CN104624917A

CN104624917A - Process for manufacturing semisolid copper alloy multi-channel valve body through radial forging strain provocation method

Info

Publication number: CN104624917A
Application number: CN201410828999.9A
Authority: CN
Inventors: 赵升吨; 张晨阳; 王永飞; 韩晓兰; 范淑琴
Original assignee: Xian Jiaotong University
Current assignee: Xian Jiaotong University
Priority date: 2014-12-26
Filing date: 2014-12-26
Publication date: 2015-05-20
Anticipated expiration: 2034-12-26
Also published as: CN104624917B

Abstract

Disclosed is a process for manufacturing a semisolid copper alloy multi-channel valve body through a radial forging strain provocation method. Copper alloy rod materials are preheated firstly and then forged in the radial direction, a blank is remelted again after radial forging, and then semisolid thixoforming of the alloy multi-channel valve body is carried out until the part is fully condensed. Through the process, the uniform copper alloy semisolid blank without micro defects can be manufactured, the multi-channel valve body which has a few micro structure defects, and is good in mechanical performance and sealing performance can be formed, a few production procedures are needed, and production efficiency is high.

Description

Radial forging strain provocation method prepares the technique of semi solid copper alloy multichannel valve body

Technical field

The invention belongs to semisolid Metal Processing and forming technique field, particularly relate to the technique that radial forging strain provocation method prepares semi solid copper alloy multichannel valve body.

Background technology

Copper alloy multichannel valve body is mainly used in closing frequently in pipe-line system opening pipeline, requires that it has higher mechanical strength and sealing property.The shape relative complex of valve body, Conventional processing methods is forge hot method and hot extrusion method, but at high temperature the oxidation and thermal expansion etc. of blanks make thermal forging technology can not ensure the quality of drip molding, and overlap surplus causes more greatly materials'use rate lower, subsequent mechanical manufacturing procedure is more, and die forming load is large, the life-span is short, energy consumption is large, cost is relatively high; Although the production of part multichannel valve body adopts the technique of liquid extrusion casting or hot investment casting, but the forming temperature of these techniques is higher, die life shortens, mould cavity manufacture cost is higher, in addition due to the turbulent flow of liquid metal, inevitably there is the microdefect such as pore, shrinkage cavity in formation of parts inside, mechanical property and sealing property poor, percent defective is higher.

Namely semi-solid processing forming technique adopts microstructure to be the technique that semi-solid blank that spheric grain is suspended in eutectic liquid phase forms, spherical or subglobose semi solid slurry has obvious thixotropic behavior: namely along with the increase of shear rate, apparent viscosity exponentially declines, and makes slurry in forming process have good fluidity, feature that plastic force is low.In forming process, semi solid slurry, with the mode of laminar motion order filling mold cavity, decreases the microstructure defects such as Shrinkage cavity, enhances the mechanical property of part.The key of semi-solid state forming technique is to prepare has the semi-solid blank that globular crystal is suspended in eutectic liquid phase.But the technique that the mechanical mixing method of routine and electromagnetic stirring method prepare semi solid slurry has following shortcoming: high temperature exists serious corrosiveness to mechanical agitator, etching residue mixes with semi solid slurry and causes slurry impure.In electromagnetic agitation process, temperature of high temperature slurry has strong heat radiation effect to magnetic stirrer, and needing increases extra heat insulation cooling device, and equipment is complicated.No matter the semi solid slurry that in addition prepared by electromagnetic agitation or mechanical mixing method all exists component segregation phenomenon, the microstructure of blank center is poor, and inevitably there is Micro porosity, can not obtain uniform, flawless semi-solid blank.And the conventional methods such as the deformation method that the technique adopting strain-induced activation method to prepare semi-solid blank relates to mainly compresses, rolling, Equal Channel Angular Pressing, repeatedly pier are thick, pulling.When preparing bulk blank, the plastic deformation force needed for these methods is excessive, and existing equipment is difficult to realize.Therefore can not the large-sized semi-solid blank of large batch of production, therefore can not be directly used in and produce the part that such as this kind of size of multichannel valve body is relatively large and complex-shaped.

Summary of the invention

In order to overcome the shortcoming of above-mentioned prior art, radial forging strain provocation method is the object of the present invention is to provide to prepare the technique of semi solid copper alloy multichannel valve body, can be prepared uniformly by this technique, without microdefect copper alloy semi-solid blank and be shaped that microstructure defect is few, good mechanical property, the multiple valve system part that sealing property is strong.

In order to achieve the above object, the present invention takes following technical scheme to be:

Radial forging strain provocation method prepares the technique of semi solid copper alloy multichannel valve body, comprises the following steps:

1) preheating copper alloy bar, is heated to 200 ~ 250 DEG C by copper alloy bar with stove, and is incubated, the diameter of the concrete temperature retention time of the bar for different-diameter to be 0.5D ~ 0.7D minute, D be bar;

2) radial forging is carried out to copper alloy bar, by manipulator preheating copper alloy bar taken out and clamp axial rotary and send to, four tups that radial forging machine is symmetrical around blank, radially carry out high-frequent reciprocating to blank to forge, blank is pulled out in multi-head spiral extensional situation attenuate, the contraction percentage of area reaches more than 60%, for the part of different size, according to the blank diameter needed for its part, forge to required diameter;

3) secondary remelting of blank after radial forging, blank after radial forging is put back in electric furnace or Medium Frequency Induction Heating Furnace and carries out secondary remelting, remelting temperature is between 900 ~ 925 DEG C, temperature retention time is 15 ~ 20min, namely obtain and have the semi solid copper alloy blank that globular crystal is suspended in eutectic liquid phase, the solid rate of now corresponding copper alloy bar is 35.5 ~ 42.5%;

4) thixoforging of copper alloy multichannel valve body, preheating is carried out to mold cavity and core, preheat temperature is 300 ~ 400 DEG C, and put into mold cavity by according to the secondary remelting blank after the cutting of copper alloy multiple valve chaeta base volume segments, after closed multiple valve mould, upper core is with the pressing speed filling mold cavity of 30mm/s ~ 50mm/s, the levorotation core in left side inwardly extrudes simultaneously, after extruding puts in place, upper core and levorotation core continue persistent pressure simultaneously, ensure that its specific pressure is 80-100Mpa, until part solidifies completely.

Relative to prior art, the present invention by Radial Forging Technology for the preparation of copper alloy semi-solid blank and manufactured copper alloy multichannel valve body piece have the following advantages:

1. the present invention adopts Radial Forging Technology, the large plastometric set of copper blank is realized by the mode that repeatedly small deformation forges continuously, greatly reduce Plastic Forming power, can on the equipment of little tonnage continuous manufactured copper alloy semi-solid blank in enormous quantities, have the advantages that cost is low, continuous seepage ability is strong and performance is high.And by secondary remelting radial forging copper alloy bar prepare spherical particle good, be evenly distributed evenly, microdefect is few, the semi solid copper alloy slurry that forming property is good, and technical process is simple, easily operates.This technique not only avoid the component segregation of mechanical mixing method and electromagnetic stirring method existence, the defect that microstructure is uneven, and solving the deformable material size of the technique such as Equal Channel Angular Pressing, rolling, the repeatedly forging appearance that traditional strain-induced method adopts, to increase then deformation force excessive, is difficult to the problem of being out of shape on existing.

2. the thixoforging technique that the present invention adopts prepares multichannel Copper Alloy Valve, and forming parts temperature is lower relative to liquid extrusion casting, and has thixotropy due to semi solid copper alloy blank, its resistance of deformation is lower, shaping is more prone to, and the precision of drip molding is high, dimensionally stable.In addition, the viscosity of copper alloy semi solid slurry is greater than liquid copper alloy, ensure that in stowing operation, semi solid slurry is with layer flow mode filling mold cavity, avoid the microstructure defect such as pore and Shrinkage cavity that in extrusion process, the turbulent flow of liquid metal brings, the microdefect of part is less, mechanical performance strengthens, air-tightness becomes better, part after shaping is that independent tiny globular crystal is distributed on low-melting-point eutectic due to its metallographic structure, and the microstress avoiding traditional arborescent structure appearance that extrusion process produces is concentrated.And mould structure is simple, production process is few, and productivity ratio is high.

Accompanying drawing explanation

Fig. 1 is technological principle schematic diagram of the present invention.

Fig. 2 is process chart of the present invention.

Detailed description of the invention

Below in conjunction with accompanying drawing, the present invention is described in detail.

See figures.1.and.2, with the citing of the Copper alloy bar of Φ 150mm, radial forging strain provocation method prepares the technique of semi solid copper alloy multichannel valve body, comprises the following steps:

1) preheating copper alloy bar, is heated to 200 ~ 250 DEG C by Φ 150mm copper alloy bar with stove, and is incubated 60 ~ 80 minutes, ensures whole blank heat penetration;

3) secondary remelting of blank after radial forging, blank after radial forging is put back in electric furnace or Medium Frequency Induction Heating Furnace and carries out secondary remelting, remelting temperature is between 900 ~ 925 DEG C, temperature retention time is 15 ~ 20min, namely obtain and have the semi solid copper alloy blank that globular crystal is suspended in eutectic liquid phase, the solid rate of now corresponding copper rod is 35.5 ~ 42.5%;

By above step, the spheric grain that can obtain 80 ~ 100um to be evenly distributed in eutectic matrix and the less copper alloy semi-solid blank of microstructure defect, decreases the microdefect such as component segregation, Shrinkage cavity that mechanical agitation and electromagnetic stirring method occur significantly.Ensured the laminar-flow type order filling mold cavity of semi solid copper alloy blank by Semi-Solid Thixoforming Extrution casting technique, the multichannel Copper Alloy Valve pore prepared is few, and Shrinkage cavity is few, even tissue, enhances mechanical performance and the sealing property of this part.

Claims

1. radial forging strain provocation method prepares the technique of semi solid copper alloy multichannel valve body, it is characterized in that, comprises the following steps: