CN1292315A - Macroscopic method for predicting diffusion-connection condition - Google Patents
Macroscopic method for predicting diffusion-connection condition Download PDFInfo
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- CN1292315A CN1292315A CN 99115868 CN99115868A CN1292315A CN 1292315 A CN1292315 A CN 1292315A CN 99115868 CN99115868 CN 99115868 CN 99115868 A CN99115868 A CN 99115868A CN 1292315 A CN1292315 A CN 1292315A
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- diffusion
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- surface roughness
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Abstract
The method for predicting diffusion-connecting condition is mainly characterized by that in regard to the statistical characteristics of degree of roughness of surface to be connected and according to the principle of plasticity, deducing the pressure required for flattening rough leptokurtosis in the course of diffusion-connecting process and using the macroscopic yielding equation based on the diffusion-connecting mechanism to represent the relationship of yield strength and other conditions for diffusion-connection, such as temperature and time, etc. by solving the conditions of rough-surface flattening extent and temp., pressure, time and surface roughness it can implement prediction of diffusion-connecting condition, and as compared with traditional mathod said invented method is simple, easy and accurate.
Description
The invention belongs to the diffusion connection area of machine-building and processing subject.
The diffusion interconnection technique is when the workpiece that satisfies suitable surface roughness, under the condition of certain temperature, pressure and time, realizes the method for the solid-state connection of diffused.The diffusion interconnection technique is used in industrial production widely, it can realize the solid-state connection between similar or inhomogeneity material, two or more workpiece, thereby bring the parts or the connector number that reduce its structure, improve its security and life-span, save remarkable advantages such as man-hour.As certain engine compartment cover, after the employing diffusion interconnection technique, weight saving 20.5%, cost reduces by 55.0%, and linking number reduces 58.1%, and connector quantity reduces 77.0%, frock quantity minimizing 75.0%, the frock cost reduces by 63.0%.But one of technical barrier that the diffusion connection area exists always is: be difficult to accurately and predict easily the condition of diffusion connection, such as surface roughness, temperature, pressure and time.For a long time, people attempt to adopt foundation diffusion connection micromechanism (to generally comprise always, plastic deformation, creep, diffusion, three mechanism) and macroscopic conditions (roughness, temperature, pressure, time) between relational model, the custom be called micromodel, predict diffusion-connection condition.But all micromodels all have the following disadvantages or shortcoming on its essence and method: a) the diffusion-connection condition poor accuracy of micromodel prediction.This is because micromodel often is simplified to the unidirectional symmetry geometry of uniformity again to surface roughness, has used a lot of simplified conditions; Three micromechanisms are again naturally by competitive way in addition, individual event or the alternately property effect of multinomial ground, and the natural criterion of this alternating action, order and effect degree are to be difficult to thoroughly divide clearly from micromodel.B) poor practicability of micromodel, inconvenience.This is because micromodel comprises a lot of material properties, thermodynamics and kinetics parameter, and these parameters need could obtain through a large amount of and complicated experiment.In addition, for the understanding of micromodel with calculate and also all need special knowledge, be not easy to engineering and use.
The objective of the invention is to propose a kind of macro approach of predicting diffusion-connection condition at this technical barrier that can't predict diffusion-connection condition at present accurately, easily.Use this method in the engineering and predict diffusion-connection condition, not only accurately but also convenient.
Technical scheme of the present invention is as follows: 1) use the gauss of distribution function statistical and express surface roughness, this expression ratio was idealized as the more approaching reality of simple geometric shape to surface roughness in the past, by the plasticity method, derive rough surface and realize the needed pressure of leveling then with gaussian distribution characteristic.When 2) deriving pressure in above-mentioned, this pressure is relevant with the yield stress and the surface roughness of material.3) application comprises the macroscopic yield equation that spreads connection mechanism, reflects that yield pressure is connected other condition such as temperature, time relation with diffusion.In case matsurface all flattens, theory and practice is known as, and diffusion connects fine finishing.The condition of temperature, pressure, time and surface roughness when flattening by optimizing matsurface can realize the condition of predicting that diffusion connects.With traditional comparing according to micro kinetics model prediction diffusion-connection condition method, this method is simple and easy accurately.
Details are as follows for concrete scheme,
1) when a rigid plane contacts with a ductility flat convex-concave peak, by the slip-line Solution of Prandl as can be known, the load g on arbitrary contact peak
(δ)The result who calculates by desirable plasticity compression situation is
Wherein δ is that the top contact is to the drafts between current depressed state, Y
0Be the yield pressure that is connected material, K
sBe the curvature at contact peak.For simplifying, can think that each contact peak curvature is identical, as total contact load being removed the long-pending A of yield surface in the name of
0, then nominal pressure can be tried to achieve by following integration,
Wherein N is contact peak sum, z
MaxBe top height, ρ
sBe the area density (unit are contact peak number order) at contact peak, Greewood is by discovering contact problems, area density ρ in a large number
sWith line density ρ
lBetween the pass be ρ
s=1.8 ρ
l 2When h is the current pressure state, the distance between matsurface benchmark and rigid face.Ф
zBe the gauss of distribution function of matsurface height statistical value, expression formula is
σ wherein
hBe respectively the standard variance and the average height of roughness height statistical value, above z, K with z
s, ρ
1, z
Max, z and σ
hAll can easily measure by surface profiler.Aggregative formula 1-3 can draw the pressure that is calculated by contact mechanics
This formula has reflected that contact pressure is relevant with the yield stress and the surface roughness of connected piece material.According to comprising the surrender equation that diffusion connects three mechanism, can get in touch yield stress Y
0And diffusion connects other condition such as temperature, the relation between the time, and relational expression is as follows:
Wherein α, β, γ, C
1, α
1, β
1, γ
1Be the parameter of material and temperature, μ is a parameter independent and temperature and material, and d is the average-size of crystal grain, and X is interior sclerosis variable, and κ is the initial yield stress of material.Application of formula 5-7 match is connected the drawing by high temperature curve of material, can draw the yield stress Y that is connected material under arbitrary diffusion-connection condition
0Y
0Substitution formula 4 just can be set up diffusion-connection condition and be connected the relation of degree (the flat degree of protruding peak pressure) with diffusion, thereby realize predicting diffusion-connection condition from macroscopic view.
With traditional comparing according to micro kinetics model prediction diffusion-connection condition method, this method is simple and easy accurately.
Claims (1)
- The invention discloses a kind of method of predicting diffusion-connection condition; Its principal character is: connect the statistical property of surface roughness by considering desire, according to the plasticity principle, direct derivation goes out to spread the flat required pressure of coarse protruding peak pressure in the connection procedure, this pressure be connected YIELD STRENGTH and surface roughness is relevant; Application reflects that based on the macroscopic yield equation of diffusion connection mechanism yield strength is connected other condition such as temperature, time relation with diffusion.In case matsurface all flattens, theory and practice is known as, and diffusion connects fine finishing.By finding the solution the condition that matsurface flattens degree and temperature, pressure, time and surface roughness, can realize the condition of predicting that diffusion connects.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 99115868 CN1292315A (en) | 1999-10-08 | 1999-10-08 | Macroscopic method for predicting diffusion-connection condition |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 99115868 CN1292315A (en) | 1999-10-08 | 1999-10-08 | Macroscopic method for predicting diffusion-connection condition |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1292315A true CN1292315A (en) | 2001-04-25 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 99115868 Pending CN1292315A (en) | 1999-10-08 | 1999-10-08 | Macroscopic method for predicting diffusion-connection condition |
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| CN (1) | CN1292315A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116275449A (en) * | 2023-05-15 | 2023-06-23 | 杭州沈氏节能科技股份有限公司 | Diffusion welding furnace based on displacement control and control method thereof |
-
1999
- 1999-10-08 CN CN 99115868 patent/CN1292315A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116275449A (en) * | 2023-05-15 | 2023-06-23 | 杭州沈氏节能科技股份有限公司 | Diffusion welding furnace based on displacement control and control method thereof |
| CN116275449B (en) * | 2023-05-15 | 2023-08-29 | 杭州沈氏节能科技股份有限公司 | Diffusion welding furnace based on displacement control and control method thereof |
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| WD01 | Invention patent application deemed withdrawn after publication |