among the figure, and (2) are fitting sleeve, and (3) are solder of the present invention.

Embodiment 1-6

Press composition shown in the table 1 each alloying element is mixed,, measure its solidus curve and liquidus line, density and mechanical property (hardness HV, tensile strength sigma then by the welding rod of general metallurgical method founding one-tenth (15～22) * (15～20) * 320mm _b, slip resistance τ _b), and and the solder performance of German DIN3029-79 standard compare, it the results are shown in Table 2.As seen from Table 2, solder of the present invention is approaching with the salient features of German solder, and slip resistance is better than German solder.

With the solder of embodiments of the invention 2 one of Hunan heavy-duty machinery head factory brazing filler metal 6T (29)+7 * 7-15.0 wireline, two of 40Cr fitting sleeves, joint form as shown in Figure 1.On 30 tons of drawing machines, the maximum breaking force of wireline is respectively 135kN (+80 ℃) under the differing temps, 142kN (160 ℃), 588kN (room temperature); Experimental result, wireline is broken, and fracture position is respectively 89-100mm from the distance of welding joint, 200-250mm, 150-250mm, fitting sleeve and brazing alloy are not found breakoff phenomenon.These experiments connect fruit and show, during solder of the present invention can satisfy fully, the soldering needs of large-tonnage truck-mounted crane wireline.

Table 1

Alloying constituent weight % specimen coding

Sn Sb Cu Ag P Re Pb embodiment 1 8.0 11.0 1.2 2.0 0.1 surplus embodiment 2 12.0 11.0 1.0 0.5 0.01 surplus embodiment 3 15.5 16.0 2.5 1.75 0.3 surplus embodiment 4 14.0 13.0 0.5 1.0 0.02 surplus embodiment 5 9.0 11.5 1.5 1.3 0.08 surplus embodiment 6 13.0 14.0 2.0 0.7 0.5 surpluses

Table 2

Solidus curve liquidus line density hardness σ _bτ _bSpecimen coding, (℃), (℃), (g/cm) HV, (MPa), (MPa) embodiment 1 246 252 9.76 290 245 194 embodiment 2 244 250 9.78 295 247 196 embodiment 3 240 249 9.80 291 246 190 embodiment 4 248 254 9.00 292 241 193 embodiment 5 241 251 9.77 293 246 195 embodiment 6 245 253 9.73 290 242 192DIN3029-79 240 248.7 9.89 320 250 160 standards

Claims

1. a high strength soft solder lead-base alloy is characterized in that, alloying constituent (weight %) is Sn8～15.5, Sb11～16, Cu0.5～2.5, Ag0.5～2.0, P or Re0.01～0.5, the Pb surplus.